Full zoology dictionary for Bsc students, Study notes of Zoology

Download Full zoology dictionary for Bsc students and more Study notes Zoology in PDF only on Docsity! University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Armand R. Maggenti Online Dictionary of Invertebrate Zoology Parasitology, Harold W. Manter Laboratory of September 2005 Online Dictionary of Invertebrate Zoology: Complete Work Mary Ann (Basinger) Maggenti University of California, Davis (emerita) Armand R. Maggenti University of California, Davis (emeritus) Scott Lyell Gardner (Editor) University of Nebraska - Lincoln, slg@unl.edu Follow this and additional works at: http://digitalcommons.unl.edu/onlinedictinvertzoology Part of the Zoology Commons This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Armand R. Maggenti Online Dictionary of Invertebrate Zoology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. (Basinger) Maggenti, Mary Ann; Maggenti, Armand R.; and Gardner, Scott Lyell (Editor), "Online Dictionary of Invertebrate Zoology: Complete Work" (2005). Armand R. Maggenti Online Dictionary of Invertebrate Zoology. 2. http://digitalcommons.unl.edu/onlinedictinvertzoology/2 Online Dictionary of Invertebrate Zoology Compiled and directed by Mary Ann Basinger Maggenti University of California, Davis (emerita) Armand R. Maggenti, Ph.D. University of California, Davis Honorary Curator of Nemata Harold W. Manter Laboratory of Parasitology University of Nebraska State Museum University of Nebraska–Lincoln Edited by Scott L. Gardner, Ph.D. Harold W. Manter Laboratory of Parasitology W-529 Nebraska Hall University of Nebraska State Museum University of Nebraska–Lincoln Lincoln, Nebraska 68588-0514 http://hwml.unl.edu Tel: 402-472-3334 Fax: 402-472-8949 E-mail: slg@unl.edu digitalcommons.unl.edu 2005 The roots and origins of the terms presented in this dictionary were taken from textbooks and from the original literature. Wherever possible the original first reference was located so that the original meaning was preserved. Original use, subse- quent or current usage, and common acceptable uses of terms are also presented. Many of the terms were taken from Charles T. Brues and A. L. Melander, Key to the Families of North American Insects (1915) and their Classification of In- sects: A Key to the Known Families of Insects and Other Ter- restrial Arthropods (1932). The authors wish to acknowledge the dedication to this project given by Mr. Gaylen Paxman. Abbreviations a. adjective A.S. Anglo-Saxon Ab.Am. Aboriginal American ACANTHO Acanthocephala adv. adverb ANN Annelida Ar. Arabic ARTHRO Arthropoda BRACHIO Brachiopoda BRYO Bryozoa CHAETO Chaetognatha CNID Cnidaria Corn. Cornish CTENO Ctenophora D. Dutch Dan. Danish dim. diminutive ECHI Echiura ECHINOD Echinodermata ENTO Entoprocta F. French GASTRO Gastrotricha Ger. German GNATHO Gnathostomulida Gr. Greek HEMI Hemichordata Hind. Hindi It. Italian KINOR Kinorhyncha L. Latin LL. Late Latin LORI Loricifera Mal. Maldivean MD. Middle Dutch ME. Middle English MESO Mesozoa MF. Middle French ML. Medieval Latin MOLL Mollusca n. noun NEMAT Nematoda NEMER Nemertina NL. New Latin Obs. obsolete OE. Old English OF. Old French ON. Old Norse ONYCHO Onychophora pert. pertaining pl. plural PLATY Platyhelminthes POGON Pogonophora PORIF Porifera PRIAP Priapula ROTIF Rotifera Russ. Russian sing. singular SIPUN Sipuncula Skt. Sanskrit Sp. Spanish Sw. Swedish TARDI Tardigrada Turk. Turkish v. verb v.t. verb, transitive Jump to: A ..............1 B .......... 109 C .......... 151 D .......... 272 E........... 311 F........... 352 G .......... 381 H .......... 416 I ........... 463 J ........... 492 K .......... 495 L........... 500 M ......... 527 N ..........595 O ..........620 P...........650 Q ..........768 R ..........771 S...........799 TT ...........888 U ..........927 V ..........937 W .........953 X ..........956 Y...........958 Z...........959 Online Dictionary of Invertebrate Zoology 3 rating the aspidosoma (prodorsum) and the podosoma of mites. ablation n. [L. ablatus, taken away] Removal of a part as by excision or amputation. aboral a. [L. ab, from; os, mouth] 1. Pertaining to, or situated away from the mouth; surface opposite the mouth. 2. (ECHINOD: Asteroidea) The surface opposite that bearing the mouth and ambulacral grooves; abactinal; apical; dor- sal. see oral. aboriginal a. [L. aborigineus, ancestral] 1. Of or pertaining to an aborigine, the first, original. 2. Native fauna and flora of a geographic region. abortion n. [L. abortus, premature birth] Arrest or failure of development of any entity or normally present part or or- gan rendering it unfit for normal function. abranchiate a. [Gr. a, without; branchia, gills] Pertains to be- ing without gills. abreptor n. [L. ab, from; reptere, to crawl] (ARTHRO: Crusta- cea) The postabdomen of water fleas terminating in two claws. abscised n. [L. abscissus, cut off] Cut off squarely; with a straight margin. abscission n. [L. abscissus, cut off] The separation of parts. absolute a. [L. absolutus, finished, perfect, complete] Any en- tity existing in and of itself free from impurities or imper- fections. absorption n. [L. ab, from; sorbere, to suck] The passage of water and dissolved substances into a living cell or tissue. see adsorption. abterminal a. [L. ab, from; terminus, limit] Passing from the end toward the center. abullate a. [Gr. a, without; L. bulla, bubble] Lacking a bulla. abyss n. [Gr. abyssos, the deep sea] Bottomless, sometimes used to denote very deep. Maggenti and Gardner 4 abyssal a. [Gr. abyssos, the deep sea] Pertaining to the ocean depth beyond the continental shelf; dark area of the ocean below 2,000 meters. abyssobenthos a. [Gr. abyssos, the deep sea; benthos, depth of sea] Pertaining to all organsims that are sessile, or creep or crawl over the ocean bottom. abyssopelagic a. [Gr. abyssos, the deep sea; pelagos, sea] Pertains to all organisms inhabiting the deep abyssal zone; they are either active swimmers, or float with the current. acantha n. [Gr. akantha, thorn, spine] Spinous process; prickle. acanthaceous a. [Gr. akantha, thorn, spine] Pertaining to be- ing armed with spines or prickles. acanthella larva (ACANTHO) Transitional larva developed from an acanthor after crossing through the gut wall into the intermediate host hemocoel; stage between an acanthor and a cystacanth in which the definitive organ systems are developed. acantho- [Gr. akantha, thorn, spine] A prefix meaning spine. Acanthocephala, acanthocephalans n.; n.pl. [Gr. akantha, thorn, spine; kephale, head] A phylum of parasitic pseu- docoelomate, bilateral animals distinguished by a generally eversible proboscis with recurved, sclerotized, retractable hooks; commonly called spiny-headed worms. acantho- cephalous a. acanthocyst n. [Gr. akantha, thorn, spine; kystis, bladder] (NEMER) The stylet apparatus housed in the middle (stylet bulb) portion of the proboscis, including two to several ac- cessory stylet pouches containing replacement stylets. acanthodion n.; pl. -dia [Gr. dim. akanthodes, thorn, spine] (ARTHRO: Chelicerata) In Acari, a tarsal seta that contains an extension of a sensory basal cell. acanthodrilin set (ANN: Oligochaeta) With reference to male terminalia, having prostatic pores in segments xvii and xix, and male pores in segment xviii, all pores are in seminal furrows. Online Dictionary of Invertebrate Zoology 5 acanthoparia n.; pl. -iae [Gr. akantha, thorn, spine; pareion, cheek] (ARTHRO: Insecta) In Coleoptera, the lateral spiny paired region of the paria (epipharynx) in scarabaeoid lar- vae. acanthophore n. [Gr. akantha, thorn, spine; phoreus, bearer] (NEMER) A conical mass that forms the basis of the median stylet. acanthophorites n. [Gr. akantha, thorn, spine; phoreus, bearer] (ARTHRO: Insecta) In Diptera, spine bearing plates at the tip of the female abdomen used to aid oviposition in soil. acanthopod n. [Gr. akantha, thorn, spine; pous, foot] (AR- THRO: Crustacea) A barnacle appendage (cirrus) bearing a short row of strong sharp spines distally at each articula- tion of greater curvature, and few or no spines of lesser curvature. see centopod, basipod(ite). acanthopore n. [Gr. akantha, thorn, spine; poros, passage] (BRYO) 1. A tubular spine in certain fossils. 2. In Stenolae- mata, sometimes referred to as style, stylet, or acan- thorod. acanthor n. [Gr. akantha, thorn, spine] (ACANTHO) The first stage larva that emerges from the egg; the infective stage in the gut of the arthropod (intermediate host); has 6-8 blade-like hooks forming an aclid organ or rostellum. acanthorod n. [Gr. akantha, thorn, spine; A.S. rod] (BRYO: Stenolaemata) A style or stylet. see acanthopore. acanthosoma n. [Gr. akantha, thorn, spine; soma, body] (AR- THRO: Crustacea) In Decapoda, the last larval stage pre- ceding the postlarva; zoea; mysis; schizopod larvae. acanthosphenote a. [Gr. akantha, thorn, spine; sphen, wedge] (ECHINOD: Echinoidea) Pertaining to a spine com- posed of solid wedges separated by porous tissue. acanthostegous a. [Gr. akantha, thorn, spine; stegos, roof] (BRYO) Pertaining to an overlay of spines, as the ovicell. acanthostyle n. [Gr. akantha, thorn, spine; stylos, pillar] 1. (BRYO: Stenolaemata) A type of stylet with a smooth rod Maggenti and Gardner 8 accessory pigment cells (ARTHRO: Insecta) As many as twenty-four cells that surround the retinulae of a com- pound eye; in superposition eyes the pigment granules as- sume different positions in light and darkness; also known as secondary pigment cells, secondary iris cells, iris pig- ment cells and outer pigment cells. accessory pulsatile organs (ARTHRO) Pulsating structures connected with the hemocoel that are concerned with maintaining a circulation through the appendages, but pul- sating independently from the heart. accessory sac (PLATY: Cestoda) A sac in the proglottid wall that opens into the genital atrium. accessory spicule (PORIF) A category of megasclere, supple- mental to the primary skeleton, may be located anywhere. accessory stylets (NEMER) Replacement stylets that are stored in reserve stylet sacs or pouches. accessory subcoastal vein (ARTHRO: Insecta) In Perlidae, the vein given off from the subcosta, branching toward the apex of the wing. accessory testis (ARTHRO: Insecta) In Coleoptera, the coiled middle section of the vas deferens serving as a reservoir for mature sperm. accidental evolution A condition that occurs as a conse- quence of mutation, but does not appear to improve sur- vival value. accidental host A host in which a pathogenic parasite is not commonly found. accidental myiasis (ARTHRO: Insecta) In Diptera, the pres- ence within a host of a fly larva that is not normally para- sitic; pseudomyiasis. accidental parasite A parasite in other than its normal host; an incidental parasite. accidental transport Unintentional movement of a pathogen from one location to another by an animal not normally as- sociated with the parasite or disease. see phoresis. Online Dictionary of Invertebrate Zoology 9 acclimation n. [L. ad, to; Gr. klima, climate] The habituation of an organism to a foreign or different climate or environ- ment; acclimatization. acclivous a. [L. acclivis, ascending] Pertaining to an upward slope. see declivous. accretion n. [L. accrescere, to increase] Growth or increase by external addition. see intussusception. acelomate see acoelomate acentric a. [Gr. a, without; kentrol, center] Pertaining to not being centered; lacking a centromere when referring to a chromosome or chromosome fragment. acentric inversion An inversion of any part of the chromo- some not involving the centromere. Acephala (MOLL) Former name for Class Bivalvia. acephalocyst n. [Gr. a, without; kephale, head; kystis, blad- der] (PLATY: Cestoda) A hydatid larval stage; bladderworm; cysticercus. acephalous a. [Gr. a, without; kephale, head] (ARTHRO: In- secta) Pertains to the absence of any structure comparable to a head, as in certain dipteran larvae; acephalic. see eucephalous, hemicephalous. acerata n. [Gr. a, without; keratos, horn] 1. Without true an- tennae. 2. (ARTHRO) In former classifications, the name Acerata comprised a class combining Merostomata and Arachnida. acerate a. [L. acer, sharp] Of or pertaining to needle-shaped; acerose; acicular. acerose a. [L. acer, sharp] Having a sharp, rigid point; acer- ate; acicular. acerous a. [Gr. a, without; keras, horn] Lacking horns, anten- nae or tentacles. acervate a. [L. acervare, to heap] Pertaining to heaped or growing in heaps or clusters. see coacervate. acervuline a. [L. acervare, to heap] Resembling small heaps. Maggenti and Gardner 10 acescence n. [L. acesceres, to turn sour] Acetic acid fermen- tation. acetabular caps (ARTHRO: Insecta) The coxal cavity of Hemiptera. acetabuliform a. [L. acetabulum, cup; forma, shape] Resem- bling the shape of a shallow cup or saucer. acetabulum n.; pl. -la [L. acetabulum, cup] 1. A cup-shaped socket or cavity. 2. (ANN: Hirudinoidea) In leeches, the large posterior sucker. 3. (ARTHRO: Chelicerata) In Acari, the genital sucker. 4. (ARTHRO: Insecta) a. Any cavity into which an appendage is articulated; the coxal cavity. b. The conical cavity at the anterior of some larvae; in Diptera, the cavity in the sucking mouth. c. In dytiscid water bee- tles, stalked cuplets or sucker discs on the anterior tarsi, in some, also the second tarsi, thought to act as adhesive or- gans during copulation; a pallette. 5. (ECHINOD: Echin- oidea) The cavity located on the proximal end of a spine. 6. (MOLL: Cephalopoda) The sucker on the arm. 7. (PLATY: Cestoda) The sucker on the scolex. 8. (PLATY: Trematoda) The ventral sucker. achaetous, achetous a. [Gr. a, without; chaite, hair] Without setae, bristles, or chaetae. achatine, achatinus a. [L. achates, agate] Pertaining to lines resembling those of an agate; in bands of more or less concentric circles. achelate a. [Gr. a, without; chele, claw] Lacking pincherlike organs or claws. achilary a. [Gr. a, without; cheilos, lip] Lacking a lip. achlamydate a. [Gr. a, without; chlamys, mantle] Lacking a mantle. achroacyte n. [Gr. a, without; chroa, colored; kytos, con- tainer] A colorless cell; a lymphocyte. achroglobin n. [Gr. a, without; chroa, colored; L. globus, sphere] (MOLL) A colorless respiratory pigment. achroic see achroous Online Dictionary of Invertebrate Zoology 13 without a clitellar tumescence of the epidermis; the second growth stage. acme n. [Gr. akme, point] 1. The highest point. 2. That period of greatest development in the phylogenetic history of a group of organisms. Acoelomata n. [Gr. a, without; koilos, hollow] A coined term denoting those lower phyla of zoological classification that lack a body cavity or coelom as Cnidaria (=Coelenterata), Nemertea, Platyhelminthes, Porifera, or Ctenophora. acoelomate, acelomate a. [Gr. a, without; koilos, hollow] Refers to any Metazoa with no internal cavities in the body other than the lumen of the gut. acoelous a. acone eye (ARTHRO: Insecta) A condition (possibly primitive) of a compound eye in which the ommatidium is lacking a crystalline cone, but is modified in the form of elongated transparent bodies called Semper cells. see pseudocone, eucone, exocone. acontioids n.pl. [Gr. akon, dart; eidos, shape] (CNID: Antho- zoa) Simple or branched adhesive threads of tube anem- ones situated on the lower portion of the mesenteries. acontium n.; pl. -ia [Gr. akon, dart; ium, nature of] (CNID: Anthozoa) An elongate, hollow, nematocyst-studded thread of sea anemones. acoustic a. [Gr. akouein, to hear] Auditory; pertaining to the organs or sense of hearing, or produce sound such as a stridulatory organ. acquired a. [L. acquirere, to seek] 1. Pertaining to being devel- oped as a result of environmental effects; noninheritable. 2. Resulting from experience or learning. acquired character A trait or somatic modification that origi- nates during the life of an organism as the result of an en- vironmental or functional cause. acraein n. [Gr. akrasia, bad mixture] (ARTHRO: Insecta) In Lepidoptera, a secretion of certain butterflies of protective or distasteful function. Acraspeda n. [Gr. akraspedos, without fringes] (CNID: Hydro- Maggenti and Gardner 14 zoa) In former classifications, a group of jellyfish having a medusa without a velum. acraspedote a. [Gr. a, without; kraspedon, border] 1. (CNID: Hydrozoa) Refers to medusae without a velum. 2. (PLATY: Cestoda) Pertaining to tapeworm segments that do not overlap. acrembolic proboscis (MOLL) Having a completely invaginable proboscis. see pleurembolic proboscis. acridophagus n. [Gr. akridion, locust, grasshopper; phagein, to eat] (ARTHRO: Insecta) The act of preying and feeding on members of the Acrididea. acroblast n. [Gr. akros, tip; blastos, bud] In spermatogenesis, Golgi material giving rise to an acrosome. acrocentric a. [Gr. akros, tip; kentron, center] Pertaining to chromosomes with the centromere at or near one of the ends; rod-shaped chromosomes. see telocentric. acrocercus see cercus acrocyst n. [Gr. akros, tip; kystis, sac] (CNID: Hydrozoa) A chitinous sac containing a planula in which development is completed; may protrude from the gonangium. acrodendrophily a. [Gr. akros, tip; dendron, tree; philein, to love] Inhabiting the tree-tops. acron n. [Gr. akros, tip] 1. (ARTHRO) The anterior unseg- mented, or indistinguishably fused, body segments. a. In Crustacea, ophthalmic somite; presegmental region. b. In Insecta, the prostomium. 2. (MOLL) The prostomal region of trochophore larva. acronematic a. [Gr. akros, tip; nema, thread] Referring to smooth, whip-like flagella. acroneme n. [Gr. akros, tip; nema, thread] The slender sec- tion of a flagellum. acroparia n.; pl. -ae [Gr. akros, tip; pareion, cheek] (ARTHRO: Insecta) In Coleoptera, the anterior part of the paria bear- ing the bristles of scarabaeoid larvae. acroperiphallus n.; pl. -li [Gr. akros, tip; peri, around; phal- Online Dictionary of Invertebrate Zoology 15 los, penis] (ARTHRO: Insecta) In Protura, the distal part of the periphallus, sometimes retractable into basiperiphallus. acrophilous a. [Gr. akros, tip; philein, to love] Preferring re- gions of high altitude. acrorhagus n.; pl. -gi [Gr. akros, tip; rhax, berry] (CNID: An- thozoa) A marginal tubercle of sea anemones containing specialized nematocysts. acroscopic a. [Gr. akros, tip; skopein, to view] Looking to- wards the apex. see basiscopic. acrosome n. [Gr. akros, tip; soma, body] A cap-like structure investing the front part of the sperm head allowing pene- tration of the cover of the egg cell; formed from Golgi ma- terial. acrosternite n. [Gr. akros, tip; sternon, chest] (ARTHRO: In- secta) That part of the narrow marginal flange anterior to the antecosta of a definitive sternal plate, including the preceding primary intersegmental sclerotization; normally found on abdominal sterna, but absent on thoracic sterna. acrostical see acrostichal area, bristles, scales acrostichal area (ARTHRO: Insecta) In Diptera, the median longitudinal area of the scutum between the anterior prom- ontory and prescutellar area, bearing bristles or scales. acrostichal bristles (ARTHRO: Insecta) In Diptera, setae oc- curring in a median longitudinal row on the acrostichal area of the scutum. acrostichal hairs/seta/setulae see acrostichal bristles acrostichal scales (ARTHRO: Insecta) In Diptera, scales occur- ring in one or two lines on the acrostichal area. acrosyndesis n. [Gr. akros, tip; syndesai, to bind together] Incomplete end-to-end pairing of two chromosomes during meiosis; telosyndesis. acrotergite n. [Gr. akros, tip; L. tergum, back] (ARTHRO: In- secta) The anterior precostal part of the tergal plate of a secondary segment usually in the form of a narrow flange, varying in size or sometimes obliterated. Maggenti and Gardner 18 linkage in myofilaments that shortens when stimulated re- sulting in muscle contraction. acuate a. [L. dim. acus, needle] Sharpened; needle-shaped; sharp pointed. aculea n.; pl. -eae [L. dim. acus, needle] (ARTHRO: Insecta) 1. In Diptera, one of the minute spines comprising the to- mentum that covers the cuticula (except the wing mem- brane), usually dense in adults but sparse or absent in im- matures. 2. In Lepidoptera, one of the minute spines on the wing membrane. aculeate a. [L. dim. acus, needle] 1. Pertaining to being armed with a sting or short, sharp points. 2. Furnished with acu- leae. aculeate-serrate Armed with saw-like teeth inclined toward one direction. aculei pl. of aculeus aculeiform a. [L. dim. acus, needle; forma, shape] Formed like a thorn. aculeus n.; pl. -lei [L. dim. acus, needle] (ARTHRO: Insecta) 1. In Hymenoptera, an ovipositor in the form of a sting. 2. In Diptera, a sharp spine projected from the margin of the eighth sternite of Tipulidae. acumen n. [L. acumen, point] 1. (ARTHRO: Crustacea) In De- capoda, the pointed tip of the rostrum. 2. (ARTHRO: In- secta) The pointed tip of genitalia. acuminate a. [L. acumen, point] Terminating in a long taper- ing point. acuminose a. [L. acumen, point] Nearly acuminate. acuminulate a. [L. acumen, point] Minutely acuminate. acupunctate a. [L. acus, needle; punctus, a pricking] Pertain- ing to fine superficial punctures as if made with a needle. acutangular a. [L. acutus, sharpened; angulus, angle] Form- ing or meeting at an acute angle. acute a. [L. acutus, sharpened] Pointed; forming an angle of Online Dictionary of Invertebrate Zoology 19 less than 90°; having a sharp or sharply tapering point. see obtuse. acutilingual a. [L. acutus, sharpened; lingus, tongue] Having a sharp pointed tongue or mouth structure. acutilingues n. pl. [L. acutus, sharpened; lingua, tongue] A former classification (Acutilinguae) of bees that have a short pointed tongue. see obtusilingues. acyclic a. [Gr. a, without; kyklos, circle] Referring to noncyclic; not arranged in circles or whorls. adactyl, adactyle a. [Gr. a, without; daktylos, finger] Lacking fingers, toes, or claws. adambulacral a. [L. ad, near; ambulare, to walk] (ECHINOD: Asteroidea) Relates to structures situated along the ambu- lacral grooves in starfish. adanal a. [L. ad, near; anus, anus] Pertaining to being located near the anus. adanal bursa (NEMATA) Referring to a bursa not enclosing the tail terminus; leptoderan. adanal copulatory papillae (NEMATA) Male adanal supple- ments, glandular or sensory. adanale n. [L. ad, near; anus] (ARTHRO: Insecta) The fourth axillary sclerite of a wing. adanal segment (ARTHRO: Chelicerata) In Actinotrichida Acari, segment XIV plus one of the paraproctal segments. adanal supplements (NEMATA) Organs of secretion and at- tachment near the male anus. adapertural a. [L. ad, near; apertura, opening] (MOLL: Gastro- poda) Refers to being toward the shell aperture. adapical a. [L. ad, near; apex, top] (MOLL: Gastropoda) Slightly oblique or along the axis toward the top. adaptation n. [L. ad, near; aptus, fit] The process and condi- tion of showing fitness for a particular environment, as ap- plied to characteristics of a structure, function, or entire organism; also the process by which such fitness is ac- Maggenti and Gardner 20 quired. adaptive a. [L. ad, near; aptus, fit] Capable of or showing ad- aptation. adaptive divergence Evolutionary new forms from a common ancestry due to adaptation to different environmental con- ditions. adaptive ocelli (ARTHRO: Insecta) Simple eyes or ocelli of most larvae. see stemmata, ocellus. adaptive race A race that is physiologically, rather than mor- phologically, distinguished. adaptive radiation Evolutionary diversification of members of a single phyletic line into a series of different niches or adaptive zones. adaxial a. [L. ad, near; axis, axle] 1. Situated on the side of, or facing toward an axis. 2. (MOLL: Gastropoda) Inward to- ward the shell axis. adcauline a. [L. ad, near; caulis, stalk] (CNID: Hydrozoa) Per- taining to polyps that bend towards, or are near to the common stem. addendum n.; pl. -da [L. addere, to add] Something to be added; an addition, extension or supplement. additive variance Gradation due to the average value of dif- ferent genes. addorsal a. [L. ad, near; dorsum, back] Near to, but not on the middle of the dorsum. addorsal line (ARTHRO: Insecta) A longitudinal line between the dorsal and subdorsal line of caterpillars. adduct v.t. [L. ad, near; ducere, to lead] To draw towards a median axis or plane, or one part toward another. see ab- duct. adduction n. [L. ad, near; ducere, to lead] 1. Drawn toward or beyond the median line or axis. see abduction. 2. (AR- THRO: Insecta) In describing the movement of the legs, the movement of the coxa towards the body. Online Dictionary of Invertebrate Zoology 23 adenosine monophosphate (AMP) A compound of impor- tance in the release of energy for cellular activity, com- posed of adenine, d-ribose and phosphoric acid; also called AMP, adenylic acid, adenine ribotide. adenosine triphosphate (ATP) A major energy contributor in biokinetic systems that upon hydrolysis yields adenosine diphosphate (ADP). adenotaxy n. [Gr. aden, gland; taxis, arrangement] (ARTHRO: Chelicerata) In Acari, the number and distribution of the openings of the tegumentary glands of mites. adenotrophic viviparity Reproduction characterized by fully developed, shelled eggs passing to and retained in the uterus, where the egg hatches and the larva is nourished by special maternal glands until fully developed. adeoniform a. [L. Adeona, Roman goddess; forma, shape] (BRYO: Gymnolaemata) Pertaining to a lobate, bilamellar colony; resembling the fossil Adeona. adermata n. [Gr. a, without; derma, skin] (ARTHRO: Insecta) Transparent cuticle in pupa allowing the wings and other parts of the forming imago to be seen. adesmatic a. [Gr. a, without; desmos, ligament] Pertaining to a segment of an appendage, or to the articulation between segments of an appendage, lacking its own tendons and muscles. see eudesmatic. adetopneustic a. [Gr. adetos, free; pnein, to breathe] (ECHI- NOD) Dermal gills occurring beyond the abactinal surface. adfrontal areas/plates (ARTHRO: Insecta) A pair of narrow oblique plates on the head of Lepidoptera larvae, extending upwards from the base of the antennae and meeting medi- ally above. adfrontal setae (ARTHRO: Insecta) Setae borne on the ad- frontal areas of immature insects, usually numbered ac- cording to their proximity to the vertex. adfrontal sutures (ARTHRO: Insecta) In immature insects, sutures separating the adfrontal sclerites or areas from the epicranium. Maggenti and Gardner 24 adherent a. [L. ad, near; haerere, to stick] Referring to being attached, clinging or sticking fast. adhesion n. [L. ad, near; haerere, to stick] 1. Act or state of adhering. 2. Attraction between two molecules of different substances. adhesion organs 1. Any of numerous invertebrate organs used for adhesion to various surfaces. 2. (ARTHRO: Insecta) Abdominal suckers, tarsal suckers and ventral tube. 3. (NEMATA) The spinneret. 4. (PLATY: Cestoda) Suckers, bothria and bothridia. 5. (PLATY: Trematoda) Oral and ven- tral suckers. 6. (ROTIF) Pedal glands in the toes. adhesion tubes (NEMATA) Specialized hollow, tubelike struc- tures, that may be supplied with muscles, associated with glands presumed to secrete a sticky substance; sometimes referred to as tubular setae, adhesive bristles or ambula- tory setae. adhesive bristles see adhesion tubes adhesive capsule (CNID) A type of nematocyst used for at- taching to objects. adhesive cells Various glandular or specialized cells capable of causing adhesion in cnidarians and tubellarians; sometimes referred to as colloblasts, glue cells, or lasso cells. adhesive gland Various invertebrate glands that secrete a sticky substance. adhesive pad (CNID: Hydrozoa) In some medusae, an adhe- sive sucker near tip of the tentacles utilized for clinging to sea weed. adhesive papillae (PLATY: Turbellaria) In triclads, the protu- berant structures for the purpose of attachment at the ends of the marginal adhesive glands. adiabatic a. [Gr. a, without; dia, through; bainein, to go] Without gaining or losing heat. adiaphanous, adiaphanus a. [Gr. a, without; diaphanes, transparent] Impervious to light; opaque. adient a. [L. adire, to approach] Turning toward or approach- Online Dictionary of Invertebrate Zoology 25 ing a source of stimulation. see abient. adipocytes n.pl. [L. adeps, fat; Gr. kytos, container] (ARTHRO: Insecta) Cells that form the fat-bodies of insects; adipo- hemocytes; trophocytes. adipogenesis n. [L. adeps, fat; Gr. gennaein, to produce] The formation of fat or fatty tissue. adipohemocytes n.pl. [L. adeps, fat; Gr. haima, blood; kytos, container] (ARTHRO: Insecta) Hemocytes characterized by refringent fat droplets and other inclusions; spheroidocytes. see adipoleucocytes. adipoleucocytes n.pl. [L. adeps, fat; Gr. leukos, white; kytos, container] 1. Leucocyte blood cells with fat inclusions. 2. (ARTHRO: Insecta) In Hemiptera, large cells containing fat droplets, often thought to be hemocytes. adipose a. [L. adeps, fat] Pertaining to fat. adipose tissue see fat body A-disc see A-band adiscota n. [Gr. a, without; diskos, circular plate] (ARTHRO: Insecta) Adult development without forming imaginal discs. see discota. aditus n.; pl. aditus, adituses [L. aditus, entrance] Anatomical passage or opening to a part or structure. adiverticulate a. [Gr. a, without; L. divertere, to turn away] Without diverticula. adjustor n. [L. ad, near; justus, just] 1. Any central nervous organ of an animal that links receptors with effectors. 2. (BRACHIO) The muscle linking stalk and valve. adjustor neuron A neuron that is neither sensory nor motor, but which correlates the activities of both. admedial, admedian a. [L. ad, near; medial, middle] 1. Near the median plane. 2. (MOLL) The lateral teeth of a radula between central and marginal. adminiculum n.; pl. -ula [L. adminiculum, support] 1. A sup- port or prop. 2. (ARTHRO: Insecta) a. Minute hairs, spines Maggenti and Gardner 28 such as the heart, or blood vessels. adventitious a. [L. adventitius, extraordinary] Acquired; acci- dental; additional; occurring in abnormal places; ectopic foci. adventitious bud (BRYO: Phylactolaemata) The small bud pri- mordium on the dorsal side of the main bud near the pa- rental polypide. adventitious vein (ARTHRO: Insecta) A secondary wing vein, neither accessory nor intercalary, usually the result of cross veins lined up to form a continuous vein. adventive a. [L. advenire, to arrive] Referring to an organism that has been accidentally introduced to a new area; not native. adventral line (ARTHRO: Insecta) A line that extends along the underside of caterpillars between the middle and the base of the legs. adventral tubercle (ARTHRO: Insecta) In caterpillars, a small pimple, sometimes bearing setae, located on each of the abdominal segments on the inner base of the leg and apo- dal segment. advolute n. [L. ad, near; voluta, spiral] (MOLL: Gastropoda) A condition of whorls that barely touch one another, not dis- tinctly overlapping. aedaeagus, aedagus, aedoeagus see aedeagus aedeagal fulcrum see juxta aedeagus n.; pl. -agi [Gr. aidoia, genitals; agein, to lead] (AR- THRO: Insecta) In males, the intromittent organ; distal part of the phallus: penis plus parameres. see penis, telopod. aedoeotype n. [Gr. aidoia, genitals; typos, type] The first specimen in which the genitalia are studied. aeneous, aeneus a. [L. aeneus, of bronze] Bright brassy or golden green in color. aerate v.t. [Gr. aer, air] To combine or charge with air; to supply or impregnate with common air. Online Dictionary of Invertebrate Zoology 29 aeration n. [Gr. aer, air] 1. Exposure to air. 2. Impregnation of a liquid with air or oxygen. 3. Oxygenation of blood in lungs. aerial a. [Gr. aer, air] Living or occurring in air. aeriduct, aeriductus n. [L. aer, air; ducere, to lead] (ARTHRO: Insecta) Tubes concerned with respiration, such as internal trachea or breathing tubes. aeriform a. [Gr. aer, air; L. forma, shape] Of the nature or form of air; gaseous. aerobe, aerobiont n. [Gr. aer, air; bios, life] An organism utilizing air. aerobiotic a. see anaerobe. aerobic respiration That which requires oxygen. aerobiology n. [Gr. aer, air; bios, life; logos, discourse] The study of aerial organisms. aerobiosis n. [Gr. aer, air; biosis, manner of life] Life in air or oxygen. aerophore n. [Gr. aer, air; phorein, to bear] (ARTHRO: Insecta) In caterpillars, a hollow hair on the body containing liquid. aeropyle n. [Gr. aer, air; pyle, orifice] (ARTHRO: Insecta) 1. Rings of cells. 2. In the follicular epithelium, functioning in secretions for chorion formation. 3. Small pores between plastron and spiracles in spiracular gills. aeroscepsin, aeroscepsy n. [Gr. aer, air; skepsis, observe] The theoretical power possessed by certain organisms of observing the quality of air by means of special sense or- gans. aeroscopic plate (ARTHRO: Insecta) The air-containing part of the chorion of an egg. aerostat n. [Gr. aer, air; statos, placed] (ARTHRO: Insecta) Air sacs in the body. aerostatic a. [Gr. aer, air; statos, placed] Said of any organ- ism or object that is, by certain means, supported chiefly by buoyancy derived from surrounding air. aerotaxis n. [Gr. aer, air; taxis, arrangement] Movement of Maggenti and Gardner 30 organisms toward or away from oxygen. aeruginous, aeruginose, aeruginus a. [L. aerugo, copper rust] Nature or color of copper rust or verdigris (green). aesthacyte, esthacyte n. [Gr. aisthetes, perceiver; kytos, container] A sensory cell of certain primitive organisms. aesthesia, esthesia n. [Gr. aisthetes, perceiver] Sensibility; sense-perception. aesthetasc, aesthetask, esthestasc n. [Gr. aisthetes, per- ceiver; askos, bag] (ARTHRO: Crustacea) Sensory seta cov- ered by a delicate cuticular membrane, often projecting from an antenna or antennule; an olfactory hair. aesthete, esthete n. [Gr. aisthetes, perceiver] 1. Any inverte- brate sense organ. 2. (ARTHRO) Usually applied as sensory nerve endings, but also used for sensory hairs and bristles. 3. (MOLL: Polyplacophora) Sensory organs terminating in the tegmentum. see megalaesthetes, micraesthetes. aestivate, estivate v. [L. aestas, summer] To pass the sum- mer in a quiet, torpid condition. aestivation, estivation n. [L. aestas, summer] A form of dormancy during the summer months in high tempera- tures, or dry seasons. see hibernestivation. aetiology see etiology afference n. [L. ad, near; ferre, to bear] Impulses from the external sense organs of an animal because of events in the environment. see reafference. afferent a. [L. afferre, to bring] Refers to a structure or vessel that leads to or toward a given position. see efferent. afferent channel (ARTHRO: Crustacea) The opening through which water passes to the gills. afferent fiber A nerve fiber carrying impulses from a receptor to the central nervous system. afferent nerve A nerve that conducts impulses from the pe- riphery toward a nerve center; the axon of a sensory neu- ron between a receptor and the central nervous system. afferent neuron (neurone) A sensory neuron that conveys inward impulses received or perceived by a sense organ Online Dictionary of Invertebrate Zoology 33 aggregate a. [L. ad, to; gregare, to collect] Clustering or crowding together to form a dense mass. aggregation n. [L. ad, to; gregare, to collect] 1. Collection or grouping into a mass or sum. 2. A group of individuals comprised of more than a mated pair or family, collecting in the same place, that do not construct nests or rear off- spring in a cooperative manner. see colony. aggressin n. [L. aggressus, attacked] A substance produced in the body of a host by a pathogenic organism that paralyzes the defense mechanisms of the host. aggression n. [L. aggressus, attacked] The behavior of an or- ganism involving threats or attack of another organism or object. aggressive mimicry A method of mimicry of one species by another that is hostile to it. agigeriate a. [Gr. a, without; gigerium, gizzard] Gizzardless; without a gizzard. Aglossa see Bivalvia aglossate n. [Gr. a, without; glossa, tongue] Lacking a tongue. agminate a. [L. agminis, crowd] Grouped together; aggre- gated. see cluster. agnathous a. [Gr. a, without; gnathos, jaw] Lacking a jaw. agnotobiotic culture Any population with one or more kinds of organisms present. see gnotobiotic culture. agonist n. [Gr. agonistes, contestant] A primary muscle re- sponsible for the movement of a part or appendage. agonistic a. [Gr. agonistes, contestant] Behavior signaling ag- gressive attitude. agriotype n. [Gr. agrios, wild; typos, type] Ancestral type. agriotypiform a. [Gr. agrios, wild; typos, type; L. forma, shape] (ARTHRO: Insecta) In Hymenoptera, referring to the peculiar form of larval Agriotypidae, with the first instar having a heavily sclerotized, mandibulate head, rows of spiniform setae on the succeeding segments, and a slen- der, bifurcate caudal appendage. Maggenti and Gardner 34 ahermatype corals (CNID) Non-reef building species of corals. ahermatic a. see hermatype corals. aileron n. [F. dim. aile, wing] (ARTHRO: Insecta) A large scale or structure in front of the base of the fore wing; some- times used as synonymous with alula. air chamber (MOLL: Cephalopoda) The gas-filled cavity of a nautilus shell that was previously occupied by that organ- ism. air sacs 1. (ARTHRO: Insecta) Pouch-like enlargements of tra- cheal tubes in winged forms, usually lacking taenidia, ca- pable of inflation and thought to function as an aid in flight and to lessen specific gravity. 2. (CNID: Hydrozoa) In Si- phonophora, that portion of a pneumatophore that contains gas. air stores (ARTHRO: Insecta) The covering of bubbles of air carried by hydrofuge structures of certain aquatic forms. air tube A respiratory tube or siphon. aitiogenic a. [Gr. aitios, causing; gennaein, to produce] Refer- ring to the resultant reaction from stimulation. akanth see acanth akaryote, acaryote n. [Gr. a, without; karyon, nut] 1. Lacking a nucleus. 2. A non-nucleated cell. akinesis, akinesia n. [Gr. a, without; kinesis, motion] Loss or disturbance of motion, as in certain insects, resulting from loss of antennae. ala n.; pl. alae [L. ala, a wing] Any wing-like process or struc- ture; a thin, cuticular projection or fin, running longitudi- nally, usually lateral or sublateral, frequently paired. alabastrine a. [Gr. alabastros, alabaster box] Pertaining to, or like alabaster; smooth and white. alacardo n. [L. ala, a wing; cardo, hinge] (ARTHRO: Insecta) The distal sclerite of the cardo. alacercus n. [L. ala, a wing; Gr. kerkos, tail] (ARTHRO: In- secta) The caudal filament; the middle cercus when three are present. alacoxasuture n. [L. ala, a wing; coxa, hip; sutura, seam] Online Dictionary of Invertebrate Zoology 35 (ARTHRO) The suture that appears to divide the coxa into an anterior and posterior part; found on only one side of the coxa. alacrious a. [L. alacer, lively] Brisk; active; lively. alacrista n.; pl. -ae [L. ala, a wing; crista, ridge] (ARTHRO: In- secta) In Coleoptera, a ridge on each side of the anterior scutal area that converges posteromesally. alae pl. of ala alaglossa n. [L. ala, a wing; Gr. glossa, tongue] (ARTHRO: In- secta) Glossae fused into a single plate. alar a. [L. alaris, of the wing] Pertaining to a wing, or wing- shaped. alar area (ARTHRO: Insecta) In certain coleopteran scarabaeoid larvae, an integral area immediately above the epipleural area, separated in the thorax by an oblique suture. alar frenum (ARTHRO: Insecta) 1. In Diptera, a ligament di- viding the supra-alar cavity into anterior and posterior ar- eas. 2. In Hymenoptera, a ligament crossing the supra-alar groove toward the wing base. alaria n. [L. alaris, of the wing] (ARTHRO: Insecta) The notal wing processes. alarima n. [L. ala, wing; rima, cleft] (ARTHRO: Insecta) The opening between the two paraglossae. alarm pheromone A chemical released into the environment inducing a fright response in other members of the same species. alar squama (ARTHRO: Insecta) In Diptera, one of three mem- branous lobes in the region of the wing base that repre- sents the jugum. see alula, thoracic squama. alary a. [L. alaris, of the wing] Wing-like; aliform. alary muscles see aliform muscles alary polymorphism (ARTHRO: Insecta) Two or more shapes of wings in the same species, not necessarily correlated to sex. alassostasy n. [Gr. allassein, to alter; stasis, standing] (AR- THRO: Chelicerata) An orthostasic stage in the life cycle in- Maggenti and Gardner 38 open-chain structure, and those cyclic compounds that re- semble the open-chain structure. aliquant a. [L. alius, other; quantus, how great] In mathe- matics, dividing a smaller number into a larger number with a remainder; in biology, taking equal quantities of a solution with unequal numbers of organisms in suspension. see aliquot. aliquot a. [L. alius, other; quantus, how great] In mathemat- ics, dividing a smaller number into a larger number evenly; hence, in biology, dividing a population of organisms evenly or into equal parts. see aliquant. alitrunk n. [L. ala, wing; truncus, trunk] (ARTHRO: Insecta) Thorax to which the wings are attached, including the first abdominal segment in certain Hymenoptera; mesosoma. alivincular hinge (MOLL: Bivalvia) A somewhat flattened cord from one bivalve umbo to another, having the long axis transverse to the planes of the margins and the axis of motion. alizarin, alizarine n. [F. alizari, the juice] A transparent or- ange-red stain or dye. alkaline gland (ARTHRO: Insecta) In Hymenoptera, the Du- four's gland; an accessory gland that discharges at the base of the sting; function unknown, but thought to be concerned with lubrication of the sting. alkanes n.pl. [OF. al qualiy, ashes of salt wart] A group of saturated hydrocarbons found in Pre-Cambrian geological strata presumed to be fossils. allaesthetic, allesthetic a. [Gr. allos, other; aisthetes, per- ceiver] Recognition of characteristics of an organism, as perceived by another. allantoin n. [Gr. allas, sausage] The resultant of purine and pyrimidine metabolism occurring in allantoic fluid and urine of various invertebrates. allatectomy n. [L. allatum, brought; Gr. ektemnein, to cut out] (ARTHRO: Insecta) Total excision of the endocrine glands, corpora allata. allatum hormone see juvenile hormone Online Dictionary of Invertebrate Zoology 39 Allee's principle The concept of an optimal population level where organisms flourish. allele n. [Gr. allelon, one another] Genes occupying the same locus in homologous chromosomes, that segregate from each other at the reduction division. see dominant allele, pseudoallele, isoallele, recessive allele, multiple al- lele. allelism n. [Gr. allelon, one another] The relationship between two characters that are alleles; alleomorphism; alternative inheritance. allelochemic, allelochemical n. [Gr. allelon, one another; chemeia, pert. chemistry and chemical terms] 1. A chemi- cal agent of natural origin involved in interaction between species or individuals; sometimes divided into four sub- groups based on whether the emitter, the receiver, or both benefit in the interaction: allomones, kairomones, syno- mones and apneumones. 2. Xenomone. allelomimetic a. [Gr. allelon, one another; mimikos, imitative] Referring to imitation of behavioral habits of another ani- mal, usually of the same species. allelomorph n. [Gr. allelon, one another; morphe, form] 1. Two contrasting, although closely parallel genetic charac- ters. 2. A member of a Mendelian pair. allelopathy n. [Gr. allelon, one another; pathos, suffer] The chemical effect of plants on other organisms in the envi- ronment. allelotropism n. [Gr. allelon, one another; tropein, to turn] The mutual attraction between two cells or organisms. allelotype n. [Gr. allelon, one another; typos, type] The re- peated occurrence of alleles in a given population. allesthetic see allaesthetic alligate v.t. [L. alligare, to tie] To unite, fasten or suspend. alliogenesis see alloiogenesis allobiosis n. [Gr. allos, other; biosis, manner of life] Differen- tiation from the normal; a changed environment. allochore n. [Gr. allos, other; chorein, to spread] Any organ- ism occurring in two different habitats in the same geo- Maggenti and Gardner 40 graphic region. allochroic a. [Gr. allos, other; chroia, color of the skin] Changeable in color, or variation of color. allochronic a. [Gr. allos, other; chronos, time] Not occurring at the same period of time; not contemporary. allochronic speciation Speciation that does not occur at the same period of time, thus causing morphological disconti- nuity. see synchronic speciation. allochthonous a. [Gr. allos, other; chthon, earth] Exotic; im- ported or migrated from another area; peregrine. see autochthonous. allocryptic a. [Gr. allos, other; kryptos, conceal] Concealing; said of organisms that conceal themselves with coverings of other organisms or with inanimate materials. allogamy n. [Gr. allos, other; gamos, marriage] Cross-fertili- zation. see autogamy. allograft n. [Gr. allos, other; OF. greffe, graft] A piece of tis- sue or organ from one individual grafted to another of the same species. alloheteroploid n. [Gr. allos, other; heteros, different; aploos, onefold; eidos, form] Heteroploid individuals whose chro- mosomes derive from various chromosome sets. see auto- heteroploid. alloiogenesis n. [Gr. alloios, of another kind; genesis, begin- ning] Alternation of sexual and parthenogenetic genera- tions: alternation of generations. alloiometron n. [Gr. alloios, of another kind; metron, meas- ure] Measurable variability in the physical development within a species or race. allokinesis n. [Gr. allos, other; kinesis, movement] Passive or reflex movement. allokinetic a. see autokinesis. allomeristic a. [Gr. allos, other; meros, part] Refers to any organism differing in the number of parts of any organ from that which is customary in the group. allometric coefficient The slope of the logarithmic growth curve of the measurement of an organ or part against that of the whole remainder or another part; sometimes re- Online Dictionary of Invertebrate Zoology 43 allotropous a. [Gr. allos, other; tropos, turn] (ARTHRO: In- secta) Refers to insects that are not limited to or adapted to visiting certain kinds of flowers. allotropy see allotropism allotype n. [Gr. allos, other; typos, type] A paratype of the opposite sex to the holotype. allozygote n. [Gr. allos, other; zygotos, yoked] A homozygote with only recessive characters. alluring coloration (ARTHRO: Insecta) Patterns or colorings adapted by predators that attract other species; aggressive mimicry. alluring glands Glandular structures that disperse an odor at- tractive to the opposite sex; sex pheromones. allux n. [L. ad, to; luxus, dislocated] (ARTHRO: Insecta) In Cur- culionidae, the next to the last joint of the tarsus. alpha-chlorophyll n. [Gr. alpha, a; chloros, green; phyllon, leaf] (ARTHRO: Insecta) Chlorophylic properties producing coloration. see beta-chlorophyll. alpha-female n. [Gr. alpha, α Α; L. femina, female] (ARTHRO: Insecta) In Formicidae, the intermediate form between the teratogyne and normal female. alpha taxonomy That level of taxonomy involved with the characterization and naming of species. see beta taxon- omy. alpine a. [L. alpinus, of or like high mountains] Applied to or- ganisms occurring in high mountain meadows; also re- ferred to as alpestrine. altaceratubae n. [L. alter, the other; Gr. keras, horn; tuba, trumpet] (ARTHRO: Insecta) In certain scale insects, ceratubae shaped like large broad cylinders with oblique openings, located at or near the margin of the pygidium. alteration theory Explanation of the phenomenon of electro- motive forces of nerve and muscle by changes in chemical composition of tissue in cross-section. alternate host One that alternates with another in the life cy- cle of a parasite. see intermediate host. Maggenti and Gardner 44 alternating cleavage see spiral cleavage alternation of generations The alternation of two or more generations reproducing in different ways; an alternation of sexual and asexual, or parasitic with a free-living cycle. see alloiogenesis, digenesis, heterogamy, heterogenesis, heterogony, metagenesis. alternative inheritance see allelism altitude see height altricial a. [L. altrix, nourisher] Having young at hatching or birth that require care for sometime. altruism n. [L. alter, the other] Behavior disadvantageous to the individual, but benefits other individuals of the species. alula n.; pl. -lae [L. dim. ala, wing] (ARTHRO: Insecta) 1. In some Diptera, one of the membranous lobes in the region of the wing base, thought to be part of the vannal region. see thoracic squama, alar squama. 2. In some Coleop- tera, the alula is folded beneath the elytron/jugum. alulet n. [L. dim. ala, wing] (ARTHRO: Insecta) In Diptera, a lobe at the basal posterior part of the wing; wing append- age; posterior lobe. see alula. alutaceous a. [L. alutaceus, soft leather] Pertaining to brown or brownish-yellow; leathery; covered with, or appearing like, minute cracks. alveator n. [L. alveatus, hollowed out] (ECHINOD) A form of pedicellaria; usually two valved and recessed into an al- veolus or depression in the endoskeleton. alveola n.; pl. -lae [L. alveolus, small cavity] A small pit or depression on the surface of an organ; faveolus; alveolus. alveolar a. alveolar hydatid cyst (PLATY: Cestoda) A larval form of Echi- nococcus multilocularis comprised of many compartments containing many protoscolices that infiltrate body tissues. alveolate a. [L. alveolus, small cavity] Deeply pitted or having the appearance of a honeycomb. alveolus n.; pl. -eoli [L. alveolus, small cavity] Any small cav- ity, pit or depression; alveola. Online Dictionary of Invertebrate Zoology 45 amacrine a. [Gr. a, without; makros, long; inos, fiber] (AR- THRO: Insecta) Pertaining to a unipolar nerve cell within a synaptic region of the brain, i.e., the antennal lobes or the medulla. amacrinal a. amalgamated lips (NEMATA) Lips combined together giving a smooth contour, not discernibly separated from each other. amastigophore n. [Gr. a, without; mastix, whip; pherein, to bear] (CNID) A nematocyst with no tube beyond the hempe; in microbasic types , the hempe is not more than three times the capsule length; in macrobasic types , the hempe is more than four times the capsule length. see mastigophore. amber n. [Ar. anbar ambergris, a fossilized resin] A transpar- ent, clear, pale yellow-brown gummy resin of coniferous trees in which insects and spiders were trapped and fossil- ized in the hard transparent state as much as 30 million years ago. ambient a. [L. ambire, to go around] Moving around; sur- rounding. ambient vein (ARTHRO: Insecta) 1. The vein that partially en- circles the wing close to the margin. 2. The vein-like structure that serves to stiffen the margin of a wing. ambifenestrate a. [L. ambo, both; fenestra, window] (NEMATA) A term used to describe two semifenestrae in the vulval cone formed by a narrow vulval bridge, but not sur- rounding the vulva. see bifenestrate. ambiguous a. [L. ambigere, to wander about] Vague or doubtful in meaning; having more than a single meaning. ambilateral a. [L. ambo, both; latus, side] Pertaining to or af- fecting both sides; bilateral. ambisexual see monoecious, hermaphrodite ambital see ambitus ambitus n. [L. ambitus, going around] The periphery or outer edge of an organism. ambital a. amblychromatic a. [Gr. amblys, dull; chroma, color] Staining only slightly, as opposed to trachychromatic. ambosexous see hermaphrodite Maggenti and Gardner 48 interbreeding between members of the same species or races due to morphological, geographical or physiological isolation. ammochaeta n.; pl. -tae [Gr. ammos, sand; chaite, long hair] (ARTHRO: Insecta) In Hymenoptera, specialized hairs or bristles on the head or lower lip of desert ants, used for removing sand from the strigils on the forelegs. ammonite n. [Gr. Ammon, Jupiter] (MOLL: Cephalopoda) Any fossil ammonean shell curved into a spiral like a ram's horn, common in Paleozoic and Mesozoic rocks of all parts of the world. ammonitiferous a. [Gr. Ammon, Jupiter; ferre, to carry] Said of rocks containing ammonites. ammonoid a. [Gr. Ammon, Jupiter] (MOLL: Cephalopoda) Per- taining to a shell covered cephalopod. ammonotelic a. [Gr. ammoniakon, temple of Jupiter Ammon; telos, end] The excretion of nitrogen principally as ammo- nia. see uricotelic. ammophilous a. [Gr. ammos, sand; philos, loving] Sand-lov- ing; living in or frequenting sand. amnion n.; pl. -nions, -nia [Gr. amnion, membrane around the fetus] (ARTHRO) The inner cellular, membranous em- bryonic covering of various insects and other arthropods. amniotic a. amnios n. [Gr. amnion, membrane around the fetus] (ARTHRO: Insecta) Cuticular covering of an embryo that is shed be- fore or very shortly after hatching. amniotic cavity The cavity between the amnion and the em- bryo in the developing egg of various invertebrates. amniotic fluid Liquid surrounding the embryo while in the egg. amniotic folds Lateral folds of the amnion that meet to en- close the germ band in the ovum. amniotic pore (ARTHRO: Insecta) An opening to the amniotic cavity during embryonic development. amoeba, ameba n. [Gr. amoibe, change] Any amoeba-like cell or corpuscle of the blood or other parts of an organism. Online Dictionary of Invertebrate Zoology 49 amoebocyte n. [Gr. amoibe, change; kytos, container] 1. Certain body cells or tissues capable of independent amoeba-like movement. 2. (PORIF) Any mesohyl cell where no special activity is evident. see plasmatocyte. amorph n. [Gr. a, without; morphe, form] An inactive allele that acts as a genetic block to biosynthesis. amorpha n. [Gr. a, without; morphe, form] (ARTHRO: Insecta) Those pupa that share no resemblance with the imago. amorphous a. [Gr. a, without; morphe, form] Lacking distinc- tive form or structure; shapeless. AMP Adenosine monophosphate ampherotoky see amphitoky amphiapomict n. [Gr. amphi, on both sides; apo, away; miktos, mixed] Biotypes that propagate facultatively, i.e. amphimictally and parthenogenetically. amphiasters n.pl. [Gr. amphi, on both sides; aster, star] 1. The two asters in cell division, one at each end of the cell, from which the spindle fibers diverge. 2. (PORIF) Strep- tasters stellate at each end. amphibiotic a. [Gr. amphi, on both sides; biotikos, pert. to life] Being aquatic during one period of the life history and terrestrial during the rest. amphibious a. [Gr. amphi, on both sides; bios, life] Capable of living both on land and in the water. amphiblastula n. [Gr. amphi, on both sides; dim. blastos, bud] A blastula in which the cells of one pole are markedly different in size or shape from the other pole. amphiblastula larva (PORIF: Calcarea) A type of free-swim- ming larva possessing a central cavity, and two morpho- logically distinct types of cells, one anterior and the other posterior. amphicoelous a. [Gr. amphi, on both sides; koilos, hollow] Being biconcave. amphicyrtic a. [Gr. amphi, on both sides; kyrtos, curved] Having both sides curved, said of angles between curves; biconvex. Maggenti and Gardner 50 amphid n. [Gr. amphi, on both sides] (NEMATA) One of a pair of lateral chemosensory organs opening on or near the lip region; variable in size and shape according to taxa. amphid aperture see amphidial aperture amphidelphic a. [Gr. amphi, on both sides; delphys, womb] (NEMATA) Pertaining to uteri opposed; position and direc- tion of the uteri, not the ovary. see didelphic. amphidetic a. [Gr. amphi, on both sides; detos, bound] (MOLL: Bivalvia) Refers to the ligament extending both before and behind the umbo or beak. see opisthodetic, parivincular. amphidial aperture (NEMATA) The amphid opening pore or orifice through which stimuli are received. amphidial duct (NEMATA) The passage connecting the am- phidial aperture and the amphidial pouch. amphidial gland (NEMATA) A gland originating posterior to the nerve ring that connects with the anterior lateral amphids. amphidial nerve (NEMATA) The nerve originating posterior to the nerve ring that extends anteriorly, connecting to the amphid. amphidial pouch or pocket (NEMATA) The anterior cavity or chamber of the amphid; a fovea. amphidial tubes (NEMATA) Passages containing the amphidial nerves connecting the fibrillar terminals and the sensilla. amphidiploid see allopolyploid, allotetraploid amphidiscs, amphidisks n.pl. [Gr. amphi, on both sides; diskos, round plate] (PORIF: Hexactinellida) Small spicules with hooks at both ends, grapnel shape; no six rayed spi- cules. amphigean, amphigaean a. [Gr. amphi, on both sides; gaia, the earth] Pertaining to both the Old and New Worlds. amphigenesis n. [Gr. amphi, on both sides; genesis, begin- ning] Development induced by the fusion of two unlike gametes; amphigony. amphigonic a. [Gr. amphi, on both sides; gonos, seed] Refer- ring to sperm and ova being produced in separate gonads in different individuals; biparental reproduction. see di- Online Dictionary of Invertebrate Zoology 53 amplexiform wing coupling (ARTHRO: Insecta) Lepidopterous wing coupling by virtue of an extensive area of overlap between the fore and hind wing. ampliate a. [L. ampliatus, made wider] To enlarge; to make greater. amplification n. [L. amplificare, to enlarge] An enlargement or extension; expanding a statement or description. anamorphosis n.; pl. -ses [Gr. ana, backwards; morphosis, forming] 1. A process of slow, steady evolution without ap- parent gross mutant variation. 2. (ARTHRO: Insecta) a. The increase of number of segments after hatching. b. Devel- opment in which the young gradually become more like the adult in body form after each ecdysis, as opposed to metamorphosis. anamorphic a. see ametabolous, meta- morphosis, epimorphosis. anandric a. [Gr. an, without; aner, man] (ANN: Oligochaeta) Designating earthworms without testes. anaphase n. [Gr. ana, up; phasis, appearance] The period of mitotic division in which the daughter chromosomes move toward opposite poles. anaphylaxis n. [Gr. ana, again; phylax, guard] A state of ex- cessive sensitivity to a serum or foreign protein that can result in a state of shock, that may develop with marked circulatory disturbances and possible death. anaphylactic a. anaplasis n. [Gr. ana, up; plassein, to form] Progressive onto- genetic development. anapleurite n. [Gr. ana, up; pleuron, side] (ARTHRO: Insecta) A dorsal sclerite of the thoracic pleural region. anapolysis n. [Gr. an, without; apo-, separate; lysis, loosen] (PLATY: Cestoda) The detachment of a spent proglottid af- ter it has shed its eggs. anapolytic a. see apolysis. anapterygote a. [Gr. an, not; a, without; pterygotos, winged] (ARTHRO: Insecta) Designates apterous insects that are de- rived from winged ancestors. anaptychus n. [Gr. an, without; apo-, away from; ptychos, fold] (MOLL: Cephalopoda) A shelly plate found in some fos- Maggenti and Gardner 54 sil cephalopods, thought to function as an operculum. see synaptychus. anarsenosomphic a. [Gr. an, without; arsen, male; somphos, porous] (ANN: Oligochaeta) Designates earthworms without male terminalia, such as parthenogenetic morphs, cephalic regenerates, or abnormal individuals. anarthrous a. [Gr. an, without; arthron, joint] Lacking a dis- tinct joint or joints. anascan n. [Gr. an, without; askos, sac] (BRYO: Gymnolae- mata) Cheilostomata in which the autozooids have a hydro- static system including the flexible part of the frontal wall, thus lacking an ascus. anastomosing colony (BRYO) A branching erect colony where branches join and rebranch to form an open network. anastomosis n.; pl. -ses [Gr. anastomosis, formation of a network] A union or joining between two or more struc- tures forming a network. anastral a. [Gr. an, without; aster, star] Lacking an aster, with reference to mitosis. anastrophic a. [Gr. ana, backwards; strephein, to turn] (MOLL: Gastropoda) In Prosobranchia, as in Architectonica , per- taining to a heterostrophic shell with the protoconch coiled about the same axis as the teloconch and the nucleus di- rected toward the base of the shell. anatomy n. [Gr. ana, again; temnein, to cut] The science of internal morphology, as revealed by dissection. see zo- otomy. anatoxin n. [Gr. ana, backwards; toxikon, poison] A toxin modified by heat or chemical treatment eliminating its toxic properties, but retaining its antigenic properties; toxoid. anatrepsis n. [Gr. anatrepein, to turn over] 1. Increase of movement during blastokinesis. 2. (ARTHRO: Insecta) In blastokinesis, a term used to describe the movement of the embryo inside the egg from one pole to another; refers to different activities in different groups of insects, i.e., ven- tral to dorsal, dorsal to ventral. see katatrepsis. anatriaene n. [Gr. ana, up; triaina, trident] (PORIF) A tetracti- Online Dictionary of Invertebrate Zoology 55 nal megasclere with three short recurved rays and a single long shaft. anautogeny a. [Gr. an, without; autos, self; genes, producing] (ARTHRO: Insecta) Refers to the necessity of a blood meal of certain Diptera before eggs can develop within the fe- male. see autogeny. anaxial a. [Gr. an, without; L. axis, axle] Lacking a distinct axis; asymmetrical. anaxon, anaxone n. [Gr. an, without; axon, axis] A nerve cell having no apparent axon. ancestral a. [L. antecedere, to go before] Referring to deriva- tion from an earlier form or ancestor; primitive. ancestrula n. [L. antecedere, to go before] (BRYO) The first formed colony founding zooid. a. In Stenolaemata and most Gymnolaemata, the zooid formed by metamorphosis of a sexually produced larva. b. In Phylactolaemata, the zooid formed from a statoblast. anchialine a. [Gr. anchi, near; hals, salt] Pertaining to land- locked pools or cave lakes that have subterranean connec- tions to the ocean. anchor n. [L. ancora, anchor] 1. (ARTHRO: Crustacea) In Cope- poda, enlarged first thoracic segment of an anchor worm. 2. (ARTHRO: Insecta) In Ephemeroptera, a distal fibrous knob of the egg, terminating an elongate adhesive thread coiled around the base. 3. (ECHINOD: Holothuroidea) An anchor-shaped ossicle or spicule of sea cucumbers. 4. (PLATY: Cestoda) In Monogenea, large curved hooks on the opisthaptor; hamuli. anchorate a. [L. anchora, anchor] (PORIF) Pertaining to a chela with four clads at each end. anchor process (ARTHRO: Insecta) An anterior process of some dipterous larvae; sternal spatula. see breastbone. anchylosis see ankylosis anci see anko ancipital a. [L. anceps, double-headed] 1. Having two opposite edges or angles. 2. (MOLL) A two-edged, double-faced, double-formed shell having two varices that are continu- Maggenti and Gardner 58 anepisternum n. [Gr. ana, up; epi, upon; sternon, breast- bone] (ARTHRO: Insecta) The upper division of the epister- num. see infraepisternum. aner n. [Gr. aner, male] (ARTHRO: Insecta) Male, especially in Formicidae. anestrus, anoestrus n. [Gr. an, without; oistros, desire] A period of sexual inactivity; a non-breeding period. aneucentric translocation One that involves the centromere of a chromosome; one daughter chromosome is acentric and the other dicentric. aneuploid a. [Gr. an, without; eu, well; aploos, onefold] Re- fers to cells or individuals having one, two or a few whole chromosomes, more or less than the basic number of the species in question. see heteroploid, euploid. aneuronic a. [Gr. an, without; neuron, nerve] Absence of in- nervation. aneurose a. [Gr. an, without; neuron, nerve] 1. Without nerves. 2. (ARTHRO: Insecta) Term used for a wing with veins near the costa only. anfractuose a. [L. anfractus, circuitous] Wavy, winding, turn- ings, sinuous. angiogenesis n. [Gr. angeion, vessel; genesis, beginning] The development of blood vessels. angiostomatous a. [Gr. angeion, vessel; stoma, mouth] Hav- ing a non-distensible mouth. angstrom n. [after A. J. Angstrom] One hundred-millionth of a centimeter, or one-tenth of a nanometer (nm); a unit used in measuring the length of light waves. angulate a. [L. angulare, to make angular] Having angles or sharp corners. angulation n. [L. angulus, angular] An angular formation or edge where two surfaces meet at an angle. anguli frontales (ARTHRO: Insecta) In immatures, the anterior projections from the frons situated laterad to a median projection, the nasale; may or may not be symmetrical. angustate antenna (ARTHRO: Insecta) An antenna in which Online Dictionary of Invertebrate Zoology 59 the intermediate and terminal joints are thinner. angusticorn trumpet (ARTHRO: Insecta) In Diptera, a respi- ratory structure of Culicidae pupae bearing the longest axis vertically and approximately in line with the stem, funnel- shaped when closed, with a split (meatal cleft) down one side allowing it to open widely at the water surface. angustirostrate a. [L. angustus, narrow; rostrum, beak] Having a narrow rostrum or snout. see latirostrate. anholocyclic a. [Gr. an, without; holos, whole; kyklos, circle] Having only parthenogenetic reproduction. see holocyclic. anhydrobiosis n. [Gr. an, without; hydor, water; biosis, man- ner of life] A state of dormancy in various invertebrates due to low humidity or desiccation. anhydrous a. [Gr. an, without; hydor, water] Being without water; completely lacking in water. animal n. [L. animalis, a living being] Any member of a group of living organisms distinguished from plants by a definite body form, absence of rigid cell walls of cellulose, locomo- tion responses to external stimuli, and inability to manu- facture foods from inorganic substances. Animalia n. [L. animalis, a living being] A kingdom of organ- isms that contains the animals. animal starch see glycogen anion n. [Gr. ana, up; ienai, to go] Any ion bearing a negative charge. see cation. anisochela n. [Gr. anisos, unequal; chele, claw] 1. (ARTHRO) A chela with two unlike parts. 2. (PORIF) A diactinal micro- sclere with unlike, recurved hooks, plates or flukes at each end. see isochela. anisocytic a. [Gr. anisos, unequal; kytos, container] Having cells in the intestinal epithelium unequal in height in a given cross section. anisogametes n.pl. [Gr. anisos, unequal; gametes, spouse] Outwardly dissimilar male and female gametes; het- erogamete. anisogamy n. [Gr. anisos, unequal; gamos, marriage] Gam- etes when fusing during fertilization vary in size, shape and Maggenti and Gardner 60 behavior. see heterogamy. anisoglottid a. [Gr. anisos, unequal; glottis, mouth of the windpipe] (NEMATA: Secernentea) Having a glottoid appa- ratus with metarhabdions at different levels. see isoglot- tid. anisognathous a. [Gr. anisos, unequal; gnathos, jaw] Bearing unequal jaws. anisomorpha n. [Gr. anisos, unequal; morphe, form] (AR- THRO: Insecta) Insects whose metamorphosis differ in vari- ous ways. anisomorphic a. [Gr. anisos, unequal; morphe, form] Varying in form, size or structure. see isomorphic. anisomyarian a. [Gr. anisos, unequal; myos, muscle] 1. Hav- ing unequal muscles. 2. (MOLL: Bivalvia) Having the ante- rior adductor muscle reduced or absent. see mon- omyarian. anisotropic a. [Gr. anisos, unequal; tropein, to turn] Doubly refracting, such as dark bands in the sarcomere of a mus- cle fiber. see isotropic. ankistroid see ancistroid ankylosis, anchylosis n. [Gr. angcheein, to press tight] 1. The union or fusion of parts into one structure. 2. A stiff- ness or immobility of a joint. anlage n.; pl. -en, -es [Ger. anlage, predisposition] A primor- dium or cell group that constitutes identification of a part or organ. see blastema. annectent a. [L. annectere, to bind together] Linking; an in- termediate; connecting together. annelet n. [L. dim. annellus, little ring] (ARTHRO: Insecta) In Hymenoptera, a small ring-joint between the basal scape and the funicule of the antenna. Annelida, annelids n.; n.pl. [L. annulus, ring; Gr. eidos, form] A phylum of segmented or cylindrical ringed worms, en- compassing the Polychaeta, mainly free-living and marine, the Oligochaeta, mainly free-living, either terrestrial (earthworms), fresh water, or marine, and the Hirudinoidea or leeches, that are ectoparasitic, fresh water, marine, or Online Dictionary of Invertebrate Zoology 63 anoxybiont n. [Gr. an, without; oxys, sharp; bios, life] An or- ganism incapable of using oxygen as opposed to one that is aerobic. ansa n. [L. ansa, handle] A loop or loop-like structure. ansiform a. [L. ansa, handle; forma, shape] Looped, or loop- like in shape. antafossa see antennal fossa antagonism n. [Gr. antagonistes, competitor] 1. Inhibition or interference in growth of an organism due to unfavorable conditions created by the presence of another species. 2. Opposing action by two different muscles or structures. 3. Neutralizing ability of one drug or hormone upon another; chalone. antagonistic symbiosis A symbiotic association in which one symbiont seeks to establish domination over the other. see parasitism. anteal a. [L. ante, before] Being in front or forward. antealar a. [L. ante, before; ala, wing] (ARTHRO: Insecta) Pertaining to being positioned anterior to the front wing. antealar sinus (ARTHRO: Insecta) In Odonata, the transverse grooved area in front of the base of the front wings. anteapical a. [L. ante, before; apex, summit] Proximal of the apex. anteapical cell (ARTHRO: Insecta) A cell in the distal part of the wing. anteclypeus n. [L. ante, before; clypeus, shield] (ARTHRO: In- secta) The anterior division of the clypeus when differenti- ated from the postclypeus by a sulcus or suture. see clypeus. antecosta n. [L. ante, before; costa, rib] (ARTHRO: Insecta) The anterior marginal or submarginal interior tergal or sternal plate, on which the longitudinal muscles are at- tached. antecostal sulcus/suture (ARTHRO: Insecta) The groove of the intersegmental sclerite that marks the base of the an- tecosta. Maggenti and Gardner 64 antecoxal piece (ARTHRO: Insecta) An inner sclerite between the trochantin and the episternum; the lateral sclerites of the clypeus. antecoxal sclerite (ARTHRO: Insecta) A part of the metaster- num just anterior to the hind coxae. antecubital see antenodal cross veins antecurrent see prosocline antefrons n.pl. [L. ante, before; frons, forehead] (ARTHRO: In- secta) Frons situated anterior to the antennal base lines. antefurca n.; pl. -furcae [L. ante, before; furca, fork] (AR- THRO: Insecta) The internal chitinous forked process pro- jecting into the thoracic cavity from the anterior thoracic segment. antehumeral a. [L. ante, before; humerus, shoulder] (AR- THRO: Insecta) Designating the area immediately anterior to the basal portion of the wing. antelabrum n. [L. ante, before; labrum, lip] (ARTHRO: Insecta) The anterior part of the labrum when differentiated. antemarginal process (ARTHRO: Insecta) In Scarabaeoidea, a process distad of the lateroproximal marginal region of the phallobase. ante mortem a. [L. ante, before; mors, death] Before death. see post-mortem. antenna n.; pl. -nae [L. antenna, feeler] 1. Analogous, un- segmented structures in mollusks, polychaete worms and rotifers. 2. (ARTHRO) A movable sensory appendage of various arthropods; usually segmented and located on the head above the mouth parts; most arthropods bear anten- nae, although some are greatly reduced; missing in all arachnids. 3. (ARTHRO: Crustacea) The second antennae proper; the second pair of appendages posterior to anten- nules; primarily sensory in function, but often adapted for other functions; derived from appendages on primitive third preoral somite; postantennal appendages; no ho- mologous appendage in insects. see antennua, anten- nule. antennal appendage (ARTHRO: Insecta) In Anoplura, protu- Online Dictionary of Invertebrate Zoology 65 berance on the first or third antennal segment of male bit- ing lice. antennal carina (ARTHRO: Crustacea) A prominent ridge ex- tending posteriorly from a decapod antennal spine. antennal club (ARTHRO: Insecta) The enlarged distal segment of a clubbed antenna. antennal fossa (ARTHRO: Insecta) A cavity or depression in which the antenna is located; antennal groove; antafossa. antennal fovea see antennal groove antennal gland 1. (ARTHRO: Crustacea) In Malacostraca, a complex excretory gland with ducts opening on the second antenna; green gland. 2. (ARTHRO: Insecta) One of a pair of glands that open on the antenna. antennal groove (ARTHRO) A groove or depression in the head of many arthropods, extending posteriorly from the basal segment of the antenna. antennal lobes see deutocerebrum antennal muscle scar (ARTHRO: Crustacea) In Ostracoda, an impression of the antennal muscle on the inner surface of a valve, situated in front of the adductor muscle scar, usually above the mandibular scar. antennal organs (ARTHRO: Insecta) In Collembola, sensory structures of springtails situated on the distal segment of the antenna. antennal region (ARTHRO: Crustacea) In Decapoda, the ante- rior marginal part bordering orbital region laterally, adjoin- ing hepatic, pterygostomial, and occasionally also the frontal regions of the carapace. antennal scale see scaphocerite antennal sclerite (ARTHRO: Insecta) The sclerotic rim of the basal antennal socket. see annulus antennalis. antennal segment (ARTHRO) That segment of an arthropod head from which the antennae arise, usually second seg- ment; deuterocerebral segment. antennal spine (ARTHRO: Crustacea) A decapod spine situated on the anterior margin of the carapace, slightly below the Maggenti and Gardner 68 anterior keel (MOLL) The high point of the whorl next to the suture at the lower edge of the shell nearest to the anterior end. anterior lateral tooth (MOLL: Bivalvia) A lateral tooth in front of the beak. anterior promontory (ARTHRO: Insecta) In Diptera, the me- dian area of the mesonotum, at the anterior end of the acrostichal area. anterior setae see ventral setae anterior stigmatal tubercle (ARTHRO: Insecta) Prominence on the thoracic and abdominal segments of caterpillars. anterior tentorial arms (ARTHRO: Insecta) An apodeme aris- ing from the anterior tentorial pits, meeting the posterior tentorial arm at a visible fusion point; sometimes bearing a small dorsal or ventral tentorial arm. anterior tentorial pits (ARTHRO: Insecta) External depressions in the epistomal suture marking the base of the anterior tentorial arm(s). anterior tubercle (ARTHRO: Crustacea) A swelling or small projection in the anterior region of the carapace of ar- chaeostracans; polygenetic, sometimes including the optic tubercle. anterobiprostatic a. [L. antero, anterior; bis, twice; Gr. pro- histanai, to set before] (ANN: Oligochaeta) Pertaining to the male terminalia of parthenogenetic earthworm morphs in which the posterior prostates of an acanthodrilin set are absent. anterodorsal a. [L. antero, anterior; dorsum, back] Toward the front and the top or upper side. anterolateral region (ARTHRO: Crustacea) The lateral part of the carapace bordering the subhepatic or hepatic regions. anteromesal a. [L. antero, anterior; mesos, middle] In the front and along the midline of a body. anteroposterior axis The longitudinal axis, from head to tail. anteroventral a. [L. antero, anterior; venter, belly] In the front on the lower side. Online Dictionary of Invertebrate Zoology 69 antesternite n. [L. ante, before; Gr. sternon, breastbone] (AR- THRO: Insecta) The anterior ventral plate or spicule; basis- ternum; eusternum. anthelmintic, anthelminthic a. [Gr. anti, against; helmins, worm] Pertaining to therapeutic agents used against intes- tinal helminths causing death or expulsion. see vermicide, vermifuge. anthobian n. [Gr. anthos, flowers; bios, life] Feeding on flow- ers. anthoblast n. [Gr. anthos, flower; blastos, bud] (CNID: Antho- zoa) In stony corals, a young sessile polyp producing an anthocyathus. anthocaulus n. [Gr. anthos, flower; kaulos, stalk] (CNID: An- thozoa) The stalk of a solitary coral after the separation of the disklike anthocyathus. anthocodium n.; pl. -ia [Gr. anthos, flower; kodeia, head] (CNID: Anthozoa) The distal end of an alcyonarian coral; the upper tentacular part of the polyp that can be retracted into the calyx. anthocyanins n.pl. [Gr. anthos, flower; kyanos, blue] Impor- tant plant pigments (flavones) that may contribute to the blue or red coloration of insects. see anthoxanthins. anthocyathus n.; pl. -ia [Gr. anthos, flower; kyathos, cup] (CNID: Anthozoa) The disklike crown portion of solitary cor- als that separates from the stalk (anthocaulus). anthogenesis n. [Gr. anthos, flower; genesis, beginning] The production of both males and females by parthenogenesis. anthophilous a. [Gr. anthos, flower; philein, to love] Desig- nating attraction to or feeding on flowers; anthobian. anthostele n. [Gr. anthos, flower; stele, column] (CNID: An- thozoa) The stiff proximal part of certain stoloniferan pol- yps into which the tentacular portion is retracted. anthoxanthins n.pl. [Gr. anthos, flower; xanthos, yellow] Plant pigments (flavones) responsible for the ivory to yel- low color of some true bugs and Lepidoptera. see antho- cyanins. Anthozoa, anthozoans n.; n.pl. [Gr. anthos, flower; zoon, Maggenti and Gardner 70 animal] Any coelenterate of the class Anthozoa, phylum Cnidaria, including the sea anemones and corals. anthracene, anthracine n. [Gr. anthrax, coal] Coal black; shiny black with a bluish tint. anthraquinones n.pl. (ARTHRO: Insecta) A group of orange or red pigments found in certain insects. anthropochorous a. [Gr. anthropos, man; chorein, to spread] Refers to any disease or organism transported by man, usually unintentionally; peregrine. anthropogenic a. [Gr. anthropos, man; genes, producing] Caused by, or resulting from, the influence of man. anthropomorphic a. [Gr. anthropos, man; morphe, form] At- tributing human attributes to animals. anthropophilous a. [Gr. anthropos, man; philein, to love] Used to describe insects that prefer human blood. anthropozoic a. [Gr. anthropos, man; zoe, life] Designating that period of time since man appeared upon the earth. anthropozoonosis n. [Gr. anthropos, man; zoon, animal; nosos, disease] A disease of humans transmissible to other animals. see zooanthroponosis, zoonosis. antiaposematic a. [Gr. anti, against; apo, away; sema, sig- nal] Referring to coloration that disguises a predator. see parasematic, aposematic. antibiosis n. [Gr. anti, against; biosis, manner of life] An asso- ciation between two organisms in which one secretes a substance destroying or inhibiting the other. anticlinal a. [Gr. anti, against; klinein, to bend] Radial; inclin- ing in opposite directions; at right angles to the surface of a part. anticlypeus see anteclypeus anticoagulant a. [Gr. anti, against; L. coagulare, to curdle] Pertaining to any substance that prevents or delays the co- agulation of blood. anticoagulin n. [Gr. anti, against; L. coagulare, to curdle] (ARTHRO) The secretion of certain parasitic species that prevents or delays the coagulation of the host's blood. Online Dictionary of Invertebrate Zoology 73 sinus. anucleate a. [Gr. an, without; L. nucleus, kernel] Lacking a nucleus. anural a. [Gr. an, without; oura, tail] Lacking a tail. anuria n. [Gr. an, without; ouron, urine] Absence of or inability to excrete urine. anus n. [L. anus] The terminal orifice of the alimentary canal, through which unabsorbed food and waste products are voided; in some groups it is associated with the cloaca. see uropore. aorta n. [Gr. aorte, the great artery] The main vessel carrying blood from the heart; the dorsal blood vessel. aortal chamber The thoracic expansion of the aorta. aortic valve The closure mechanism of the dorsal vessel, separating the aorta and the heart proper. apatetic color Those colors that enable an organism to mimic either its environment or another species. apertum n. [L. aperire, to open] (ARTHRO: Insecta) In Coleop- tera, a basal cell opening on the hind wing. apertural a. [L. aperire, to open] Pertaining to or on the same side as the aperture. apertural muscle (BRYO: Gymnolaemata) One of either two pairs of muscles of cheilostomate autozooids, the occlusor muscle of the operculum or the diaphragmatic dilator mus- cle. aperture n. [L. aperire, to open] 1. An opening or hole, cleft, or gap. 2. (ARTHRO: Crustacea) The postero-ventral open- ing into the mantle cavity of barnacles. see orifice. 3. (BRYO: Stenolaemata) The terminal skeletal opening of a zooid. 4. (MOLL) An opening at the last-formed margin of a shell, providing the outlet for the head-foot mass. apex n.; pl. apexes, apices [L. apex, tip] 1. That portion of any structure opposite the base of attachment; the tip. 2. (ARTHRO: Crustacea) The upper angle of the scutum or ter- gum of certain barnacles. 3. (ARTHRO: Insecta) Wing tip. 4. (MOLL) a. In Polyplacophora, the beak or umbo of a valve. b. In Gastropoda, the first-formed end of a shell. Maggenti and Gardner 74 aphagia n. [Gr. a, not; phagein, to eat] Unable to ingest. apharyngeate cercariae (PLATY: Trematoda) Larvae that de- velop in daughter sporocysts in pulmonate or prosobranch snails. Aphasmidia see Adenophorea aphelenchoid bursa see bursa aphideine see aphidilutein aphidicolous a. [NL. aphis, plant-louse; L. colere, to dwell] (ARTHRO) Pertaining to associating with aphid colonies, as certain ants. aphidilutein n. [NL. aphis, plant-louse; L. luteus, yellow] The yellowish liquid found in plant lice. see aphins. aphidivorous a. [NL. aphis, plant-louse; L. vorare, to devour] Feeding on aphids. aphins n.pl. [NL. aphis, plant-louse] Fat soluble pigments de- rived from various aphids that impart a purple or black color to the whole insect. aphodus n.; pl. aphodi [Gr. aphodos, departure] (PORIF: Desmospongiae) The short channel connecting the flagel- lated chamber with the excurrent canal. see prosodus. aphorism n. [Gr. aphorizein, to define] The concise definition of a principle. aphotic zone That zone of ocean water that lies below 800 meters and which receives little or no light. aphototropic a. [Gr. an, without; phos, light; tropein, to turn] Turning away from light. aphrodisiac pheromone (ARTHRO: Insecta) A pheromone that facilitates copulation. aphytal zone Those waters in which the penetration of light is too poor to support photosynthesis. apian a. [L. apianus, of bees] Of or pertaining to bees. apiary n.; pl. -ies [L. apiarium, beehive] The area where bees are kept; a collection of hives maintained for honey pro- duction. apicad adv. [L. apex, tip; ad, toward] Toward the apex. Online Dictionary of Invertebrate Zoology 75 apical a. [L. apex, tip] Refers to the apex or top, as of a coni- cal or spherical structure. apical angle 1. (ARTHRO: Insecta) The angle of a wing at its apex. 2. (MOLL: Gastropoda) In a plane through the axis, that angle subtended between two straight lines that touch adjacent whorls on opposite sides near the apex; identical with the spire angle if whorls increase at a regular rate. apical area 1. (ARTHRO: Insecta) see petiole. 2. (MOLL: Poly- placophora) The short part of the periostracum and teg- mentum on the head and intermediate valves that is adja- cent to the posterior dorsal edge of a valve and which ex- tends over the edge and onto the ventral side. apical carina (ARTHRO: Insecta) In ichneumonid Hymenoptera, the posterior transverse carina. apical cell 1. A cell situated at the apex of a structure distin- guished by location, shape, size and function. 2. (ARTHRO: Insecta) Apical testicular cell of Orthoptera, Dictyoptera, Diptera and Homoptera, and some Lepidoptera, that sup- plies mitochondria to the spermatogonial cytoplasm during spermatogenesis; Verson's cell; Versonian cell. 3. (NEMATA) An epithelial cell that forms the gonoduct wall. apical chamber (ARTHRO: Insecta) Pertaining to the germar- ium in the acrotrophic egg tubes. apical cross vein (ARTHRO: Insecta) A cross vein near the apex of the wing. apical field (ROTIF) The central anterior unciliated area of the corona. apicalia n. [L. apex, tip] (GNATHO) Paired sensory cilia on the head. apical lip notches (NEMATA) Indented lip margins at the junc- tion of the lips. apical margin (ARTHRO: Insecta) The outer margin of the wing. see costal margin, anal margin. apical organ A sensory organ located at the apex of tro- chophore larvae and some cestodes. apical orifice (MOLL) An opening at the top or apex of a shell. apical plate An external sensory organ of a primitive nervous Maggenti and Gardner 78 apogamete n. [Gr. apo, away; gamete, spouse] A gamete formed by apomixis. apogamy see apomixis apolar a. [Gr. an, without; polos, pivot pole] Lacking a pole; without radiating processes. apolegamic a. [Gr. apolegein, to choose; gamos, marriage] Pertaining to sexual selection. apolysis n. [Gr. apo, away; lysis, loosen] 1. (ARTHRO) The first process of molting, characterized by the detachment of the old cuticle from the underlying hypodermal (epidermal) cells. see ecdysis. 2. (PLATY: Cestoda) The detachment of a gravid proglottid in tapeworms. apolytic a. see an- apolysis. apomict n. [Gr. apo, away; miktos, mixed] Any organism pro- duced by apomixis. apomictic (ameiotic) parthenogenesis No reduction division occurs, so that the offspring have the same genetic con- stitution as the mother and all are female. apomixis n. [Gr. apo, away; mixis, mixing] Botanical term sometimes used in invertebrates. see parthenogenesis. apomorph n. [Gr. apo, away; morphe, form] A derived char- acter. apomorphy n. [Gr. apo, away; morphe, form] A term pertain- ing to derived characters, normally used in cladistic taxon- omy. apomorphic a. see plesiomorphy. apophysary see apophysis apophysis n.; pl. -ses [Gr. apo, away; phyein, to grow] 1. An internal or external tubercular or elongate process of the body wall; a prominence, swelling or expansion. see apo- deme, apodome. 2. (ARTHRO: Insecta) see pleural apophysis, sternal apophyses. 3. (MOLL) a. In Bivalvia, a large, styloid projection, one in each valve, extending from beneath the umbos to which the foot muscles are at- tached. b. In Polyplacophora, see sutural laminae. apophystegal plates (ARTHRO: Insecta) In Orthroptera, plate- or blade-like sclerites covering the gonapophyses. apopore n. [Gr. apo, away; poros, passage] (PORIF) An aper- Online Dictionary of Invertebrate Zoology 79 ture forming an exit from the apochete; may be equivalent to an oscule. apopyle n. [Gr. apo, away; pyle, gate] (PORIF) An exhalent aperture from a choanocyte chamber. aporrhysa n.pl. [Gr. aporrhyein, to flow away] (PORIF) The ex- halent canals. see epirrhysa. aposematic a. [Gr. apo, away; sema, signal] Warning colora- tion or structures that repel predators, also including movements, sounds, smells, etc. see allosematic color, sematic. aposeme n. [Gr. apo, away; sema, signal] A population in which all the individuals, even though taxonomically dis- tinct, share the same aposematic coloration. apostatic a. [Gr. apostates, deserter] Widely departing from the norm; said of a phenotype that differs strikingly from the search image of a predator. a posteriori weighting The weighting of taxonomic characters on the basis of their proved contribution to the establish- ment of sound classifications. see a priori weighting. aposymbiotic a. [Gr. apo, away; syn, together; bios, life] Re- ferring to an organism separated from its symbiotes; sym- biote-free; usually refers to mutualistic symbiotes. see mutualism. apotele n. [Gr. apo, away; telos, end] (ARTHRO: Chelicerata) The terminal eudesmatic segment of the appendages of mites, generally constituting two tendons and two articula- tion-points. apotelic a. see pretarsus. apotome n. [Gr. apo, away; tomos, a cut] A part or subdivi- sion appearing as if separated from the whole. apotorma n.; pl. -mae [Gr. apo, away; tormos, socket] (AR- THRO: Insecta) In Scarabaeoidea larvae, a process that extends forward from the torma between the pternotorma and the interior end of the torma. apotype see hypotype apotypic a. [Gr. apo, away; typos, type] Varying from a type. apparatus n.; pl. -ratus, -ratuses [L. apparatus, equipment] Any group of structures or parts that unite together in a Maggenti and Gardner 80 common function. apparition n. [L. appareo, manifest] Something appearing. appeasement behavior That which follows after the attack of one animal on another of the same species with the loser assuming a submissive attitude. appeasement substance The secretion by a social parasite of attractive substances that reduce aggression in a host in- sect and aid the parasite's acceptance by the host colony. appendage n. [L. ad, to; pendere, to hang] A structure at- tached or appended to a larger structure, as parts or or- gans that are attached to the body of various inverte- brates. appendicle n. [L. ad, to; pendere, to hang] A small appendage or appendix. appendicular a. appendiculate a. [L. ad, to; pendere, to hang] Bearing or forming small appendages. appendiculate cell (ARTHRO: Insecta) In Hymenoptera, a small cell just beyond the apex of the marginal cell of the wing. appendicule n. [L. ad, to; pendere, to hang] (NEMATA) A large, single, ventral, extensible preanal supplementary male or- gan. appendiculum n. [L. appendicula, small appendage] (CNID: Scyphozoa) The remainder of the partial veil on the pileus rim of jellyfish. appendifer n. [L. ad, to; pendere, to hang; ferre, to carry] (ARTHRO: Trilobita) A ventral projection for the attachment of thoracic muscles. appendix n.; pl. -dixes, -dices [L. ad, to; pendere, to hang] Any supplementary or additional piece or part appended to a regular structure. appendix interna (ARTHRO: Crustacea) In Malacostraca, the median process of the pleopodal endopod uniting members of each pair; stylamblys. appendix masculina (ARTHRO: Crustacea) In Isopoda, the modified second (sometimes first also) pleopod(s) in the form of a long, often grooved, rodlike organ that functions Online Dictionary of Invertebrate Zoology 83 arachnidium n. [Gr. arachne, spider] (ARTHRO: Chelicerata) The spinning apparatus of spiders, consisting of the spin- ning glands and their ducts and the spinnerets. arachnid- ial a. arachnism n. [Gr. arachne, spider; ismos, denoting condition] (ARTHRO: Chelicerata) Poisoning, or poisoned condition due to envenomation by a spider. see arachnidism. arachnoid, arachnoideal a. [Gr. arachne, spider; eidos, form] (ARTHRO: Chelicerata) 1. Resembling a member of the Arachnida. 2. Resembling a spider's web, thin and fine, filmy. arachnologist n. [Gr. arachne, spider; logos, discourse] One who studies the arachnids. aragonite n. [fr. Aragon, in Spain] 1. A calcium carbonate, di- morphous with calcite. 2. The innermost layer of a shell. 3. (CNID: Anthozoa) The skeleton of coral, produced by the calicoblastic epithelium. arakoderan a. [Gr. arake, bowl; deros, skin] (NEMATA: Se- cernentea) Pertaining to a caudal ala that completely sur- rounds the cloacal area. see leptoderan; peloderan. araneiform a. [L. aranea, spider; forma, form] Spiderlike in appearance. araneology n. [L. aranea, spider; Gr. logos, discourse] That branch of zoology that treats only of spiders. arboreal a. [L. arbor, tree] Pertaining to or living in or among trees. arborescent a. [L. arbor, tree] Tree-like in character or ap- pearance; branching like a tree, as some species of mol- lusks and corals. arborizations n.pl. [L. arbor, tree] A tree-like branching of terminal fibers of axons or collaterals. arbovirus n. Any of a group of (ar)thropod-(bo)rne (virus)es, including the causative agents of yellow fever, viral en- cephalitis and certain febrile infections, that are transmit- ted to man by various mosquitoes and ticks. arc n. [L. arcus, bow] Any object having a bowlike curvature. arcade n. [L. arcus, arch] (NEMATA: Secernentea) Lateral col- Maggenti and Gardner 84 lecting tubules of the excretory system of Ascaris. arcade cells (NEMATA) The nine anteriormost cells that are be- lieved to form the lips, two opposite each esophageal lu- men radius and one opposite each sector. archaeocytes n.pl. [Gr. arche, beginning; kytos, container] 1. (PORIF) Large, wandering amoebocytes with multiple phagosomes in the mesenchyme; nurse cells; trophocytes. 2. A totipotent amoeboid cell. archaestomatous a. [Gr. arche, beginning; stoma, mouth] (ANN) Describing a group, Archaeostomata of former clas- sifications, with a mouth derived directly from the blas- topore of the embryo. archebiosis n. [Gr. arche, beginning; biosis, manner of life] Abiogenesis. archecentric a. [Gr. arche, beginning; kentron, center] Desig- nating or pertaining to an original type. see apocentric. archedictyon n. [Gr. arche, beginning; diktyon, net] (ARTHRO: Insecta) The irregular network of cuticular ridges on the wings of many fossils. archegenesis n. [Gr. arche, beginning; genesis, beginning] Abiogenesis. archencephalon see archicerebrum archenteric pouch One of the paired, segmented, dorsoven- tral prominances of the archenteron from which the meso- derm derives. archenteron n. [Gr. arche, beginning; enteron, intestine] The primitive digestive cavity of many invertebrates, formed by gastrulation; the gastrocoele; precursor to the gut. archeocyte see archaeocytes archetype, architype n. [Gr. arche, beginning; typos, type] A hypothetical ancestral type arrived at by the elimination of specialized characters of known later forms. see phylog- eny. Archiacanthocephala n. [Gr. arche, beginning; akantha, thorn; kephale, head] A class of Acanthocephala that are parasites of predacious birds and mammals; insects and myriapods are the intermediate hosts. Online Dictionary of Invertebrate Zoology 85 archibenthic a. [Gr. arche, beginning; benthos, depths of sea] Refers to the continental deep-sea zone, extending from the edge of the continental shelf (200-400 m.) to depths of about 800-1100 m. see abyssal. archicephalon n. [Gr. arche, beginning; kephale, head] The primitive annelid-arthropod head; the prostomium. archicerebrum n.; pl. -bra [Gr. arche, beginning; L. cere- brum, brain] 1. (ANN) The ganglionic nerve mass of a prostomium. 2. (ARTHRO) The primitive suprastomodeal nerve mass of a prostomium; the primitive brain. archidictyon see archedictyon archigastrula n. [Gr. arche, beginning; gaster, stomach] A type of gastrula in which the endoderm is produced by in- vagination; emboly. archigenesis see abiogenesis archinephridium n. [Gr. arche, beginning; nephros, kidney] An excretory organ of many invertebrate larvae; a soleno- cyte. archiplasm n. [Gr. arche, beginning; plasma, formed or molded] A former name for the substance of the spindle fi- bers and astral rays; was thought to exist during the entire cell cycle, but to only become visible after aggregation at mitosis. Archiptera see Pseudoneuroptera architomy n. [Gr. arche, beginning; tome, cut] (ANN) Desig- nating reproduction by fission, with regeneration after separation of heads and/or tails. see paratomy. architype see archetype archoophorans n.pl. [Gr. arche, beginning; pherein, to carry] (PLATY: Turbellaria) 1. Individuals with modified cleavage in which yolk is stored in the oocytes; entolecithal eggs. see neophorans. 2. Archoophora A former division of the Tubellaria; a superorder. arciform a. [L. arcus, bow; forma, shape] Being arcuate; shaped like a bow or arch. arctic a. [Gr. arktos, bear] 1. Pertaining to the region of the North Pole within the Arctic Circle. 2. Pertaining to the high Maggenti and Gardner 88 shell. arm n. [A.S. arm, forelimb] 1. Anything resembling or corre- sponding to an arm. 2. (ECHINOD) a. In Asteroidea, the ra- dial extension of the body surrounding the axis; the ambu- lacra. b. In Crinoidea, the radial evagination of the body extending from the theca; undivided distal branches. 3. (ECHI) The forked section of the proboscis. 4. (MOLL: Cephalopoda) a. In squids and cuttlefish, eight of the ten short and heavy appendages around the head, the other two larger dorsal appendages being tentacles. b. The ten- tacles of an octopod. armate cercaria (PLATY: Trematoda) A larva of the xiphidio- cercariae group with oral and ventral suckers unequal, without a virgula organ and with a Y-shaped excretory bladder. armature n. [L. armare, to arm] Defensive or protective structures of invertebrates, such as spinous or chitinous processes in the form of hooks, horns, teeth, spines and claws on various parts of the body. armilla n.; pl. -lae [L. armilla, bracelet] Bearing a bracelet-like ring or annulus. armillate a. arolium n.; pl. -ia [Gr. arole, protection] (ARTHRO: Insecta) A medium lobe or pad-like cushion of the foot. a. Between the claws of Orthoptera. b. The base of each tarsal claw of Hemiptera. c. Between the tarsal claws and comprising part of the pretarsus of Hymenoptera. see pseudarolium. aromorphosis n.; pl. -ses [Gr. airein, to raise; morphosis, shaping] An advancement in organization of an organism, without a marked increase in specialization; an aromorph. see allomorphosis. arrhenogeny n. [Gr. arrhen, male; genos, offspring] The con- dition of producing only male offspring. see monogeny, thelygeny. arrhenoidy n. [Gr. arrhen, male; eidos, form] (NEMATA: Se- cernentea) Sex reversal from female to male; recognized by males having two testes, instead of one. arrhenoid a. arrhenoplasm n. [Gr. arrhen, male; plasma, formed or molded] The male element of idioplasm. Online Dictionary of Invertebrate Zoology 89 arrhenotoky n. [Gr. arrhen, male; tokos, birth] The haplodip- loid parthenogenesis in which males arise from unfertilized, haploid egg cells. see thelyotoky. arsenosomphic a. [Gr. arsen, male; somphos, porous] (ANN: Oligochaeta) Pertaining to earthworms with male termina- lia. artatendon n. [L. artus, joint; tendere, to stretch] (ARTHRO: Insecta) The tendon articulating the post-tarsus. artefact see artifact artenkreis see superspecies arterial a. [L. arteria, artery] Pertaining to an artery. arteriole n. [L. dim. arteria, artery] A small artery. artery n. [L. arteria, artery] A vessel conveying blood from the heart to the tissues. arthral a. [Gr. arthron, joint] Pertaining to a joint. arthrium n. [Gr. arthron, joint] (ARTHRO: Insecta) In Coleop- tera, minute tarsal joints, trimera (3 tarsal joints) and tetramera (4 tarsal joints). arthrobranchia n.; pl. -iae [Gr. arthron, joint; branchia, gills] (ARTHRO: Crustacea) In Decapoda, a gill attached to the articulating membrane between the appendage and body; arthrobranchiata. arthroderm n. [Gr. arthron, joint; derma, skin] (ARTHRO) The outer covering of skin, or the outer body-wall. arthrodial membrane (ARTHRO) Articular membranes that permits unrestricted motion; flexible joints. arthromere n. [Gr. arthron, joint; meros, part] (ARTHRO) A segment, somite or metamere. arthrophragm see endophragm arthropleure n. [Gr. arthron, joint; pleura, side] (ARTHRO) That portion of the body that bears the limbs. Arthropoda, arthropod n. [Gr. arthron, joint; pous, foot] A phylum of invertebrates that contains the chitinous seg- mented, exoskeletoned, jointed-legged animals, such as centipedes, millipedes, insects, crustaceans, spiders, scor- pions, and many other less well-known types. Maggenti and Gardner 90 arthropodin n. [Gr. arthron, joint; pous, foot] (ARTHRO) A protein constituent part of the chitinoproteinic structures. arthropodization n. [Gr. arthron, joint; pous, foot] (ARTHRO) Evolutionary development of the combination of character- istics associated with arthropods, including the chitinous exoskeleton. arthrostracous a. [Gr. arthron, joint; ostrakon, shell] (AR- THRO: Crustacea) Having the thorax and abdomen seg- mented, and bearing seven pairs of thoracic legs. article n. [L. dim. artus, joint] 1. A distinct segment or jointed part or structure. 2. (ARTHRO) a. In Chelicerata, the ser- rated process on the chelicera of a tick. b. In Crustacea, a subdivision of the antennal or antennular flagella or ap- pendage. c. In Insecta, a segment of a leg. see segbment. articulamentum n. [L. articulare, to divide] (MOLL: Polypla- cophora) The shell layer between the tegmentum and hy- postracum, that is composed of several separate compo- nents of crystalline shell structure; formerly the hard, semiporcellaneous shell layer projecting past the tegmen- tum forming the insertion plates and the sutural laminae. articular a. [L. articulare, to divide] Pertaining to a joint. articular area (ARTHRO: Insecta) The basal portion of a wing. articular corium see articular membrane, corium articular furrow (ARTHRO: Crustacea) A groove near the tergal margin of the scutum, or scutal margin of the tergum, forming part of articulation between the two valves of bar- nacles. articularis n. [L. articulare, to divide] The pre-tarsus. articular membrane (ARTHRO) The nonsclerotized, flexible membrane between the segments of arthropods, and the joints of arthropod appendages. articular pan A cup or dish-like impression into which an ar- ticulation is fitted; frogga. articular ridge (ARTHRO: Crustacea) In barnacles, a linear elevation on the scutum or tergum bordering the articular furrow and together forming an articulation between the two valves.