Crustacea Glossary Complete List
Introduction
Joel Martin
jmartin@nhm.org
Because crustaceans are the most morphologically diverse group of animals on the planet, it comes as no surprise that there exists a huge number of morphological terms that are being used, or that have been used in the past, to describe them. As far as I have been able to determine, there is no single, standard glossary that is widely accepted. This is in part because different terms may mean different things for different groups of crustaceans, and in part because many existing glossaries tend to deal with selected subgroups or local faunas rather than with the taxon as a whole. More general glossaries do exist, and include McLaughlin's (1980) book on crustacean morphology and the glossary in the Treatise on Invertebrate Paleontology (Moore and McCormick, 1969), upon which McLaughlin's glossary seems to have been largely based.
The following glossary includes terms and their definitions taken verbatim from a variety of sources. In all cases, the reference is given in brackets [ ] following the definition. In cases where the same term is defined in slightly different ways, both definitions are given and both references are listed. If the definitions are identical, I have simply cited both references after the definition. The references also include the name of the group or groups of crustaceans with which that reference primarily deals. For example, the terms taken from Williams (1984) deal only with the Decapoda, specifically those of the east coast of the United States, and this is so indicated. In some publications, the glossary also contains more adjectival terms and non-morphological entries, in addition to the strictly descriptive terms. I have opted to list everything found in the original publication, so that you will occasionally find unusual entries that seem to deal not with crustacean morphology in general but with descriptive terms or even more specialized topics (e.g., "Moult to puberty").
References to figures refer to original illustrations in the original publications, and not to any figures in this computer file. Perhaps some day we will be able to add appropriate figures to this file as well, as in some cases the figures are much more clear than the verbal definitions given.
Please be sure to cite the original source of the definition, and not this electronic file, as your source for these definitions.
I have not made any attempt to correct definitions, grammar, or spelling, preferring instead to list each entry as it originally appeared without inserting my own biases or judgment. An obvious exception with regard to biases is that my specialty is the Decapoda, and so initially most terms will have been taken from publications on this group. I hope that as time goes by and more definitions are received by other workers in the field, this bias will correct itself.
Some descriptive adjectival terms are included here as well, and definitions for some of these have been taken from the American Heritage Dictionary of the English Language, third edition [AHD].
If you are aware of other publications that contain good glossaries for crustaceans, please let us know so we can add them to our list.
Corrections? Additions? Comments? Please send them to me. I promise to at least consider them.
Joel Martin
jmartin@nhm.org
Definitions
Current as of 28 August 2008
Note that this is a web reference,
and hence may change over time.
Please send us corrections using the
online comment form.
This resource is found at: http://crustacea.nhm.org//glossary
Abdomen
- Posterior part of body, of six segments or somites, sometimes including tailfan. [Poore, 2004]
- Region of the body posterior to cephalothorax, consisting of six body segments and telson (see Fig. 13). [Hobbs and Jass, 1988]
- That part of the body posterior to the cephalothorax, consisting of six body segments or somites plus the telson (Fig. 1).
(syn. Tail) [Perez Farfante and Kensley, 1997] - That portion of the body posterior to the cephalothorax, consisting of the telson and six body segments ot somites; the "tail". [Hobbs, Hobbs, and Daniel 1977]
- The "tail or that part of the body posterior to the cephalothorax, consisting of six body segments or somites and the telson. [Chace and Hobbs, 1969]
- The part of the body posterior to cephalothorax, the 'tail." [Butler, T. H.]
- The posterior region of the trunk (body). [Brusca and Brusca, 2002]
- The segmented hindmost part of the body held flexed forward beneath the thorax. Composed of six segments and a telson, referred to here as seven-segment. [Ingle, 1983]
- Trunk somites (tagma) between thorax and telson; somites with or without limbs.
(syn. pleon) [McLaughlin, 1980] - Trunk tagma following thorax and including telson; somites either without limbs or (in Malacostraca) bearing pleopods or uropods or both; in crabs bent sharply forward under thorax and much wider in females than in males.
(syn. pleon)
See: Metasome, Urosome [Moore and McCormick, 1969] - (Taxon-specific: Order Cladocera) Trunk. [Stachowitsch, 1992]
- (Taxon-specific: Order Notostraca) Posterior division (tagma) of body (head, thorax, abdomen), Consists of large and variable number of segments (body rings), the anterior abdominal rings each bearing several appendages. [Stachowitsch, 1992]
- (Taxon-specific: Order Diplostraca) Trunk. [Stachowitsch, 1992]
- (Taxon-specific: Order Anostraca) Posterior division (tagma) of body (head, thorax, abdomen). Consists of eight segments (somites) and bears terminal telson with caudal rami. lacks appendages except for anterior two somites, which are fused (genital somite) and bear reproductive structures. [Stachowitsch, 1992]
- (Taxon-specific: Class Cephalocarida) Posterior division (tagma) of body (cephalon, thorax, abdomen). Consists of 11 segments (somites) and bears terminal telson (anal somite) with caudal furca, With the exception of a reduced pair of appendages ("genital appendages"), abdomen lacks limbs. Thorax and abdomen together occasionally termed trunk. [Stachowitsch, 1992]
- (Taxon-specific: Order Cumacea) Pleon. [Stachowitsch, 1992]
- (Taxon-specific: Order Tanaidacea) Pleon. [Stachowitsch, 1992]
- (Taxon-specific: Order Decapoda) Posterior division (tagma) of body (cephalothorax, abdomen). Consists of six somites (pleomeres), each bearing pair of appendages (pleopods). Sixth pleomere (with uropods) bears posterior telson. (extended, bent upon itself, folded under cephalothorax, spirally coiled; symmetrical, asymmetrical; compressed, depressed; acutely triangular, broadly triangular, broadly oval, subcircular, T-shaped; smooth, sculptured).
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Order Amphipoda) Pleon. [Stachowitsch, 1992]
- (Taxon-specific: Order Isopoda) Pleon. [Stachowitsch, 1992]
- (Taxon-specific: Order Mysida) Posterior of three basic divisions (tagmata) of body (head, thorax, abdomen). Consists of six somites (pleomeres) bearing posterior telson.
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Order Stomatopoda) Posterior division (tagma) of body (cephalon, thorax, abdomen). Consists of six somites (pleomeres), each bearing pair of appendages (pleopods). Sixth pleomere (with uropods) bears or is fused with telson. (compressed, depressed).
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Order Leptostraca) Posterior division (tagma) of body (cephalon, thorax, abdomen). Consists of seven segments (somites), the first six each bearing pair of pleopods; bears telson and caudal furca posteriorly. Anterior region of abdomen covered, along with thorax and posterior part of head (cephalon), by carapace.
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Subclass Branchiura) Unsegmented posterior division (tagma) of body (cephalothorax, abdomen, or cephalon, pereon, abdomen). Relatively small, dorsoventrally flattened, and drawn out posteriorly into two lobes; bears pair of caudal rami and anus in cleft (sinus) between two lobes. (acorn-shaped, broadly elliptical, cordate, obcordate, obovate, spindle-shaped; lobes: acutely pointed, bluntly pointed, rounded).
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Subclass Cirripedia) In ascothoracican, posteriormost division (tagma) of body (head, thorax, abdomen). Consists of four or five segments (somites), the last bearing caudal furca. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Copepoda) Posterior and typically narrowest of three basic divisions of body (cephalon, thorax, abdomen). Consists of five somites (pleomeres), the first often being termed genital somite, the last termed anal somite (posterior to caudal rami). Typically lacks appendages. (symmetrical, asymmetrical; segmented, unsegmented).
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Subclass Copepoda) That part of the body of a copepod posterior to the somite bearing the genital opening. The abdomen includes four somites, three of which do not bear a paired appendage; the posterior somite bears the caudal rami and is the first abdominal somite to appear during development. [Ferrari and Dahms, in press]
- (Taxon-specific: Subclass Mystacocarida) According to interpretation dividing body into cephalon, thorax, and abdomen, last five somites of body. Lacks appendages yet bears telson and caudal furca. [Stachowitsch, 1992]
- (Taxon-specific: Class Ostracoda) Rudimentary region of body bearing caudal rami; indistinguishably fused to thorax. [Stachowitsch, 1992]
- (Taxon-specific: Superorder Syncarida) Posterior of three divisions (tagmata) of body (head, throrax, abdomen). Consists basically of six somites (pleomeres) bearing posterior telson, although in bathynellacean, last pleomere is fused with telson to form pleotelson. Bears varying number of pleopods.
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Order Thermosbaenacea) Posterior of three divisions (tagmata) of body (cephalon, thorax, abdomen). Consists basically of six somites (pleomeres) bearing posterior telson. (See also pleotelson).
(syn. pleon) [Stachowitsch, 1992] - (Taxon-specific: Order Euphausiacea) Posterior division (tagma) of body (cephalo-thorax, abdomen); consists of six somites (pleomeres), the first first five bearing pleopods, the sixth bearing uropods. Bears posterior telson. [Stachowitsch, 1992]
Abdominal aorta
- (Taxon-specific: Order Mysida) Posterior aorta. [Stachowitsch, 1992]
Abdominal appendage
- (Taxon-specific: Order Stomatopoda) Pleopod. [Stachowitsch, 1992]
Abdominal ganglion
- (Taxon-specific: Subclass Branchiura) Ganglion adjoining last thoracic ganglion in anterior region of thorax (forming last lobe of six-lobe ganglion mass). May bear smaller pair of lobes; gives rise to two pairs of nerves extending into abdomen. [Stachowitsch, 1992]
Abdominal limb
- See: Pleopod, Uropod [Martin, 2005]
Abdominal process
- Finger-like projection ( one to several ) on dorsal surface of cladoceran abdomen; may help to retain eggs in brood chamber. [Moore and McCormick, 1969]
- (Taxon-specific: Order Cladocera) Finger-like projection(s) on dorsal surface of abdomen. [McLaughlin, 1980]
- (Taxon-specific: Order Cladocera) One of typically two dorsal processes projecting from border of trunk and postabdomen. Considered to serve in closing off brood chamber posteriorly.
(syn. abdominal outgrowth) [Stachowitsch, 1992]
Abdominal segment
- (Figure only.) [Baba, 2005]Entire animal, right appendages omitted, dorsal view, based on Munida. [Baba, 2005]
Abdominal seta
- (Taxon-specific: Order Cladocera) One of two elaborate setae located on small protuberance on dorsal surface of postabdomen.
(syn. setae natatoriae) [Stachowitsch, 1992]
Abdominal somite
- Any single division of body behind thorax.
(syn. pleomere, pleonite) [Moore and McCormick, 1969] - Any single division of body between thorax and telson.
(syn. pleomere, pleonite) [McLaughlin, 1980] - (Taxon-specific: Class Cephalocarida) One of 11 segments of abdomen. First abdominal somite ( = 9th postcephalic segment) bears reduced pair of appendages ("genital appendages"). Last abdominal somite (19th postcephalic segment) bears telson. [Stachowitsch, 1992]
- (Taxon-specific: Order Decapoda) Pleomere. [Stachowitsch, 1992]
Abdominal spine
- (Taxon-specific: Order Anostraca) Spine-shaped projection on each side of abdominal somite. [Stachowitsch, 1992]
Abreptor
- Postabdomen of cladocerans, bent forward from junction with body and terminating in 2 claws with spines and teeth on their concave sides. [Moore and McCormick, 1969]
- (Taxon-specific: Order Cladocera) Postabdomen, bent forward from junction with body, terminating in 2 claws. [McLaughlin, 1980]
- (Taxon-specific: Order Cladocera) Postabdomen. [Stachowitsch, 1992]
Acanthopod
- In Cirripedia (Thoracica), appendage where rami of cirrus have setae along lesser curvature much reduced; setae of greater curvature arranged in transverse row, as strong sharp spines at each articulation (cf., ctenopod, lasiopod). [Moore and McCormick, 1969]
- (Taxon-specific: Subclass Cirripedia) Appendage (cirrus) with short row of strong sharp spines distally at each articulation of greater curvature and few or no spines along lesser curvature. [McLaughlin, 1980]
Acanthosoma
- (Taxon-specific: Order Decapoda) Zoea. [Stachowitsch, 1992]
Accessory Antennule
- (Taxon-specific: Subclass Copepoda) The atrophied and offset terminal segment of the antennary endopod. [Boxshall and Halsey, 2004]
Accessory flagellum
- (Taxon-specific: Order Amphipoda) Small inner flagellum of antennule (as opposed to larger primary flagellum). Number of articles is of taxonomic importance. [Stachowitsch, 1992]
- (Taxon-specific: Order Isopoda) In antenna of certain isopods, small, many-segmented flagellum projecting from fourth segment of peduncle. [Stachowitsch, 1992]
Accessory flexor muscle
- A small muscle which flexes the leg at the MC joint. It is in two parts, proximal and distal, and inserts on a long thin apodeme in the merus (Fig. 19). [Warner, 1977]
Accessory gill
- (Taxon-specific: Order Amphipoda) One in a series of I small respiratory structures projecting from bases of coxal gills. [Stachowitsch, 1992]
Accessory gland
- (Taxon-specific: Order Stomatopoda) In male reproductive system, pair of slender glands in thorax under heart; fused anteriorly and opening at tips of penes (via ducts running parallel to sperm ducts). [Stachowitsch, 1992]
Accessory heart
- (Taxon-specific: Order Decapoda) Cor frontale. [Stachowitsch, 1992]
Accessory lobe
- Small lobe at base of median lobe, on anterior surface of petasma in the genus Gennadas. [Perez Farfante and Kensley, 1997]
- (Taxon-specific: Order Cumacea) One posteriorly directed part of epipod of first maxilliped pair, single respiratory projection set apart from series of remaining branchial lobules. [Stachowitsch, 1992]
Accomodation groove
- (Taxon-specific: Class Ostracoda) Hinge structure; longitudinal groove above median hinge element. Receives dorsal edge of opposite valve. [Stachowitsch, 1992]
Acicle
- Antennal scale reduced to a spine. [Williams, 1984]
- Small scaphocerite or antennal scale. [Poore, 2004]
- (Taxon-specific: Order Decapoda) Spine-shaped outer branch (exopod) of antenna; represents reduced antennal scale (scaphocerite). May also refer to spine-like ophthalmic scale on eyestalk. (unarmed, spinose). [Stachowitsch, 1992]
- (Taxon-specific: Order Leptostraca) Ocular scale. [Stachowitsch, 1992]
Acron
- Anteriormost part of body carrying eyes, not considered to be true cephalic somite.
(syn. ophthalmic somite, presegmental region. [Some authors recognize as protocephalon anterior part of h) [Moore and McCormick, 1969] - Anteriormost part of the body carrying the eyes; not considered true cephalic somite.
(syn. opthalmic somite, presegmental region) [McLaughlin, 1980] - (Taxon-specific: Order Decapoda) Anterior segment of body (although not considered to be a true somite); bears eyestalks (ocular peduncles). Acron and first cephalic somite occasionally interpreted as representing protocephalon.
(syn. ophthalmic somite, pre-segmental region) [Stachowitsch, 1992] - (Taxon-specific: Order Stomatopoda) Anteriormost segment of body (although not considered to be a true somite); divided into three plates-fastigial, ocular, and postocular- of which the median ocular plate bears the eyestalks (ocular peduncles). Not covered by carapace, although rostrum may partially or entirely extend across acron.
(syn. opthalmic somite) [Stachowitsch, 1992]
Acumen
- Pointed apical part (tip) of rostrum, frequently delineated basally by marginal spines (see Fig. 14). [Hobbs and Jass, 1988]
- The apical part of the rostrum frequently delimited basally by marginal spines. [Hobbs, Hobbs, and Daniel 1977]
Acute
- Tapering to sharp point. [Butler, T. H.]
Adductor muscle (of carapace)
- Muscle attached to carapace for pulling it to the body (thorax) or connecting halves of bivalve shell (e.g. Conchostraca, Ostracoda, Leptostraca) or valves of cirriped capitulum for closure of them. In Cirripedia, any transverse muscles, particularly that of maxillary segment, for closure of aperture; in Thoracica, adductor (adductor scutorum) acts upon scutal plates or valves. [Moore and McCormick, 1969]
- (Taxon-specific: Order Diplostraca) Well-developed muscle attaching each side of head region to carapace. (See also ligament). [Stachowitsch, 1992]
- (Taxon-specific: Order Leptostraca) Carapace adductor muscle. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Cirripedia) Conspicuous transverse muscle joining both scuta and serving to close aperture. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Cirripedia) Muscle attached to carapace for pulling it to body or connecting halves of bivalve carapace. [McLaughlin, 1980]
- (Taxon-specific: Class Ostracoda) Well-developed transverse muscle extending from body to inner surface of each valve. Forms characteristic muscle scars on valves and serves to close carapace. [Stachowitsch, 1992]
Adductor muscle scar pattern
- (Taxon-specific: Class Ostracoda) Rather central pattern of scars (raised or depressed) indicating where central adductor muscles attach to valves; not always clearly visible. [Cohen, Peterson, and Maddocks, in press]
Adductor pit
- In cirripeds, depression on interior of scutum for attachment of adductor muscle, located between adductor ridge and occludent margin. [Moore and McCormick, 1969]
- (Taxon-specific: Subclass Cirripedia) Barnacle plate feature: on inner surface of scutum, depression marking attachment point of adductor muscle. In unstalked barnacle, located between adductor ridge and occludent margin. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Cirripedia) Depression on inner surface of scutum between adductor ridge and occludent margin for attachment of adductor muscle (thoracic Cirripedia). [McLaughlin, 1980]
Adductor ridge
- In cirripeds (Balanomorpha), linear elevation on interior of scutum between adductor pit and tergal margin. [Moore and McCormick, 1969]
- Linear elevation on inner surface bounding adductor pit on tergal pit in sessile barnacles. [McLaughlin, 1980]
- (Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
- (Taxon-specific: Subclass Cirripedia) Barnacle plate feature: on inner surface of scutum in unstalked form, linear elevation between adductor muscle pit and tergal margin. [Stachowitsch, 1992]
Adhesion pads
- (Taxon-specific: Subclass Copepoda) Raised areas of specialised integument, ornamented with fine ridges, found in some siphonostomatoids parasitic on fish. [Boxshall and Halsey, 2004]
Adhesive gland
- (Taxon-specific: Subclass Cirripedia) Cement gland. [Stachowitsch, 1992]
Adont hinge
- (Taxon-specific: Class Ostracoda) Single element hinge, bar on one valve fits into groove of other valve. [Cohen, Peterson, and Maddocks, in press]
Adrostal carina
- Ridge flanking the rostrum, sometimes nearly reaching the posterior margin of the carapace (Fig. 2B). [Perez Farfante and Kensley, 1997]
Adrostral ridge
- Ridge parallel to and separated by narrow groove from rostrum (Penaeoidea). [Poore, 2004]
Adrostral sulcus
- Groove flanking the rostrum mesial to the adrostral carina, sometimes nearly reaching the posterior margin of the carapace (Fig. 2B). [Perez Farfante and Kensley, 1997]
Aesthetasc seta
- Confined to antennule; thin-walled, smooth, non-tapering seta, rounded tip; without pore; annulus not evident. [Ingle, 1992]
Aesthetascs
- See: Esthetasc [Martin, 2005]
- A long, tubular, sensory seta having thin cuticle, found on the antennula or antenna. Aesthetascs may have a chemosensory function, because males generally have more of these structures than females. [Wilson, 1989]
- Sensory seta covered by delicate cuticle, often projecting from antenna or antennule.
(syn. olfactory hair, esthetasc, esthete...) [McLaughlin, 1980] - Simple, tubular, thin-walled, chemosensory seta often found on the antennular flagellum. [Holdich and Jones, 1983]
- Spinelike cuticular processes often occurring in clumps or rows and functioning in chemoreception, usually located on the antennules. [Brusca and Brusca, 2002]
- (Taxon-specific: Order Cladocera) One in a tuft of sensory projections at tip of each antennule.
(syn. esthete, olfactory seta) [Stachowitsch, 1992] - (Taxon-specific: Class Cephalocarida) Elongate sensory projection at tip of each antennule.
(syn. esthete) [Stachowitsch, 1992] - (Taxon-specific: Order Cumacea) One in a series of sensory projections on main flagellum of antennule. [Stachowitsch, 1992]
- (Taxon-specific: Order Tanaidacea) One in a series of sensory projections on flagella of antennules. [Stachowitsch, 1992]
- (Taxon-specific: Order Decapoda) One in a series of small sensory projections on outer flagellum of antennule.
(syn. esthetasc, esthete, olfactory hair) [Stachowitsch, 1992] - (Taxon-specific: Order Amphipoda) One in a series of thin-walled sensory projections on antennule.
See: Calceolus [Stachowitsch, 1992] - (Taxon-specific: Order Isopoda) One in a series of sensory projections on antennules. (uniramous, biramous, triramous). [Stachowitsch, 1992]
- (Taxon-specific: Order Isopoda) Thin-walled sensory setae usually on flagellum of antennule. [Kensley and Schotte, 1989]
- (Taxon-specific: Order Leptostraca) One in a series of sensory projections on antennules and ocasionally also on antennae. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Copepoda) A thin-walled, sensory element with putative chemoreceptive function, found on the antennules. [Boxshall and Halsey, 2004]
- (Taxon-specific: Subclass Copepoda) A transformed seta of antenna 1 or another oral appendage of copepodids. An aesthetasc usually has a sclerotized base but otherwise is poorly sclerotized; it often is considered to have a chemosensory function. [Ferrari and Dahms, in press]
- (Taxon-specific: Subclass Copepoda) One in a series of small sensory projections along antennule.
(syn. esthetasc, esthete) [Stachowitsch, 1992] - (Taxon-specific: Subclass Mystacocarida) Small sensory projection at tip of each antennule.
(syn. aesthete) [Stachowitsch, 1992] - (Taxon-specific: Class Ostracoda) One in a series of small sensory projections along antennule or antenna; considered to be modified setae. [Stachowitsch, 1992]
- (Taxon-specific: Class Remipedia) One of numerous robust, long sensory projections aggregated in several dense rows at base of antennules (on pad on first article of peduncle); directed posteriorly and partially covering antennae.
(syn. esthetasc, esthete, olfactory hair) [Stachowitsch, 1992] - (Taxon-specific: Order Thermosbaenacea) One of several senory projections on larger of two flagellaf antennule. [Stachowitsch, 1992]
- (Taxon-specific: Order Euphausiacea) One in a series of small sensory projections on each antennule. [Stachowitsch, 1992]
Afferent branchial channels
- Pair of channels between ridges, supplying water to branchial cavity and opening in front of chelipeds or alongside epistome (some Brachyura). [Poore, 2004]
Afferent channels
- Opening through which water passes to gills. [McLaughlin, 1980]
- Openings through which water passes to gills, in brachyuran crabs generally located in front of bases of chelipeds. [Moore and McCormick, 1969]
- Openings through which water passes to gills. In brachyuran crabs, usually opening behind pterygostomian regions and in front of chelipeds except in certain Oxystomata in which they open at anterolateral angles of palate or endostome. [Williams, 1984]
Afferent respiratory channels
- Channels through which water passes to the gills, that open in front of the chelipeds and behind the pterygostomial region except in some oxystomata where they open at the sides of the endostome.
(syn. afferent branchial channels) [Ingle, 1980] - (Taxon-specific: Order Decapoda) Opening through which water enters branchial chamber under carapace. Typically applied to more restricted opening in crab-like (brachyuran) decapod; located anteroventrally on each side of body, either behind pterygostomial regions or in front of chelipeds.
(syn. afferent branchial channel)
See: Efferent respiratory channels [Stachowitsch, 1992]
Ala
- One of pair of posteriorly directed cephalic-shield extensions; in cirripeds (Balanomorpha), triangular lateral part of compartment plate delimited from paries, which is overlapped by adjacent compartment plate with or without radius.
(pl. alae) [Moore and McCormick, 1969] - (Taxon-specific: Subclass Branchiura) One of two posterolateral extensions of carapace. (broad, broadly rounded, narrowly rounded, elongate and coiled behind thorax, greatly elongated; extending to second, third, or fourth thoracomere, to abdomen, beyond abdomen). [Stachowitsch, 1992]
- (Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
- (Taxon-specific: Subclass Cirripedia) Barnacle plate feature: in unstalked form, triangular lateral part of compartmental plate. Delimited from median part (paries) and overlapped by lateral part (radius) of adjoining compartmental plate. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Cirripedia) One of pair of posteriorly directed cephalic-shield extensions (Branchiura and some parasitic Copepoda); triangular lateral part of compartmental plate, with or without radii, overlapped by adjacent compartmental plate (balanomorph Cirripedia).
(pl. alae) [McLaughlin, 1980] - (Taxon-specific: Subclass Copepoda) In parasitic copepod, one of two posterolateral extensions of cephalic shield. [Stachowitsch, 1992]
- (Taxon-specific: Class Ostracoda) Wing-like extension of valve, typically located ventrally and directed posteriorly. (simple, carinate). [Stachowitsch, 1992]
Aliform apophyses
- Incurved anterior and posterior extremities of growth lines (e.g., Conchostraca, characteristic of Ipsilonia). [Moore and McCormick, 1969]
- (Taxon-specific: Order Diplostraca) Incurved anterior and posterior extremities of growth lines. [McLaughlin, 1980]
Alimentary tract
- Tubular organ comprising the oesophagus, foregut, hepatopancreas, and hindgut. [Holdich and Jones, 1983]
Allometric growth
- Growth of one part of the body relative to another part in which there is a change in relationships of proportions and/or shape. [Ingle, 1983]
Ambulatory leg
- See: Pereiopod [Moore and McCormick, 1969]
- See pereopod. [McLaughlin, 1980]
- (Taxon-specific: Order Isopoda) (as applied to pereopods). Used for walking. [Kensley and Schotte, 1989]
Ambulosome
- The part of the thorax of munnopsid isopods that bears the walking legs. It consists of pereonites 1-4. [Wilson, 1989]
Ambulosomite
- A body segment of the ambulosome. [Wilson, 1989]
Amphidont hinge
- (Taxon-specific: Class Ostracoda) A modified entomodont hinge in which the four elements are well differentiated (Families Hemicytheridae, Trachyleberididae). [Cohen, Peterson, and Maddocks, in press]
Ampulla
- (Taxon-specific: Order Amphipoda) One in a series of spinose and setose ridges surrounding border between esophagus and stomach. [Stachowitsch, 1992]
- (Taxon-specific: Order Isopoda) One of two spinose or setose internal ridges on each side of foregut. Serves in crushing food. [Stachowitsch, 1992]
- (Taxon-specific: Order Stomatopoda) In digestive tract, diverticulum at junction of posterior (pyloric) stomach, digestive ceca, and midgut.
(syn. pars ampullaris) [Stachowitsch, 1992]
Anal flap
- (Taxon-specific: Class Remipedia) Small lobe covering anus at posterior end of anal segment. [Stachowitsch, 1992]
Anal furca
- (Taxon-specific: Subclass Branchiura) Caudal ramus. [Stachowitsch, 1992]
Anal operculum
- (Taxon-specific: Subclass Copepoda) A small median process on dorsal surface of the anal somite protecting the anus. [Boxshall and Halsey, 2004]
- (Taxon-specific: Subclass Copepoda) Lid-like structure covering anus. (smooth, toothed). [Stachowitsch, 1992]
Anal papilla
- (Taxon-specific: Subclass Branchiura) Caudal ramus. [Stachowitsch, 1992]
Anal segment
- (Taxon-specific: Order Diplostraca) Telson.
(syn. anal somite) [Stachowitsch, 1992] - (Taxon-specific: Order Anostraca) Telson.
(syn. anal somite) [Stachowitsch, 1992] - (Taxon-specific: Class Cephalocarida) Telson.
(syn. anal somite) [Stachowitsch, 1992] - (Taxon-specific: Class Remipedia) Posteriormost segment of body; partially fused to reduced last trunk segment and bearing both anus and caudal rami. Occasionally also referred to as telson. (Length longer than, equal to, or shorter than width). [Stachowitsch, 1992]
Anal somite
- Postsegmental plate or lobe bearing anus. [Brusca and Brusca, 2002]
- (Taxon-specific: Order Leptostraca) Telson.
(syn. anal segment) [Stachowitsch, 1992] - (Taxon-specific: Subclass Copepoda) Last (fifth) segment of abdomen; bears anus dorsally and pair of caudal rami posteriorly. Occasionally termed telson. [Stachowitsch, 1992]
- (Taxon-specific: Subclass Copepoda) The posterior somite and abdominal somite onto which the anus opens. The anal somite bears a paired appendage called the caudal rami. The anal somite is considered the first abdominal somite, despite its posterior position, because it is the first abdominal somite to appear during post-embryonic development. [Ferrari and Dahms, in press]
- (Taxon-specific: Subclass Mystacocarida) Telson. [Stachowitsch, 1992]
Anal spines
- Single row of spines on either side of cladoceran postabdomen (e.g., Sididae, Holopedidae, Daphniidae). [In addition, some cladocerans possess lateral spines (e.g., Macrothricidae, Chydoridae).]. [Moore and McCormick, 1969]
- Single row of spines on either side of postabdomen (cladocera) or prominent telsonal spines (Conchostraca). [McLaughlin, 1980]
- (Taxon-specific: Order Cladocera) One in a series of spines along (morphological) dorsal surface of postabdomen.
(syn. anal tooth) [Stachowitsch, 1992] - (Taxon-specific: Order Diplostraca) One of two blade-like, serrate spines projecting from posterodorsal end of telson. [Stachowitsch, 1992]
Anameric
- The addition of only one somite to the body at each molt during development. [Ferrari and Dahms, in press]
Anamorphic development
- In which a series of similar larval stages are passed through after hatching. [Ingle, 1992]
- Indirect development in which the embryo hatches as a nauplius larva and the adult form is achieved via a series of gradual changes in body morphology as new segments and appendages are added. [Brusca and Brusca, 2002]
Androdioecy
- Rare type of mixed mating system in which males coexist with hermaphrodytes but there are no true females. [Brusca and Brusca, 2002]
Androgenic gland
- (Taxon-specific: Order Decapoda) In male, small gland associated with terminal end of each vas deferens. Secretes hormones stimulating spermatogenesis and development of secondary sex characteristics. [Stachowitsch, 1992]
Anecdysis
- A prolonged period without ecdysis; occurs in crustaceans that molt seasonally. [Bliss, 1982]
- An intermoult stage in which all tissue growth has been completed. [Ingle, 1983]
Angulate
- (Taxon-specific: Order Isopoda) Having an angle or an angular shape. [Kensley and Schotte, 1989]
Annulate seta, with setules
- These are always mechanoreceptors; they always form in invaginated pockets, may be of a variety of sizes and shapes, may have the setules distributed along the shaft in many kinds of patterns, and may have denticules distally along the shaft. [Watling, 1989]
Annulate seta, without setules
- These usually are chemoreceptive, but may be mechanoreceptive in large groups; they always form in invaginated pockets and may be smooth or denticulate, elongate and stiff, or short and robust. [Watling, 1989]
Annulations
- Spaced rings on a segment of appendage, not articulated, yet wth flexability. [Butler, T. H.]
Annulus
- A faint ring circumscribing the shaft; may be located near the base or well along the shaft. [Watling, 1989]
Annulus ventralis
- Crayfish seminal receptacle, consisting of median sclerite between fourth and fifth pereiopods; the spermatophore receptacle on sternum of female (see Fig. 23d). [Hobbs and Jass, 1988]
- Seminal receptacle of cambarids, consisting of a median sclerite between the fourth and fifth pereiopods. [Hobbs, Hobbs, and Daniel 1977]
- Seminal receptacle of female crayfish. [McLaughlin, 1980]
Anomura
- A suborder of decapod crustaceans in which the fifth pair of pereiopods are extremely reduced and often concealed beneath the carapace; the antennae are placed to the outside of the eyestalks and the sub-hepatic regions of the carapace are not fused with the endostome. (Hermit crabs, Porcelain crabs, Lithodid crabs). [Ingle, 1980]
Anomuran crabs
- Hermit crabs; coconut crab; also crab-like members of the infraorder Anomura, in which the last (fifth) pair of thoracic legs is very small and often kept hidden within the branchial chambers. [Bliss, 1982]
Anomuran seta
- A small (pappose-type seta in species studied) occuring on or near the outermost part of the telson posterior margin in anomuran larvae (and also Dromia), and distinct from all other types of telson setae. [Ingle, 1992]
Antenna
- (Figure only.) [Baba, 2005]Antennal peduncle consisting of 5 articles, based on Uroptychus. [Baba, 2005]
- Mobile sensory appendages arising below the eyes at the front of the head. There are two pairs of these appendages, the first and second antennae. The first antennae are uniramous and may have two or three flagellae each. The second antennae are biramous, one branch being similar in gross form to the first antenna, the other being flattened and scale-like (referred to as a scale). [Mauchline, 1984]
- More lateral of the two paired, usually flagellate appendages projecting distally from the anterior end of the cephalothorax (Fig. 1).
(pl. antennae) [Perez Farfante and Kensley, 1997] - One of pair of anterior appendages of head region placed morphologically next behind antennule, uniramous in some crustaceans but biramous in all nauplii and in adults of most classes; may be extremely long and composed of multitudinous small segments or reduced to mere rudiment or lacking.
(syn. second antenna) [Moore and McCormick, 1969] - One of pair of appendages of second cephalic somite.
(syn. 2nd antenna) [McLaughlin, 1980] - Second cephalic appendage, usually with peduncle of five articles and multiarticulate flagellum (sometimes antenna 2); plural sometimes used to refer to both antennules and antennae.
(pl. antennae) [Poore, 2004] - Second pair of cephalic appendages (antenna 2). [Holdich and Jones, 1983]
- The appendages of the second and third head segments are the first and second pairs of antennae respectively. The first antennae are secondarily biramous (Fig. 3) Both pairs of antennae are sensory. [Warner, 1977]
- The more lateral of the the two paired flagellate appendages projecting anteriorly from anterior end of the body.
(pl. antennae) [Butler, T. H.] - The more lateral of the two paired flagellate appendages projecting anteriorly from the anterior end of the body.
(pl. antennae) [Chace and Hobbs, 1969] - The second pair of appendages situated between the antennules and the orbits, sometimes referred to as second antennae. [Ingle, 1983]
- The second, paired, cephalic appendage. It consists of four short, robust, proximal segments, two long, intermediate segments, and a long series of tapering annuli, called the flagellum. The third basal segment bears a smaller, lateral appendage called the antennular scale that is homologous to the exopod in other Crustacea.
(syn. second antenna) [Wilson, 1989] - Whiplike, generally long sensory organ arising from anterior region of cephalothorax (see Figs. 13, 14). [Hobbs and Jass, 1988]
- (Taxon-specific: Order Cladocera) Second and much larger pair of antennae; located laterally near posterior margin of head. Biramous, consisting of relatively large basal part (peduncle) bearing two- to four-segmented dorsal and ventral branches (rami). Serves as principle locomotory organ and moved by relatively large muscles (antennal muscles). (biramous and flattened, simple and cylindrical, branched, not branched).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Notostraca) Second and smaller pair of antennae; uniramous, extending from each side of labrum on underside of head. (very small, vestigial, absent).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Diplostraca) Second and much larger pair of antennae on head; biramous, consisting of long, terminally annulate basal part (protopod, with basal lobe) and pair of segmented branches (flagella, rami).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Anostraca) Second and larger of two pairs of antennae; uniramous, projecting ventrally from head. In female, typically unsegmented and reduced. In male, forms clasper generally consisting of exapanded basal segment (with antennal appendage) and more slender distal segment. (fused at base, not fused at base; basal segment: with/without hand; with/without finger-like process on median surface near midlength; with prominent, dorsally directed, peg-like process on median surface just below mid-length; with row of spines along median margin; with spinous pad, median protuberance, and many small distal spines; distal segment: laminate, not laminate, with/without calcar) (See also clypeus, hand).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Class Cephalocarida) Second pair of antennae. Biramous, consisting of two-segmented protopod, relatively short, two-segmented endopod, and longer, multi-segmented exopod. Serves in locomotion and feeding.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Cumacea) Second pair of antennae; uiramous. If fully developed, consisting of proximal five-segmented peduncle and distal flagellum.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Tanaidacea) Second, relatively small pair of antennae.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Decapoda) Second and typically larger pair of antennae. Originates from second (antennal) somite of head. Biramous, consisting of basal peduncle (typically composed of protopod, endopod, and scaphocerite) and distal flagellum. Bears pore of antennal gland. (elongate, spatulate, squamiform).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Amphipoda) Second pair of antennae. Uniramous, consisting of proximal five-segmented peduncle and distal flagellum. May bear sensory structures (aesthetascs, calceoli). (short, long; slender, robust; naked, setose, spinose; similar, sexually dimporphic; pediform).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Isopoda) Paired appendage of the third cephalon segment; sometimes referred to as antenna 2. [Kensley and Schotte, 1989]Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
- (Taxon-specific: Order Isopoda) Second, usually longer appendage of cephalon. Uniramous, consisting of basal peduncle and distal lagellum. (pediform).
See: Antennal scale, Accessory flagellum [Stachowitsch, 1992] - (Taxon-specific: Order Mysida) Second pair of antennae. Biramous, consisting of peduncle bearing scale-like outer branch (antennal scale, squama, exopod) and elongate inner branch (flagellum).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Stomatopoda) Second and smaller pair of antennae; originating from second somite of head (cephalon). Biramous, consisting of basal, two-segmented peduncle, two-segmented exopod (distal segment = antennal scale), and three-segmented endopod (with distal flagellum). (See also antennule).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Leptostraca) Second pair of antennae. Uniramous, relatively long, and consisting of three- or four-segmented peduncle and variously shaped endopod (flagellum). (peduncle: three-/four-segmented; flagellum: long with many small joints, small with few large joints).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Subclass Branchiura) Second pair of appendages on underside of head. Relatively short, uniramous, and consisting of four to six segments. Armed basally with large spines/hooks, terminally with smaller spines. Serves in attachment to host.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Subclass Cirripedia) Biramous second pair of antennae. Present, with the exception of certain ascothoracicans, only in early larval stages (nauplius).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Subclass Copepoda) Second and typically shorter pair of antennae on underside of head. Highly setose and serving in suspension feeding or, in certain parasitic copepods, with terminal claw and serving in attachment to host. If uniramous, outer branch (exopod) is missing. The term second antenna is often preferentially applied. (biramous, uniramous; prehensile).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Subclass Copepoda) The limb of the cephalon posterior to antenna 1; on most naupliar stages, it bears a distinct protopodal masticatory arthrite which is not present on copepodid stages or on non-feeding naupliar stages, especially those of species with lecithotrophic embryos.
(syn. antenna 1) [Ferrari and Dahms, in press] - (Taxon-specific: Subclass Copepoda) The second cephalic appendage. [Boxshall and Halsey, 2004]
- (Taxon-specific: Subclass Mystacocarida) Second and smaller pair of antennae. Biramous, consisting of basal protopod bearing nine-segmented exopod and four-segmented endopod. Serves in locomotion and feeding.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Class Ostracoda) Second pair of antennae on head. Basically biramous, consisting of basal protopod and distal endopod and exopod (the latter often being reduced). Serves, along with antennules, as chief locomotory appendage. Carapace margin may be indented (rostral notch) for antenna. (biramous, uniramous).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Class Remipedia) Second and smaller, more paddle-shaped pair of antennae on underside of head (cephalon); biramous and consisting of protopod (with two articles) bearing scale-like exopod and three-segment endopod. Endopod articles arc around anterior aspect of exopod. Setae on antenna are plumose.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Superorder Syncarida) Second pair of antennae. Consists of basal peduncle and either single flagellum (stygocaridacean), single or paired (flagellum and small exopod) branches (bathynellacean), or flagellum and scaphocerite (anaspidacean). (uniramous, biramous).
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Thermosbaenacea) Second, relatively small pair of antennae. Uniramous, consisting of peduncle and flagellum.
(syn. second antenna) [Stachowitsch, 1992] - (Taxon-specific: Order Euphausiacea) Second pair of antennae. Biramous, consisting of proximal single-segmented peduncle, scale-shaped outer branch (exopod = scaphocerite), and inner branch (endopod) consisting of three larger segments and multiarticulate flagellum. Peduncle bears opening of antennal gland.
(syn. second antenna) [Stachowitsch, 1992]
Antennae
- The second pair of antennae. [Brusca and Brusca, 2002]
Antennal acicle
- (Taxon-specific: Order Decapoda) Acicle. [Stachowitsch, 1992]
Antennal appendage
- (Taxon-specific: Order Anostraca) Variously shaped process extending from basal segment of each antenna; more common in male. (conical, lamelliform, robust, slim; extending/not extending beyond basal segment of antenna; with small teeth, with large teeth; with teeth longer on one side, with teeth not greatly different in size; with/without conical processes).
(syn. basal antennal appendage) [Stachowitsch, 1992]
Antennal artery
- (Taxon-specific: Order Decapoda) Artery.
(syn. antennary artery) [Stachowitsch, 1992]
Antennal carina
- See: Carapace carina a [Martin, 2005]
- Ridge extending posteriorly along dorsal extremity of antennal region, often continuous with antennal spine (Fig. 2B). [Perez Farfante and Kensley, 1997]
- (Taxon-specific: Order Decapoda) On each side of carapace, narrow, longitudinal ridge extending posteriorly from antennal spine.
(syn. postannular crest) [Stachowitsch, 1992]
Antennal flagellum
- Multiarticulate, whiplike terminal part of the antenna (Fig. 1).
(pl. antennal flagella) [Perez Farfante and Kensley, 1997]
Antennal gland
- See: Green glands [Martin, 2005]
- Excretory gland situated in the basal article of the antennal peduncle. [Holdich and Jones, 1983]
- Nephridial excretory organs exiting via a pore at the base of the antennae. [Brusca and Brusca, 2002]
- One of pair of complex excretory glands in many malacostracans with duct opening on antenna.
(syn. green gland) [McLaughlin, 1980] - (Taxon-specific: Order Decapoda) One of two glands located in anterior region of head and consisting basically of end sac (divided into saccule and labyrinth), bladder, and excretory duct. Opens via excretory pore on basal segment (coxa) of each antenna. Functions in excretion and controls internal fluid pressure as well as ion concentration.
(syn. green gland, excretory organ) [Stachowitsch, 1992] - (Taxon-specific: Order Amphipoda) Pair of excretory glands in head, one opening to exterior at base (peduncle) of each antenna.
See: Gland cone [Stachowitsch, 1992] - (Taxon-specific: Order Isopoda) Pair of poorly developed excretory organs in head of certain isopods, one opening at base of each antenna. [Stachowitsch, 1992]
- (Taxon-specific: Order Mysida) Excretory gland located in head; consists of long, coiled excretory canal and bladder. Opens to exterior on basal segment of either antenna. (See also maxillary gland). [Stachowitsch, 1992]
- (Taxon-specific: Order Leptostraca) Pair of excretory glands in head, one opening to exterior at base of each antenna. (See also maxillary gland). [Stachowitsch, 1992]
- (Taxon-specific: Subclass Copepoda) Excretory organ, one opening at each base of antenna. Characteristic for larval stages and cetain parasitic copepods. (See also maxillary gland). [Stachowitsch, 1992]
- (Taxon-specific: Class Ostracoda) One of two excretory glands opening at base of antennae (See also maxillar gland). [Stachowitsch, 1992]
- (Taxon-specific: Order Euphausiacea) Pair of excretory glands in head, one opening to exterior at base (peduncle) of each antenna. [Stachowitsch, 1992]
Antennal groove
- See: Carapace groove a [Martin, 2005]
- See: Carapace grooves a [McLaughlin, 1980]
- (Taxon-specific: Order Decapoda) On each side of carapace, longitudinal groove extending posteriorly from vicinity of antennal spine. [Stachowitsch, 1992]
Antennal muscle
- (Taxon-specific: Order Cladocera) One of several well-developed muscles spanning from antenna to dorsal part of head. According to position and function one may distinguish, e.g., antennal levator muscle and antennal adductor muscle. [Stachowitsch, 1992]
Antennal notch
- (Taxon-specific: Order Cumacea) On each side of carapace, notch in anterior border below pseudorostrum. Antennules and occasionally antennae project through antennal notch. Lower extension of notch termed anterolateral angle or corner. (deep, shallow).
(syn. antennal sinus) [Stachowitsch, 1992]
Antennal peduncle
- Basal segments of antennule from which the flagella arise. [Butler, T. H.]
- Five basal segments of the antenna, from which the antenna arises distally. [Perez Farfante and Kensley, 1997]
- The basal segments of the antenna, from which the flagellum arises. [Chace and Hobbs, 1969]
Antennal region
- See: Carapace region a [Martin, 2005]
- See: Carapace regions a [McLaughlin, 1980]
- Area on lateral surface of the carapace posterior to and encompassing antennal spine. [Butler, T. H.]
- Area on the lateral face of the carapace posterior to and encompasing the antennal spine. [Perez Farfante and Kensley, 1997]
- The area on the lateral surface of the carapace of shrimps posterior to and encompassing the antennal spine. [Chace and Hobbs, 1969]
- (Taxon-specific: Order Decapoda) In shrimp-like (natantian) decapod, one of two relatively small regions along anterolateral margin of carapace; corresponds to position of antenna. Adjoining regions include orbital, hepatic, and pterygostomial regions. [Stachowitsch, 1992]
Antennal scale
- See: Stylocerite,