Anatomy of a Shrimp
Glossary and Illustrations
(plurals in parentheses)
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Abdomen: The tail, consisting of six body segments and the telson/uropods.
Adrostral Carina: The ridge flanking the rostrum, sometimes nearly reaching the end of the carapace.
Adrostral Sulcus: The groove flanking the rostrum to the adrostral carina, sometimes nearly reaching the end of the carapace.
Antenna (Antennae): Long, paired, usually flagellate appendage projecting from the front of the cephalothorax.
Antennal Carina: The ridge extending posteriorly along dorsal extremity of antennal region, often continuous with antennal spine.
Antennal Flagellum (Antennal Flagella): Multiarticulate, whip-like terminal part of the antenna.<br>
Antennal Peduncle: Five basal segments of the antenna, from which the flagellum arises.
Antennal Region: Area on the lateral face of the carapace posterior to and encompassing the antennal spine.
Antennal Spine: Spine situated on the anterior margin of the carapace just ventral to the orbital margin.
Antennular Flagellum (Anmnnular Flagella). Multiarticulate paired filaments (sometimes flattened and lamellate) of the antennule.
Antennular Peduncle: Three basal segments of the antennule, from which the flagella arise.
Antennule: Short, paired, usually flagellate appendages projecting from the front end of the cephalothorax.
Anterolateral Carina: Longitudinal ridge extending along the anterior part of the carapace, ventral to the gastro-orbital carina.
Arthrobranchia (Arthrobranchiae): Branchia (gill) attached to the joint area between the body and the first podomere of the leg.
Article: Any one of the subdivisions of an appendage segment.
Articular Membrane: Uncalcified integument at a joint, permitting movement of the exoskeleton, as between the segments of a pereopod.
Basial Spine: Spine projecting from a thoracic appendage.
Branchia (Branchiae): Respiratory organ (gill) associated with an appendage or with the body wall.
Branchial Region: Area of the carapace overlying the branchial cavity and gills.
Branchiocardiac Carina. Ridge extending along the posterodorsal limit of the branchiostegite.
Branchiocardiac Sulcus: Groove extending along the dorsal limit of the branchiostegite, running parallel to the branchiocardiac carina.
Branchiostegal Carina: Longitudinal ridge extending along the anteroventral part of the carapace, usually continuous with the branchiostegal spine.
Branchiostegal-Hepatic Carina: Longitudinal ridge consisting of the fusion of the branchiostegal and hepatic carinae.
Branchiostegal Spine: Short spine on or near the anterior margin of the carapace ventral to the antennal spine and dorsal to the anteroventral angle of the carapace.
Branchiostegal Sulcus: Groove often accompanying the branchiostegal carina, located on the anteroventral part of the carapace.
Branchiostegite: Expanded ventrolateral part of the carapace covering the gills.
Carapace: The "head shield" cuticular structure arising from the posterior margin of the cephalon, extending anteriorly and posteriorly, and covering the cephalothoracic somites of the body.
Carina (Carinae): A ridge or keel of the exoskeleton.
Cephalothorax: Anterior part of the body consisting of the fused cephalon (head) and thorax, bearing all the appendages except the pleopods and uropods.
Cervical Carina: Transverse ridge starting at the top of the carapace and extending down and toward the front of the carapace.
Cervical Sulcus: Transverse groove starting at the top of the carapace and extending down and toward the front of the carapace.
Chela (Chelae): Pincer formed by the two distal podomeres of a pereopod in which the movable finger (dactyl) opposes a fixed finger formed by a distal extension of the propod.
Chelate: Appendage ending in a chela (claw).
Cicatrix (Cicatrices): Longitudinally disposed ridge often present on the lateral part of the sixth abdominal somite.
Cincinnuli (Cincinnulus): Minute interlocking processes projecting from the dorsomesial margins of the petasmal endopods.
Cornea: Faceted, usually pigmented portion of the eye.
Coxa (Coxae): First or proximal podomere of a typically seven-segmented appendage.
Coxal Spine: Spine projecting from the coxa of a thoracic appendage.
Dactyl: Terminal podomere of a typically seven-segmented appendage.
Dendrobranchiate Gill: One in which the paired primary branches are subdivided, sometimes highly so.
Distal Fold: Distal pleat in the dorsolateral lobule of the petasma.
Distolateral Projection: Distolateral, ventrally inclined projection or spur of the basis of the endopod of the male second pleopod.
Distomedian Projection: Distal, relatively narrow extension of the dorsomedian lobule of the petasma.
Dorsolateral Carina: Longitudinal ridge on the dorsolateral region of the carapace running dorsal to the orbital region.
Dorsolateral Lobule: Dorsal part of the lateral lobe of the petasma.
Dorsolateral Sulcus: Longitudinal groove sometimes present close to the dorsomedian line of the sixth abdominal somite.
Dorsomedian Carina: Ridge extending along the middorsal line of the abdominal somites.
Dorsomedian Lobule: Part of the median lobe of the petasma.
Endopod: Mesial ramus of a biramous appendage, especially one arising from the basis or from the protopodite of the pleopod.
Endite: Lobe of several proximal podomeres of various appendages.
Epigastric Tooth: Tooth on the carapace situated above the gastric region behind the first (posteriormost) rostral tooth.
Epipod: Lateral exite of the coxa of a thoracic appendage, sometimes branchial in function.
Epistome: Transverse plate anterior to mouth area.
Exopod: Lateral ramus of a biramous appendage, arising from the basis, or from the protopodite.
Eyestalk: Peduncle or unfaceted part of the eye supporting the cornea.
Flagellum (Flagella): Multiarticulate, usually whip-like terminal part of the antennule or antenna.
Frontal Region: Anterior area of the carapace lying between the orbits and bounded posteriorly by the gastric region.
Gastric Region: Principal median area of the carapace bounded anteriorly by the frontal and orbital regions, and posteriorly by the cardiac region, and laterally by the branchial and hepatic regions.
Gastrofrontal Carina: Short longitudinal ridge extending posteriorly from the ventral extremity of the orbital region.
Gastrofrontal Sulcus: Short longitudinal depression accompanying the gastrofrontal carina dorsally.
Gastrohepatic Gland: Digestive gland associated with the midgut, within the cephalothorax.
Gastro-Orbital Carina: Short longitudinal ridge extending (often curving) anterodorsally from the cervical sulcus towards the orbital region.
Genitalia: The external reproductive structures.
Hepatic Carina: Longitudinally or obliquely disposed ridge of variable length lying ventral to the hepatic region, sometimes extending almost to the anterior margin of the carapace.
Hepatic Region: Paired anterolateral areas of the carapace bounded anteriorly by the antennal region, posteriorly by the branchial region, and mesially by the gastric region.
Hepatic Spine: Lateral spine situated near the anterior margin of the hepatic region of the carapace.
Hepatic Sulcus: Groove ventral to the hepatic region extending posteriorly, sometimes from near the anterior margin of the carapace.
Incisor Process: Cutting process, often toothed or cusped, of the mandible.
Insemination: The act of placing or introducing sperm onto or into the thelycum or seminal receptacles of the female
Integument: Outer covering or exoskeleton.
Ischial Spine: Spine projecting from the ischium or third segment of the thoracic appendage.
Ischium (Ischia): Third podomere from the proximal end of a typically seven-segmented appendage.
Labrum: Upper lip or unpaired structure arising anterior to the mouth and often covering it.
Lateral Lobe: One of the paired lateral parts, often folded, of the petasma.
Longitudinal Suture: Fine longitudinal line extending posteriorly just above the base of the antennal spine.
Mandible: One of the heavily calcified jaws lying anterior to (beneath, in ventral view) other mouth-parts.
Mandibular Palp: Segmented endopods attached laterally to the masticatory part of the mandible.
Maxilla (Maxillae): Paired mouthpart appendages of the fourth and fifth cephalic somites.
Maxilliped: One of a pair of three sets of thoracic appendages, arising posterior to the primary mouthparts. The two anterior pairs are often modified for feeding, while the third pair is often pediform, resembling the pereopods.
Median Lobe: One of the paired dorsal parts, often folded, of the petasma.
Median Sulcus: Dorsomedian groove on the carapace.
Merus (Meri): Fourth segment from the proximal end of a typically seven-segmented appendage.
Mesial Tubercle: A conical to low, rounded protuberance on the surface of the optic calathus.
Ocular Plate: Median cephalic plate bearing the eyestalks laterally.
Ocular Scale: Scale-like structure located on the basal segment of eyestalk.
Optic Calathus: Terminal article of the eyestalk supporting, often embracing, the cornea of the eye.
Orbital Margin: Anterior border of the carapace, often contiguous to the eye.
Orbital Region: Paired areas on the carapace just posterior to the eyes.
Orbital Spine: Spine projecting from the ventral extremity of the orbital margin.
Orbito-Antennal Sulcus: Longitudinal or oblique depression between the orbital margin and the hepatic spine.
Palm: Portion of the chela proximal to the propodal finger.
Pereopod: One of the five posterior paired appendages or legs of the cephalothorax.
Petasma (Petasmata): The male genital structure consisting of the much enlarged and coupled endopods of the first pair of pleopods. The presence or absence of a petasma, or in juveniles, the position of the first endopods (situated more distally in females than in males), is the easiest means of distinguishing between the sexes in penaeid shrimps.
Petasma, Open: The lateral lobes are quite flexible, partially or entirely extended laterally, with the ventral costae not or barely turned ventrally.
Petasma, Semi-Open: The lateral lobes are flexible but folded, with the ventral costae distinctly turned ventromesially, delimiting relatively ample space extending from proximal to distal ends.
Petasma, Semi-Closed: The lateral lobes are rather flexible, markedly folded, supported by strong ribs, with the ventral costae approaching rather closely, delimiting a moderately large space, narrowly open distally where usually overlapped by well-developed distomedian projections.
Petasma, Closed: The lateral lobes are heavily sclerotized, sometimes making the structure virtually rigid, with the ventral costae situated ventromesially, almost abutting, and delimiting a small, sometimes extremely so, space; lateral lobe is usually produced distally into lateral spouts or horns.
Phyllobranchiate Gill: A gill in which the branches are plate-like, usually occurring in paired series along the gill axis.
Pleopod: One of the biramous paired appendages typically arising ventrally from each of the anterior five abdominal somites. They are primarily swimming organs.
Pleurobranchia (Pleurobranchiae): Gill attached to the body wall (pleural membrane), dorsal to the articulation of the appendage.
Pleuron (Pleura): One of the lateral flaps on each of the anterior five abdominal somites.
Podobranchia (Podobranchiae): Gill borne on the basal segment (coxa) of a thoracic appendage.
Podomere: Any one of the segments of an appendage, such as a segment of a pereopod or maxilliped.
Postantennal Spine: Spine located on the anterolateral area of the carapace (on the posterior part of the antennal region).
Postcervical Spine: Spine located immediately posterior to the cervical carina.
Postcervical Sulcus: Subvertical carapace groove located posterior to the cervical sulcus.
Posterior Process: Posterior part of an elongate median protuberance projecting caudally onto the last (XIV) thoracic sternite.
Posterior Protuberance: Conspicuous elevation arising from the posteromedian part of the last (XIV) thoracic sternite.
Posthepatic Carina: Ridge posterior to the hepatic carina, extending onto the lower branchiostegite.
Postocular Sulcus: A small groove situated near the dorsal extremity of the orbital margin.
Postorbital Spine: Spine situated near the orbital margin posterior to the antennal spine.
Postrostral Carina: Dorsomedian ridge extending posteriorly from the base of the rostrum, sometimes nearly reaching the posterior margin of the carapace.
Propodus (Propodi): Sixth or penultimate segment of a typically seven-segmented appendage.
Prosartema: Variable in shape, thin, sometimes scale-like process arising from the mesial base of the first antennular segment, and extending distally.
Protocephalon: Anteriormost part of the body bearing eyes.
Pterygostomian Carina: Ridge running posterior to pterygostomian spine on anteroventral part of carapace.
Pterygostomian Region: Anteroventral area of the carapace.
Pterygostomian Spine: Marginal spine arising from the anteroventral angle or border of the carapace.
Ramus (Rami): A branch of an exopod or endopod.
Rostrum (Rostra): Anteromedian projection of the carapace between the eyes.
Scaphocerite: Laterally rigid lamellate exopod of the antenna; the antennal scale.
Segment: Division of an appendage.
Seminal Receptacles: Unpaired or paired bulbous or tubular sacs associated with the thelycum for the storage of spermatophores or sperm.
Unpaired Receptacles: Noninvaginated, opening either through an exposed median longitudinal slit flanked by lateral plates of sternite XIV, or opening anterior to a single plate.
Paired Receptacles: Invaginated into the cephalothoracic cavity, opening through well protected slits usually on anterior border of sternite XIV, or on anterior part of XIII.
Somite: Each of the main divisions of the body.
Spermatophore: The sperm-carrying, variously complex mass, issuing from the male petasma during copulation.
Statocyst: Sensory organ of awareness of rotation and position located at the base of the first antenna.
Sternite: Ventral part of a thoracic or abdominal somite.
Sternum: Ventral surface of the cephalothorax or abdomen.
Stylocerite: Pointed scale arising from the lateral base of the first segment of the antennular peduncle.
Subhepatic Sulcus: Groove located well ventral to the hepatic region of the carapace and the hepatic spine.
Sublateral Sulcus: Groove located ventral to the lateral carina of the carapace.
Submarginal Carina: An almost longitudinal ridge extending between the rigid and the membranous part of the branchiostegite.
Subrostral Sulcus: A longitudinal elongate groove extending along the dorsal limit of the orbital region.
Sulcus (Sulci): Groove.
Suprahepatic Spine: Spine arising from the edge of the cervical carina dorsal to the hepatic spine.
Supraorbital Spine: Spine located posterior to the orbital margin of the carapace.
Suture: Either transverse or longitudinal, weakly sclerotized line or seam on the carapace.
Telson: Terminal unit of the abdomen bearing the anus.
Tergum (Terga): Arched dorsal part of each of the anterior five abdominal somites.
Thelycum (Thelyca): The female genitalia consisting of modifications of the posterior two, or sometimes three, thoracic sternites (XIIXIV) serving for the storage or transfer of the sperm, usually in spermatophores, and often shielding seminal receptacles.
Thelycum, Open: One in which the seminal receptacles are absent.
Thelycum, Closed: One in which the seminal receptacles are present.
Thoracic Ridge: Highly sclerotized, rib-like transverse structure across posterior margin of sternite XIV.
Transverse Suture: Fine, short vertical line extending dorsally from the ventral margin of the carapace.
Trichobranchiate Gill: A gill in which the branches are fingerlike and project from a central axis.
Uropod: Paired, biramous appendage attached to the sixth abdominal somite, usually combining with the telson to form a tailfan.
Ventral Costa: Ridge extending along the ventropiesial margin of the ventrolateral lobule of the petasma.
Ventrolateral Lobule: Ventral part of the lateral lobe of the petasma.
Ventromedian Lobule: Lateral part of the median lobe of the petasma.
Sources: 1. Adapted from Penaeoid and Sergestoid Shrimps and Prawns of the World (Keys and Diagnoses for the Families and Genera). Dr. Isabel Pérez Farfante and Dr. Brian Kensley (llustrations by Molly Kelly Ryan). 1997. Information (in France): Delphine Henry, Sales Manager, Muséum National d'Histoire Naturelle, Publications Scientifiques Division, 57, rue Cuvier, 75231 Paris Cedex 05, France (phone 33-01-40-79-37-00, fax 33-01-40-79-38-40, email firstname.lastname@example.org); and (outside of France) Backhuys Publishers, P.O. Box 321, NL-2300 AH Leiden, The Netherlands (phone 31-71-517-0208, fax 31-71-517-1856, email email@example.com, webpage http://www.backhuys.com). 2. Bob Rosenberry, Shrimp News International, October 1, 2005.