Amphipoda: Families and Subfamilies

J.K. Lowry & R.T. Springthorpe

Cystisomatidae Willemoes-Suhn, 1875

Description. Head free, not coalesced with peraeonite 1; exposed; longer than deep; anteroventral margin rounded, anteroventral corner rounded; rostrum absent; eyes present, well developed or obsolescent; not coalesced; 1 pair; not bulging. Body laterally compressed; cuticle smooth.

Antenna 1 longer than antenna 2; peduncle with sparse robust and slender setae; 1- or 2-articulate; accessory flagellum absent; antenna 1 callynophore present. Antenna 2 present; short; articles not folded in zigzag fashion; without hook-like process; flagellum shorter than peduncle, or as long as peduncle, or longer than peduncle; less than 5-articulate; not clavate; calceoli absent.

Mouthparts well developed. Mandible incisor dentate; lacinia mobilis present on both sides; accessory setal row without distal tuft; molar present, medium; palp absent. Maxilla 1 present; inner plate absent; palp present, not clavate, 1 -articulate. Maxilla 2 inner plate absent; outer plate present. Maxilliped inner and outer plates well developed or reduced, palps absent; inner plates well developed, fused medially; outer plates present. Labium smooth.

Peraeon. Peraeonites some or all of peraeonites 1-5 coalesced; complete; sternal gills absent; pleurae absent.

Coxae 1-7 vestigial or absent, coxae 1-7 fused with peraeonites.

Gnathopod 1 not sexually dimorphic; smaller (or weaker) than gnathopod 2; gnathopod 1 merus and carpus not rotated; gnathopod 1 carpus/propodus not cantilevered; longer than propodus; gnathopod 1 strongly produced along posterior margin of propodus; dactylus large. Gnathopod 2 not sexually dimorphic; carpochelate; ischium short; merus not fused along posterior margin of carpus or produced away from it; carpus/propodus not cantilevered, carpus elongate, shorter than propodus, strongly produced along posterior margin of propodus.

Peraeopods heteropodous (3-4 directed posteriorly, 5-7 directed anteriorly), some or all prehensile or none prehensile. Peraeopod 3 well developed. Peraeopod 4 well developed. 3-4 not glandular; 3-7 without hooded dactyli, 3-7 propodi without distal spurs. Coxa well developed; carpus subequal to propodus, not produced; dactylus minute. Carpus not produced. Peraeopods 5-7 with few robust or slender setae; dactyli without slender or robust setae. Peraeopod 5 well developed; longer than peraeopod 6; basis linear, without posteroventral lobe; merus/carpus free; carpus linear; setae absent. Peraeopod 6 longer than peraeopod 7; merus/carpus free; dactylus without setae. Peraeopod 7 with 6-7 well developed articles; shorter than peraeopod 5; different in structure to peraeopod 6; with 7 articles; basis linear, without dense slender setae; dactylus without setae.

Pleon. Pleonites 1-3 without transverse dorsal serrations, without dorsal carina; without slender or robust dorsal setae. Epimera 1-3 present. Epimeron 1 well developed. Epimeron 2 without setae.

Urosome not dorsoventrally flattened; urosomites 1 free, 2 and 3 coalesced; urosome urosomites not carinate; urosomites 1-2 without transverse dorsal serrations. Uropods 1-2 apices of rami without robust setae. Uropods 1-3 similar in structure and size. Uropod 1 peduncle without long plumose setae, without basofacial robust seta, without ventromedial spur. Uropod 2 absent. Uropod 3 not sexually dimorphic; peduncle elongate; outer ramus shorter than peduncle, 1-articulate, without recurved spines. Telson laminar; entire; broader than long; apical robust setae absent.

Habitat. marine.

Habitat. planktonic.


Cite this publication as: 'J.K. Lowry & R.T. Springthorpe (2001 onwards). Amphipoda: Families and Subfamilies. Version 1: 1 September 2001. http://crustacea.net/'. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).

Index