Amphipoda: Families and Subfamilies

J.K. Lowry & R.T. Springthorpe

Platyscelidae Bate, 1862

Description. Head free, not coalesced with peraeonite 1; exposed; deeper than long; anteroventral margin rounded, anteroventral corner rounded; rostrum present, short; eyes present, well developed or obsolescent; coalesced; 1 pair; not bulging. Body conglobate; cuticle smooth.

Antenna 1 shorter than antenna 2, or longer than antenna 2; peduncle with sparse robust and slender setae; 1- or 2-articulate; peduncular article 1 longer than article 2; accessory flagellum absent; antenna 1 callynophore present. Antenna 2 present; short, or greater than body length; male peduncular and flagellar articles folded in zigzag fashion, or articles not folded in zigzag fashion; without hook-like process; flagellum shorter than 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 absent; palp present or absent. Maxilla 1 present; inner plate absent; palp absent, 0 -articulate. Maxilla 2 inner plate present; outer plate present. Maxilliped inner and outer plates well developed or reduced, palps absent; inner plates well developed or reduced, fused medially; outer plates present. Labium smooth.

Peraeon. Peraeonites 1-7 separate; complete; sternal gills absent; pleurae absent.

Coxae 1-7 well developed, none fused with peraeonites. Coxae 1-4 longer than broad or broader than long, overlapping, coxae not acuminate. Coxae 1-3 not successively smaller, none vestigial. Coxae 2-4 none immensely broadened.

Gnathopod 1 not sexually dimorphic; smaller (or weaker) than gnathopod 2, or subequal to gnathopod 2; smaller than coxa 2, or subequal to coxa 2; gnathopod 1 merus and carpus not rotated; gnathopod 1 carpus/propodus not cantilevered; shorter than propodus, or subequal to propodus, or longer than propodus; gnathopod 1 strongly produced along posterior margin of propodus, or not produced along posterior margin of propodus; dactylus minute. Gnathopod 2 not sexually dimorphic; simple, or carpochelate, or subchelate; coxa smaller than but not hidden by coxa 3, or subequal to but not hidden by coxa 3; ischium short; merus not fused along posterior margin of carpus or produced away from it; carpus/propodus not cantilevered, carpus short or elongate, shorter than propodus or subequal to propodus or longer than propodus, strongly produced along posterior margin of propodus or not 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, longer than broad or broader than long; carpus subequal to propodus or longer than propodus, not produced; dactylus well developed, or minute. Coxa subequal to coxa 3 or larger than coxa 3, not acuminate, without posteroventral lobe; carpus not produced. Peraeopods 5-7 with few robust or slender setae; dactyli without slender or robust setae. Peraeopod 5 well developed; shorter than peraeopod 6; coxa larger than coxa 4, without posterior lobe; basis expanded, without posteroventral lobe; merus/carpus free; carpus linear; setae absent. Peraeopod 6 longer than peraeopod 7; merus/carpus free; dactylus without setae. Peraeopod 7 coxa and basis well developed, remaining articles reduced or absent, or with 6-7 well developed articles; shorter than peraeopod 5; different in structure to peraeopod 6; with coxa and basis plus one or more rudimentary articles; basis expanded, without dense slender 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 well developed; without ventromedial spur, without dorsal flange; inner ramus longer than outer ramus. Uropod 3 not sexually dimorphic; peduncle short; outer ramus longer than peduncle, 1-articulate, without recurved spines. Telson laminar; entire; apical robust setae absent.


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