Amphipoda: Families and Subfamilies

J.K. Lowry & R.T. Springthorpe

Phoxocephalidae Sars, 1891

Description. Head free, not coalesced with peraeonite 1; exposed; longer than deep; anteroventral margin weakly recessed or moderately recessed or strongly recessed or straight or concave or oblique, anteroventral margin deeply excavate or shallowly excavate, anteroventral corner hooked; rostrum present or absent (check), short or moderate or long; eyes present, well developed or obsolescent, or absent; coalesced, or not coalesced; 1 pair; not bulging. Body laterally compressed; cuticle smooth.

Antenna 1 shorter than antenna 2, or subequal to antenna 2, or longer than antenna 2; peduncle with many robust and slender setae, or with sparse robust and slender setae; 3-articulate; peduncular article 1 shorter than article 2, or subequal to article 2, or longer than article 2; antenna 1 article 2 longer than article 3; peduncular articles 1-2 not geniculate; accessory flagellum present; antenna 1 callynophore present, or absent. Antenna 2 present; short, or medium length, or long, or greater than body length; articles not folded in zigzag fashion; article 1 with hook-like (ensiform) process, or without hook-like process; flagellum shorter than peduncle, or as long as peduncle, or longer than peduncle; less than 5-articulate, or 5 or more articulate; not clavate; calceoli present, or absent.

Mouthparts well developed. Mandible incisor dentate, or smooth, or minutely serrate; lacinia mobilis present on both sides; accessory setal row without distal tuft; molar present, medium, triturative or non-triturative; palp present. Maxilla 1 present; inner plate present, weakly setose apically or without setae; palp present, not clavate, 1 -articulate or 2 -articulate. Maxilla 2 inner plate present; outer plate present. Maxilliped inner and outer plates well developed or reduced, palps present, well developed or reduced; inner plates well developed or reduced, separate; outer plates present, small or vestigial; palp 4-articulate, article 3 without rugosities. 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, overlapping, coxae not acuminate. Coxae 1-3 not successively smaller, none vestigial. Coxae 2-4 coxa 4 immensely broadened, or none immensely broadened.

Gnathopod 1 not sexually dimorphic; smaller (or weaker) than gnathopod 2, or subequal to gnathopod 2; subequal to coxa 2, or larger than coxa 2; gnathopod 1 merus and carpus not rotated; gnathopod 1 carpus/propodus cantilevered on narrow hinge, or carpus/propodus not cantilevered; shorter than propodus, or subequal to propodus, or longer than propodus; gnathopod 1 not produced along posterior margin of propodus; dactylus large. Gnathopod 2 not sexually dimorphic; subchelate, or parachelate, or chelate; coxa smaller than but not hidden by coxa 3, or subequal to but not hidden by coxa 3; ischium short, or elongate; merus not fused along posterior margin of carpus or produced away from it; carpus/propodus cantilevered on narrow hinge or carpus/propodus not cantilevered, carpus short or elongate, shorter than propodus or subequal to propodus or longer than propodus, not produced along posterior margin of propodus.

Peraeopods heteropodous (3-4 directed posteriorly, 5-7 directed anteriorly), 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; carpus shorter than propodus, not produced; dactylus well developed, or small or poorly developed. Coxa larger than coxa 3, not acuminate, with well developed posteroventral lobe; carpus not produced. Peraeopods 5-7 with many rows of facial and marginal robust setae, or with many marginal slender setae and few or no robust setae, or with few robust or slender setae; dactyli without slender or robust setae. Peraeopod 5 well developed; shorter than peraeopod 6; coxa smaller than coxa 4, with ventrally produced posterior lobe or with posterodorsal lobe; basis expanded or linear, subrectangular or subtriangular, with posteroventral lobe or without posteroventral lobe; merus/carpus free; carpus expanded, or weakly expanded, or 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, or subequal to peraeopod 5; different in structure to peraeopod 6; with 7 articles; basis expanded, with long dense slender setae or 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 setose, or without setae.

Urosome not dorsoventrally flattened; urosomites 1 to 3 free; urosomite 1 subequal to urosomite 2, or longer than urosomite 2, or much longer than urosomite 2; urosome urosomite 1 carinate, or urosomites not carinate, or urosomite 3 carinate; urosomites 1-2 without transverse dorsal serrations. Uropods 1-2 apices of rami with robust setae, or without robust setae. Uropods 1-3 similar in structure and size. Uropod 1 peduncle without long plumose setae, without basofacial robust seta, with ventromedial spur or without ventromedial spur. Uropod 2 well developed; without ventromedial spur, without dorsal flange; inner ramus subequal to outer ramus. Uropod 3 sexually dimorphic, or not sexually dimorphic; peduncle short; outer ramus shorter than peduncle or subequal to peduncle or longer than peduncle, 1-articulate or 2-articulate, without recurved spines. Telson laminar; deeply cleft; longer than broad, or as long as broad, or broader than long; apical robust setae present, or 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