Family PHOXOCEPHALIDAE Sars, 1891

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Introduction

The Phoxocephalidae were J.L. Barnard's special group and because of this they are probably the best known amphipods in a modern context. Individually and with other authors he described about 150 phoxocephalid species, around half from Australian waters. Barnard & Drummond (1978) set up a modern subfamily classification for the group, recently slightly modified by Jarrett and Bousfield (1994). However, Taylor and Poore (2001) questioned the monophyly of all of the subfamilies and genera established by Barnard and Drummond (1978) and Jarrett and Bousfield (1994). Currently 43% of the 67 known genera and 30% of the 254 known species occur in Australian waters.

Phoxocephalids are almost entirely benthic amphipods. They are known as deposit feeders (Enequist 1949), and predators (Oliver et al. 1984; Oliver & Slattery 1985). Slattery (1985) and Fenwick (1985) studied life histories of several phoxocephalid species. Sainte-Marie (1991) summarised life history traits for a range of phoxocephalid species and Conlan (1991) reviewed their mating behaviour. Phoxocephalids are known from all oceans and depths, but do not occur in freshwater. They vary in size from about 2 mm to 15 mm.

The main Australian work of Barnard and Drummond (1978) thoroughly documents the fauna from the south-eastern part of the country, but much work remains to be done for the rest of Australian waters. A recent key to all genera can be found in Barnard and Karaman (1991).

 

Diagnosis

Head longer than deep; anteroventral margin weakly, moderately, or strongly recessed, straight, concave or oblique and deeply or shallowly excavate; anteroventral corner hooked; rostrum short, moderate, long or absent; eyes well developed (round, ovoid, reniform or subrectangular), obsolescent or absent. Body laterally compressed; smooth; with sparse slender setae or without setae. Antenna 1 shorter than, subequal to, or longer than antenna 2; peduncle with many or sparse robust or slender setae; peduncular article 1 shorter than, subequal to, or longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; primary flagellum less than or more than 5-articulate; callynophore present or absent. Antenna 2 short, medium length, long, or longer than body; peduncle with many or sparse robust or slender setae; article 1 with or without hook-like (ensiform) process; flagellum shorter than, as long as or longer than peduncle; less than or more than 5-articulate; calceoli present or absent. Mandible incisor dentate, smooth or minutely serrate; lacinia mobilis present on both sides; molar triturating, weakly triturating, a small triturating hump with large robust setae or a smooth protuberance with large robust setae. Maxilla 1 inner plate weakly setose apically or without setae; palp 1- or 2-articulate. Maxilliped inner plates well developed or reduced; outer plates small or vestigial. Coxae 1–4 longer than broad, overlapping; coxa 4 immensely broadened or not. Gnathopod 1 not sexually dimorphic; smaller (or weaker) than or subequal to gnathopod 2; subchelate or chelate; coxa subequal to, or larger than coxa 2; carpus/propodus cantilevered on narrow hinge or not; carpus shorter than, subequal to or longer than propodus. Gnathopod 2 not sexually dimorphic; subchelate, parachelate or chelate; coxa smaller than or subequal to but not hidden by coxa 3; ischium short or long; carpus short or long, shorter than, subequal to, or longer than propodus; dactylus well developed or minute. Pereopod 3 coxa longer than broad; carpus shorter than propodus, not produced; dactylus well developed, small or poorly developed. Pereopod 4 coxa larger than coxa 3, with well-developed posteroventral lobe; carpus shorter or longer than propodus, not produced; dactylus well developed, small or poorly developed. Pereopods 5–7 with many rows of facial and marginal robust setae, with many marginal slender setae and few or no robust setae or with few robust or slender setae. Pereopod 5 shorter than pereopod 6; coxa smaller than coxa 4, with ventrally produced posterior lobe or with posterodorsal lobe; basis expanded or linear, subrectangular or subtriangular, with or without posteroventral lobe; carpus expanded, weakly expanded or linear; dactylus well developed, small or poorly developed. Pereopod 6 longer than pereopod 7; basis expanded or slightly expanded. Pereopod 7 shorter than or subequal to pereopod 5; different in structure to pereopod 6; basis expanded, with broad posteroventral lobe or subovate and shield-like, with or without dense long slender setae. Epimeron 2 setose or without setae. Urosomites 1–3 free; urosomite 1 subequal to, longer or much longer than urosomite 2; urosomite 1 carinate, urosomite 3 carinate or urosomites not carinate. Uropods 1–2 apices of rami with or without robust setae. Uropod 1 peduncle with or without ventromedial spur. Uropod 3 biramous; peduncle short; rami styliform or lanceolate; outer ramus shorter than, subequal to, or longer than peduncle, without recurved spines; inner ramus apically setose or not. Telson laminar; deeply cleft; longer than broad, as long as broad or broader than long; dorsal and apical robust setae present or absent.

 

General References

Barnard, J.L. & Drummond, M.M. 1978. Gammaridean Amphipoda of Australia, Part III: The Phoxocephalidae. Smithsonian Contributions to Zoology 245: 1-551

Barnard, J.L. & Karaman, G.S. 1991. The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement 13: 1-866

Conlan, K.E. 1991. Precopulatory mating behavior and sexual dimorphism in the amphipod Crustacea. pp. 255-282 in Watling, L. (ed.). VIIth International Colloquium on Amphipoda. Hydrobiologia 223: i-viii, 1-299

Enequist, P. 1949. Studies on the soft-bottom amphipods of the Skagerak. Zoologiska Bidrag Från Uppsala 28: 297-492

Fenwick, G.D. 1985. Life-histories of four co-occurring amphipods from a shallow, sand bottom at Kaikoura, New Zealand. New Zealand Journal of Zoology 12: 71-105

Jarrett, N.E. & Bousfield, E.L. 1994. The amphipod superfamily Phoxocephaloidea on the Pacific coast of North America. Family Phoxocephalidae. Part I. Metharpiniinae, new subfamily. Amphipacifica 1(1): 58-131, tables 1-12

Oliver, J.S., Oakden, J.M. & Slattery, P.N. 1984. Phoxocephalid amphipod crustaceans as predators on larvae and juveniles in marine soft-bottom communities. Marine Ecology Progress Series 7: 179-184

Oliver, J.S. & Slattery, P.N. 1985. Effects of crustacean predators on species composition and population structure of soft-bodied infauna from McMurdo Sound, Antarctica. Ophelia 24: 155-175

Sainte-Marie, B. 1991. A review of the reproductive bionomics of aquatic gammaridean amphipods: variation of life history traits with latitude, depth, salinity and superfamily. pp. 189-227 in Watling, L. VIIth International Colloquium on Amphipoda. Hydrobiologia 223: i-viii, 1-299

Sars, G.O. 1891. An Account of the Crustacea of Norway, with Short Descriptions and Figures of all the Species. Vol. 1 Amphipoda. Pts 4–9. Christiania & Copenhagen : Alb. Cammermeyer pp. 69-212, pls 25-72.

Slattery, P.N. 1985. Life histories of infaunal amphipods from subtidal sands of Monterey Bay, California. Journal of Crustacean Biology 5(4): 635-649

Taylor, J. & Poore, G.C.B. 2001. Descriptions of new species of Birubius (Amphipoda: Phoxocephalidae) from Australia and Papua New Guinea with comments on the Birubius-Kulgaphoxus-Tickalerus-Yan complex. Memoirs of Museum Victoria 58(2): 255-295

 

History of changes

Published	As part of group	Action Date	Action Type	Compiler(s)
05-Aug-2022	AMPHIPODA	06-Feb-2013	MOVED	Dr Jim Lowry (AM)
05-Aug-2022		22-Nov-2012	MODIFIED
05-Aug-2022		16-Dec-2011	MODIFIED
05-Aug-2022		30-Sep-2011	MODIFIED
		12-Feb-2010	(import)