Family OCHLESIDAE Stebbing, 1910

Ochlesis eridunda

© Copyright from Barnard 1972: fig. 168.

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Introduction

Barnard & Karaman (1991) considered ochlesids as a subfamily, but other workers (e.g. Watling & Thurston 1989; Coleman & Barnard 1991) considered them as a family level group. Ochlesids form a small group of mainly Southern Hemisphere, shallow-water algal-dwelling amphipods. Two of the four genera and three of the nine known species occur in Australian waters. Almost nothing is known of the behaviour, ecology or life histories of ochlesids. Barnard & Karaman (1991) present a key to all genera.

Diagnosis

Head concealed or partially concealed; deeper than long; rostrum long; eyes round. Body laterally compressed or subglobular; smooth or processiferous. Antenna 1 subequal to, or longer than antenna 2; peduncular article 1 longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; accessory flagellum absent; primary flagellum less than 5-articulate; callynophore present or absent. Antenna 2 short; flagellum shorter than peduncle; less than 5-articulate. Mandible incisor dentate or smooth; lacinia mobilis present on left side only; molar triturating, weakly triturating or non-triturating. Maxilla 1 inner plate strongly setose along medial margin, weakly setose apically or without setae; palp reduced, 1-articulate. Maxilliped inner plates well developed; outer plates very large. Coxae 1–4 longer than broad, overlapping, coxae 1–3 ventrally acuminate. Gnathopod 1 not sexually dimorphic; smaller (or weaker) than gnathopod 2; simple; coxa smaller than coxa 2; carpus subequal to propodus. Gnathopod 2 not sexually dimorphic; simple; coxa subequal to but not hidden by coxa 3; short; carpus long, subequal to propodus, strongly produced along posterior margin of propodus. Pereopod 3 carpus subequal to propodus, not produced. Pereopod 4 coxa larger than coxa 3, with well-developed posteroventral lobe; carpus shorter than or subequal to propodus, not produced. Pereopod 5 subequal to pereopod 6; coxa subequal to, or larger than coxa 4, with ventrally produced posterior lobe or without posterior lobe; basis expanded, subovate or subrectangular, with posteroventral lobe; carpus linear. Pereopod 6 subequal to pereopod 7; basis slightly expanded. Pereopod 7 subequal to pereopod 5; basis expanded. Urosomite 1 much longer than urosomite 2; urosomite 1 carinate or urosomites not carinate. Uropods 1–2 apices of rami without robust setae. Uropod 3 biramous; peduncle long; rami lanceolate; outer ramus shorter than peduncle; inner ramus not apically setose. Telson laminar; entire; longer than broad or as long as broad; dorsal robust setae present or absent; apical robust setae absent.

General References

Barnard, J.L. 1972. Gammaridean Amphipoda of Australia, Part I. Smithsonian Contributions to Zoology 103: i-vi 1-333

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

Coleman, C.O. & Barnard, J.L. 1991. Revision of Iphimediidae and similar families (Amphipoda: Gammaridea). Proceedings of the Biological Society of Washington 104(2): 253-268

Stebbing, T.R.R. 1910. Scientific results of the trawling expedition of H.M.C.S. "Thetis" Crustacea Part V. Amphipoda. Memoirs of the Australian Museum 4(12): 567-658, pls 47-60

Watling, L. & Thurston, M. 1989. Antarctica as an evolutionary incubator: evidence from the cladistic biogeography of the amphipod family Iphimediidae. pp. 297-313 in Crame, J.A. Origins and Evolution of the Antarctic Biota. Geological Society of London, Special Publication 47: 1-322

History of changes