Family OEDICEROTIDAE Lilljeborg, 1865

Monoculodes carinatus, a non-Australian species.

© Copyright from Barnard & Karaman 1991: fig. 99.

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Introduction

Oedicerotids are cosmopolitan benthic amphipods found at all depths. Barnard & Karaman (1991) reported 30 genera and about 190 species. They are one of the poorest known groups in Australian waters; the few species reported have been incidental to other work. Oedicerotids are distinctive amphipods, often with the eyes coalesced on top of the head. They are mainly benthic infaunal animals considered to be deposit feeders by Enequist (1949). They are of moderate size, although some cold water species are up to 20 mm in length.

Pirlot (1936) and Hirayama (1992) studied the taxonomy of oedicerotid amphipods from south-east Asia. There are no life history studies on Australian species. Beare & Moore (1994) made biological observations on Monoculodes gibbosus.

Seven species are documented here, but much work is needed to document the Australian fauna. A recent key to all genera is found in Barnard & Karaman (1991).

Diagnosis

Head as long as deep or longer than deep; anteroventral margin oblique; rostrum short, long or absent; eyes well developed (round, ovoid, reniform or lageniform), obsolescent or absent. Body laterally compressed or subcylindrical; smooth. Antenna 1 shorter than, subequal to, or longer than antenna 2; peduncular article 1 shorter than, subequal to, or longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; accessory flagellum present or absent; primary flagellum 5- or more articulate; callynophore present or absent. Antenna 2 short or medium length; flagellum shorter than, as long as or longer than peduncle; 5- or more articulate; calceoli present. Mandible incisor dentate or smooth; molar triturating, weakly triturating or non-triturating. Maxilla 1 inner plate strongly setose along medial margin or weakly setose apically. Maxilliped inner plates well developed; outer plates small. Coxae 1–4 longer than broad, overlapping. Gnathopod 1 not sexually dimorphic; subequal to gnathopod 2; simple or subchelate; coxa subequal to coxa 2; carpus shorter than, subequal to, or longer than propodus, strongly, slightly or not produced along posterior margin of propodus. Gnathopod 2 not sexually dimorphic; simple or subchelate; coxa smaller than or subequal to but not hidden by coxa 3; ischium short; carpus short or long, shorter than, subequal to, or longer than propodus, strongly, slightly or not produced along posterior margin of propodus. Pereopod 3 coxa longer than broad, broader than long or as long as broad; carpus subequal to propodus, not produced. Pereopod 4 coxa subequal to, or larger than coxa 3, with well-developed posteroventral lobe or without posteroventral lobe; carpus subequal to propodus, not produced. Pereopods 5–7 with many rows of facial and marginal robust setae. Pereopod 5 shorter than or subequal to pereopod 6; coxa smaller than coxa 4, without posterior lobe or equilobate; basis expanded or slightly expanded, subrectangular or subovate, without posteroventral lobe; carpus linear. Pereopod 6 shorter than pereopod 7; basis expanded. Pereopod 7 immensely long; different in structure to pereopod 6; basis expanded. Urosomites 1–3 free or 1 free, 2 and 3 coalesced; urosomite 1 longer or much longer than urosomite 2. Uropods 1–2 apices of rami without robust setae. Uropod 3 biramous; peduncle long; rami lanceolate; outer ramus subequal to, or longer than peduncle; inner ramus not apically setose. Telson laminar; notched, emarginate or entire; as long as broad; dorsal and apcial robust setae present or absent.

General References

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

Beare, D.J. & Moore, P.G. 1994. Observations on the biology of a rare British marine amphipod: Monoculodes gibbosus (Crustacea: Amphipoda: Oedicerotidae). Journal of the Marine Biological Association of the United Kingdom 74: 193-201

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

Hirayama, S. 1992. Oedicerotidae (Crustacea: Amphipoda) from Hong Kong. Asian Marine Biology 9: 139-166

Lilljeborg, W. 1865. On the Lysianassa magellanica H. Milne Edwards and on the Crustacea of the suborder Amphipoda and subfamily Lysianassina found on the coast of Sweden and Norway. Uppsala : Royal Academic Press 38 pp. 5 pls.

Pirlot, J.M. 1936. Les amphipodes de l'expédition du Siboga. Deuxième partie: les amphipodes gammarides, II: Les amphipodes de la mer profonde. 3: Addendum et partie generale. III: Les amphipodes littoraux. I: Lysianassidae, Ampeliscidae, Leucothoidae, Stenothoidae, Phliantidae, Colomastigidae, Ochlesidae, Liljeborgiidae, Oedicerotidae, Synopiidae, Eusiridae, Gammaridae. Siboga-Expéditie Report 33(E): 237-328

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