Family SYNOPIIDAE Dana, 1852

Syrrhoe crenulata, a non-Australian species.

© Copyright from Barnard & Karaman 1991: fig. 129.

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Introduction

Synopiids form a cosmopolitan group of benthic and pelagic amphipods that live from subtidal to bathyal depths. J.L. Barnard (1972) revised the family and combined the Tironidae with Synopiidae. Barnard & Karaman (1991) reported 15 genera and about 83 synopiid species.Currently five species are reported in Australian waters (Hughes & Lowry 2006; Hughes 2009), but species in the genera Jeddo, Latacunga, Metatiron and Tiron are known from collections in central New South Wales waters, and work on deep water collections, such as those from off Bass Strait in the Museum of Victoria, will increase this number. A key to all genera is presented in Barnard & Karaman (1991).

Synopiids may be benthic, demersal or pelagic. Echelman & Fishelson (1990a, 1990b) studied the ecology of the pelagic species Synopia orientalis and S. variablilis off reefs in the Gulf of Aqaba. In the collections of the Australian Museum there are species of Synopia from the reefs at Lizard Island, One Tree Island, Heron Island, Queensland, and from sublittoral Ecklonia communities off Cape Banks and off Port Hacking in New South Wales.

Diagnosis

Head as long as deep or longer than deep; rostrum long; eyes well developed (round), obsolescent or absent. Body laterally compressed; smooth. Antenna 1 shorter than antenna 2; peduncular article 1 longer than article 2; article 2 subequal to, or longer than article 3; article 3 shorter than article 1; primary flagellum 5- or more articulate; callynophore present or absent. Antenna 2 medium length; flagellum shorter or longer than peduncle; 5- or more articulate. Mandible incisor dentate; lacinia mobilis present on both sides; molar medium, vestigial or completely dominating mandible, triturating, weakly triturating or non-triturating; palp present or absent. Maxilla 1 inner plate strongly setose along medial margin. Maxilliped inner plates well developed; outer plates large. Coxae 1–4 longer than broad, overlapping; coxae 1–2 vestigial. Gnathopod 1 not sexually dimorphic; subequal to gnathopod 2; simple or subchelate; coxa subequal to coxa 2; carpus longer than propodus. Gnathopod 2 not sexually dimorphic; simple or subchelate; coxa smaller than or subequal to but not hidden by coxa 3; ischium short; carpus long, longer than propodus. Pereopod 3 coxa longer than broad or broader than long and expanded distally; carpus shorter or longer than propodus, not produced. Pereopod 4 coxa smaller than coxa 3, acuminate ventrally or not acuminate, with well-developed posteroventral lobe; carpus shorter or longer than propodus, not produced. Pereopod 5 shorter than pereopod 6; coxa smaller than coxa 4 or larger than coxa 4, with ventrally produced posterior lobe; basis expanded or slightly expanded, subovate, with or without posteroventral lobe; carpus linear. Pereopod 6 shorter than or subequal to pereopod 7; basis expanded. Pereopod 7 longer than pereopod 5; basis expanded. Pleonites 1–3 with or without transverse dorsal serrations, each with or without dorsal carina. Urosomite 1 subequal to, or longer than urosomite 2; urosomites 1–3 carinate or not. Uropod 3 biramous; peduncle short; rami lanceolate; outer ramus longer than peduncle; inner ramus apically setose or not. Telson laminar; deeply or moderately cleft or entire; longer than broad or as long as broad; apical robust setae absent.

General References

Barnard, J.L. 1972. A review of the family Synopiidae (=Tironidae), mainly distributed in the deep sea (Crustacea: Amphipoda). Smithsonian Contributions to Zoology 124: i-iv, 1-94

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

Dana, J.D. 1852. On the classification of the Crustacea Choristopoda or Tetradecapoda. American Journal of Science and Arts 2 14(41): 297-316

Echelman, T. & Fishelson, L. 1990a. Surface zooplankton dynamics and community structure in the Gulf of Aqaba (Eilat), Red Sea. Marine Biology, Berlin 107: 179-190

Echelman, T. & Fishelson, L. 1990b. Surface zooplankton dynamics in the northern Gulf of Aqaba (Elat), Red Sea. pp. 67-77 in Godeaux, J. (ed.). A Propos des Migrations Lessepsiennes. Bulletin de l'Institut Océanographique Monaco 7: 1-152

Hughes, L.E. 2009. Synopiidae. pp. 880–891 in Lowry, J.K. & Myers, A.A. (eds). Benthic Amphipoda (Crustacea: Peracarida) of the Great Barrier Reef, Australia. Zootaxa 2260: 1-930

Hughes L.E. & Lowry J.K. 2006. New species of Amphipoda (Crustacea: Peracarida) from the Solitary Islands, New South Wales, Australia. Zootaxa 1222: 1-52

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