Family CYSTISOMATIDAE Willemöes-Suhm, 1875

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Introduction

The Cystisomatidae, a monotypic family of large, fragile amphipods, are rarely collected and little is known of them. The genus Cystisoma currently comprises about five species, most with wide distributions in tropical and temperate waters. Répelin (1978) recorded three species from the western and central Pacific Ocean. According to Zeidler (1992), Cystisoma is in need of revision. Vinogradov et al. (1982) provided a key to the world species.
Zeidler (2003) proposed a new superfamily, Cystisomatoidea, to accommodate the family Cystisomatidae, primarily based on the unique method of brooding the young.
Following the results of Lowry & Myers (2017), Cystisomatidae turns out to be sister taxon of Dairellidae and deeply embedded in the Phronimoidea.

Diagnosis

Head longer than deep; anteroventral margin rounded; rostrum absent. Body laterally compressed. Antenna 1 longer than antenna 2; peduncle 1-articulate; calceoli present. Mandible palp absent. Maxilla 1 inner plate absent; palp 1-articulate. Maxilla 2 inner plate absent. Coxae 1–7 vestigial or absent; fused with pereonites. Gnathopod 1 carpochelate; carpus longer than propodus. Pereopods some, all or none prehensile. Pereopod 3 carpus subequal to propodus. Pereopod 5 longer than pereopod 6; without posteroventral lobe; carpus linear. Pereopod 6 longer than pereopod 7; basis linear. Pereopod 7 basis linear. Uropod 1 uniramous. Uropod 2 absent. Uropod 3 not sexually dimorphic; uniramous; peduncle with medial process.

General References

Lowry, J.K. & Myers, A.A. 2017. A Phylogeny and Classification of the Amphipoda with the establishment of the new order Ingolfiellida (Crustacea: Peracarida). Zootaxa 4265: 1–89 [41]

Répelin, R. 1978. Les amphipodes pélagiques du Pacifique occidental et central. Travaux et Documents de l'ORSTOM, Paris 86: 1-381

Vinogradov, M.E., Volkov, A.F. & Semenova, T.N. 1982. Amphipoda — Hyperiidea of the World Ocean. Nauka Leningrad U.S.S.R. Opred. po Faune S.S.S.R 132: 1-491 [in Russian]

Willemöes-Suhm, R.V. 1875. On some Atlantic Crustacea from the "Challenger" Expedition. Transactions of the Linnean Society of London 2nd Series Zoology 1: 23-59, pls 6-13

Zeidler, W. 1992. Hyperiid amphipods (Crustacea: Amphipoda: Hyperiidea) collected recently from eastern Australian waters. Records of the Australian Museum 44(1): 85-133

History of changes