Family LAPHYSTIOPSIDAE Stebbing, 1899

Laphystiopsis zomerysis

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Family LAPHYSTIOPSIDAE Stebbing, 1899

Introduction

Laphystiopsids are rare deep-sea amphipods divided among three genera, with eight species. J.L. Barnard (1999) considered the Laphystiidae and the Laphystiopsidae to be sister families. Based on one record of Laphystiopsus iridometrae Shoemaker, 1919, embedded in the tissues of the crinoid Iridometra melpome, J.L. Barnard (1999) considered laphystiopsids to be "parasites" on other organisms. Only two species of Laphystiopsis are known from Australian waters. J.L. Barnard (1999) gives a key to world genera and a key to world species of Laphystiopsis.

Diagnosis

Head longer than deep; rostrum moderate, long or absent; eyes well developed, obsolescent or absent. Body dorsoventrally flattened or subcylindrical; smooth. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2; article 2 longer than article 3; article 3 shorter than article 1; accessory flagellum absent; primary flagellum 5- or more articulate; callynophore present or absent. Antenna 2 short or medium length; flagellum shorter than peduncle; 5- or more articulate. Mandible incisor dentate; molar fully triturating. Maxilla 1 inner plate weakly setose apically; palp 1- or 2-articulate. Maxilliped inner plates well developed; outer plates vestigial. Coxae 1–4 broader than long, overlapping or discontiguous. Gnathopod 1 not sexually dimorphic; smaller (or weaker) than or subequal to gnathopod 2; simple, weakly subchelate or parachelate; coxa smaller or subequal to coxa 2; carpus subequal to propodus. Gnathopod 2 not sexually dimorphic; simple; coxa smaller than or subequal to but not hidden by coxa 3; ischium short; carpus short, subequal to propodus. Pereopod 3 coxa broader than long; carpus shorter than propodus, not produced. Pereopod 4 coxa subequal to, or larger than coxa 3, without posteroventral lobe; carpus shorter than propodus, not produced. Pereopod 5 shorter than pereopod 6; coxa larger than coxa 4, with ventrally produced posterior lobe or equilobate; basis slightly expanded, subovate, without posteroventral lobe; carpus linear. Pereopod 6 shorter than pereopod 7; basis slightly expanded. Pereopod 7 longer than pereopod 5; basis expanded. Pleonite 3 with or without dorsal carina. Urosome dorsoventrally flattened; urosomite 1 longer or much longer than urosomite 2, carinate. Uropod 3 biramous; peduncle short; rami lanceolate; outer ramus longer than peduncle; inner ramus not apically setose. Telson laminar; entire; longer than broad or as long as broad; dorsal and apical robust setae absent.