Family STEGOCEPHALIDAE Dana, 1852

Andaniotes wallaroo

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Family STEGOCEPHALIDAE Dana, 1852

Introduction

Stegocephalids are a cosmopolitan, mainly cold water group living from moderate depths on continental shelves to bathyal depths. Little is known of the biology or ecology of stegocephalids, but Steele (1967) reported Stegocephalus inflatus Krøyer as a protandrous hermaphrodite. Other workers (Moore 1979; Moore & Rainbow 1984, 1989) showed that some species are predators on coelenterates. Lowry & Stoddart (1995) reported species of Andaniotes as scavengers. Sars (1891), Arndt (1933) and Vader (1984) recorded stegocephalids from sponges and the branchial cavities of ascidians. Berge & Vader (2001) consider that stegocephalids are 'predominately micropredators feeding on cnidarians' except for species of Andaniotes which are known scavengers. Berge (2001a, 2001b) and Berge & Vader (2000, 2001, in press) revised the Stegocephalidae of Australian and New Zealand waters and provided a key to all genera and species in the area. Berge & Vader (2001) provided keys to the world subfamilies and genera of the Stegocephalidae.

Diagnosis

Head deeper than long or much deeper than long; rostrum short, moderate, long or absent; eyes well developed (round), obsolescent or absent. Body laterally compressed or subglobular; smooth. Antenna 1 shorter than or subequal to antenna 2; peduncular article 1 longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; primary flagellum less than or more than 5-articulate; callynophore present. Antenna 2 short; flagellum shorter than peduncle; 5- or more articulate. Mandible incisor dentate or smooth; lacinia mobilis present on left side only; molar absent; palp absent. Maxilla 1 inner plate strongly setose along medial margin or weakly setose apically; palp large or reduced, 1- or 2-articulate. Maxilliped inner plates well developed; outer plates very large, large or small. Coxae 1–4 longer than broad, overlapping; coxa 1 or coxae 1–3 ventrally acuminate. Gnathopod 1 not sexually dimorphic; smaller (or weaker) than, subequal to, or larger (or stouter) than gnathopod 2; simple or subchelate; coxa smaller or subequal to coxa 2; carpus shorter than or subequal to propodus. Gnathopod 2 not sexually dimorphic; subchelate; coxa smaller than or subequal to but not hidden by coxa 3; ischium long; carpus short or long, longer than propodus. Pereopods some, all or none prehensile. Pereopod 3 coxa longer than broad; carpus shorter than propodus, not produced. Pereopod 4 coxa larger than coxa 3, with well-developed posteroventral lobe; carpus shorter than propodus, not produced. Pereopod 5 shorter or longer than pereopod 6; coxa smaller than coxa 4, with ventrally produced posterior lobe or without posterior lobe; basis linear, subrectangular, without posteroventral lobe; carpus linear. Pereopod 6 longer than pereopod 7; basis expanded, slightly expanded or linear. Pereopod 7 shorter than, subequal to, or longer than pereopod 5; similar or different in structure to pereopod 6; basis expanded. Pleonite 3 with or without dorsal carina. Epimeron 2 setose or without setae. Urosomites 1–3 free or 1 free, 2 and 3 coalesced; urosomite 1 shorter than, subequal to or longer than urosomite 2; urosomite 1 carinate or urosomites not carinate. Uropods 1–2 apices of rami without robust setae. Uropod 3 biramous, uniramous or rami absent; peduncle short or long; rami lanceolate; outer ramus longer than peduncle; inner ramus not apically setose. Telson laminar; moderately or weakly cleft or entire; longer than broad or as long as broad; dorsal and apical robust setae absent.