Family HYPERIIDAE Dana, 1852

Diagnosis

Body length 5–30 mm, rarely longer, generally with pigmented cuticle. Head large, spherical, without projections except in Pegohyperia . Eyes large, occupying most of head surface. Pereonites all separate. Coxae separate from pereonites. Antennae 1, four­articulate in females; multi­articulate in males, sometimes same as in female (e.g. some species of Themisto), with enlarged callynophore with two­field brush of aesthestascs medially. Antennae 2, four­articulate in females, multi­articulate in males. Mandibles with palp in both sexes. Maxillae 1 with palp and well­developed outer lobe; inner lobe absent. Maxillae 2 bilobed, well­developed. Maxilliped with relatively slender outer lobes; inner lobe well­developed, often longer than half­length outer lobes. Gnathopod 1 ranging from barely chelate to distinctly chelate. Gnathopod 2 chelate. Pereopods 3–7 simple. Pereopods 3 & 4 sometimes prehensile. Pereopod 7 subequal in length to, or slightly shorter than, P6. Uropods with articulated endopods and exopods. Telson of moderate size but rarely longer than half of peduncle of U3. Gills on pereonites 2–6. Oostegites on pereonites 2–5.

Six genera: Hyperia, Themisto, Hyperiella, Hyperoche, Pegohyperia and Laxohyperia .

Remarks

Only updated information is provided here as genera of this family have either been reviewed by previous authors (except for Hyperoche), or are monotypic.

Key to the genera of the Family HYPERIIDAE

1. Head produced anteriorly into prominent, sharp lobe between A1 & A2....................... ............................................................................................. Pegohyperia Barnard, 1931

­ Head rounded, not produced between A1 & A2 ......................................................... 2

2. Gnathopods 1 & 2; carpal process laterally compressed, knife­shaped, subequal in length to propodus Hyperoche Bovallius, 1887

­ Gnathopods 1 & 2; carpal process spoon­shaped, or petaloid, length distinctly less than propodus, or if reaching limit of propodus, then G1 simple ............................... 3

3. Gnathopod1 simple.Pereopods3& 4prehensile, propodus closing against dilated carpus .................................................................................................... Themisto Guérin, 1825

­ Gnathopod 1 subchelate, or chelate (carpal process sometimes short). Pereopods 3 & 4 not prehensile, without especially dilated carpus 4

­ Gnathopods 1 & 2 with similarly shaped, broad, flat, petaloid carpus and propodus ... ....................................................................... Laxohyperia Vinogradov & Volkov, 1982

­ Gnathopods 1 & 2 with spoon­shaped carpus; always more developed in G2 ............ 5

5. Pereopods 3 & 4 longer than P5 or P6 .............. Hyperia Latreille in Desmarest, 1823

­ Pereopods 3 & 4 shorter than P5 or P6 .............................. Hyperiella Bovallius, 1887