METALANCEOLIDAE, Zeidler, 2009

Zeidler, Wolfgang, 2009, A review of the hyperiidean amphipod superfamily Lanceoloidea Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 2000, pp. 1-117 : 70

Family METALANCEOLIDAE , new family

Diagnosis. Body length up to 8 mm. Pereon inflated in females, not markedly inflated in males. Head without rostrum. Eyes relatively small, round. Pereonites all separate. Coxae separate from pereonites. Antennae 1 with stout callynophore, peduncle 3-articulate. Antennae 2 shorter than A1. Mandibles with moderately strong palp, length about 1.3x body length of mandible; third article of palp slightly shorter than second; left with lacinia mobilis reduced to small protuberance. Maxillae 1 with broad, rectangular palp, shorter than outer lobe; outer lobe also rectangular, with straight distal margin armed with three robust setae and two smaller setae subterminally; inner lobe oval-shaped, armed with numerous fine setae. Maxillae 2 with narrow lobes. Maxilliped with semi-circular outer lobes with distal margin slightly excavate between two strong setae; inner lobes short, rounded, relatively narrow, mostly separate, projected laterally from outer lobes. Gnathopod 1 simple with carpus marginally broadened distally. Gnathopod 2 simple, slightly longer and more slender than G1. Pereopods 3-7 simple. Pereopods 3 & 4 with relatively strong, curved dactylus. Pereopods 5–7 with fully retractile and hooded dactyls; spoon-shaped formation hypertrophied, swollen posterodistally. Urosomite 2–3 with partial suture ventrally. Uropoda relatively slender with slender, articulated exopoda and endopoda. Telson triangular with rounded apex, about half-length peduncle of U3. Gills on pereonites 4–6. Oostegites on pereonites 2–5.

One genus: Metalanceola .

Remarks. This new family is proposed here to accommodate Metalanceola which, prior to this study, was placed in the family Lanceolidae . However, like the previous taxon, this genus is very distinctive possessing unique characters that distinguish it from all other families of Hyperiidea . The structure and relative lengths of the antennae, the short and rectangular palp of the first maxillae, the bulbous nature of the spoon-shaped process of pereopods 5–7 and the fact that the gills are restricted to pereonites 4–6, are particularly distinctive characters that distinguish Metalanceola and the family Metalanceolidae . The latter character is especially noteworthy because a reduction in the number of gills (usually on pereonites 2–6) is rare amongst the Hyperiidea . Otherwise this family resembles the Lanceolidae in the general morphology of the gnathopoda, pereopoda and the mandibles.