MICROSCINIDAE, Zeidler, 2012

Zeidler, Wolfgang, 2012, A review of the hyperiidean amphipod families Mimonectidae and Proscinidae (Crustacea: Amphipoda: Hyperiidea: Scinoidea) 3533, Zootaxa 3533, pp. 1-74 : 68

Family MICROSCINIDAE fam. nov.

Diagnosis. Known only from one female specimen, measuring about 12.0 mm; presumably mature, judging by the well-developed oostegites. Head with distinct, curved, elongate rostrum over-lapping most of A1; slightly shorter than first three pereonites combined, excluding rostrum. Eyes absent. Pereonites 1–2 fused; pereonites decreasing in size posteriorly. Coxae relatively small, separate from pereonites. Pleon relatively slender. Antennae 1 as long as head (minus rostrum) and first four pereonites combined; with stout callynophore, triangular in cross-section, with serrated margins and 2–3 short, stout terminal articles; peduncle two-articulate. Antennae 2 slender, about half length A1; consisting of four articles. Buccal mass (mouthparts) unusually small. Left mandible with narrow lacinia mobilis, about half as wide as incisor; incisor with row of small teeth, similar to, and aligned with, lacinia mobilis, then followed by three larger teeth and a bunch of smaller teeth. Right mandible with incisor like left but with the three larger teeth offset along the face of the body. Maxillae 1 with broad palp, armed with three strong setae distally; outer lobe broad, armed with four strong setae distally; inner lobe rounded with inner corner slightly produced. Maxillae 2 with relatively slender lobes of similar length; armed with 2–3 strong setae. Maxilliped with broad, rounded outer lobes; inner lobes separate, relatively short, length about one-third outer lobes. Gnathopods simple, relatively slender. Pereopods very slender, all with relatively small, retractile dactyls. Urosomites 2–3 with partial suture ventrally. Uropoda slender with articulated rami. Telson length 0.3x peduncle of U3; apex very rounded. Gills on pereonites 2–6. Oostegites on pereonites 2–5.

One genus: Microscina gen. nov.

Remarks. This new family has been established here to accommodate the new genus and species described below, from the tropical South Atlantic, near the Gulf of Guinea. This new species belongs with the Scinoidea primarily because the mandibles lack a palp, but it also possess several characters that preclude it from all other families of the superfamily, and thus, a new family is required to accommodate it. The most significant characters that distinguish this family are as follows; the head has a distinct rostrum; pereonites 1–2 are fused; pereopods 3–7 have retractile dactyls; the mouthparts are relatively small, and the mandibles have an incisor with three larger teeth and a relatively narrow lacinia mobilis. It is most similar to Mimoscinidae in having slender pereopods with retractile dactyls, but in that family only pereopods 5–7 have retractile dactyls.