MICROPHASMIDAE Stephensen & Pirlot, 1931

Zeidler, Wolfgang, 2009, A review of the hyperiidean amphipod superfamily Lanceoloidea Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 2000, pp. 1-117 : 87-89

Family MICROPHASMIDAE Stephensen & Pirlot, 1931

Diagnosis. Body length of mature specimens 6–10 mm. Pereon arched, inflated due to strongly inflated pereonites 2–4 (more so in female than male); pereonites 5–7 and pleon slender. Pereonites all separate. Coxae separate from pereonites. Head without rostrum; with massive, protruding mouth cone. Eyes absent or very small and poorly discernable. Antennae 1 lanceolate, longer than head but shorter than head and first pereonite combined; peduncle 3-articulate; callynophore stout with three small terminal articles. Antennae 2 much shorter than A1 with grossly enlarged gland cone. Mandibles with slender palp, as long as body of mandible; third article of palp shorter than second; body of mandible narrowed distally; incisor broad; left with lacinia mobilis reduced to small protuberance. Maxillae 1 with broad palp, armed with row of small, strong setae along outer margin and one longer, feathered seta distally; outer lobe broad, with five strong setae distally and covering of fine setae; inner lobe with broad distal margin, covered with numerous fine setae. Maxillae 2 with relatively slender lobes, the inner slightly shorter than outer one; both armed with 4–5 strong setae distally. Maxilliped with oval or semi-circular outer lobes; inner lobes short, less than half-length outer lobes, fused proximally, separate distally, projected laterally from outer lobes. Gnathopoda simple with carpus broadened distally; propodus conical. Pereopods without retractile or hooded dactyls. Pereopods 3–5, or only P5, prehensile/pseudochelate. Pereopods 5–7 with relatively short carpus, about half-length propodus. Urosomite 2–3 with partial suture ventrally. Uropoda slender, with articulated exopoda and endopoda. Telson triangular, usually shorter than half-length peduncle of U3. Gills on pereonites 2–6. Oostegites on pereonites 2–5.

Two genera: Microphasma and Microphasmoides .

Remarks. Stephensen and Pirlot (1931), in a study of the genus Mimonectes Bovallius, 1885 and related genera, proposed the family Microphasmidae for Microphasma but retained Mimonecteola in the family Archaeoscinidae . Later, Vinogradov (1957) removed Mimonecteola from Archaeoscinidae and placed it in the family Microphasmidae because it differs from Archaeoscina in several important characters such as the general habitus of both sexes, the antennae and the mandibles, but is similar to Microphasma , differing mainly in that the second antennae lack an enlarged antennal gland and pereopods 3–5 are not prehensile. However, while it is clear that Mimonecteola does not belong in the family Archaeoscinidae it possesses additional characters that differ significantly from Microphasma (and Microphasmoides ) which, together with the above, warrant its removal from the family. Thus, a new family, Mimonecteolidae fam. nov., is proposed here to accommodate Mimonecteola . Another genus, Microphasmoides was added to the family by Vinogradov (1960a) to accommodate a new species, M. vitjazi , that is very similar to Microphasma but differs in the structure of pereopods 3–5.

This family resembles the Lanceolidae in the morphology of the mouthparts, particularly the mandibles, and the Chuneolidae in the swollen antennal gland of the second antennae. It is also similar to most of the Scinoidea in that the pereopods lack retractile/hooded dactyls.