Pseudomacrinella Kudinova-Pasternak 1990

Pseudomacrinella Kudinova-Pasternak, 1990

Diagnosis. (modified after Kudinova-Pasternak, 1990). Female: Body tapering posteriorly. Pereonites all broader than long. Pleonites short and subequal. Pleotelson posterior half tapering to a rounded apex. Antennule fourarticled. Antenna six-articled; article-4 relatively short, slightly longer than articles 2 and 3 combined. Incisor process of mandible with sharp teeth, mandibular molar acuminate, unarmed. Maxilliped basis cordiform (heartshaped). Cheliped attached via sclerite; propodus with one ventral seta; fixed finger cutting edge with distal bifid tooth. Pereopods 4–6 with three carpal spiniform setae. Pleopods absent. Uropods stout; exopod one-articled, longer than half the length of endopod article-1, with one long and one short seta; endopod two-articled, article-2 slightly longer than article-1. Adult male: Antennule articles relatively broader than in female; pleopods with simple setae. Subadult male: pleopods without setae.

Remarks. At present not assigned to an existing family, Pseudomacrinella shows morphological similarities to several other genera including Pseudoarthrura (family incertae sedis), and the colletteids Arthrura Kudinova- Pasternak, 1966, Caudalonga Larsen, 2005, and Macrinella Lang, 1971. These have pleon and pleotelson shapes, mouthpart, pereopod and uropod morphologies quite similar to those of agathotanaids that hint at a phylogenetic affinity, i.e., short, annular pleonites (usually narrower than pereon and pleotelson in females); pleotelson widest posterior to margin with pleon (also invariant in the family Neotanaidae); weak, often deflexed and acuminate mandible molars; ‘stick-like’ pereopods with slender basis and distal articles (merus-propodus) with slender, bayonet-like setae; pleopods absent in females but often simple and stiff in males; and uropods short relative to pleotelson, with short rami, exopod often fused with basal article.

The genus currently comprises two species including the one described below. Pseudomacrinella can be distinguished from the other genera mentioned above by the combination of a cordiform maxilliped basis, an acuminate-unarmed molar process, and stout uropods with a short, one-articled exopod and a two-articled endopod. Unfortunately, the nature of the labial lobes (which has a very characteristic sharply-acuminate shape in P. macrocephala Kudinova-Pasternak, 1990) could not be properly assessed in the present material. Both species are found in waters greater than 1000 m.

Type species. Pseudomacrinella macrocephala Kudinova-Pasternak, 1990, southeastern Atlantic.

Other species. Pseudomacrinella larseni n. sp., northeastern Gulf of Mexico.