Pseudomimonectes robustus Vinogradov 1960
Creators: name: Zeidler, Wolfgang
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Mimonectidae
Pseudomimonectes
Pseudomimonectes robustus

description: Pseudomimonectes robustus Vinogradov, 1960   
(Fig. 27)  
 Pseudomimonectes robustus Vinogradov, 1960: 219–222, figs. 12–13. — Bowman & Gruner 1973: 11–12, fig. 12. Vinogradov et al. 1982: 110–112, figs. 44–45. Vinogradov & Vinogradov 2006: 62. Mori et al. 2010: 8 (list).   
 Type material. This species was described from one, immature specimen (sex unknown), 4.5 mm in length, from the Pacific Ocean, in the Ryukyu Trench (27°49’S 130°37’W), Vityaz stn. 3528, 4080– 5500 m, 28 October 1958. The unique holotype is in the ZMMU (Mb-1061).   
 Diagnosis. According to Vinogradov (1960) and Vinogradov et al. (1982). Known only from the unique holotype. Pereon slightly inflated. Antennae 1 relatively robust; about as long as head and first 2.5 pereonites combined (medially). Antennae 2 much reduced, consisting of four small articles; as long as peduncle of A1. Gnathopod 1; basis almost as long as remaining articles combined; carpus with broad distal margin, slightly shorter than propodus; dactyl short, curved. Gnathopod 2 slightly longer and more slender than G1; otherwise similar in structure. Pereopods 3 & 4 similar in structure and length; basis length equal to merus and carpus combined; merus length about two-thirds carpus; propodus slightly longer than carpus; dactyl relatively strong, curved, length about 0.2x propodus. Pereopod 5 sub-equal in length to P4 and more slender; basis with slight bulge mid-way on distal margin, length about 1.7x merus; carpus slightly longer than merus and propodus; merus and propodus similar in length; dactyl relatively strong, marginally longer than 0.2x propodus. Pereopod 6; length about 0.8x P5; basis length about 1.8x merus; carpus slightly longer than merus; propodus as long as carpus, with slight bulge mid-way on anterior margin; dactyl relatively strong, curved, length about 0.3x propodus. Pereopod 7 with relatively broad articles; length about 0.8x P6; basis about twice as long as wide, almost 3x length merus; carpus bulging anteroproximally, narrowed distally, about 1.6x length merus; propodus slightly longer and more slender than carpus, with slight bulge mid-way on anterior margin; dactyl strong and falcate, length almost one-third propodus. Uropoda with slender, but not particularly lanceolate rami, with rounded tips. Uropod 1; inner ramus length twice outer, similar in length to peduncle. Uropod 2; inner ramus length 1,8x outer, marginally longer than peduncle. Uropod 3; inner ramus length almost 1.4x outer, as long as peduncle; peduncle width 0.4x length. Telson ovaltriangular, length marginally more than one-third peduncle of U3.   
Colour not known for living specimen.  
 Remarks. I have not seen any specimens of this species and have been unable to examine the unique holotype, but accept its validity based on the observations of Vinogradov (1960).   
 The one-articulate palp, and relatively broad lacinia mobilis of the mandibles, readily distinguishes this species, and the genus, from other members of the family. Otherwise it is very similar to Mimonectes. In having simple gnathopods and relatively strong dactyls, it resembles M. spandlii, but is readily distinguished by the relatively longer merus of pereopods 3–6. It is also similar to M. colemani, but in that species the dactyls are not as strong, and that of pereopod 7 is not falcate, and pereopods 6 & 7 lack the bulge mid-way on the anterior margin of the propodus. The structure of pereopod 7 is also similar to M. alexanderi, and initially I thought that this species might also belong to Pseudomimonectes but the mandibles lack the characteristic one-articulate palp (fig. 27).   
 Distribution. Known only from the type locality, from the unique holotype, as detailed above.
description: Published as part of Zeidler, Wolfgang, 2012, A review of the hyperiidean amphipod families Mimonectidae and Proscinidae (Crustacea: Amphipoda: Hyperiidea: Scinoidea) 3533, pp. 1-74 in Zootaxa 3533 on pages 53-55