Proscina vinogradovi Shih & Hendrycks, 1996

Zeidler, Wolfgang, 2012, A review of the hyperiidean amphipod families Mimonectidae and Proscinidae (Crustacea: Amphipoda: Hyperiidea: Scinoidea) 3533, Zootaxa 3533, pp. 1-74 : 16-17

Proscina vinogradovi Shih & Hendrycks, 1996

( Fig. 6)

Proscina vinogradovi Shih & Hendrycks, 1996: 592–596 , figs. 1–3.

Type material. This species was described from a sub-adult male, 4.7 mm in length (head to end of inner ramus of U3), from the North Pacific, off the Alaskan Peninsula (54°40’N 155°10’W); 700–900 m, 14 April 1930. The unique holotype is in the USNM (264246); the mouthparts and appendages from the right side, including the telson, are mounted on a microscope slide; the remainder is preserved in alcohol .

Material examined. The unique type as detailed above.

Diagnosis. Following examination of the holotype male, 4.7 mm, and according to Shih & Hendrycks (1996). Pereon not inflated. Head rounded dorsally, without rostrum. Antennae 1 as long as head and first four pereonites combined; callynophore lanceolate, with serrated margins and numerous aesthetascs. Antennae 2 slightly shorter than first peduncular article of A1, consisting of three small articles. Gnathopod 1; basis relatively short, length 0.6x remaining articles combined, 1.6x carpus; propodus length about 1.4x carpus, with numerous long setae on lateral and medial surfaces, especially for distal half; dactyl relatively straight, length about one-third propodus. Gnathopod 2 slightly longer than G1; basis length twice carpus, similar in length to propodus; propodus slightly expanded medially with distinct postero-distal excavation, forming palm for dactyl, posterior margin and palm armed with several, relatively strong setae; dactyl strong, curved, length slightly more than one-third propodus. Pereopods not particularly slender. Pereopods 3 & 4 similar in length and structure; basis length twice merus; carpus length about 1.4x merus; propodus as long as carpus, with few long setae on antero-distal corner; dactyl relatively strong, curved, length about one-quarter propodus. Pereopod 5 slightly more slender than P4 but of similar length; basis length twice merus; carpus length 1.3x merus; propodus as long as carpus, with tuft of long setae on postero-distal corner; dactyl curved, length 0.2x propodus. Pereopod 6 similar in length to P5; basis length almost twice merus; carpus length 1.3x merus; propodus length 0.8x carpus, armed with setae as for P5; dactyl as for P5. Pereopod 7 slightly shorter than P6; basis length 2.6x merus; merus relatively short, about 2.5x ischium; carpus slightly broader than other articles, length marginally more than twice merus; propodus length 0.7x carpus, armed with setae as for P6; dactyl as for P6 but slightly longer. Uropoda with lanceolate rami, with serrated margins; all with inner ramus distinctly longer than outer; both longer than peduncle. Uropod 1; inner ramus length 1.4x outer, almost twice peduncle. Uropod 2; inner ramus length 1.4x outer, and 1.6x peduncle. Uropod 3; inner ramus length 1.3x outer, and 1.9x peduncle; peduncle width marginally more than half length. Telson with rounded apex, 1.3x as long as broad, about half length of peduncle of U3.

Colour not known for living specimen.

Remarks. This species resembles Mimonectes sphaericus Bovallius, 1885 in many respects, particularly in regard to the characters listed by Shih & Hendrycks (1996) to distinguish this species from other members of Proscina . Namely, the excavation on the distal margin of the outer lobe of the maxilliped; the propodus of gnathopod 2 is excavate postero-distally and is relatively long, about twice as long as the carpus and as long as the basis; the merus of pereopod 7 is relatively short and the carpus is relatively broader than in other pereopods. It differs primarily from M. sphaericus in having pereopods 3–7 with more robust dactyls and with a relatively longer propodus that is not especially tapering distally. With respect to the stronger dactyls, it also resembles Mimonectes neosphaericus sp. nov., but in that species gnathopod 1 is sub-chelate and pereopods 3 & 4, especially pereopod 4, are significantly longer than pereopods 5–7.

Shih & Hendrycks (1996) also note the similarity of P. vinogradovi to the specimen of P. stephenseni illustrated by Vinogradov (1957), which I believe most likely represents M. sphaericus , as noted previously. Thus, in consideration of the above, the status of P. vinogradovi is questionable but should be maintained pending the availability of more material of this, and related species. It is here transferred to the genus Mimonectes .

Distribution. Known only from the type locality, from the unique type, as detailed above.