Proscina magna Stephensen & Pirlot, 1931

Zeidler, Wolfgang, 2012, A review of the hyperiidean amphipod families Mimonectidae and Proscinidae (Crustacea: Amphipoda: Hyperiidea: Scinoidea) 3533, Zootaxa 3533, pp. 1-74 : 12-14

Proscina magna Stephensen & Pirlot, 1931

( Fig. 4)

Proscina magna Stephensen & Pirlot, 1931: 545–500 , figs. 17–18.— Pirlot 1932: 23, fig. 15. Pirlot 1939: 25–28, pl. 2, fig. 4. Vinogradov 1957: 210, fig. 14. Vinogradov 1960: 222. Thurston 1976: 384–385 (table), 391–392. Vinogradov et al. 1982: 123 (key), 125–126, fig. 53. Shih & Hendrycks 1996: 591, 595, 596 (key), 599 (table). non — Mori et al. 2010: 3–4 (list), 8 (list) (see remarks).

Type material. This species was described from a male measuring about 9 mm, from the North Atlantic , southwest of the Azores (36°17’N 28°53’W); Princesse Alice II, stn. 1851, 0–3000 m, 8 September 1904. The unique holotype is in the MOM (3721 30) .

Remarks. It is clear from the description and figures of the type by Stephensen & Pirlot (1931) that it resembles Mimonectes loveni Bovallius, 1885 in many respects. The gnathopods are identical and the relatively broader articles of pereopod 5, and the more slender pereopod 6, with relatively smaller dactyls, are also characteristic of M. loveni . The remaining pereopods (P3, 4 & 7) are illustrated as being slightly more slender than typical specimens of M. loveni , but it should be noted that for this species the pereopods become more slender with maturity. In this respect, the type of P. magna is like the specimens of M. loveni from the south-east Atlantic ( Dana stn. 3978 viii), as noted under that species (see later). The mouthparts are also indistinguishable from M. loveni .

Although I have been unable to examine the type I am reasonably confident that P. magna is a junior synonym of M. loveni . It should be noted that, until this study, the male of M. loveni has never been illustrated, and was unknown before Stephensen & Pirlot’s (1931) review of the group, and this may account for them not recognising their specimen as M. loveni .

There are only three additional literature records of P. magna as follows.

1. Vinogradov (1957) records a female (18 mm) from the north-west Pacific, Kurile Trench (30°52’N 153°16’E); Vityaz stn., 0–5500 m. The characters of this specimen, as figured, are identical to M. loveni and, although I have been unable to examine this specimen, I am confident that it cannot be distinguished from M. loveni . In the past, mature females of Mimonectidae were considered to have a grossly inflated pereon, with those of Proscina having a more slender pereon, similar to males. However, this character is demonstrated here to be erroneous, and females of M. loveni , even at 18 mm, would only have a slightly inflated pereon, not much different from males. Thus, reliance on this character may account for the above error in identification.

2. Thurston (1976) recorded two juveniles (3 & 5 mm) from the north-east Atlantic , near the Canary Islands, which he doubtfully attributed to this species. It is likely that these are also M. loveni .

3. Mori et al. (2010) list records from Sagami Bay and off Kamogawa, Japan. I have examined two of these specimens, from Sagami Bay, and one is M. gaussi and the other is Scypholanceola aestiva . Thus, this record should be ignored.