Vibilioides alberti Chevreux (Figs 34 & 35)

Vibilioides alberti Chevreux, 1905: 1–5, figs 1, 2. — Behning 1913a: 533–534. Behning 1913b: 223. Stephensen 1918: 56. Pirlot 1929: 103. Chevreux 1935: 176–178, pl. 15, figs 1, 2. Vinogradov et al. 1982: 237–239, fig. 118. Vinogradov 1990a: 57, 93 (Table), fig. 10. Vinogradov 1990b: 107, fig. 3 (map). Vinogradov 1993: 43 (Table). Vinogradov 1999: 1181, fig. 4.91.

Type material

There are five syntypes. Two from Princesse­Alice Stn 1851 (36°17’N, 28°53’W) are in the MNHN (unregistered) and the remainder, including the figured female, are in the MOM. No precise type locality is designated by Chevreux (1905), but he had specimens from near the Canary Islands (26°16’N, 16°11’W) and from near the Azores (37°08’N, 8°28’30”W; 36°17’N, 28°53’W; 36°46’N, 26°41’W).

Material examined (6 specimens)

Only six female specimens of this species are available for study. Three from the southern side of the Bay of Biscay (Thor Stn 74, ZMUC CRU 2831: Dana Stn. 1104, ZMUC), one from off Rio de Janeiro (ZMUC CRU 2832) (see Stephensen 1918), one from just north of the Cape Verde Islands (Dana Stn. 1159, ZMUC) and one from the South China Sea (Dana Stn. 3689).

Diagnosis

Body length up to 22 mm. Antennae 1 as long as head and first pereonite; flagellum elongate, oval, with anterior margin rounded, almost flat, with dorsal margin projected above peduncular articles. Gnathopod 1; posterior margin of merus, posterior and anterior margin of carpus, and anterior margin of propodus, with fringe of long setae. Gnathopod 2; posterior margin of ischium and merus, and anterior margin of carpus and propodus, with fringe of long setae; carpal process about 0.7x length of propodus. Pereopods 3­6; dactylus about 0.4x length of propodus. Pereopod 7; basis oval, width about 0.6x length. Lateral corners of last urosomite not produced. Uropod 3; peduncle slightly longer than rami; endopod slightly longer than exopod.

Remarks

This is a relatively rare species easily recognised by its general shape and the morphology of pereopod 7. Chevreux (1905) presumed that its rarity was due to its deep­water habitat, because most of the catches were at a depth of 1000 m or more. However, some subsequent records are from near the surface.

It has only been figured twice in the literature, the figures of Chevreux (1935) and Vinogradov et al. (1982) being copies of the original (Chevreux 1905). More detailed figures, especially of the mouthparts and pereopods 3­6, are thus provided here (Figs 34 & 35). Fortunately the specimen from off Rio de Janeiro (ZMUC CRU 2832) is very large (21.5 mm) enabling an easy examination of the mouthparts. The maxilliped and mandible are as illustrated by Chevreux (1905) and Vinogradov (1990a), but the first maxillae have a reduced inner lobe similar to that found in Vibilia, and the second maxillae, although reduced, are present as small rounded lobes; the inner and outer lobes being completely fused. The generic diagnosis has been amended accordingly, to include these characters which were previously thought to be absent.

Distribution

This species is only known from a few localities. It seems to be most common in the Atlantic Ocean having been recorded from the Bay of Biscay, Canary Islands, Azores, Cape Verde Islands and near Rio de Janeiro. Vinogradov (1990a, b) recorded it once in the Indian Ocean (33°S, 45°E) and the Pacific Ocean (22°S, 83°W) and it is recorded here from the South China Sea (7º13.5’S, 111º49’E) for the first time.