Porphyrocrinus incrassatus Gislen 1933

Porphyrocrinus incrassatus (Gislén, 1933)

Table 5.

Synonymy: Monachocrinus incrassatus Gislén, 1933: 483 –485, text figs 6–9, pl. 23 (figs 5–7); 1938: 20; A.M. Clark, 1973: 281–282; Porphyrocrinus incrassatus Roux, 1977: 38, 55–56, text figs 1A, 15, pl. II (figs 4–5), pl. X (figs 1–7); 1985: 481; Roux et al., 2002: 806, 824, fig. 2D.

Material examined (Table 5). Seven specimens collected from the Bay of Biscay (Roux 1977) are housed in the collections of the Muséum national d’Histoire naturelle, Paris (catalogue numbers MNHN IE- 2012-758 and IE- 2012-759). One additional specimen (catalogue number MNHN IE- 2012-757) was collected during the French cruise “Hydrosnake” in Central Atlantic using the submersible “Nautile” (dive HS18) on the western wall of the axial valley of the Mid Atlantic Rise.

Description of Hydrosnake specimen. Complete stalk, aboral cup and first ring of brachials. Aboral cup height 1.63 mm, upper radial diameter 1.89 mm, basal ring low (ratio of radial to basal height 3.2) with conspicuous sutures. Stalk length 177 mm, proximalmost diameter 1.45 mm, decreasing to 1.02 mm at a distance of 17.9 mm from aboral cup, then progressively increasing with development in distalmost columnals of strongly elliptical synarthries up to 4.01 mm at fulcral ridge axis; proxistele of 10 thin columnals of equal height united by non-functional articulations; maximum columnal height 4.92 mm at a distance of 30 mm from distal end. Roux et al. (2002: fig. 2D) showed a well-developed distalmost elliptical synarthry with the same proximal mesistele with circular synarthries as in specimens from the Bay of Biscay (Roux, 1977: pl. X, figs 4–5).

Occurrence. North Atlantic (Mid-Atlantic Rise, Bay of Biscay) and South Atlantic (Saint Helena), at depths of 1300 to 2400 m, possibly 1300 to 2780 m.

known close affinities (*). N: number of specimens..

DIVA II, 1994/M 63/ 2-42 28 °0,206’ S– 7°16,905’ E 5089–5082 1 This paper* 28°4,029’ S – 7°20,821’ E