Pseudostichopus aemulatus Solís-Marín and Billett, 2004

O'Loughlin, P. Mark & Ahearn, Cynthia, 2005, A review of pygal-furrowed Synallactidae (Echinodermata: Holothuroidea), with new species from the Antarctic, Atlantic and Pacific oceans, Memoirs of Museum Victoria 62 (2), pp. 147-179 : 169-170

Pseudostichopus aemulatus Solís-Marín and Billett, 2004

Figures 11a, b , 12m

Pseudostichopus sp. — Billett, 1988: 196–197.—Billet et al., 2001: 325–348.

Pseudostichopus aemulatus Solís-Marín and Billett (in Solís-Marín et al.), 2004: 1079–1084, figs 1, 2, tables 5, 6. Material examined. Paratypes. Northeast Atlantic Ocean, Porcupine Abyssal Plain, 48°45'– 48°48'N, 16°36'– 16°41'W, 4835–4838 m, RRS Discovery, stn 54901#5, 28 Apr 1999, USNM 1025525 (3).

Description. Up to 146 mm long; body wall thick, gelatinous, opaque, sometimes encrusted with foraminiferans and sand; distinct brim, flat ventrally, convex dorsally; body surface smooth, lacking close wrinkling with ridges and digitate projections; tapering papillae in double irregular series on dorsolateral radii, series not widely separated, papillae typically up to 1.5 mm long, 1.0 mm diameter at base; papillae in widely separated double series ventrolaterally, dorsal to or ventral to or on brim; ossicles in tentacles and gonad; tentacle ossicles abundant, tapering rods, thick to thin, finely to bluntly spinous or smooth, with or lacking mid-rod swelling, rarely with short branches, up to 260 µm long; gonad ossicles predominantly small, thin, pointed, unbranched rods with mid-rod swelling, some with sparse blunt spines, rods up to 140 µm long.

Colour. Body off-white.

Distribution. NE Atlantic Ocean, Porcupine Abyssal Plain, 4350–4850 m ( Solís-Marín et al., 2004).

Remarks. P. aemulatus is similar to P. peripatus (below), but is distinguished by: body wall off-white (not greyish), opaque (not semi-translucent), smooth (lacking ridges with digitate projections); dorsolateral double series of papillae not widely separated; ventrolateral double series of papillae widely separated; papillae lack ossicles; gonad ossicles predominantly unbranched pointed rods with mid-rod swelling. These characters also distinguish P. aemulatus from other Pseudostichopus species.

Figures

Figure 11. Tentacle ossicles (SEM). a–b, Pseudoshichopus aemulatus (USNM 1025525, paratype). c–d, P. elegans (USNM E16505). e–f, P. mollis (USNM E48656). g–h, P. tuberosus sp. nov. (USNM E16721, holotype). i–l, P. peripatus, i (USNM 12198), j (USNM E38794), k (USNM E38796), l (USNM E49349).

Figure 12. Gonad ossicles (SEM). a–d, Meseres villosus (USNM E9929). e–f, M. translucens sp. nov. (USNM E48652, holotype). g–h, Pseudostichopus peripatus, g (USNM 12198), h (USNM E48638). i–l, P. tuberosus sp. nov. (USNM E16721, holotype). m, P. aemulatus (USNM 1025525, paratype). Posterior lobe ossicles (compound microscope). n–p, P. hyalegerus, n–o (NMV F80181), p (NMV F80178). Tentacle ossicles (compound microscope). q–t, M. ustulatus sp. nov. (NMV F101858, paratype).