Pseudostichopus peripatus (Sluiter, 1901) O'Loughlin & Ahearn, 2005

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 : 174-175

Pseudostichopus peripatus (Sluiter, 1901) comb. nov.

Figures 1f , 10f–h , 11i–l , 12g, h

Meseres peripatus Sluiter, 1901a: 10–11 .— Sluiter, 1901b: 48–49, pl. 5 fig. 5, pl. 8 fig.7.— Perrier, 1902: 359.— Rowe, 1995: 285.

Pseudostichopus occultatus .— Hérouard, 1902: 14–15, pl. 2 figs 4–14 (part, illustrated; non Pseudostichopus occultatus Marenzeller, 1893 ).

Pseudostichopus occultatus var. plicatus Koehler and Vaney, 1905: 9–10 , pl. 3 fig. 8, pl. 9 figs 1–3.— Heding, 1940: 353 (non Pseudostichopus occultatus Marenzeller, 1893 ).

Pseudostichopus propinquus Fisher, 1907: 691–693 , pl. 71 fig. 3, pl. 72 fig. 2, pl. 73 fig. 3, pl. 74 fig. 1, pl. 76 fig. 3.— Imaoka, 1978: 382 (new synonym).

Pseudostichopus aleutianus Ohshima, 1915: 228 , pl. 8 figs 5a–c.— Imaoka, 1978: 380.

Pseudostichopus unguiculatus Ohshima, 1915: 230–231 , pl. 8 figs 7a–c.— Imaoka, 1978: 384.— Rowe, 1995: 285.

Pseudostichopus marenzelleri Hérouard, 1923: 25 .— Mortensen, 1927: 287–288.— Deichmann, 1930: 90.

Pseudostichopus lapidus Hérouard, 1923: 26–28 , pl. 4 fig. 5.

Pseudostichopus (Pseudostichopus) lapidus .— Heding, 1940: 353–360 (new synonym).

Pseudostichopus (Pseudostichopus) marenzelleri . — Heding, 1940: 353–359.— Imaoka, 1978: table 1–1.— Thandar, 1992: 167 (synonymy by O’Loughlin, 2002).

Pseudostichopus (Pseudostichopus) unguiculatus .— Heding, 1940: 353–360.— Imaoka, 1978: table 1–1.— Imaoka, 1990: 152.— Thandar, 1992: 167 (synonymy by Rowe, 1995).

Pseudostichopus (Trachostichopus) aleutianus .— Heding, 1940: 353–359.— Imaoka, 1978, table 1–2 (synonymy by O’Loughlin 2002).

Plicastichopus plicatus .— Heding, 1940: 354–359.— Heding, 1942: 6. (synonymy by O’Loughlin, 2002).

Pseudostichopus (Trachostichopus) propinquus .— Heding, 1940: 357.— Imaoka, 1978: table 1–1.— Imaoka, 1990: 148, 152.

Plicastichopus ingolfi Heding, 1942: 5–6 , figs 4–5, pl. 1 figs 4–5.

Pseudostichopus (Trachostichopus) tuberculatus Imaoka, 1990: 149–152 , pl. p. 149, fig. P. 15. (synonymy by O’Loughlin, 2002).

Meseres ingolfi . — Rowe, 1995: 285 (synonymy by O’Loughlin, 2002).

Meseres propinquus .— O'Loughlin, 2002: 309.

Material examined. Meseres peripatus Sluiter, 1901 . Lectotype (designated here). Indonesia, Flores Sea, 7°24'S, 118°15'E, 794 m, Siboga stn 45, ZMA V.Ech.H9500. Paralectotypes. Type locality and date, ZMA V.Ech.H1048 (2); Maluka Sea, 1°59'N, 125°01'E, 1200 m, Siboga stn 122, ZMA V.Ech.H1049 (1); Banda Sea, 5°41'S, 120°46'E, 1158 m, Siboga stn 211, ZMA V.Ech.H1050 (2).

Pseudostichopus propinquus Fisher, 1907 . Holotype. Hawaiian Is, 21°11'N, 156°35'W, 518–519 m, USNM 21217 .

Pseudostichopus lapidus Hérouard, 1923 . Syntypes. North Atlantic Ocean , off the Azores, 4020 m, Monaco stn 527, 1895, MOM (3) (examination by M. Bruni, pers. comm., MOM) .

Pseudostichopus (Trachostichopus) tuberculatus Imaoka, 1990 . Holotype. Japan, Tosa Bay , 660–700 m, H. Horikawa, 23 May 1989, OMNH Iv1190.

Pseudostichopus unguiculatus Ohshima, 1915 . Syntypes. North Pacific Ocean , off Japan, 1058–1680 m, Albatross stns 4960, 5083, 5084, USNM 34151 (2), E24543 (1), E24544 (1).

Other material. Pacific Ocean, Tasman Sea, eastern Australia continental slope, 823–1750 m , AM J20026 , J20027 (3); J23219 (1); J23267 (2); J22980 (9) ; NMV F80449 , F80450 (3); F90070 (2); Philippines, 878 m , USNM E48764 (2); est. 1300 m , E48770 (2); off Thailand, 370 m , 1017465 (7); off Oregon , 1646 m , E48586 (3); 411 m, E17035 (2); 1946 m, E1972 (29); Mexico, 1608 m , 32389 (1); 2014 m, 32391 (2); Costa Rica, 1789 m , 18267 (1); Peru-Chile Trench , 3500 m , E53272 (1); NMV F101841 (1); Galapagos Is , 2418 m , USNM 18272 (4); 1158 m , E949 (1); 3667 m, 1008450 (1); 1008457 (2); South-west Pacific Basin , 3386–3422 m , E49306 (1); South-east Pacific Basin, N of Amundsen Sea , 4978–5043 m , E48660 (5); 4709 m, E48590 (1); 4682 m, 1022459 (1); 4575–4813 m, E48629 (1); W Balleny Is , 2836–2864 m , E48632 (2); off Victoria Land , 3459–3492 m , E48624 (2); 566–569 m, 1022604 (2); Ross Sea, 3495–3514 m, 1008176 (1).

North Atlantic Ocean, off Florida, 931m, USNM E1990 (1); off Massachusetts, 3235 m, 12198 (1); 3682 m, E53743 (1); off South Carolina, 1337 m, E2581 (2); Bahamas, 4763–4803, 1021900 (1); 4578–4778 m, 1021902 (1); 4783–4823 m, 1021901 (1); Caribbean Sea, Venezuelan Basin, 3428–3476 m, E38794 (2); 3411–3459 m, E38796 (1).

Weddell Sea, 1025–1153 m, USNM E48573 (1).

South Atlantic Ocean, Scotia Sea, 52°00'– 62°30'S, 14°54'– 60°40'W, 267–5453 m, USNM E48572 (1) ; E48574– E48577 (15); E48581 (1); E48585 (9); E48587, E48588 (2); E48592 (1); E48596 (6); E48599 (2); E48602, E48603 (5); E48607, E48608 (5); E48628 (2); NMV F101840 (1) ; USNM E48638 (45) ; E48648 (23); NMV F101839 (5) ; USNM E49241 (5) ; E49255 (10); E49325, E49326 (7); E49348, E49349 (2); E49351 (1); E49444, E49445 (3); 1008141 (6); NMV F101838 (3) ; USNM 1008159 , 1008160 (7) ; 1008166 (5); 1008297 (4); 1022445 (2); 1022463 (3).

Antarctic Ocean, South Orkney Is , 3250–3285 m, USNM 1008177 (3) ; 1228–1400 m, E49393 (1); South Shetland Is, 662–1120 m , E48570 (1); 884–935 m, E48610 (7); 213–311 m, E49350 (1); South Sandwich Trench , 5350 m, USNM 1071584 (2) ; Palmer Peninsula , 134 m , E49259 (1).

Description. Up to 140 mm long; form of body variable, typically with encrusting globigerine or grit attachments; body elongate, slightly tapered anteriorly and posteriorly, depressed to varying degrees dorsoventrally, flat ventrally, typically low convex dorsally; body wall firm, leathery, thick to thin, semi-gelatinous, frequently with deep transverse grooves and ridges, frequently wrinkled with low reticulate ridges surmounted by small digitate projections, frequently pitted with withdrawn very small interradial tube feet; ventrolateral margin acute to subacute, rounded, variably serrated by the transverse body folds and irregular transverse creases; ventrolateral margin variable from rounded, to mammiform, to rounded protuberances surmounted by elongate to multiple-knobbed extensions, to knobbed domes further surmounted by smaller knobs or small tube feet or larger radial tube feet; larger tube feet surmount double radial series of mammiform bases, not present midventrally, mammiform base and papilla typically 2.0 mm long; ossicles in tentacles and gonad, larger papillae; tentacle ossicles abundant large irregular rods, thick to thin, terminally tapered, frequently with central swelling, sometimes swollen distally, sometimes with small terminal knobs, sometimes bluntly spinous, sometimes branched along rod with branches closed to create perforations, rods up to 360 Μm long; papillae with spinous to smooth rods, frequently with central swelling, up to 160 Μm long; “endplates” sometimes detected in papillae as perforated plates with mesh collar or tangled mesh of joined irregular rods, up to 340 Μm diameter; gonad ossicles frequently present, abundant, typically small predominantly slender tapering rods with small central hub, spinous to smooth, unbranched or Y- or X-shaped, sometimes irregular thick variably spinous branched rods, up to 200 Μm long.

Colour. Body grey to off-white, to residual pale reddish-brown on some small specimens, sometimes semi-translucent; radial tube feet brown, smaller tube feet off-white.

Distribution. Indo-Pacific Region, North and South Pacific Ocean, North and South Atlantic Ocean, Scotia Sea, Antarctic Ocean, Ross Sea, Weddell Sea; 134–5453 m.

Remarks. Seven syntypes of Meseres peripatus Sluiter, 1901 are listed (ZMA E1050) by Jangoux (1991). Only two were present when the syntypes were examined (April 2002). M. peripatus has the diagnostic characters of Pseudostichopus detailed above, and is reassigned.

The description of P. propinquus Fisher, 1907 referred to: thin translucent body wall, with some foraminiferan attachment; distinct thickened lateroventral margin, with mammiform tubercles surmounted by tube feet; paired radii with tube feet; round longitudinal muscles; unbranched gonad tubules; gonad with fine branched sometimes spinous rod ossicles, up to about 200 µm long; respiratory tree ossicles similar to gonad. All of these characters accord with the diagnosis of Pseudostichopus above, and propinquus is returned to its original combination. All of the features of P. propinquus , except the presence of respiratory tree ossicles, are diagnostic features of Pseudostichopus peripatus . Fisher (1907) referred to two specimens. The holotype is in very poor condition, and respiratory tree ossicles could not be confirmed. The second specimen was not located. If gonad-type ossicles were found in the respiratory trees of material otherwise conspecific with P. peripatus , this would be judged to be an individual variation rather than a basis for a separate species. P. propinquus is considered here to be a junior synonym of P. peripatus . Rowe (1995) made P. propinquus a junior synonym of P. pustulosus Sluiter, 1901 . This synonymy is rejected. P. propinquus has the diagnostic characters of Pseudostichopus , and P. pustulosus those of Molpadiodemas (above).

Based on the description by Hérouard (1923), on observations communicated by M. Bruni (MOM), and on photographs by Francisco Solis-Marin (UNAM) of a tentacle ossicles slide prepared by Gustav Cherbonnier (MNHN box 108 slide 45), the characters of P. lapidus are: up to 15 mm long; pygal furrow; encrusting cover of foraminiferans, sand, stones; tube feet on paired radii, small to absent on midventral radius; longitudinal muscles narrow; gonad tubules unbranched; ossicles in tentacles only, lacking in body wall and internal organs; tentacle ossicles predominantly rods without branches and associated mesh. Although gonad ossicles have not been detected, P. lapidus has the distinctive characters of Pseudostichopus peripatus and it is judged here to be a junior synonym.

O’Loughlin (2002) considered P. marenzelleri to be a junior synonym of P. peripatus , based on the description and figures by Hérouard (1923). Based on the additional description by M. Bruni (MOM, pers. comm.) of cylindrical longitudinal muscles and unbranched gonad tubules, the synonymy is confirmed here. O'Loughlin (2002) considered P. tuberculatus to be a junior synonym of P. peripatus , based on the photograph and description in Imaoka (1990). Following an examination of the holotype the synonymy is confirmed.

The considerable variety in ossicle and body form, and cosmopolitan distribution and depth range, suggested to us that there are probably more than one species involved. We were unable to recognize discrete diagnostic characters on which to distinguish further species.

The distribution summary by O’Loughlin (2002) indicated an Indo-Pacific and North Atlantic distribution for P. peripatus . Data above extend the distribution to the eastern Pacific, western and southern Atlantic, and Antarctic Oceans, and to significantly shallower and greater depths.

Amongst Pseudostichopus species, the distinguishing characters of P. peripatus are: dorsoventrally depressed body, with strong wrinkling and transverse creases creating a serrated ventrolateral margin; typical encrusting cover of globigerines or rounded grit attachments, not sponge spicules; rods of various forms in gonads, no mesh ossicles.

Figures

Figure 1. Characters of pygal-furrowed Synallactidae. a, ventral mouth and anus (M. helios sp. nov., USNM E31104, paratype, 91 mm long); b, ventral peltate tentacles, polian vesicle (P. mollis, TM H2004; anterior end dissected off); c, respiratory tree (P. mollis, TM H2004); d, drawing of dorsal posterior pygal furrow; e, posterioventral view of pygal furrow and anus (M. violaceus, BMNH 86.10.2.150); f, anterior dorsal madreporite (arrow) (P. peripatus, USNM 1008159); g, drawing of calcareous ring (radial plate right, as in P. spiculiferus); h, calcareous ring (M. crinitus sp. nov., USNM E48644, paratype); i, calcareous ring (M. violaceus, BMNH 86.10.2.145).

Figure 10. a, Pseudostichopus hyalegerus, sponge spicule cover (P. japonensis, paratype, SMBL 314, junior synonym, 29 mm long). b–c, P. mollis; b, rugose ventrum (TM H3111, 145 mm long); c, calcareous ring (TM H2004). d–e, P. papillatus (RAS, syntype, 27 mm long); d, dorsal view of paired radial tubercles; e, ventrolateral view, tube feet. f–h, P. peripatus; f, ventral view, marginal tubercles, grit attachment, transverse creases (NMV F101840, 60 mm long); g, ventral view, marginal tubercles, grit attachment, transverse creases (NMV F101839, 45 mm long); h, cylindrical muscles (arrows), gonad tubules (P. tuberculatus, holotype, OMNH Iv1190, junior synonym). i, P. tuberosus sp. nov. (USNM E16721, holotype, 115 mm long), ventral view, lateroventral tubercles (arrow).

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).