Hedingia glabra (Théel, 1886), Theel, 1886

Davey, Nicola & O’Loughlin, Mark, 2013, The caudinid sea cucumbers of New Zealand (Echinodermata: Holothuroidea: Molpadida: Caudinidae), Zootaxa 3613 (4), pp. 357-368 : 358-361

Hedingia glabra (Théel, 1886)

Figures 1 a, 2

Synonymy.

Trochostoma albicans var. glabra . Théel, 1886: 46, pl. 3 fig. 2, pl. 11 fig. 3.

Caudina albicans . H. L. Clark, 1908: 174−175, pl. 10 fig. 12. Deichmann, 1930: 201−202, pl. 24 fig. 1. Heding, 1931: 283. H. L. Clark, 1935: 269, 271, 277, 278. [All part].

Haplodactyla albicans . Heding, 1935: 65−67, fig. 18 (1−13), pl. 4 fig. 9, pl. 5 fig. 17, pl. 8 fig. 10. [part].

Hedingia albicans . Deichmann, 1938: 112−113. Deichmann, 1940: 216−217. Pawson, 1965: 2, 14. Pawson, 1970: 49. Pawson, 1977: 120.? Rowe & Gates, 1995: 264. Pawson et al. 2001: 324−325, fig. 4C. Pawson et al. 2009: 1202. Mah et al. 2009: 398. [All part].

Hedingia albicans var. glabra . Madsen, 1953: 167.

Material examined (Number in bracket denotes number of specimens). NIWA registered specimens: New Zealand: Hikurangi Margin: 63069 (4) Stn TAN1004/7, 41.69 S, 175.63 E, 1324–1362 m, 15/04/2010; 64053 (2) Stn TAN1004/116, 42.04 S, 174.69 E, 1391– 1327 m, 26/04/2010; 64262 (1) Stn TAN1004/136, 41.89 S, 174.93 E, 1077– 977 m, 27/04/2010; 64286 (1) Stn TAN1004/138, 41.89 S, 174.93 E, 1323– 1153 m, 28/04/2010; 64137 (1) Stn TAN1004/120, 41.98 S, 174.69 E, 730– 685 m, 26/04/2010; 63081 (2) Stn TAN1004/9, 41.72 S, 175.66 E, 1486– 1473 m, 15/04/2010; 64078 (2) Stn TAN1004/118, 42.04 S, 174.70 E, 1310– 1250 m, 26/04/2010; 64312 (1) Stn TAN1004/140, 41.91 S, 174.95 E, 1303–1593 m, 28/04/2010; 61895 (1) Stn TAN1004/138, 41.89 S, 174.93 E, 1323– 1153 m, 28/04/2010.

Description. Hedingia species up to 110 mm total length, diameter up to 22 mm, caudal taper and tail up to 40 mm long (NIWA 64078); tail ranging from continuous taper through to discrete long thin tail, can be up to two thirds length of body; main body wall leathery, smooth or sparsely prickly, anterior and posterior fine wrinkling (preserved); tail leathery, parchment-like, distinctly prickly compared to main body, wrinkled (preserved).

Ossicles in mid-body wall predominantly absent, or can be sparse tables up to 250 µ m disc length; tail ossicles dense tables, table disc concave, extensively perforated, up to 360 µ m length, variable in shape from triangular, to oval, to 4–5 lobed, with 3–6 central perforations, predominantly more than 3, disc surface smooth or sparsely finely spinous, disc margin with irregular, sometimes spinous projections (visible under high microscopy), table spire is predominantly 3 pillared but can be 2–4. Each pillar is attached to disc in two places and then fuses to a final distal pillar. This single pillar then splays out to 3 distally spinous teeth. Pillars often lost on preparation and discs appear with large holes in centre.

Colour (preserved). Off-white to grey.

Distribution. New Zealand: Hikurangi Margin (material examined), East Cape (Théel 1886) (type specimen, existence unknown), 685–1593 m depth.

Remarks. We raise Trochostoma albicans var. glabra Théel, 1886 out of synonymy with Trochostoma albicans Théel, 1886 , and elevate to species status. The species is maintained in Hedingia Deichmann, 1938 . As originally noted by Théel (1886), tables are rare to absent in the body wall of Hedingia glabra and the main body is consequently not calcareous but smooth. This is diagnostically different to H. albicans that has tables throughout the body wall but denser in the tail. Other diagnostic differences include the nature of the surface of the table discs in H. glabra being frequently smooth and consisting of 3–6 central perforations compared to H. albicans which has notably a spinous disc surface and 3 central perforations. The margins of the disc in H. glabra are frequently spinous, and discs can be triangular to oval to rectangular or 5-lobed compared to the consistent triangular shape of H. albicans .

We note that Rowe and Gates (1995) reported specimens of Hedingia albicans from New South Wales (NSW) at depths of 846–2700 m. We anticipate that this material is probably Hedingia glabra , and have included the reference in our synonymy. However, it might also represent an unusual southern extension of the distribution of the species reported off India as Trochostoma albicans Théel by Koehler and Vaney (1905). The drawings (Rowe and Gates, 1995) of the table discs are spinous, triangular and 3-perforated centrally suggesting H. albicans rather than H. glabra . The presence of H. glabra in NSW would extend the depth and geographic distribution. We leave this material out of the formal distribution above as it has not been confirmed.

Figures

FIGURE 1. Photos of preserved specimens of species in the family Caudinidae Heding, 1931: a, Hedingia glabra (Théel, 1886) (NIWA 64078); b, Paracaudina alta sp. nov. (NIWA 68129); c, Paracaudina chilensis (Müller, 1850) (NIWA 77411); d, Paracaudina coriacea (Hutton, 1872) (NIWA 70954); e, Paracaudina coriacea (Hutton, 1872) lectotype (NHMUK 98.10.8.1.2); f, Paracaudina reductia sp. nov. (NIWA 70957).