Massinium watsonae O’Loughlin, 2012

O’Loughlin, P. Mark, Barmos, Shari & VandenSpiegel, Didier, 2012, The phyllophorid sea cucumbers of southern Australia (Echinodermata: Holothuroidea: Dendrochirotida: Phyllophoridae), Memoirs of Museum Victoria 69, pp. 269-308 : 293-295

Massinium watsonae O’Loughlin sp. nov.

Figures 13c, d, e , 16

Lipotrapeza dearmatus .—H. L. Clark, 1938: 494.—H. L. Clark, 1946: 411–412. (part; Australian material non Phyllophorus dearmatus Dendy and Hindle, 1907 ).

Neothyonidium dearmatum . — Heding and Panning, 1954: 191– 192 (part; Australian material non Phyllophorus dearmatus Dendy and Hindle ).— Hickman, 1978: 32, pl. 1, figs 15–24 (non Phyllophorus dearmatus Dendy and Hindle ).

Neothyonidium sp. — Rowe, 1982: 466, pls 31.5, 31.6.

Neothyonidium? dearmatum .— Edgar, 1997: 369 (with photo of tentacles).

Material examined. Holotype. Southeast Tasmania, Bruny Island, Simpsons Bay , 43º17'S 147º18'E, 11 m, 15 Feb 1972, J. E. Watson, NMV F97435 .

Paratypes. Type locality and date, NMV F174898 (1) ; NMV F174899 (1) ; off Bruny Island , D’Entrecasteaux Channel, 12 m, Feb 1972, J. E. Watson, NMV F97420 (2).

Other material. D’Entrecasteaux Channel, off Green Island, 56 m, D. F. Turner, 21–25 July 1948, TMAG H169 (1; det. F. W. E. Rowe 1974 as Neothyonidium dearmatum ); Derwent River, Blackmans Bay, on beach after storm, E. Turner, 12 Jun 1988, TMAG H1988 (1, tentacle crown and ring only); Kettering, 43º08'S 147º15'E, 10 m, A. J. Dartnall and T. Sward, 29 Mar 1977, AM J12385 (1; as Lipotrapeza dearmatus ; ring damaged posteriorly prohibiting type status); slides for AM J12385 specimen prepared by V. V. Hickman, tentacles and body wall TMAG H2089, introvert TMAG H2090, dorsal body wall TMAG H2091, mid-body wall TMAG H2092, anal TMAG H2093, posterior TMAG H2094, anal papilla TMAG H2095, cloaca TMAG H2096; Eastern Tasmania, Great Oyster Bay, no other data, AM J1538 (1). “ New South Wales ”, no other data, AM J18132 (1; presumed locality error, SE Tasmania distribution).

Neothyonidium dearmatum ( Dendy and Hindle, 1907) . New Zealand, near Cook Strait , 40ºS 174ºE, 67 m, NIWA 4187 (2) ; 55 m, NIWA 73992 (1) ; off Christchurch , 43ºS 173ºE, 59 m, NIWA 28443 (1) ; 44ºS 173ºE, 54 m, NIWA 76793 (1) ; 64 m, NIWA 73987 (4) ; off Stewart I., 47ºS 168ºE, 33 m, NIWA 45522 (2).

Diagnosis. Massinium species up to 110 mm long, up to 40 mm diameter (preserved, tentacles withdrawn), wide orally, tapered to rounded end anally, thin firm body wall; exterior anal scales not detected; 20 tentacles, 5 outer pairs large, 5 inner pairs small; complete cover of tube feet, single series of close tube feet on each side of longitudinal muscle interior attachment, scattered inter-radially, across introvert in irregular paired radial series, diameters up to 0.4 mm; white leathery tubular composite calcareous ring up to 50 mm long; radials with anterior taper and notch, posterior notch; inter-radials tapered to anterior point, posterior inter-radial indentation closed by continuous band of small plates to create oblong non-calcareous space; 1–2 tubular polian vesicles, as long and longer than calcareous ring; long thin stone canal with globular madreporite attached by mesentery to pharynx; cylindrical longitudinal muscles, not divided; gonad tubules long thin.

Ossicles disappear with age / size; per-oral tables only in 110 mm long holotype; eroded ossicle remnants only in 70 mm long paratype (NMV F97420); in specimen 65 mm long (AM J12385), mid-body wall lacking ossicles; tube feet with few endplates up to 216 µ m diameter, irregular small perforations, larger peripherally, rare curved support rods up to 80 µ m long around endplate margin; peri-oral region with tables, sometimes rosettes, table discs oval to rounded, irregular, up to 144 µ m long, up to about 40 perforations, spires with 2 pillars, distal cross-bar sometimes perforated, pillars with few blunt spines apically; introvert ossicles tables with oval to rounded rectangular discs, sometimes rosettes, table discs up to 96 µ m long, up to 24 perforations, 4 large central perforations, many smaller surrounding ones, spires up to 48 µ m long, 2 (rarely 1) pillars with 2–3 blunt spines apically; larger specimens tentacles lacking ossicles in trunks and branches, 50 mm long specimen with rare rods, up to 80 µ m long, few distal perforations; posterior/anal body with tube foot endplates up to 192 µ m diameter, rare curved endplate support rods up to 80 µ m long; anal papilla with anal scale fragments, tube foot endplates, rods and rosettes; anal scales comprising multi-layered base with digitiform calcareous papilla about 800 µ m long comprising mass of thick linear, X, Y, H shaped rods; anal tube foot endplates up to 152 µ m diameter; numerous short irregular anal rods intergrading with rosettes, up to 48 µ m long.

Colour (preserved). Variable, body pale pinkish-brown with dark brown patches to uniform pale brown, tentacle trunks brown to dark brown, branches dark brown to grey-brown.

Type locality. Tasmania, Bruny Island, Simpsons Bay , 11 m.

Distribution. Southeast Tasmania, D’Entrecasteaux Channel to Derwent Estuary; 11– 56 m.

Etymology. Named for Jan E. Watson, Honorary Associate of Museum Victoria, hydroid systematist, significant contributor to the marine invertebrate collections of Museum Victoria, and collector of the types of this species.

Remarks. The diagnostic description of ossicles is based principally on the comprehensive set of V. V. Hickman slides (see Material examined) of a smaller Kettering specimen (65 mm long, up to 15 mm diameter) registered to the Australian Museum (AM J12385). The presence and form of tables in the introvert and absence of ossicles in the tentacles are consistent with the Blackmans Bay part-specimen, except that there are also rosettes in the introvert. The presence or absence of rosettes is judged to be variable in specimens of some phyllophorid species.

H. L. Clark 1938 referred Phyllophorus dearmatus Dendy and Hindle, 1907 to his new genus Lipotrapeza with considerable reservation, based on the entirely different calcareous ring. In the same year Deichmann erected the genus Neothyonidium to which Heding and Panning 1954 subsequently referred Phyllophorus dearmatus . No specimen of Neothyonidum dearmatum ( Dendy and Hindle, 1907) has been found in Australian waters. Material determined by Joshua (1914) to be Phyllophorus dearmatus has been examined and found to represent our new species Thyone flindersi O’Loughlin sp. nov. (below). Deichmann (in H. L. Clark 1946) correctly judged that the Joshua specimens should be referred to Thyone .

Hickman (1978) reported a specimen of Neothyonidium dearmatum from Kettering on the D’Entrecasteaux Channel in southeast Tasmania, but noted some differences from the descriptions of this New Zealand species. The specimen is not held in the TMAG but ossicle slides prepared by Hickman are available and were examined by us. The specimen is now held by the AM and has been examined here. Based on the description by Hickman (1978) and the ossicle slides, the Kettering specimen is conspecific with specimens referred here to our new species Massinium watsonae O’Loughlin sp. nov. (above). Rowe (1982) referred to the Kettering specimen as Neothyonidium sp.

Based on the descriptions by Dendy and Hindle (1907), Mortensen (1925), and Pawson (1970) and our observations the diagnostic characters that distinguish Neothyonidium dearmatum (Dendy and Hindle) from Massinium watsonae O’Loughlin sp. nov. (characters in bracket) are: size up to 65 mm long (up to 110 mm); tentacle rod ossicles present (lacking tentacle ossicles); inter-radial plates of calcareous ring divided for most of their length by non-calcareous space (short distal closed oblong non-calcareous space); distal end of each inter-radial plate with two narrowing tails that may be contiguous but not joined by small plates (distal end of calcareous ring a continuous collar of small plates, the generic diagnostic character for Massinium Samyn and Thandar, 2003 ); single polian vesicle (2 polian vesicles); if present tables in anterior and posterior body wall (in introvert only); table disc lengths average 75 µ m (average about 90 µ m); perforations in table discs usually 8 (up to 24). The combination of unique diagnostic characters of Massinium watsonae O’Loughlin sp. nov. is given in the key (above).

Figures

Figure 13. Photos of preserved specimens. a, Massinium melanieae O’Loughlin sp. nov. (holotype NMV F174897); b, Massinium vimsi O’Loughlin sp. nov. (holotype, NMV F76629) (insert: form of the calcareous ring plates); c, Massinium watsonae O’Loughlin sp. nov. (holotype, NMV F97435); d, calcareous ring, stone canal (along alimentary canal) and madreporite, and 2 polian vesicles (top left corner) of Massinium watsonae (TMAG H1988); e, colour morph of Massinium watsonae (NMV F174899) (insert: form of the calcareous ring plates); f, exceptional calcareous ring from specimen of Phyllophorella thyonoides (H. L. Clark, 1938) with posterior prolongations joined as in Massinium species (WAM Z31975) (insert: form of the calcareous ring plates).

Figure 16. SEM images of ossicles from specimen of Massinium watsonae O’Loughlin sp. nov. (TMAG H1988). Tables and rosette from introvert (top); tables and rosettes from peri-oral body wall (bottom).