Mesothuria murrayi (Théel, 1886)

Gebruk, Andrey V., Solis-Marin, Francisco A., Billett, David S. M., Rogacheva, Antonina V. & Tyler, Paul A., 2012, Review of the genus Zygothuria Perrier, 1898 and the Atlantic group of species of the genus Mesothuria Ludwig, 1894 (Synallactidae: Holothuroidea) with description of the new species Mesothuria milleri sp. nov., Journal of Natural History 46, pp. 265-348 : 303-307

Mesothuria murrayi (Théel, 1886)

( Figure 11 )

Holothuria murrayi – Théel, 1886a: 185–186, pl. 10, figs. 16–18.

Mesothuria murrayi (Théel, 1886) – Sluiter, 1901b: 24; Hérouard, 1902: 23–24; Fisher, 1907: 683–685, pl. 71, figs. 1a–h; Hérouard, 1912: 23–24; Ohshima, 1915: 226; Hansen, 1956: 45–46, fig. 14b, d, e; Jangoux et al., 1989: 163 (list), 165–166, text fig. 3, figs. a–d.

Holothuria murrayi var. parva – Théel, 1886a: 186–187, pl. 9, fig. 2; pl. 16, figs. 4–5; Perrier, 1902: 316; Augustin, 1908: 18–20, text fig. 14.

Mesothuria parva (Théel, 1886) – Ludwig, 1894; Fisher, 1907: 686–687, pl. 71, figs. 2a–c; Ohshima, 1915: 226; Thandar, 1984: 341–343, textfig. 63; 1992: 161–163, figs. 1a–h.

Mesothuria (Mesothuria) murrayi (Théel, 1886) – Heding, 1940: 333.

Mesothuria (Mesothuria) parva (Théel, 1886) – Heding, 1940: 119.

Material examined

See Table 10.

Type material

Syntypes, NHM 86.10.2.176 (one specimen); NHM 86.10.2.178 (one specimen), HMS Challenger St. 300, 17 October 1875, 33 ◦ 42 ′ S, 78 ◦ 18 ′ W, 2502 m .

(Continued)

Type locality

South-east Pacific, 2502 m.

Diagnosis

After Théel (1886a): body elongated, more or less distinctly cylindrical, with mouth and anus almost terminal. Twenty tentacles. Each lateral ventral ambulacrum with numerous pedicels, larger of which seem to form continuous row along each side of body; remaining pedicels of unequal size, sparsely distributed over adjacent interambulacra. Median ventral ambulacrum with numerous minute, almost imperceptible, pedicels. Dorsal surface with few, small, scattered papilla-like pedicels. Dorsal as well as ventral interambulacra have only few minute ambulacral appendages in their middle line. Perisome thin, flexible. Calcareous ring well developed. One Polian vesicle. Respiratory trees well developed.

Ossicles tables, consisting of more or less irregular, perforated disk, typically with six large holes around central hole, and spire of three rods and one transverse beam. Spire terminates in three rather long arms, free ends spinous or branched ( Figure 11 ).

Remarks

The type material of M. murrayi comes from the Pacific, off the Chilean coast, at a depth of c. 2500 m. Hérouard’s M. rugosa from off the Cape Verde Islands is identical in detail to M. murrayi of Théel. This was first noticed by Deichmann, who surprisingly considered M murrayi as a junior synonym of M. rugosa , although the priority of Théel’s name is obvious. There is also a clear similarity between M. murrayi and Perrier’s M. maroccana from off Morocco, also known from the Caribbean, the east Gulf of Mexico and the north-east Atlantic ( Billett 1988). The two species have identical ossicles, but there are some differences in the arrangement of the tubefeet that may well be an age variation, because Théel’s specimens were 240 mm long whereas those of Perrier were only 50 mm. Perrier has pointed out the similarities between his specimens and M. murrayi (var.?) known from Gibraltar. The similarity between M. maroccana and M. murrayi (var.?) was also noticed by Grieg (1921). Further confusion was created by Deichmann (1930, 1940, 1954), who gave the morphological details of M. murrayi (Théel) in her descriptions, but assigned her specimens, 40–60 mm long, from the West Indian seas, to M. maroccana Perrier. This group of species evidently requires further study. That is also true for M. murrayi var. grandipes . Illustrations of the ossicles of this species are lacking, but the size given for the table disks, 0.15–0.18 mm in the 80-mm long specimen, significantly exceeds that of the main ‘murrayi group’ (0.07–0.12 mm). Mesothuria murrayi has also been reported from the Indonesian seas, from 400–522 m ( Sluiter, 1901b) ( Figure 9 ).

Distribution

Rather cosmopolitan ( Figure 9 ), though many records are unreliable owing to confusion with other species (see remarks).

Bathymetric range

Depth 245–6650 m, but not reliable either.

Figures

Figure 9. Ossicles of Mesothuria maroccana Perrier, 1902 (A,B) and Mesothuria intestinalis (Ascanius, 1805) (C,D). (A,B) Specimen from St. 50519 #1; (C,D) specimen from St. 51403 #7.

Figure 11. Mesothuria murrayi (Théel, 1886). Ossicles from Théel (1886a), redrawn.