Mesothuria maroccana Perrier, 1898

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 : 301-303

Mesothuria maroccana Perrier, 1898

( Figure 9A,B )

Mesothuria maroccana – Perrier, 1898: 1665; 1899: 245; 1902: 312–317, pl. 16, figs. 32–35; Hérouard, 1923: 17; Deichmann, 1930: 97, pl. 7, figs. 2–7; 1940: 191; 1954: 385; Grieg, 1921: 4; Hansen, 1956: 46, fig. 14 a.

Mesothuria (Mesothuria) maroccana – Heding, 1940: 333; 1942: 8.

Holothuria murrayi (var.?) – Théel, 1886a: 187, pl. 9, fig. 3.

Mesothuria murrayi var. grandipes – Hérouard, 1923: 15–17, pl. 4, figs. 7–9.

Holothuria intestinalis var. verrilli – Hérouard, 1896: 163.

Material examined

See Table 9.

Type material

Syntypes, MNHN, Talisman, St. 35, 18 June 1883, 32 ◦ 4 ′ N, 12 ◦ 43 ′ W, 2105 m, one syntype ; St. 39, 23 June 1883, 30 ◦ 8 ′ N, 14 ◦ 2 ′ W, 2200 m, one syntype.

Type locality

Atlantic Ocean, off Morocco, 2105–2200 m.

Diagnosis

After Deichmann (1954): mouth ventral, anus terminal. Tentacles 20. Tubefeet of unequal size, largest along sides of body, where zig-zag or double row seems to be present; they are small but well developed on dorsum and totally lacking on ventrum.

Ossicles regular tables, mostly with six marginal holes and quite large central hole ( Figure 9A ); margin smooth or undulating; spire relatively low, composed of three short rods, and ending in three diverging arms with few teeth ( Figure 9B ). Feet with end plate and small tables of same type as in skin, sometimes deformed.

Remarks

The species was first described from off Gibraltar by Théel (1886a) as Holothuria murrayi (var.?). Later Perrier (1899) gave a very careful description of it. Hérouard’s (1923) Mesothuria murrayi var. grandipes is identical to Perrier’s species. Hérouard (1923) pointed out several differences, (1) the arrangement of the lateral pedicels is in two rows rather than one, a very doubtful character when the variation caused by contraction or age is considered; (2) the serial arrangement of the dorsal appendages, also a very doubtful matter; and (3) larger deposits than those described by Théel and Perrier, the disk having a diameter of 0.15–0.18 by 0.10–0.12 mm. With our present imperfect knowledge of the variation within species, this character is of secondary importance. It may be that M. murrayi var. grandipes is a specimen that has retained some of its larger juvenile tables, as shown by Deichmann (1930). Hérouard does not mention the deposits in the tubefeet. He gives no figures for the ossicles.

See also remarks for M. murrayi .

Distribution

Widely distributed in the north Atlantic, both in the east and the west: off the Moroccan coast, the Azores; south of Iceland, Jamaica, eastern Gulf of Mexico, east of Florida ( Figure 10 ).

Bathymetric range

Depth 700–3120 m.

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 10. Distribution of a group of Mesothuria species.