Mesothuria Ludwig, 1894

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 : 268

Genus Mesothuria Ludwig, 1894

Mesothuria – Ludwig, 1894: 31; Östergren, 1896: 351; Perrier, 1899: 244; 1902: 301–304; Hérouard, 1906: 6–7; Fisher, 1907: 679; Mortensen, 1927: 379; Deichmann, 1930: 91; Heding, 1940: 331–334; Thandar, 1992: 161; Madsen and Hansen, 1994: 76; Rowe and Gates, 1995: 330.

Allantis – Hérouard, 1902: 21.

Mesites – Ludwig, 1893a: 2; 1893b: 179.

Diagnosis

Modified from Hérouard (1906) and Deichmann (1930): Body usually nearly cylindrical, slightly attenuating toward both ends, without marginal fringe ( Figure 1 ). Ventral side usually somewhat flattened; dorsal side more or less uniformly covered with small pedicels, of small and equal size, or much smaller dorsally, where they can be hardly visible. Tubefeet with sucking disks scattered over entire body. Usually 20 tentacles, very occasionally varying from 18 to 22. No tentacle ampullae; stone canal attached to body wall without penetrating it. Mouth terminal, anus ventral, or subventral, without special arrangement. Calcareous ring with rectangular radial segments. Gonads only on left side of dorsal mesentery, in single tuft. Ossicles of body wall quadriradiate or triradiate tables with central primary cross elevated from disk.

Type species

Mesothuria multipes Ludwig, 1894 , by monotypy.

Included north Atlantic species

Mesothuria bifurcata Hérouard, 1901 ; M. cathedralis Heding, 1940 ; M. gargantua Deichman, 1930 ; M. intestinalis ( Ascanius, 1805) ; M. maroccana Perrier, 1902 ; M. milleri sp. nov.; M. murrayi (Théel, 1886) ; M. rugosa ( Hérouard, 1912) and M. verrilli (Théel, 1886) .

Figures

Figure 1. External morphology of Mesothuria intestinalis (from Ascanius, 1805).