Molpadia musculus Risso 1826

• Main Author: Thandar, Ahmed S.
• Format: Text
• Language: unknown
• Published: Zenodo 2009
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Holothuroidea; Molpadida; Molpadiidae; Molpadia; Molpadia musculus; Arctic; Antarctic; The Antarctic; Pacific; Indian; Pawson; Antarc*
• Online Access: https://dx.doi.org/10.5281/zenodo.6212603; https://zenodo.org/record/6212603

Molpadia musculus Risso, 1826 Figure 3 Molpadia musculus Risso, 1826: 293; H.L. Clark, 1907: 165, Pl. 11; Pawson, 1977: 100, text-figs: 1, 2, 3, 4a–c, e, Map 1 (synonymy). Material examined. SAM-A 28044, ‘Nansen 404 ’, Trawl TO 16, west coast of South Africa (33 ° 53.7 ’S, 17 ° 26.9 ’E), 407 m, 10.iv. 2007, Louise Lange, 1 spec. Description. Specimen large, well preserved, barrel-shaped with short tail. Length along ventral surface 80 mm, width of mid-body 15 mm, tail length 2 mm. Colour uniformly violet except at extreme anterior end and the tail which are white to greyish-white. Body wall rough to the touch. Phosphatic deposits abundant (Figure 3 B). Calcareous deposits of body wall delicate, localised mostly in tail and at extreme anterior end, and include fusiform and tri-forked rods, up to 600 µm, with 1 – 4 (usually 3) small central holes and easily fragmented racquet-shaped bodies (Figure 3 A); anchors may be present but only a single broken one detected in the body wall sampled, may be of foreign origin. Distribution. Essentially cosmopolitan but not yet known from above the Arctic Circle, 35–5205 m. (Pawson 1977) Remarks. Pawson (1977) revised the molpadiid sea cucumbers of the Southern, Atlantic, Pacific and Indian Oceans, describing four new species and presenting a key to the nine species he recognized as valid. Since then, a few more species have been added. After having examined 170 specimens, Pawson showed that Molpadia musculus is a very varied species with its calcareous deposits changing drastically with age. His synonymy of M. musculus hence appears rather drastic but despite this he comments that it is incomplete “for the limits of variation of the species are far from clearly defined.” (Pawson 1977: 100). Based on this, the single southern African specimen, briefly described above, appears referable to this species. It is characterized by the presence of fusiform rods in the body wall, best developed in the tail and much smaller racquet-shaped bodies. Pawson states that anchors, rosettes of racquet-shaped plates and tables with three or more perforations and a solid spire are usually absent in specimens over 30 mm, “having being transformed into very numerous light to dark red phosphatic deposits.”(Pawson 1977: 100). Hence the propensity of phophatic bodies and the scarcity of racquet-shaped bodies and spired tables. This is the second record of this species from southern Africa, the first is that of Cherbonnier (1965) from a single 41 mm specimen collected at 480 m from Cabinda (Angola). The South African material differs from Cherbonnier’s specimen by the rarity of racquet-shaped deposits and spired tables, perhaps due to its size and/or age. : Published as part of Thandar, Ahmed S., 2009, New species and a new record of sea cucumbers from deep waters of the South African temperate region (Echinodermata: Holothuroidea), pp. 30-42 in Zootaxa 2013 on pages 33-34, DOI: 10.5281/zenodo.185850 : {"references": ["Risso, A. (1826). Histoire naturelle des principales productions de l'Europe meridionale et particulierement de celles des environs de Nice et des Alpes maritimes. 5: 289 - 293. F. - G. Levrault, Paris.", "Clark, H. L. (1907) The Apodous Holothurians: A monograph of the Synaptidae and Molpadiidae, including a Report on the representatives of these families in the Collections of the United National Museum. Smithsonian Contributions to Knowledge, 35, 1 - 231.", "Pawson, D. L. (1977) Molpadiid sea cucumbers (Echinodermata: Holothuroidea) of the southern Atlantic, Pacific and Indian Oceans. 3. In: Biology of the Antarctic Seas VI. (Pawson, D. L., ed.) American Geophysical Union, Antarctic Research Series, 26: 97 - 123.", "Cherbonnier, G. (1965) Expedition Oceanographique Belge dans les Eaux Cotieres Africaines de l'Atlantique Sud (1948 - 1949). R e sultats Scientifiques: Holothurides. Institut Royal des Sciences Naturelles de Belgique, 3 (2), 3 - 23."]}