Mithrodia clavigera (Lamarck, 1816)

Gondim, Anne Isabelley, Christoffersen, Martin Lindsey & Pereira Dias, Thelma Lucia, 2014, Taxonomic guide and historical review of starfishes in northeastern Brazil (Echinodermata, Asteroidea), ZooKeys 449, pp. 1-56 : 11

Mithrodia clavigera (Lamarck, 1816) Figure 7f-i

Asterias clavigera Lamarck, 1816: 562.

Mithrodia clavigera Verrill, 1870: 289.

Mithrodia spinulosa Gray, 1840: 288.

Ophidiaster echinulatus Müller & Troschel, 1842: 32.

Echinaster echinulatus von Martens, 1866: 59.

Mithrodia clavigera Perrier, 1875: 378.

Mithrodia victoriae Bell, 1882: 123, pl. 6, fig. 2. Brito 1962: 3; 1968: 16. Tommasi 1970: 19, fig. 55.

Material examined.

Paraíba: 7°04'S; 34°41'W, 1 spec., UFPB.ECH.880, 17.II.1981, 26m.

Type locality.

Unknown ( Clark and Downey 1992).

Description.

Disk small (Fig. 7f). Five cylindrical and narrow arms (~2.52 mm) (Fig. 7f, g). Abactinal and actinal surfaces granulose (Fig. 7h). Skeleton formed by polygonal primary figs (usually hexagonal) that are widely spaced and united by secondary figs of rectangular shape, forming a reticulum. Some carinal and adradial figs with a long, narrow, and blunt spine (~0.77 mm). Papula large and single, found between the abactinal figs. Papulae restricted to abactinal surface. Granules covering body and spines small and with spinous tip. Granules from base of spines larger than at other localities. One conical and elongate subambulacral spine (~0.32 mm), forming a well defined row at base of ambulacral groove (Fig. 7i). Four slightly flattened adambulacral spines, the median ones being the largest. Eight short and rectangular oral spines, of which the median ones are largest (Fig. 7g).

Colour. Arms banded with dark brown or red lines, unusually green ( Clark and Downey 1992). Specimens preserved in alcohol become uniformly white.

Distribution.

Mexico, Cuba, Nicaragua, Brazil, Indo-Pacific (except Hawaii) ( Hayashi 1940, Abreu-Pérez et al. 2005, Alvarado et al. 2008). In Brazil: ES ( Vitória Banks) ( Brito 1968, Clark and Downey 1992). In this study we provide the first record for northeastern Brazil. From 24 to 71m in depth ( Clark and Downey 1992).

Remarks.

Mithrodia clavigera is the only species of the family Mithrodiidae recorded for the Western Atlantic. For some time, two species were considered present: Mithrodia clavigera and Mithrodia victoriae . The later species was described by Bell (1882), based on two small specimens from submerged banks of Vitória (Victoria Bank) ( Espírito Santo, Brazil). Since its description the validity of Mithrodia victoriae was questioned, and the distinction between these two species was discussed by Engel et al. (1948) and Pope and Rowe (1977). These authors concluded that the species should be synonymized but, due to the lack of material, this action was not formally carried out. Clark and Downey (1992) analised a large number of individuals of several sizes and agreed with the observations of Engel et al. (op. cit.) and Pope and Rowe (op. cit.), considering the two species to be synonyms. The individual we analised is juvenile (R = 9.80 mm) and corresponds to the characterization of juvenile specimens by Engel et al. (1948). These authors provide details on the aspect of the pedicellariae of Mithrodia clavigera , but pedicellariae were not found in our specimen.

Ecological notes.

This species lives on hard substrates covered by incrusting organisms and in reef gravel ( Abreu-Pérez et al. 2005). For Paraíba it was recorded associated with rhodolith banks. According to Guille et al. (1986) this species is more active during the night.