Luidia ludwigi scotti Bell, 1917

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 : 5

Luidia ludwigi scotti Bell, 1917 Figure 4a-d

Luidia scotti Bell, 1917: 8-9. Tommasi 1970: 8, fig. 25. Carrera-Rodriguez and Tommasi 1977: 62, 65-66.

Luidia doello-juradoi Bernasconi, 1941: 117; 1943: 8-11. Brito 1962: 3.

Luidia rosaurae Jonh & Clark, 1954: 142-145.

Luidia doello-juradol Brito, 1968: 12, pl. 3, fig. 5.

Luidia ludwigi Walenkamp, 1976: 32-37, fig. 9, pl. 2, figs 1-3, pl.4, fig. 3. Machado et al. 2008: 179-180. Xavier 2010: 75.

Luidia ludwigi scotti A.M.Clark, 1982: 171-173. Tommasi 1985: 3. Tommasi et al. 1988: 6. Manso 1989: 357.

Luidia rosaurae John & Clark, 1954: 142-145, pl. 6, fig. 1.

Material examined.

Paraíba: 6°39'05"S; 34°49'W, 1 spec., UFPB/ECH.878, 28.V.1981, 20m.

Type locality.

Rio de Janeiro, Brazil ( Clark and Downey 1992).

Description.

Body flattened. Five arms that taper gradually towards their extremities (Fig. 4a, b). Abactinal surface with paxillae (Fig. 4a). Dorsal paxillae small, ordered, with 1-6 central, short, blunt spinelets, and 18 marginal, slender, and denticulate spinelets (Fig. 4c). Adradial paxillae rectangular or quadrangular, slightly larger than the carinal paxillae. Inferomarginal figs with one pointed, elongate spine (~2.04 mm) forming the marginal fringe (Fig. 4a). The remaining part of the fig is covered by short, hyaline and denticulate spinelets. Actinal surface with inferomarginal figs, densely covered by flattened and lanceolate spines (Fig. b, d). Actinolateral fig with three short, slender, divergent spines. The median of these is the largest. The ambulacral spine long, flattened and slender (Fig. 4d). Bivalved pedicellariae present only on the actinal surface, mainly on the ventro-lateral figs and in the areas close to the arms, never occurring on the abactinal surface. Oral spines slender, long (~1.18 mm) with blunt tip, forming a bundle of spines at apex of jaw (Fig. 4c).

Colour. The colour pattern on the aboral surface of the body is very variable. Some specimens may be whitish with black spots on arms, others are brown with white spots on arms. Most, however, have the arms more or less banded with alternating white and brown stripes ( Walenkamp 1976). Benavides-Serrato et al. (2011) and Clark and Downey (1992) observed specimens with dark pink spots in the center of the dorsal surface of the disc and transversal bands of the same tone on the arms. Oral surface with colour varying between white and cream. When observed in alcohol they are uniformly white.

Distribution.

Florida, Gulf of Mexico, Colombia, Venezuela, Guyana, French Guyana, Brazil, and Argentina (Mar del Plata) ( Bernasconi 1943, Tommasi 1970, Clark and Downey 1992, Benavides-Serrato et al. 2005). In Brazil: RJ, SP, and SC ( Brito 1962, 1968, Xavier 2010). This is the first record of the species for the littoral of northeast Brazil. From 20 to 126 m in depth. Clark and Downey (1992) considered the previous record at 5 m for the State of São Paulo to be doubtful. Thus the present study expands the bathymetric distribution to 20 m deep, previously established at 33-126 m.

Remarks.

This subspecies may be distinguished from other taxa in the genus by the presence of pedicellariae with three or four well-developed valves on the actinal surface, the delicate structure of the paxillae, and the slightly triangular shape of the arms, which become narrow distally. Luidia clathrata is similar to Luidia ludwigi scotti , but may be distinguished from it by having a stronger actinal skeleton and by the absence of pedicellariae. The synonymy between Luidia rosaurae John & Clark, 1954 and Luidia scotti was proposed by Clark (1982), who observed that the differences in the inferomarginal spines previously established between the two species were insignificant and unable to support the independence of the two species. Furthermore, with the observations of Walenkamp (1976) that Luidia rosaurae is conspecific with Luidia ludwigi Fisher, 1906, Clark and Downey (1992) recognized the subspecies Luidia ludwigi scotti for specimens from the Atlantic, as these have a paxillar arrangement that is distinct from the remaining species previously cited. According to Clark and Downey (1992), the relationships between Luidia patriae Bernasconi, 1941 and this subspecies still need to be investigated. The specimen analised in this study, even though representing a juvenile individual, did not present significant morphological variations when compared with the characters described for adult specimens, indicating that the morphological characters of Luidia ludwigi scotti do not vary significantly during ontogeny.

Ecological notes.

This subspecies occurs in non-consolidated sediments containing fine or coarse sand ( Machado et al. 2008). In contrast to other taxa of Luidia , which do not present prey selectivity, in Luidia ludwigi scotti only eight different food types have been recorded, of which bivalves, foraminiferans and ophiuroids are their main prey ( Benavides-Serrato et al. 2011). The presence of different prey species of distinct sizes in the stomachs of Luidia ludwigi scotti probably reflects a response to competition and coexistence with other species of sea-stars ( Brögger and Penchaszadeh 2008).