Luidia alternata alternata (Say, 1825)

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 alternata alternata (Say, 1825) Figure 3a-d

Asterias alternata Say, 1825: 144-145.

Luidia alternata Lütken, 1859: 42-43. Brito 1968: 12-13, pl. 3, fig. 4. Tommasi 1970: 8, fig. 24. Tommasi and Aron 1987: 5. Tommasi et al. 1988: 6. Ventura et al. 2007: 236. Miranda et al. 2012: 9.

Luidia granulosa Perrier, 1869: 109-110, pl. 2, fig. 18.

Luidia variegata Perrier, 1875: 337.

Luidia numidica Koehler, 1911: 3, pl. 1, figs 8-11.

Luidia quequenensis Bernasconi, 1942: 253. Tommasi 1970: 8, fig. 23. Carrera-Rodriguez and Tommasi 1977: 62, 65.

Luidia bernasconiae A.H.Clark, 1945: 19-21.

Luidia alternata var. numidica Madsen, 1950: 206-209, fig. 9.

Luidia alternata numidica A.M.Clark, 1953: 388-389, pl. 41, fig. 1.

Luidia alternata alternata Clark & Downey, 1992: 8-9; Magalhães et al. 2005: 63.

Material examined.

Paraíba: 6°46'S; 34°50'W, 1spec., UFPB/ECH.877, 13.II.1981, 14m; 7°01'S; 34°41'W, 1spec., UFPB/ECH.876, 13.II.1981, 24m; 7°04"S; 34°41'W, 1spec., UFPB/ECH.879, 16.II.1981, 22m.

Type locality.

Dry Tortugas, Florida Keys, Florida ( Clark and Downey 1992)-Neotype.

Description.

Body pentagonal (Fig. 3a, b). Five elongate and thin arms. Abactinal surface with paxillae (Fig. 3a). Carinal paxillae smaller than adradial paxillae, with 1-4 blunt central spinelets and with one or two series of marginal spinelets, numbering 12-20 per series. One of the central spines is slightly longer than remaining spines. Paxillae rounded and arranged into regular transversal rows. Some adradial paxillae with one long, conical and pointed central spine (~1.90 mm) (Fig. 3c). Inferomarginal fig with 1 or 2 long, thin spines (~1.76 mm), placed vertically and forming a well defined marginal row. Actinal surface with inferomarginal figs densely covered with spines of diverse shapes and sizes, there being 1-3 longer spines located centrally (Fig. 3c, d). Adambulacral fig with 4 spines placed vertically. The adambulacral spine is the smallest, being slightly curved and compressed. The two subambulacral spines are subequal in shape and size. A short spine is located laterally to the most external spine. Oral spines narrow and elongate. With bi, tri and tetravalvular pedicellariae on actinal surface (Fig. 3b).

Colour. Abactinal surface white or cream-coloured, with dark transversal bands. The colour of these bands varies, and may be brown, black, green, or purple. Actinal surface whitish or beige.

Distribution.

North Carolina, the Bahamas, Florida, Gulf of Mexico, Cuba, Jamaica, Honduras, Puerto Rico, Panama, Colombia, Venezuela, Brazil, Uruguay, and Argentina ( Bernasconi 1943, Tommasi 1958, Downey 1973, Walenkamp 1976, Clark and Downey 1992, Hendler et al. 1995, Ventura et al. 2007, Alvarado et al. 2008). In Brazil from AL, BA, RJ, and SP ( Verrill 1915, Brito 1962, 1968, Tommasi 1970, Magalhães et al. 2005, Miranda et al. 2012). This is the first record of the species for the coast of Paraíba. From 1 to 200 m in depth (Clark and Downey 2002), most common between 10 and 30 m.

Remarks.

The main characters distinguishing Luidia alternata alternata from the remaining species of the genus that occur in the Western Atlantic are their colour and the presence of long conical spines on the adradial paxillae. The abactinal colouration is distinctive. The nominal subspecies differs from its congeneric form Luidia alternata numidica Koehler, 1911, from West Africa, for attaining a larger size and for having longer paxillar spines. Clark (1982) provided a good discussion on the synonymy of the nominal subspecies and designates a neotype. Specimens analysed in this study are young individuals that may attain 200 mm along its larger ray. Furthermore, our specimens presented no morphological variations, agreeing with the descriptions of this species. Despite not receiving much attention in recent taxonomic surveys, pedicellariae are an important taxonomic character to distinguish species of asteroids. Clark (1982) and Clark and Downey (1992) furnished excellent illustrations of the species of Luidia known from the Atlantic.

Ecological notes.

This subspecies is primarily associated with sandy and muddy bottoms. It may also be found in mangroves or associated with fragments of shells and calcareous algae ( Clark and Downey 1992, Benavides-Serrato et al. 2011). According to Hendler et al. (1995), the subspecies does not occur in large numbers, but is often found among the accompanying fauna in trawling nets. Luidia alternata alterna is carnivorous, feeding on epifaunal organisms, especially other echinoderms.