Narcissia trigonaria Sladen, 1889

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 : 14

Narcissia trigonaria Sladen, 1889 Figure 10f-j

Narcissia trigonaria Sladen, 1889: 414, pl. 65, figs 5-8. Tommasi 1966: 244; 1970: 9, fig. 26. Brito 1960: 5, pl. 1, figs 4-5; 1962: 3; 1968: 5. Tommasi and Aron 1988: 3. Tommasi et al. 1988: 6. Miranda et al. 2012: 144.

Narcissia trigonaria var. helenae Mortensen, 1933: 429.

Material examined.

Alagoas: Lagoa Azeda, Jequidá da Praia, 1spec., MNRJ (no registration number), 22.VI.2002. Bahia: Salvador, north coast, 1spec., UFBA00570, 2003; Salvador, Porto da Barra, 1spec., UFBA00929, II.2008, 23m; Salvador, Barra Beach, 1spec., UFBA00962, X.2008; Itaparica, Ponta de Areia, 12°52'S; 38°40'W, 1spec., UFBA00469; Camaçari, Guarajuba, 1spec., UFBA00190, VII.2005, 23m; Camaçari, Guarajuba, Busca Vida Beach, 2spec., UFBA00042, 04.VI.1994, 1spec., UFBA01043, VII.2008, 26m, 1spec., UFBA01089, VII.2008, 32m.

Type-locality.

Bahia, Brazil ( Clark and Downey 1992).

Description.

Disk high and pyramidal (Fig. 10f, h). Five long and triangular arms in transversal section (Fig. 10f, h). Abactinal and actinal surfaces granulose (Fig. 10i). Abactinal figs rounded, placed in irregular rows, covered by flattened and polygonal granules. Among these figs are papular areas with up to three papulae. Superomarginal figs short, wide (~2.69 mm), granulose and visible only laterally. Papular areas restricted to abactinal surface. Inferomarginal and superomarginal figs similar. Actinal figs slightly rectangular and granulose, these granules being bigger and taller than the dorsal granules. Actino-lateral figs with two rows of spines, the outer series with 4-5 short and blunt spines. The inner row is formed by 3-4 large, flattened spines, being longer than the outer row. Adambulacral figs with 3-4 series of flattened and prismatic spines, of which the innermost are the largest (Fig. 10j).

Colour. Live specimens are cream-coloured with red spots ( Benavides-Serrato et al. 2011).

Distribution.

North Carolina, Florida, Panama, Colombia, and Brazil ( Tommasi 1970; Clark and Downey 1992; Alvarado et al. 2008; Benavides-Serrato et al. 2011). In Brazil: AL, BA, and RJ ( Verrill 1915, Brito 1960, 1962, Tommasi 1970, Tommasi and Aron 1988, Miranda et al. 2012). From 5 to 91 m in depth ( Tommasi 1970, Clark and Downey 1992).

Remarks.

Narcissia trigonaria is a well established species, with a small list of synonyms and little morphological variation. It differs from Narcissia canariensis ( d’Orbigny, 1839) for having subambulacral spines arranged into three series and paired papulae. Downey (1973) records the sugar-tongs type of pedicellariae among the carinal figs of Narcissia trigonaria . However, we did not observe this type of pedicellaria. Walenkamp (1976) gives an excellent discussion on the presence or absence of pedicellariae and on small morphological variations found in his material. He emphasizes the great morphological differences existing between juvenile and adult specimens. In general, very juvenile individuals have shorter and wider arms. These tend to become thinner and longer during ontogenetic development.

Ecological notes.

The species lives in consolidated substrates, either rocks or coral ( Machado et al. 2008). Presently it is considered vulnerable to extinction along the Brazilian littoral. The main causes of its populational decline are the effects of pollutants and its illegal and indiscriminate collecting for aquarium rearing ( Machado et al. 2008).