Echinocyamus grandiporus Mortensen, 1907

Gondim, Anne Isabelley, Moura, Rafael Bendayan De, Christoffersen, Martin Lindsey & Dias, Thelma Lúcia Pereira, 2018, Taxonomic guide and historical review of echinoids (Echinodermata: Echinoidea) from northeastern Brazil, Zootaxa 4529 (1), pp. 1-72 : 35-36

Echinocyamus grandiporus Mortensen, 1907

Figure 11 A–I

Echinocyamus grandiporus Mortensen, 1907: 33 –36, pl. 12, figs 1–5.― H.L. Clark, 1925: 165.― Tommasi, 1966a: 26, pl. 8b; 1966b: 239–240.― Tommasi et al., 1988a: 5.― Oliveira et al., 2010: 11.

Material examined. Ceará: 2 spms, Canopus Bank [UFPB/ECH.1974].

Description. Test oval or round (TL = 6.6 to 9.8 mm; TH = 2.6 to 8 mm), usually low and flat, oral region slightly concave ( Fig. 11 A–D). Test covered by short, slender, hyaline spines ( Fig. 11A ). Petals small and open distally ( Fig. 11C, E ). Madreporite slightly prominent. Genital and ocular pores of same size ( Fig. 11C, E ). Four genital and five ocular pores form a conspicuous circle or pentagon around the madreporite ( Fig. 11C, E ). Primary spines elongate and lanceolate. Miliary spines shorter than primary spines, with terminal crown. Peristome central, circular, three times size of periproct ( Fig. 11B, D ). Periproct small, circular, inframarginal, and usually covered by 5 to 6 regular plates that never bear spines. Phyllodes lacking.

Pedicellariae. According to Mortensen (1907), there are three types of pedicellariae (ophicephalous, tridentate and triphyllous) ( Fig. 11 F–H). In the present study, we have observed only two types, ophicephalous and triphyllous ones. The absence of tridentate pedicellariae is probably the result of their loss by inadequate fixation or conservation. Triphyllous and ophicephalous pedicellariae over entire test. Ophicephalous pedicellariae with long stalk and head, without a neck. Valves with margin denticulate.

Colour. According to Tommasi (1966b), living specimens are brown-yellow. White, cream-coloured, greenish or gray (naked test) in alcohol ( Fig. 11A, D ).

Distribution. Mexico, Gulf of Mexico, Florida, Bahamas, Antilles, Cuba, Jamaica, Colombia, and Brazil ( Borrero-Pérez et al. 2002; Alvarado 2011, Solís-Marín et al. 2013; Martínez-Melo et al. 2015). In Brazil from MA, PB, AL, BA, RJ, and SP ( Tommasi 1966a; Kempf 1972; Oliveira et al. 2010; Smithsonian Database). In this study, we record the species for the first time from the coast of Ceará. From 110 to 2500 m ( Pawson et al. 2009).

Remarks. Presently, 15–20 recent species of Echinocyamus are known ( Markello 2015), of which only three occur in the Atlantic [ E. pusillus ( Müller, 1776) , E. grandiporus and E. macrostomus Mortensen, 1907 ]. Echinocyamus grandiporus differs from E. pusillus , which has larger petals, a more rounded test in lateral view, and ophicephalous pedicellariae with a more serrate blade. Echinocyamus macrostomus differs in having ocular and genital pores of different sizes, test more elongated, and large peristoma. Mortensen (1907) provided an excellent discussion regarding morphological differences among E. grandiporus , E. pusillus and E. macrostomus . Echinocyamus grandiporus is a small echinoid which rarely exceeds 20 mm TL ( Borrero-Pérez et al. 2002). However, specimens larger than 15 mm TL are sometimes seen (A. Kroh, personal communication). In this study, the largest specimen is 9.17 mm TL.

Ecological notes. Found in muddy and sandy bottoms. Tommasi (1966b) recorded this species between 110 and 130 m on bottoms with deep-sea scleractinian corals of the genera Deltocyathus Milne Edwards & Haime, 1848 , Trochocyathus Milne Edwards & Haime, 1848 and Cladocora Ehrenberg, 1834, together with many brachiopods, ophiuroids, and gastropods. Kroh & Mooi (2016) cite the presence of the species on submarine seamounts. Almost nothing is known about its biology and ecology, probably due to its occurrence in deeper waters.

Figures

FIGURE 11. Morphological characters of Echinocyamus grandiporus (UFPB/ECH.1974). (A) Aboral view; (B) Oral view; (C) Aboral view of naked test; (D) Oral view of naked test; (E) Apical disc (F–H) Illustrations of pedicellariae of E. grandiporus provided by Mortensen (1907); (F) Valve of tridentate pedicellariae; (G) Valve of triphyllous pedicellariae; (H) Valve of ophicephalous pedicellariae; (I) Lateral view of naked test.