Chondraster Verrill, 1895

Mah, Christopher L. & Foltz, David W., 2014, New taxa and taxonomic revisions to the Poraniidae (Valvatacea; Asteroidea) with Comments on Feeding Biology, Zootaxa 3795 (3), pp. 327-372 : 333

Chondraster Verrill, 1895

Porania (Chondraster) Verrill 1895: 137 [Non Porania (Chondraster) : Madsen 1959)]

Chondraster Verrill 1914b: 21 ; H.L. Clark, 1923: 275; Spencer & Wright 1966: U69; A.M. Clark & Courtman-Stock 1976: 73; A.M. Clark 1984: 27; Clark & Downey 1992: 202.

Species included. C. elattosis H.L. Clark 1923 ; C. grandis ( Verrill 1878) .

Type species. Chondraster grandis ( Verrill 1878) .

Diagnosis. Body weakly stellate to pentagonal. Body wall thickened, surface smooth and firm. Abactinal plates strongly reduced, embedded within tissue of abactinal body wall. Surface without prominent accessories, but tiny spinelets, sclerites observed on dry specimens. Papulae prominent, present along two longtiduinal areas on each ray. Marginal plates concealed deep within the thickened body wall. Superomarginals bar-like oriented with adradial ends of the inferomarginals. Actinal surface smooth, spineless. Fasciolar grooves present, oriented between inferomarginals and adambulacrals. Adambulacral plates with two or more slightly inset furrow spines, backed but set apart by two or more subambulacrals spines contained within a fleshy sheath. (based on Clark 1984; Clark & Downey 1992)

Taxonomic comments. Clark and Downey (1992: 202) state that the only distinguishing character between C. elattosis and C. grandis is the presence of “up to four” furrow spines in the former rather than only two in the latter species. Two specimens of the west Atlantic C. grandis (USNM E50285 , E50540 ), from Baltimore Canyon, both show two to three furrow spines, indicating morphological overlap with C. elattosis . Although few characters are observed in Chondraster overall, the lack of morphological differences does suggest that C. elattosis Clark 1923 may be part of a widely occurring species similar to the widespread distribution of Hippasteria ( Foltz et al 2013), which also occurs in the North and South Atlantic. Chondraster grandis and C. elattosis also occur at comparable depths. We retain C. grandis and C. elattosis as separate species herein due to the lack of specimen data for the South Atlantic C. elattosis but effectively no characters clearly differentiate the two species.