Sphaeraster Quenstedt, 1875

Gale, Andrew Scott, 2021, Taxonomy and phylogeny of the ‘ football stars’ (Asteroidea, Sphaerasteridae), Journal of Systematic Palaeontology 19 (10), pp. 691-741 : 702-704

Genus Sphaeraster Quenstedt, 1875

Type species. Although Clark & Wright (1962) designated Sphaerites punctatus Quenstedt, 1875 as type species, this is an objective junior synonym of Asterias tabulatus Goldfuss, 1833 , which is therefore the type species. Following Hess (1975), the name S. tabulatus has been used for the common Oxfordian–Kimmeridgian species of Sphaeraster .

Diagnosis. Large Sphaerasteridae in which the abactinal surface forms a high dome, composed of numerous (450+) abactinal ossicles which are set in rows with an interradial chevron arrangement and taper towards the ambitus; primary circlet approximately one-third of diameter; larger individuals possess a ring of six to seven spines on the primary abactinal ossicles.

Included species. Sphaeraster tabulatus .

Figures

Figure 1. Homology of abactinal plating in Podosphaeraster pulvinatus Rowe & Nichols, 1980. A–C, homology adopted in the present paper, which identifies the primary ossicles (interradials, radials), inner calycinal ossicles and radials. Marginals cannot be identified, and unpaired interradial plates (I-plate, V-plate) are indicated. D, E, plating scheme of Fujita & Rowe (2002, fig. 1), who identified an ‘apical system’ and marginals. See text for discussion.