Stauraster primaevus (von Zittel, 1880)

Gale, Andrew Scott, 2021, Taxonomy and phylogeny of the ‘ football stars’ (Asteroidea, Sphaerasteridae), Journal of Systematic Palaeontology 19 (10), pp. 691-741 : 700-702

Stauraster primaevus (von Zittel, 1880)

( Fig. 5A–N )

$1880 Pentaceros primaevus von Zittel : 456, fig. 327c.

1886 Pentaceros primaevus von Zittel ; Fraas: 256, pl. 30, figs 18, 19.

$1929 Stauraster billodense Valette : 36, pl. 4/3, 1–7.

1975 Stauraster primaevus (von Zittel) ; Hess: 36.

2003 Stauraster billodense Valette ; Courville & Villier: 182, fig. 3D–G.

2004b Stauraster billodense Valette ; Villier et al.: 39.

Type. The radial ossicle figured by von Zittel (1880, fig. 327c) from the ‘Oberer Jura’ ( upper Oxfordian ) of Streitberg, Franconia, Bavaria, Germany, is the lectotype. The present whereabouts are unknown .

Diagnosis. As for the genus.

Material. A well-preserved arm, from the upper Oxfordian of Switzerland ( MZA L246 ) and numerous isolated ossicles ( Fig. 5A–N , NHMUK EE 17624–17632, 17638) from the lower Oxfordian (Couches de Passage, uppermost 3 m of section; Gale 2019, fig. 20) of Andelot-Morvan (Jura, France) .

Remarks. The ossicle figured by von Zittel (1880, fig. 327c) in the form of a rather stylized woodcut is a proximal radial ossicle that is closely similar in morphology to material from France described by Valette as S. billodense , in terms of shape, the presence of vertical, oval articulation structures and rather deeply impressed spine pits. Additionally, both species are of Oxfordian age. The ossicles appear to be similar in shape and sculpture, allowing for Von Zittel’ s stylized illustration, and I therefore follow Hess (1975) in synonomizing S. billodense with von Zittel’ s species. There is an age difference of approximately 3 million years between the two occurrences, but both are Oxfordian in age; many Jurassic asteroids have relatively long ranges, so this is not unusual. The material figured by Fraas as Pentaceros primaevus ( Fraas 1886, pl. 30, figs 17–31) appears to contain diverse taxa, including a bulbous primary radial or interradial (Frass 1886, fig. 17) which is an undescribed stauranderasterid. Two disc ossicles (Frass 1886, figs 18, 19) may belong to S. billodense .

The discovery of an articulated arm of S. primaevus demonstrates the morphology of Stauraster for the first time ( Fig. 5A–C ), and the numerous ossicles from Andelot-Morvan allow a tentative reconstruction of the disc ( Fig. 5O ).

Included species. Stauraster primaevus .

Figures

Figure 5. Morphology of the stauranderasterid outgroup, Stauraster primitivus (von Zittel, 1880). A–C, arm, in abactinal, lateral and actinal views, respectively (MZA L246). D–N, isolated ossicles; D–G, I, ossicles from primary circlet; D, E, primary interradial (NHMUK EE 17624); F, G, centrale (NHMUK EE 17625); H, ambulacral ossicle, actinal view (NHMUK EE 17626); I, inner calycinal ossicle (NHMUK EE 17627); J–L, radials (NHMUK EE 17628–17630); M, N, adambulacral ossicles, in abactinal and proximal/distal views, respectively (NHMUK EE 17631–17632). O, reconstruction of apical region of Stauraster. Provenance: A–C, upper Oxfordian of Switzerland. D–N are from the lower Oxfordian, Cardioceras bukowskii ammonite Subzone, basal Couches de Passage, Andelot-Morval, Jura, France (see Gale 2019, for locality details). Colours as in Figure 1. Scale bars: A–C = 10mm; D–G, I–L = 5 mm; H, M, N = 0.5 mm.