Bulbosphaeraster valettei, Gale, 2021

Gale, Andrew Scott, 2021, Taxonomy and phylogeny of the ‘ football stars’ (Asteroidea, Sphaerasteridae), Journal of Systematic Palaeontology 19 (10), pp. 691-741 : 718-719

Bulbosphaeraster valettei sp. nov.

( Figs 6L, M , 8H , 19B, 20A–M )

Types. The primary interradial ossicle figured here is the holotype ( Fig. 20B , NHMUK EE 17670 ); the other figured ossicles are paratypes ( NHMUK EE 17671–17679 ) .

Diagnosis. As for the genus.

Derivation of name. In honour of the late Dom Auŕelien Valette, who identified that the material belonged to a different genus and species, in his labels with the specimens in the Dijon collection.

Material. Two abactinal ossicles in the Valette Collection, Dijon (UdB, unregistered), 25 abactinal ossicles ( NHMUK EE 17670–17679, 17703) from the Bathonian, Zigzagiceras zigzag ammonite Zone of La Pouza, near La Voulte-sur-Rhone (Ard̀eche, France).

Description. The species is known from primary abactinal ossicles that can be identified with reference to articulated material of Sphaeraster tabulatus (ce, pr, pir). All abactinal ossicles have a similar sculpture of evenly placed, rather widely spaced spine pits, each of which has a broad, raised, crater-like rim ( Fig. 20A–M ). The ossicles articulate by means of rectangular to oval surfaces centrally placed on each lateral surface, which are irregularly pitted ( Fig. 20D, E ). The pir are vertically symmetrical, heptagonal, slightly broader than tall, and carry an evenly rounded, bulbous swelling on the upper central part of the outer face ( Fig. 20A, B, E ). The swelling carries large, irregular spine pits and shows probable in vivo abrasion. The pr are hexagonal and rounded in outline, vertically symmetrical and gently swollen centrally ( Fig. 20A ). The proximal articular facet is broader than the distal one. The ce ( Fig. 20L ) is equilaterally pentagonal and gently convex, and the proximal margin carries a rounded notch for the periproct. Each side carries two to four papular notches concentrated at the corners ( Fig. 20C ). Possible ico ossicles ( Fig. 20C ) are pentagonal with a dense cover of spine pits. Distal abactinal ossicles ( Fig. 20G ) are broad and concavo-convex. The position of other abactinal ossicles figured ( Fig. 20F, H, J, L, M ) is uncertain, but they all share the same distinctive sculpture. Ambulacrals ( Fig. 6L, M ) are short and broad, with a straight basal margin, and the padam and dadam sites are positioned on the lateral surfaces. A single oral ossicle ( Fig. 8H ) is tall, and the apophyse is directed proximally; the oradam is tall and narrow.

Remarks. Bulbosphaeraster gen. nov. can be distinguished from its closest relative, Eosphaeraster gen. nov., by the swollen central areas on the pr and pir, the triplet of papular openings at each triple plate boundary (there are up to 12 in Eosphaeraster gen. nov.) and the nature of the articulation of the distal abactinal ossicles. In Bulbosphaeraster gen. nov. the articulations are proximally imbricating and possess a single central articular facet. In Eosphaeraster gen. nov. they consist of vertical articular bars separated by papular notches. Ambulacrals, adambulacrals and orals are similar. The crater-rimmed spine pits present on all abactinal/actinal ossicles are found only on actinal ossicles of other sphaerasterids ( Figs 9E , 15A, B ).

Figures

Figure 6. Ambulacrals of sphaerasterids. A–D, Sphaeraster tabulatus (Goldfuss, 1833); A, B, proximal ambulacral in actinal and proximal/distal aspects, respectively (NHMUK EE 17633); C, D, actinal views of ambulacrals from mid-radius (NHMUK EE 17623a, 17634). E, P, Q, Podosphaeraster pulvinatus Rowe & Nichols, 1980; E, enlargement of actinal view of base of ambulacral; P, Q, actinal and proximal/distal views of ambulacral, respectively (Mnhnl OPH176). F, G, Eosphaeraster amellagensis gen. et sp. nov., ambulacral in actinal and proximal/distal views, respectively (NHMUK EE 17635). H–K, N, O, Valettaster argus (Spencer, 1907). H–K, proximal/distal views of ambulacral, note cavity replacing articulation facet (I); L, M, Bulbosphaeraster valettei gen. et sp. nov., ambulacral in actinal and proximal/distal views, respectively (NHMUK EE 17636); N, O, actinal views of ambulacrals (NHMUK EE 17637a, b). Provenance: A–D are from the upper Oxfordian, Hypsilum ammonite Zone, Plettenberg, near Balingen, Germany. F, G are from the upper Pliensbachian, outcrop on south side of wadi immediately to west of road, 0.5km south of the Kasbah of Amellago, Atlas Mountains, Morocco. L, M are from the lower Bathonian, Zigzagiceras zigzag ammonite Zone at La Pouza, near La Voulte-sur-Rhone, Ard̀eche, France. H–K, N–O are from the coranguinum Zone, Santonian, Broadstairs, Kent, UK. E, P, Q are Recent, Philippines. Scale bars: A, B, D, F, G, J–Q = 0.5mm; C = 1 mm; E, H, I = 0.2 mm.

Figure 8. Oral ossicles of sphaerasterids. A–E, Sphaeraster tabulatus (Goldfuss, 1833); A, D, interradial view of orals of smaller individuals (NHMUK EE 17642, 17643); B, E, interradial (B) and radial (E) views of small oral (NHMUK EE 17644); C, large oral, interradial view (NHMUK EE 17623b). F, I, Eosphaeraster amellagensis gen. et sp. nov., oral in interradial and radial views, respectively (NHMUK EE 17645). G, oral ossicle of possible stauranderasterid or sphaerasterid, interradial view (MnhnL OPH173). H, oral ossicle, probably from Bulbosphaeraster valettei gen. et sp. nov., interradial view (NHMUK EE 17646). J, L, oral ossicle of Podosphaeraster pulvinatus Rowe & Nichols, 1980, in interradial and radial views, respectively (MhnhL OPH174–176). K, M, oral ossicle of Valettaster argus (Spencer, 1907), in interradial and radial views, respectively (NHMUK EE 17637h). N, interradial view of oral ossicle of Manfredaster bulbiferus (Forbes, 1848) (NHMUK EE 17647a). Provenance: A–E are from the upper Oxfordian, Hypsilum ammonite Zone, Plettenberg, near Balingen, Germany. F, I are from the upper Pliensbachian, outcrop on south side of wadi immediately to west of road, 0.5 km south of the Kasbah of Amellago, Atlas Mountains, Morocco. G is from the Carnian (Upper Triassic), Cortina d’Ampezzo, Italy. H is from the lower Bathonian, Zigzagiceras zigzag ammonite Zone at La Pouza, near La Voulte-sur-Rhone, Ard̀eche, France. K, M, N are from the coranguinum Zone, Santonian, Broadstairs, Kent, UK. J, L are Recent, Philippines. Scale bars: A, D, G, H, K, M = 0.5mm; B, E = 0.2 mm; C, F, I, J, L, N = 1 mm.

Figure 9. Sphaeraster tabulatus (Goldfuss, 1833). A, B, reconstructed fragments of the abactinal surface of an individual (NHMUK EE 17623h, i); A, shows the space occupied by the madreporite; B, largely consists of a row of radial plates. E, actinal fragment of same specimen (NHMUK EE 17623j). C, D, G, isolated distal abactinal or actinal plates (NHMUK EE 17623k–m). F, abactinal showing growth banding (NHMUK EE 17648). H, K, radial plate showing in vivo breakage (NHMUK EE 17649). I, J, spine originally attached to abactinal plate (NHMUK EE 17623n). L, O, small radial plates (NHMUK EE 17652, 17653). M, P, radial plate (NHMUK EE 17650). N, Q, very large primary radial plate, showing ring of spine attachment sites (NHMUK EE 17651). Provenance: upper Oxfordian, Hypsilum ammonite Zone, Plettenberg, near Balingen, Germany. Scale bars: A, B, F, M, N, P, Q = 10mm; C–E, G, H, L, O = 5 mm; I, J = 1 mm; K = 0.2 mm.

Figure 15. Echinosphaeraster scutatus (Goldfuss, 1833). A, B, fragments of actinal surface; A, original of Quenstedt (1858, pl. 94, fig. 12) and Schondorf (1906a, pl. 1, figs 7, 8) (GPIT/80/94-12); B, original of Quenstedt (1858, pl. 94, figs 13, 14) and Schondorf (1906a, pl. 1, figs 9, 10) (GPIT/80/94-12). C, D, primary radial plate, in lateral (D) and external (C) views (GPIT/A5/52). E, K, large spine from abactinal plates, in basal (E) and lateral (K) views (GPIT/A5/51). F, G, I, J, abactinal plates (GPIT/A5/52). H, radial plate, external view (GPIT/A5/52). All specimens from the Weisser Jura e or Malm of the Swabian Alb, southern Germany. Scale bars: A–D, F, I, J = 10mm; E, K = 2 mm; G = 5 mm.

Figure 20. Bulbosphaeraster valettei gen. et sp. nov., abactinal ossicles. A, probable primary radial ossicle, paratype (NHMUK EE 17672); B, E, holotype, primary interradial ossicle, in external and lateral views, respectively (NHMUK EE 17670); C, D, probable inner calycinal ossicle, paratype (NHMUK EE 17671). The other specimens (F, G, H, J, L, M) are abactinal ossicles of indeterminate position, all paratypes (NHMUK EE 17674–79). I, probable centrale (NHMUK EE 17673); K, enlargement of surface of H. Provenance: all are from the lower Bathonian, Zigzagiceras zigzag ammonite Zone at La Pouza, near La Voulte-sur-Rhone, Ard̀eche, France. Scale bars: A–J, L, M = 5 mm; K = 0.2 mm.