Pouzaster pocknotata, Gale, 2021

Gale, Andrew Scott, 2021, Taxonomy and phylogeny of the ‘ football stars’ (Asteroidea, Sphaerasteridae), Journal of Systematic Palaeontology 19 (10), pp. 691-741 : 721

Pouzaster pocknotata sp. nov.

( Figs 13I–O, Q–S , 22F, I )

Types. The holotype ( Fig. 13Q ) is a primary radial ossicle ( NHMUK EE 17688 ) from the lower Bathonian , Zigzagiceras zigzag ammonite Zone of La Pouza, near La Voulte-sur-Rhone (Ard̀eche, France). A total of nine similar ossicles from the same locality are paratypes ( NHMUK EE 17689–17695 ) .

Diagnosis. As for the genus.

Additional material. Two ossicles from the serpentinus ammonite Zone (Toarcian) of Fougerolles, near Caen, France ( MHNLM 20201.2 and 20201.3).

Derivation of name. Latin for pockmarked (pock = scar, notata = marked), in reference to the surface sculpture.

Description. The abactinal plates are variable in shape, and hexagonal to oval in outline. All possess a distinctive sculpture of irregular pitting, which has a weak radial alignment in some specimens (e.g. Fig. 13I, N, Q, R ). The position of possible pr can be identified from comparison with that in other Sphaerasteridae ( Fig. 13O, R ). They are hexagonal and symmetical about the vertical axis, and the articular facet contacting the successive radial is broad. The external face is gently convex, and appears to be smooth in one specimen ( Fig. 13O ); however, under low-oblique lighting it displays radiating ridges around the margin of the plate. The ossicles are half as thick as broad, and each side has a well-defined rounded rectangular articular surface which bears a scatter of fine pits. A single poorly defined papular notch is present on each corner ( Fig. 19D ). Other abactinals with a similar sculpture include rather tall, narrow, hexagonal to lozenge-shaped plates (e.g. Figs 13J–N , 22F, I ) which were probably unpaired and occupied an interradial position, and broad hexagonal plates ( Fig. 13M ) which might be distal radials .

Remarks. The distinctive sculpture of the plates, irregular pitting with a weak radial element towards the margins, distinguish this species from all others. Reconstruction is not possible without further material.

Figures

Figure 13. A–H, P, Sphaeraster tabulatus (Goldfuss, 1833); A, actinal ossicle, to show crater-rimmed spine pits (NHMUK EE 17680); B, G, abactinal ossicles of small individuals which have smooth external faces (NHMUK EE 17682, 17683); C, D, abactinal ossicles of very small individuals (NHMUK EE 17684, 17685); E, lateral view of small abactinal plate (NHMUK EE 17686); F, abactinal ossicle with weak radial sculpture (NHMUK EE 17681); H, enlargement of sculpture of abactinal ossicle A; P, lateral view of abactinal plates of small individual, to show lack of papular pores and articulation structures (compare with Fig. 9M, N; NHMUK EE 17687). I–O, Q–S, Pouzaster pocknotata gen. et sp. nov., abactinal ossicles; I–O, paratype abactinals (I, J, NHMUK EE 17689; K, NHMUK EE 17690; L, M, NHMUK EE 17691; N, NHMUK EE 17692; O, NHMUK EE 17693; R, S, NHMUK EE 17695). Q, holotype, abactinal (NHMUK EE 17688); S, enlargement of surface detail of K. Provenance: A–H, P are from the upper Oxfordian, Hypsilum ammonite Zone, Plettenberg, near Balingen, Germany. I–O, Q–S are from the lower Bathonian, Zigzagiceras zigzag ammonite Zone at La Pouza, near La-Voulte-sur-Rhone, Ard̀eche, France. Scale bars: A, F, O = 1 mm; B–E, G, I–N, P–R = 0.5mm; H, S = 0.2mm.

Figure 19. A, C, interpretative drawings of Eosphaeraster amellagensis gen. et sp. nov. A, lateral view of large abactinal plate to show candelabra-like, outward-branching papular pores on rim of plate; C, reconstruction of part of abactinal surface; the large central ossicle is the primary interradial. Note concentration of papular pores towards corners of plates. B, Bolbosphaeraster valettei gen. et sp. nov. Note concentration of few papular pores at corners of plates. D, Pouzaster pocknotata gen. et sp. nov., to show single papular pores at plate junctions.

Figure 22. A–D, G, J, Valettaster digitatus (Quenstedt, 1858), abactinal ossicles, in external view (A, C, D, G, J) and lateral view (B) (GPIT/A5/50). E, Valettaster ocellatus (Forbes, 1848), abactinal ossicle, in external view (NHMUK EE 17696). F, I, Pouzaster pocknotata gen. et sp. nov., abactinal ossicles in external view (MHNML 2020.1.2, 1.3). H, K, Valettaster granulatus (Brunnich Nielsen, 1943), abactinal ossicles, external view (SNSB-BSGP 2020 XLV1, 2). L, Valettaster argus (Spencer, 1907), articulated group of abactinal ossicles (NHMUK EE 17637f). M, N, Valettaster thuyi sp. nov., holotype, abactinal ossicle in external and lateral views, respectively (MHNML 2020.1.1). Provenance: A–D, G, J are from the Oxfordian of Oerlingen, south Germany. B is from the Santonian of East Kent, UK. F, I are from the serpentinus ammonite Zone, Toarcian at Fougerolles, France. H, K are from the lower Maastrichtian of R¨ugen, Germany. M, N are from the bifrons ammonite Zone, Toarcian, Fougerolles, France. L is from the coranguinum Zone, Santonian, Broadstairs, Kent, UK. Scale bars: A–E, G, H, J, K = 5 mm; F, I, L = 0.5mm; M, N = 0.2 mm.