Taxonomy and phylogeny of the ‘ football stars’ (Asteroidea, Sphaerasteridae)
Author
Gale, Andrew Scott
School of the Environment, Geography and Geological Sciences, University of Portsmouth, Burnaby Building, Burnaby Road, Portsmouth PO 1 3 QL UK; & Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW 7 5 BD, UK
text
Journal of Systematic Palaeontology
2021
2021-10-01
19
10
691
741
http://dx.doi.org/10.1080/14772019.2021.1960911
journal article
293303
10.1080/14772019.2021.1960911
53749253-12aa-41cc-9eec-e28c0b075738
1478-0941
10949919
F8991F09-B5FB-40EF-B4CC-474D925085B8
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.
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 =
10 mm
; E, K =
2 mm
; G =
5 mm
.
Figure 16.
Echinosphaeraster scutatus
(Goldfuss, 1833)
. Reconstructions and interpretative drawings.
A,
abactinal view of individual, colouration as in Figure 1.
B,
primary radial plate, to show papular openings.
C,
cross section of individual.
D,
drawing of specimen figured in Figure 13.
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
).