Valettaster thuyi, Gale, 2021

Gale, Andrew Scott, 2021, Taxonomy and phylogeny of the ‘ football stars’ (Asteroidea, Sphaerasteridae), Journal of Systematic Palaeontology 19 (10), pp. 691-741 : 734-735

publication ID

https://doi.org/ 10.1080/14772019.2021.1960911

publication LSID

lsid:zoobank.org:pub:F8991F09-B5FB-40EF-B4CC-474D925085B8

DOI

https://doi.org/10.5281/zenodo.10883585

persistent identifier

https://treatment.plazi.org/id/B9207C41-9A5A-FFD6-0CF7-FACFFDF4FD77

treatment provided by

Felipe

scientific name

Valettaster thuyi
status

sp. nov.

Valettaster thuyi sp. nov.

( Fig. 22M, N View Figure 22 )

Type. The specimen figured here ( Fig. 22M, N View Figure 22 ) is the holotype, from the Hildoceras bifrons ammonite Zone (Toarcian) at Fougerolles, France ( MHNML 2020.1.1) .

Diagnosis. Valettaster with tabulate abactinal ossicles, the broad outer surface of which bears a branching reticulum of imperforate stereom.

Derivation of name. After Ben Thuy , who sent the holotype specimen to the author .

Material. Holotype, a single abactinal ossicle, obtained by Marc Chesnier from washed residues from the Gúerin quarry at Fougerolles, Normandy, France (see Hess & Thuy 2016 for details).

Description. Abactinal ossicle with outline irregularly semicircular, 3 mm in maximum dimension; one side is straight, the other bearing irregular short lobes. The ossicle is flat, with a broad external surface slightly narrower than basal breadth. The external surface shows a radial network of irregularly bifurcating ridges of smooth imperforate stereom.

Remarks. This is by a considerable margin the oldest known representative of Valettaster (185–190 Ma), and the similarity of its highly specialized sculpture (reticulum of imperforate stereom) to that of the Cretaceous V. argus and V. ocellatus confirms its placement in the genus. It differs from V. ocellatus in the thinner abactinals, the very broad external surface and the irregularly bifurcating, radial ribbing. In V. ocellatus the abactinals are stout truncated cones, and the sculpture comprises fine radial ridges and pustules ( Fig. 22E View Figure 22 ).

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