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Ophryaster argencienis
Taxonomy
Tylaster argencienis was named by Mercier (1935) [Destroyed during the world war II]. It is not extant.
It was recombined as Ophryaster argencienis by Villier (2010).
It was recombined as Ophryaster argencienis by Villier (2010).
Synonymy list
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Ophryaster argencienis Mercier 1935
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| J. Mercier 1935 | Body of large size, pentagonal, stellate with triangular arms relatively short and wide at their base. Dorsal roof of the disc paved with small rounded to rhomboidal abutting abactinal plates. Radial plates differentiated, enlarged and aligned along the arm axis. Abactinal of the arm in series but a single row join the arm tip. Secondary ossicles inserted between abactinals of the disc. 18 superomarginal plates from arm tip to arm tip. Marginals relatively small, squared and aligned in a narrow margin along the arm sides. External faces covered by tiny tubercles for articulation with acicular spines. Proximal sides of the superomarginals are slightly convex to the disc and bare. Actinal face covered by well-developed polygonal plates. External face of the actinolateral with an ornament of spinelets larger than those of the marginals and inserted in spine-pits of the plate surface. Inferomarginal plates in equal number and very similar to the superomarginal. Ambulacral furrow narrow and deep. Large adambulacral plates arranged in rows of about 25 per arm side, the size of individual plate diminishing progressively to the arm tip. Adradial side of the adambulacrals protrudes into the ambulacral furrow by triangular carinae. Each adambulacral with four to six tubercles on the external face for articulation of spines. Large diamond-shaped oral plates, forming interradial carinae. External face bearing spine-pits and bulged tubercles for articulation of spines. Terminal plate relatively small and deeply inserted in the corner of the two distal-most superomarginal plates. |