Pergamaster ultra Mah 2018, n. sp.

• Main Author: Mah, Christopher L.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2018
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Asteroidea; Valvatida; Goniasteridae; Pergamaster; Pergamaster ultra; Antarc*; Antarctic; Ross Sea
• Online Access: https://doi.org/10.5281/zenodo.5990821; http://treatment.plazi.org/id/193787A0FFA4FFD8F4CBFEAF40C3C8E7

Pergamaster ultra n. sp. Figure 28 A–E Etymology. The species epithet ultra is Latin for “beyond” or “on the other side”, alluding to Pergamaster ’s first occurrence from beyond the Antarctic region. Diagnosis. A species distinguished by its weakly stellate shape (R/r=1.76) (Fig. 28A), bare, smooth abactinal plates (Figs. 28A, B), surrounded by large peripheral granules. Marginal plates, bare smooth, form distinctive frame as viewed from above (Figs. 28A, B). Granule covered actinal surface. Furrow spines three or four (Fig. 28D). Comments. The bare abactinal plates and distinctively large peripheral granules around plates as well as the wide, smooth bare marginal plates serve to identify this specimen as a member of the genus Pergamaster, a genus known previously only from the Antarctic (Mah 2011). Mah (2011) outlined two accepted species, Pergamaster incertus from the Weddell Quadrant and Pergamaster triseriatus from the Ross Sea. Both Antarctic species share several characters absent from Pergamaster ultra n. sp, including a thick, enlarged subambulacral spine, and relatively few (two or three) thickened furrow spines (Fig. 28D), as well as much more elongate, triangular arms. This species shows overall, much finer actinal and adambulacral granulation and accessories, including more slender subambulacral and furrow spination. The holotype is also much smaller (R=2.3) than the known Antarctic species, which displayed arm radii of at least 6.0 cm. Biogeographic Significance. Pergamaster ultra n. sp. represents the first species of this genus to be found outside of the Antarctic region. Several asteroid genera and species are known to occur in both the Antarctic and in “outside” deep-sea settings. The genus Odontaster (Odontasteridae) for example, as outlined in A.M. Clark (1962), Clark & Downey (1992), Fisher (1910) and Clark and McKnight (2001) are most diverse in the Antarctic region but have species representation in the North Pacific, the tropical Atlantic, and the South Pacific region near New Zealand, ...