Hyalinothrix grangei ( Clark & McKnight, 2001 ) Mah & Fujita, 2020

Mah, Christopher L. & Fujita, Toshihiko, 2020, New species and occurrence records of Japanese Solasteridae and Ganeriidae including a new species of Paralophaster from the North Pacific with an overview of Hyalinothrix, Zootaxa 4750 (1), pp. 67-100 : 89

Hyalinothrix grangei ( Clark & McKnight, 2001) nov. comb.

Nepanthia grangei H. E. S. Clark & McKnight 2001: 159 .

Comments. A review of diagnostic characters of Hyalinothrix versus comparable taxa in the Asterinidae indicate that Nepanthia grangei Clark & McKnight, 2001 should be re-assigned to the genus Hyalinothrix . Holotype images and the description of Nepanthia grangei showed the specimen with abactinal paxillar plates, described as tabulate, with glassine spinelets, which are absent from the definition of Nepanthia (e.g., Rowe & Marsh 1982; O’Loughlin & Waters 2004) and nearly all asterinids, which display spines sitting directly on abactinal and other low-lying surface plates. Nepanthia grangei was placed into Pseudonepanthia by O’Loughlin & Waters (2004), but comparisons of the type species, Pseudonepanthia gotoi A. H. Clark 1916 show spines sitting directly on the abactinal plates ( O’Loughlin & Waters 2004), rather than on elongate tabulate or paxillar plates, as indicated on Nepanthia grangei .

If Nepanthia grangei is re-assigned to Hyalinothrix , this has an significant outcome on the interpretation of molecular phylogenetic results presented in Mah & Foltz (2011). In their trees ( Mah & Foltz 2011: Fig. 2 ), Nepanthia grangei occurs on a well supported branch (93%) with Tarachaster australis and implies a sister group relationship between Nepanthia and the “paxillate ganeriids” such as Tarachaster . This taxonomic change would support Hyalinothrix and Tarachaster on a single, relatively well-supported branch, separate from Chaetaster , which was supported as sister branch to the Odontasteridae . Hyalinothrix and Tarachaster on a single branch would separate them from the Ganeriidae sensu Spencer and Wright (1966) and Fisher (1911), which included Cycethra , Perknaster , and Cuenotaster , disputing the historical interpretation of the Ganeriidae as monophyletic.

Figures

FIGURE 2. Lophaster cactorum n. sp. Holotype, NSMT-E-11325.A.Abactinal surface. Scale bar=1.0 cm. B. Abactinal surface closeup showing paxillae. Scale bar=0.5 cm. C. Lateral view showing marginal paxillae. Scale bar=0.5 cm. D. Actinal surface. Scale bar=1.0 cm. E. Oral region. Scale bar=0.5 cm.