Astrotholus infernalis Mah 2023, n. gen.

• Main Author: Mah, Christopher L.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2023
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Asteroidea; Valvatida; Asterinidae; Astrotholus; Astrotholus infernalis; Antarc*; Antarctica; Elephant Island; Scotia Sea; Tierra del Fuego
• Online Access: https://doi.org/10.5281/zenodo.8092123; http://treatment.plazi.org/id/03C387E8663AFFEEFF68E48A829BFB52

Astrotholus infernalis n. gen. n. sp. FIGURE 2A–F Hurtado-Garcia & Manjón-Cabeza 2022: 1220 (as Anseropoda antarctica ) Etymology The species epithet “ infernalis ” describing “lower regions” and alluding to the great depth occurrence of this species. Diagnosis Body pentagonal to weakly stellate (R/r=1.3–2.5, but mostly between 1.4–1.6), arms triangular, disk arched, actinal surface concave, interradial arcs weakly curved to straight (Fig. 2A). Abactinal plates imbricate, flat to mound-like or arched (Fig. 2C). Abactinal plate surfaces each covered with spinelets, 4–20, mostly 5–10, widely spaced (Fig. 2B). Spinelet tips hyaline, 3–4. Marginal plates 30 to 38 to 40 (at R=1.0, R=1.2 to R=1.6 respectively) per interradius (arm tip to arm tip), imbricate. Superomarginal plates oval to quadrate in shape (Fig. 2C), plate surface with 5–12 spinelets bearing minute hyaline tips, 3–4 identical to those of abactinal plates. Inferomarginal plates approximately 50% the size of the superomarginal plates, quadrate in outline. Surface covered with 1–5 spinelets bearing minute hyaline tips, 3–4 identical to those on superomarginals and abactinal plates. Actinal plates imbricate, in 30–40 transverse rows showing direct continuity with inferomarginal and adambulacral plates (Fig. 2E). Plates round but elongate, each with sharp, elongate spines, 2–4 per plate (Fig. 2D, E, F). Furrow spines elongate with pointed tips, webbed (sometimes torn) 2 to 4 in palmate to straight series, subambulacral spines identically elongate with pointed tips and webbed, 2 to 4 per plate, set off from the furrow spine by a discrete space (Fig. 2F). Comments Astrotholus infernalis n. gen. n. sp. represents the deepest known member of the Asterinidae with collection from 3788–3944 m. Specimen USNM 1122403, the holotype of this species was cited as part of “ Anseropoda antarctica ” by Hurtado-Garcia & Manjón-Cabeza (2022) Occurrence Georgia Island, Elephant Island, Scotia Sea, South Atlantic, Tierra del Fuego. 1000–3944 m. Description Body ...