Atheraster, Mah, 2022

Mah, Christopher L., 2022, New Genera, Species and Occurrences of Deep-Sea Asteroidea (Valvatacea, Forcipulatacea, Echinodermata) collected from the North Pacific Ocean by the CAPSTONE Expedition, Zootaxa 5164 (1), pp. 1-75 : 25-26

Atheraster nov. gen.

Etymology. The genus name is derived from the Greek ather - for “spike” alluding to the regular, prominent spines which serve to diagnose the genus.

Diagnosis. Body strongly stellate (R/r=3.8-4.0) with arms, elongate and tapering. Abactinal arm plates twice to three times larger than those on the disk. Sharp, thorn-like spines present on all superomarginal and inferomarginal plates, forming regular series. Granules with pointed tips. Pedicellariae paddle-like. Furrow spine number, 8–15 in known species.

Comments. The persistent presence of prominent spines along both the superomarginal and inferomarginal plate series, in addition to the enlarged arm plates relative to the disk plates further constrains the character distribution for two recognized species, suggesting a very different taxon than those observed in the otherwise similar Circeaster , which lacks spines but shares enlarged abactinal arm plates.

Both species of Atheraster are known from abyssal depths (1000–3000 m) in the North Pacific. Although two species are described, many similar species were observed from in situ video which could represent further as yet undescribed species.

Although clearly sharing characters with Circeaster , the spines, pedicellariae and smooth abactinal plates are also similar to those found in Calliaster and related taxa, such as Milteliphaster whereas the granulation in the Atheraster sp. described herein are similar to those seen in Hippasteria and Evoplosoma .

Atheraster arandae ( Mah 2006) is the type species for the genus.

Included species: Atheraster arandae ( Mah 2006) , Atheraster symphoniae n. sp.