Circeaster Koehler 1909

Mah, Christopher L., 2024, Two New Taxa of Goniasteridae (Asteroidea, Echinodermata) and Noteworthy Observations of Deep-Sea Asteroidea by the NOAA Ship Okeanos Explorer in the North and Tropical Atlantic, Zootaxa 5432 (4), pp. 461-508 : 481

Circeaster Koehler 1909

Circeaster Koehler, 1909: 83 ; Halpern 1970a: 265. Downey 1973: 47, 55, pl. 21A, B; Clark &

Downey 1992: 237. A.M. Clark 1993: 250; Mah 2006; 927.

Diagnosis

R/r> 2.5. Disc swollen, large. Abactinal arm plates two to three times larger than disc plates. Arm plates generally bare. Disc plates with granules, round, hemispherical. Marginal plates wide in most species. Spinelets or granules present along dorsolateral/ventrolateral edges and surfaces of marginal plates. Greater density of spinelets/granules on inferomarginals than on superomarginals. Superomarginal plates abutted over midline in several species. Arms elongate tapering, with tips upturned. Interradial arcs linear to curved. Actinal plates irregular in some species, covered with granules or spinelets. Pedicellariae uncommonly present. Adambulacral furrow spines 6–15. Enlarged subambulacral spine or spines present. Prominent, paddle-like, bivalve, or sunken pedicellariae with jagged teeth present. Pedicellariae present on adambulacral plates. Based on Mah (2006).

Comments

Circeaster includes eight species, which primarily occur in tropical deep-sea Pacific and Indian Ocean habitats, excluding the Atlantic Circeaster americanus . Two other goniasterid genera, Lydiaster Koehler 1909 and Atheraster Mah 2022 show close morphological affinities. In situ videos show observations of several Circeaster species as well as Atheraster are predators of deep-sea coral ( Mah 2015, 2022)