Astroceramus Fisher 1906 Astroceramus Fisher 1906: 1056; 1911: 172 (in key); 1919: 309; Döderlein 1924: 60; Macan 1938: 388; H.L. Clark 1941: 45; Halpern 1970: 140; Clark & Downey 1992: 230; A.M. Clark 1993: 243; McKnight 2006: 88; Kogure & Tachikawa 2009:77. Diagnosis. Abactinal plates polygonal in outline, abutted, no surficial granules, surface smooth, bare. Glassy tubercles (aka crystalline nodules) embedded in surface of abactinal plates (e.g. Fig. 4B) of all known species. Marginal plates large, blocky, quadrate in outline, surface with coarse, surficial granules. Superomarginal plates abutted over midline variably from base of arm to paired distal penultimate plates. Actinal surface variably covered by coarse granules to bare. One to many large, thick subambulacral spines present in most species. Pedicellariae present or absent. Comments As outlined in Mah (2018), Astroceramus currently includes 11 species distributed throughout the Indian, Pacific and Atlantic Oceans. Astroceramus diversity in the tropical Pacific began with Fisher’s (1906) description of Astroceramus callimorphus from the Hawaiian Islands followed by A. sphaeriostictus and A. lionotus from the Philippine Islands (Fisher 1913). Astroceramus denticulatus has been described by McKnight (2006) from the Kermadec Ridge (New Zealand), Astroceramus boninensis from southern Japan (Kogure & Tachikawa, 2009), and Astroceramus eldredgei was described from the Hawaiian region (Mah 2015). Mah (2018) reviewed and described new Astroceramus from the Indian Ocean. A single species, A. brachyactis H.L. Clark 1941 is known from the Atlantic. The body morphologies of Astroceramus in New Caledonia is acutely diverse, ranging from species showing discoid or thick, compact forms with R/r=1.0 while other show strongly stellate forms with elongate arms, R/r>3.0.Abactinal and marginal plate arrangements, e.g. with abutted superomarginal plates along the arms are surprisingly consistent, but with variable adambulacral spines, tubercles, and pedicellariae. Discovery of further undescribed diversity of Astroceramus from samples throughout the tropical Pacific, especially in the South Pacific, is ongoing, with further specimens and additional undescribed species present in collections (Mah unpublished data).

Published as part of Mah, Christopher L., 2026, New genera, species and occurrences of Goniasteridae (Valvatida, Asteroidea) from New Caledonia, pp. 1-113 in Megataxa 19 (1) on page 34, DOI: 10.11646/megataxa.19.1.1, http://zenodo.org/record/20318264