Ethalia H. Adams & A. Adams 1854

Genus Ethalia H. Adams & A. Adams, 1854 Ethalia H. Adams & A. Adams, 1854: 409. Type species Rotella guamensis Quoy & Gaimard, 1834 (subsequent designation Pilsbry 1889 in 1889–90: 16), Recent, central Indo-West Pacific. Generic fossil record: Paleocene to Recent (Paleobiology Database 2024). Diagnosis Shell relatively large for subfamily (diameter up to 25 mm), lenticular, globose-lenticular or subglobose; smooth and glossy, or lustreless with fine, close-set spiral lirae; axial sculpture weak; umbilicus usually present, often with thickened rim and obstructed to a variable extent by callus deposition associated with umbilical funicle and parietal lip; outer lip simple, its interior smooth. Operculum corneous, thick, multispiral, but not tightly so; whorl overlap narrow, peripheral fringe scarcely evident; spiral microsculpture lacking. Radula with base-plates of rachidian and lateral teeth relatively robust; inner marginal tooth transitional with reduced cusp; cusps of marginals 3–10 largest, comprising a large bluntly lanceolate central denticle with 1–2 smaller denticles at its outer base. Ctenidium bipectinate, anterior portion free. Remarks It remains to be established whether species such as Ethalia bellardi (Issel, 1869), E. bysma Herbert, 1992, E. gilchristae Herbert, 1992 and E. minolina Melvill, 1897, which have less glossy, somewhat lustreless shells with fine, close-set, spiral sculpture, and relatively limited callus deposition in the umbilical region, are truly referable to Ethalia. Insights from preliminary molecular studies have shown that E. gilchristae does not cluster with the type species (Williams et al. 2024).