Pandalosia subfirmata (O. Boettger, 1887) Materials Type status: Other material. Occurrence: catalogNumber: STGY 71; recordedBy: Qi Lu; individualCount: 2; lifeStage: adult; occurrenceID: EDBBA5C5-74AE-557C-B169-350D9E4314E3; Taxon: taxonID: Native; scientificName: Pandalosia subfirmata; originalNameUsage: Costalynia decapitata Laseron, 1956, Costalynia truncata Laseron, 1956, Pandalosia darwinensis Laseron, 1956, Pandalosia excelsis Laseron, 1956, Pandalosia subulata Laseron, 1956, Rissoina (Schwartziella) subfirmata O. Boettger, 1887, Schwartziella (Pandalosia) darwinensis (Laseron, 1956); Location: country: China; stateProvince: Hainan; locality: Wenchang; Identification: identifiedBy: Qi Lu; dateIdentified: 2023 Description Shell minute (3 ± 0.15 mm in height, 1 ± 0.02 mm in width), conical, white, glossy, translucent (Fig. 2 A-D). Protoconch with 3.5 whorls, conical, slender, smooth, transition to teleoconch poorly defined (Fig. 2 G and H). Teleoconch comprising approximately 5 whorls, each convex with deeply impressed sutures; sculpture consisting of prosocline axial ribs, lacking spiral elements; axial ribs sparsely distributed, intercostal spaces exceeding rib width (Fig. 2 C-E). Base with prominent plica. Aperture D-shaped, posteriorly angulate, lacking distinct anterior canal; outer lip thickened, varix bearing longitudinal striae; interior of aperture with delicate spiral lirae (Fig. 2 F). Diagnosis Whorls growing fairly rapidly, rather convex, separated by a deep suture; initial whorls smooth, the others strongly ribbed, with rounded, oblique ribs and smooth interspaces. Aperture oblique, narrowly ovate (Boettger 1887). Distribution Tropical Indo-Pacific Region (China, Japan, Australia); including tropical western America (Sleurs and Strack 2021). Taxon discussion The genus Pandalosia was segregated from Schwartziella (Laseron 1956), characterised by smaller and more slender shells; protoconch comparatively large and elongate, surface smooth, lacking microsculpture, base bearing a prominent plica. Pandalosia subfirmata (O. Boettger, 1887) is not a new record from Chinese waters, as it had been previously identified in Taiwanese waters as Pandalosia darwinensis Laseron, 1956 (Liu 2008). Currently, Pandalosia darwinensis Laseron, 1956 is treated as a synonym of P. subfirmata in the World Register of Marine Species (WoRMS). Two additional species, Pandalosia moerchiella C. - K. Chang & W. - L. Wu, 2004 and Pandalosia lutaoi C. - K. Chang & W. - L. Wu, 2004, have also been reported from Taiwanese waters, though their taxonomic status remains uncertain. These two species are clearly distinguishable from P. subfirmata in shell sculpture: P. moerchiella possesses a smooth shell surface lacking prominent axial ribs, while P. lutaoi exhibits much weaker and less distinct axial ribs compared to those of P. subfirmata (Chang and Wu 2004). A comprehensive taxonomic revision of the genus Pandalosia in Chinese waters is warranted in the future.

Published as part of Qi, Lu, Liu, Songyuan, Sun, Shengming, Kong, Lingfeng & Ma, Zhenhua, 2025, Zebinidae (Caenogastropoda, Rissooidea) from Hainan Island, China, with re-description of four species, pp. e 165463 in Biodiversity Data Journal 13 on page e165463, DOI: 10.3897/BDJ.13.e165463