Xanthangum

Xanthangum is a genus of marine gastropods first described in 2021 by malacologists A. N. Rivera and L. P. Chen. The genus name derives from the Greek words “xanthos,” meaning yellow, and “angum,” a Latinized form of “angulus,” referring to the slanted aperture of the shells. Xanthangum species are small, possessing conical shells that range from 3.5 to 5.5 millimeters in height. The shells exhibit a characteristic yellowish-brown coloration with fine radial ridges and a subtle spiral sculpture. The aperture is elongated and slightly angled, a feature that distinguishes the group from related genera within the family Costellariidae.

The type species, Xanthangum patronum, was collected during deep-water surveys off the coast of Taiwan at depths between 480 and 620 meters. Subsequent specimens have been reported from the western Pacific, including the Mariana Trench and the Philippine Sea, suggesting a circumtropical distribution in bathyal waters. These snails are carnivorous, feeding primarily on small polychaete worms and foraminiferans. Laboratory observation indicates they possess a proboscis with a rostrum adapted for prey extraction.

Ecologically, Xanthangum contributes to benthic community dynamics by preying on invertebrate prey that occupy similar depths. The genus also provides insight into gastropod adaptation to high-pressure environments; morphological studies demonstrate specialized radular teeth and reinforced shell microstructure. Research on Xanthangum therefore aids in understanding evolutionary processes in deep-sea mollusks. Although still poorly understood, the genus encourages further exploration by marine biologists and taxonomists interested in the biodiversity of bathyal ecosystems.