Integrative Species Delimitation of Carrier Snails (Caenogastropoda: Stromboidea: Xenophoridae) with a New Genus and Five New Species.

Cryptic speciation is widely documented in marine gastropods, particularly in groups lacking distinct morphological characters. Carrier snails of the family Xenophoridae have long been celebrated by naturalists for their behavior of collecting and affixing foreign objects to their shells. We present the first molecular species delimitation of carrier snails (family: Xenophoridae), using cox1 sequences from 562 specimens encompassing 81% of valid species and all genera in this family. Integrating alpha-taxonomic data, we formalize five new species in descriptions-Xenophora simulans sp. nov., Xenophora brevis sp. nov., Onustus procellosus sp. nov., Collector altissimus gen. nov. et sp. nov., Collector alienus gen. nov. et sp. nov.-and recommend further investigations into other promising clades with potentially undiscovered species, pending corroboration from nuclear loci. This case study highlights the potential of species discovery using single-locus delimitation methods. We established a baseline framework for morphological species delimitation in Xenophoridae, showing that specimens distinguished only by subtle morphological characters often interpreted as intraspecific variation can exhibit species-level genetic divergence.