Systematic revision of the Indo-West Pacific mangrove-associated snails of the genus Bakawan (Cephalaspidea: Haminoeidae)

Abstract

ABSTRACT The genus Bakawan includes species of haminoeid snails associated with mangrove habitats and mud flats in the Indo-West Pacific. Here, we revise the diversity and systematics of the genus Bakawan based on our recent molecular phylogeny (Oskars & Malaquias, 2019) and detailed analysis of morphological characters. We examined a range of morphological characters (the shells, external morphology of the animal, jaw, radula, gizzard plate and male reproductive system) using light and scanning electron microscopy. We also carried out a species delimitation analysis (we used the automatic barcode gap discovery method) based on cytochrome c oxidase subunit I DNA sequence data. Four distinct species were recognized: Bakawan rotundata (A. Adams, 1850), which is the type species of the genus and ranges from the eastern Indian Ocean to the western Pacific; B. fusca (A. Adams, 1850), currently known only from the Philippines; and two species new to science, B. puti n. sp., known only from the Philippines, and B. hedleyi n. sp., restricted to tropical eastern Australia.