Systematic revision of the Indo-West Pacific bubble-snails of the genus

The genus Haloa includes dull-coloured species of haminoeid snails inhabiting tidal and shallow waters of the tropical and sub-tropical Indo-West Pacific. This paper reports on the diversity and systematics of Haloa based on the phylogenetic hypothesis generated by Oskars and Malaquias (2019) and on the morphological study of specimens. Shells, external features and anatomical characters from the jaws, radula, gizzard plates and male reproductive system were studied by optical and scanning electron microscopy. The molecular species delimitation method Automatic Barcode Gap Discovery, using DNA sequences of the cytochrome c oxidase subunit I gene, was implemented to aid delimiting candidate species. Thirteen species were recognised as valid, including two new to science, namely Haloa cobbi, sp. nov. and Haloa eora, sp. nov., and one unnamed species herein referred to as Haloa sp. 1. Species depict intraspecific variability in their colouration and little character displacement in their anatomy. Shells are of limited taxonomic use; only details of the male reproductive system (e.g. fundus) and the DNA were truly diagnostic. Three species have an Indo-West Pacific distribution and three are restricted to the Indian Ocean. The remaining seven species occur in the Western and Central Pacific Ocean, three of them having geographical ranges restricted to offshore islands.

An updated inventory of sea slugs from Koh Tao, Thailand, with notes on their ecology and a dramatic biodiversity increase for Thai waters

Improved access to field survey infrastructure throughout South-East Asia has allowed for a greater intensity of biodiversity surveys than ever before. The rocky bottoms and coral reef habitats across the region have been shown to support some of the highest sea slug biodiversity on the planet, with ever increasing records. During the past ten years, intensive SCUBA surveys have been carried out at Koh Tao, in the Gulf of Thailand, which have yielded remarkable findings in sea slug biology and ecology. In this work a brief history of sea slug biodiversity research from Thailand is covered and a complete inventory of sea slugs from Koh Tao, Gulf of Thailand is provided. This inventory is based on surveys from 2012 to 2020, with previously unreported findings since 2016. Habitat specificity and species-specific ecology are reported where available with a focused comparison of coral reef habitats and deeper soft-sediment habitats. The findings contribute 90 new species records for Thai waters (92 for the Gulf of Thailand) and report a remarkable consistency in the proportional diversity found to be exclusive to one habitat type or another. Additionally, taxonomic remarks are provided for species documented from Koh Tao that have not been discussed in past literature from Thailand, and a summary of previous records in the Indo-West Pacific is given.