A new genus of air-breathing marine slugs from South-East Asia (Gastropoda, Pulmonata, Onchidiidae).

Benoît Dayrat,Quảng Ngô Xuân,Tricia C Goulding,Joseph Comendador,Siong Kiat Tan,Munawar Khalil,Shau Hwai Tan

doi:10.3897/zookeys.877.36698

Abstract

As part of an ongoing effort to revise the taxonomy of air-breathing, marine, onchidiid slugs, a new genus, Laspionchis Dayrat & Goulding, gen. nov., is described from the mangroves of South-East Asia. It includes two new species, Laspionchis boucheti Dayrat & Goulding, sp. nov., and Laspionchis bourkei Dayrat & Goulding, sp. nov., both distributed from the Malacca Strait to the Philippines and Australia. This study is based on extensive field work in South-East Asia, comparative anatomy, and both mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) DNA sequences. The two new species are found in the same habitat (mud surface in mangrove forests) and are externally cryptic but are distinct anatomically. Both species are also strongly supported by DNA sequences. Three cryptic, least-inclusive, reciprocally-monophyletic units within Laspionchis bourkei are regarded as subspecies: L. bourkei bourkei Dayrat & Goulding, ssp. nov., L. bourkei lateriensis Dayrat & Goulding, ssp. nov., and L. bourkei matangensis Dayrat & Goulding, ssp. nov. The present contribution shows again that species delineation is greatly enhanced by considering comparative anatomy and nuclear DNA sequences in addition to mitochondrial DNA sequences, and that thorough taxonomic revisions are the best and most efficient path to accurate biodiversity knowledge.

Highlights

The diversity of invertebrate species in mangrove forests of South-East Asia is still largely unknown, mainly because mangroves have not been explored well enough, which likely has to do with the fact that mangroves are not the most inviting habitats, even for savvy field naturalists: mangroves are extremely muddy, infested with malariacarrying mosquitoes and pit vipers, and often located in remote areas
We describe a new genus, Laspionchis gen. nov., and two new species: Laspionchis boucheti sp. nov., distributed from the Malacca Strait eastwards to the Philippines and Queensland, Australia, and Laspionchis bourkei sp. nov., from the Malacca Strait eastwards to the Philippines and the Northern Territory, Australia
In the analyses based on mitochondrial c oxidase I region (COI) and 16S concatenated sequences, there are four least-inclusive units that are all reciprocally monophyletic: L. boucheti, L. bourkei bourkei, L. bourkei lateriensis, and L. bourkei matangensis (Fig. 2)

Summary

Introduction

The diversity of invertebrate species in mangrove forests of South-East Asia is still largely unknown, mainly because mangroves have not been explored well enough, which likely has to do with the fact that mangroves are not the most inviting habitats, even for savvy field naturalists: mangroves are extremely muddy, infested with malariacarrying mosquitoes and pit vipers, and often located in remote areas. Adult onchidiids live in the intertidal zone and their larvae develop in sea water, a few species are adapted to high elevation tropical rainforest (Dayrat 2010). They breathe air through a lung and are related to land snails and slugs (Dayrat et al 2011). The only other group of marine, air-breathing, true slugs is the genus Smeagol Climo, 1980, which is not closely-related to onchidiids, but rather considered to belong to the Ellobiidae (Dayrat et al 2011). The terrestrial, air-breathing, true veronicellid slugs are the most-closely related group to the onchidiids (Dayrat et al 2011)

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Conclusion