Abstract
While a growing body of modern phylogenetic research reveals that the Western Indochina represents a separate biogeographic subregion having a largely endemic freshwater fauna, the boundaries of this subregion are still unclear. We use freshwater mussels (Unionidae) as a model to reconstruct spatial patterns of freshwater biogeographic divides throughout Asia. Here, we present an updated freshwater biogeographic division of mainland Southeast Asia and describe 12 species and 4 genera of freshwater mussels new to science. We show that the Isthmus of Kra represents a significant southern biogeographic barrier between freshwater mussel faunas of the Western Indochina and Sundaland subregions, while the Indian and Western Indochina subregions are separated by the Naga Hills, Chin Hills, and Rakhine Yoma mountain ranges. Our findings highlight that the freshwater bivalve fauna of Southeast Asia primarily originated within three evolutionary hotspots (Western Indochina, Sundaland, and East Asian) supplemented by ancient immigrants from the Indian Subcontinent.
Highlights
Freshwater mussels (Unionida) are an economically and environmentally important group of aquatic animals having a broad distribution on all continents except Antarctica[1,2]
We found that available freshwater mussel taxa from Southeast Asia cluster to at least 25 genera, four of which are new to science and are described here
It was shown that freshwater basins of the Malacca Peninsula represent a part of the Sundaland Subregion[16,17] and that the Dawei and Tanintharyi river basins belong to the Western Indochina Subregion[4,5,7,24]
Summary
Freshwater mussels (Unionida) are an economically and environmentally important group of aquatic animals having a broad distribution on all continents except Antarctica[1,2]. The genus- and species-level taxonomy of freshwater mussels in Southeast Asia is still poorly known[3], but several integrative studies performed in Myanmar, Thailand, Laos, and Malaysia have recently improved our knowledge about the diversity and biogeographic patterns in the region These studies found that freshwater mussel faunas of Myanmar, from the Ayeyarwady to Salween and Dawei basins, could be considered as a separate and distinct freshwater biogeographic subregion from the Indian and Sundaland subregions[4,5,6,7,22,24]. Based on the results of a broad-scale field survey throughout Myanmar, Thailand, and northern Laos, we clarify the western and southern boundaries of the Western Indochina Subregion During this extensive assessment, we discovered several novel genera and species of freshwater mussels that are described here to improve our current understanding of the Unionidae systematics in Southeast Asia. We show that the Isthmus of Kra is a significant biogeographic barrier separating freshwater mussel faunas of the Western Indochina and Sundaland subregions
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
