Morphological differentiation, evolutionary history and biogeography of a potential cryptic species complex of terrestrial gastropods (Cyclophorus) in Vietnam

• Applicant: Dr. Katharina von Oheimb
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 277543559

Vietnam is among the regions harbouring the highest levels of biodiversity worldwide. The country is characterized by countless limestone karst outcrops, which form functional islands for various limestone-bound organisms. For these organisms, which depend on calcium-rich habitats, the insular karst outcrops are considered as centres of speciation. Although Vietnam's limestone-bound organisms are highly diverse, they are still relatively poorly studied and the evolutionary processes that have shaped their diversity remain largely unknown. One of the most prominent groups of limestone-bound organisms is the terrestrial gastropod genus Cyclophorus, which is widely distributed in Vietnam. These gastropods have large shells with conspicuous colour patterns. While the South East Asian species of this genus are typically more or less restricted to only a single karst area, in Vietnam an unusually widespread morphotype exists. This widespread Cyclophorus morphotype, which might represent a complex of cryptic species, offers the possibility to examine evolutionary processes with a particular focus on the role of the insular karst outcrops in driving speciation or leading to convergent evolution. In the present project, I will focus on four specific research goals that aim (I) to characterize the morphological diversity of the widespread Cyclophorus morphotype, (II) to examine its genetic diversity, (III) to test for a potential correspondence between morphological and phylogenetic signals, and (IV) to detect drivers that might have caused differentiation. For research goal I, I will analyse the differentiation of shell forms and colour patterns by using state-of-the-art 3D geometric morphometrics. To achieve goal II, I will study genetic differentiation by using phylogenetic analyses based on DNA sequence data of two mitochondrial marker genes. In research goal III, combined morphological and genetic data will be used for testing to which degree potential sub-morphogroups and phylogenetic lineages correspond. Goal IV, which focuses on external (geographic, biotic, and abiotic) factors, will be tackled, for example, by testing for a correspondence of karst outcrop isolation and genetic distances between populations. Within the present project, I will use one of Vietnam's most prominent limestone-bound taxa to reveal major biogeographical and evolutionary processes, which have not only shaped the diversity and distribution of this gastropod group but probably also of Vietnamese karst biota in general.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Fred Naggs