Taxonomy and Biogeography of the land Snail Genus Alycaeus (Gastropoda: Alycaeinae) in peninsular Malaysia

• Main Author: Foon, Junn Kitt
• Format: Thesis
• Language: English
• Published: 2018
• Subjects: QL Zoology
• Online Access: https://eprints.ums.edu.my/id/eprint/22513/1/Taxonomy%20and%20biogeography%20of%20the%20land%20snail%20genius%20alycaeus; https://eprints.ums.edu.my/id/eprint/22513/

The conservation of tropical limestone karsts is a priority for Malaysia. To assist karst conservation, sound understanding of the taxonomy and biogeography of karst endemic taxa is required. In this study, I used the genus A/ycaeus as a model taxon for this purpose, focusing on two aspects of the genus: species taxonomy and biogeography. First, on taxonomy: A total of 10 species and one subspecies of A/ycaeus was recognised in Peninsular Malaysia prior to this study. However, these taxonomic descriptions of A/ycaeus taxa are based on limited number of examined materials where a whole spectrum of morphological variations were not accounted for and diagnosis were often provided without sufficient comparison between congeners from across the peninsula. I reviewed Peninsular Malaysian A/ycaeus through the examination of major museum collection lots and literature sources. Based on these examined materials, I utilised a more comprehensive set of shell and operculum characters, as well as living animal colour to describe all Alycaeus species in this paper. I also noted their habitat and ecology, as well as updated the distribution of each species. Of the 11 previously described taxa, nine were reconfirmed as present on Peninsular Malaysia (Alycaeus balingensis, Alycaeus llratulus, Alycaeus thieroti, Alycaeus conformis, Alycaeus gibbosulus, Alycaeus kelantanensls, Alycaeus carlnata, Alycaeus perakensis altispirus, Alycaeus perakensis) and two were confirmed as absent on the peninsula (Alycaeus jagori,Alycaeus pyramidalls). A new record of Alycaeus robe%n/ is reported for Peninsular Malaysia. One species, Chama/ycaeus jousseaumei is confirmed as present on the peninsula and is reassigned to A/ycaeus The subspecies A/ycaeus perakensis altispirus Möllendorff, 1902, is elevated to species. Examined Peninsular Malaysian materials that do not fit previously recognised species are described as new species. A total of 11 new species are proposed (A/ycaeus se/angoriensis Foon and Liew, 2017, Alycaeus costacrassa Foon and Liew, 2017, Alycaeus ikanensis Foon and Liew, 2017, Alycaeus altico/a Foon and Liew, 2017, Alycaeus charasensis sFoon and Liew, 2017, Alycaeus kurauensis Foon and Liew, 2017, Alycaeus regal/s Foon and Liew, 2017, Alycaeus virgogravida Foon and Liew, 2017, Alycaeus senyumens/s Foon and Liew, 2017, Alycaeus expansus Foon and Liew, 2017, Alycaeus c/ementsi Foon and Liew, 2017). Overall, 23 species of A/ycaeus are now recognised in Peninsular Malaysia. Second, on biogeography: With Alycaeus species and their distributions identified, I utilised Geographic Information System tools to study their biogeography across Peninsular Malaysia. First, I examined the role of the Titiwangsa Range as a potential biogeographic barrier for A/ycaeus species. I found that the Titiwangsa Range appears to be a barrier for limestone rock dwelling A/ycaeus species while arboreal and rotten log dwelling A/ycaeus species are either restricted to one side or found on both sides of the Titiwangsa Range. Second, I elucidate and discuss the correlation between hill isolation, hill size and the degree of A/ycaeus endemism. I found that there is no correlation between hill isolation and A/ycaeus endemism, while there is a weak correlation between hill size and A/ycaeus endemism. These findings run contrary to previous conclusions of land snail community level studies whereby hill isolation and hill size have strong correlations with land snail endemism. Overall, these findings suggest that conservation of limestone karst biodiversity should consider not just endemism patterns at the community level but also at the genus level as well, especially for those genera that are known to be restricted to limestone rock habitats.