Diversity and biogeography of land snails (Mollusca, Gastropoda) in the limestone hills of Perak, Peninsular Malaysia

Abstract

Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed. To address this knowledge gap, we systematically surveyed the terrestrial malacofauna of 12 limestone hills that, based on our opinion, are a representation of the limestone land snail assemblages within the State. Our inventory yielded high sampling completeness (>85%). We found 122 species of land snails, of which 34 species were unique to one of the surveyed hills. We identified 30 species that are potentially new to science. The number of land snail species recorded at each hill ranged between 39 and 63 species. Four of the sampled limestone hills namely, Prk 01 G. Tempurung, Prk 55 G. Pondok, Prk 47 Kanthan, and Prk 64 Bt Kepala Gajah, have high levels of species richness and unique species, representing 91% of the total species recorded in this study. We identified two clusters of limestone hills in central Perak with distinct differences in land snail species composition – a northern hill cluster on elevated granite bedrock and southern hill cluster in a low-lying valley surrounded by alluvial soils. As limestone hills continue to be quarried to meet the cement demand, the four identified limestone hills, along with other hills from the two clusters, warrant urgent conservation attention in order to maintain high species diversity within Perak’s terrestrial malacofauna.

A review of the land snail genus Alycaeus (Gastropoda, Alycaeidae) in Peninsular Malaysia

“… Alycaeus conformis Fulton, 1902: 68–69; Sykes 1903 : 198; Laidlaw 1928 : 34; Laidlaw 1932 : 36; Venmans 1956 : 81, figure 1; Robertson et al 1987 : 2; Chan 1997 : 37; Tarruella and Domènech 2011 : 72; Páll-Gergely et al 2016 : 20160151; Foon et al 2017 : 10, figure 4B. …”

“… Alycaeus gibbosulus Stoliczka, 1872: 268–269, plate 10, figure 14; Pfeiffer 1876 : 58; Nevill 1878 : 295; Crosse 1879b : 339; Morgan 1885b : 402; Möllendorff 1886 : 310; Tenison-Woods 1888 : 1068; Kobelt 1902 : 344; Sykes 1902 : 62; Benthem Jutting 1960a : 13, 19; Davison 1995 : 236; Maassen 2001 : 21; Clements et al 2008 : 2760; Tarruella and Domènech 2011 : 72, figure 1F; Foon et al 2017 : 12, figure 4C. …”

“… Alycaeus gibbosulus has been reported to exist sympatrically with A. conformis in Gunung Rapat, Perak ( Foon et al 2017 ). Elsewhere range overlaps between A.…”

“…Most past studies of Alycaeus in Peninsular Malaysia are either single species descriptions or checklists. There are only two studies that focused on the anatomy and radula of Alycaeus ( Tielecke 1940 , Venmans 1956 ) and three that focused on conservation biogeography of karst land snails ( Davison and Kiew 1990 , Clements et al 2008 , Foon et al 2017 ). Besides these five non-conchological studies, all other Alycaeus taxonomic treatments to date were based on inconsistent and subjective diagnoses of few shell and operculum characters which have never been properly reviewed since their description or in the revisions by Kobelt (1902) and Egorov (2013) .…”

Competition matters: Determining the drivers of land snail community assembly among limestone karst areas in northern Vietnam

“…The scattered karst areas differ considerably in size and in degree of isolation and are partly distributed along climatic gradients. This complex, island-like system could have played a major role in shaping and maintaining the very rich total biodiversity of northern Vietnam as individual limestone karst areas harbor unique communities of taxa (a pattern reported from various regions in Southeast Asia; Clements et al, 2006Clements et al, , 2008Foon, Clements, & Liew, 2017;Sterling et al, 2006;Tongkerd, Lee, Panha, Burch, & Ó Foighil, 2004;Tweedie, 1961). The exact processes that have shaped the biotic composition of these habitats, however, still remain unclear.…”