Diversity And Distribution Of Microsnails (Mollusca : Gastropoda) In Langkawi, Kedah
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Date
2011-06
Authors
Mohammad Razalli, Norhanis
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
A study was conducted on the diversity and distribution of microsnails from
the family Vertiginidae at 16 locations that spreads across the limestone outcrops of
the Langkawi Islands in the northern Straits of Malacca. A total of 10 species of
vertiginids from three genera were identified with seven species from the genus
Gyliotrachela, namely, G. depressispira, G. hungerfordiana, G. luctans, G. salpinx,
G. transitans helioscopia, Gyliotrachela sp. 1 and Gyliotrachela sp. 2; two species
from genus Paraboysidia, namely, P. frequens and P. serpa; and one unknown
species from genus Nesopupa. Consequently the three unknown species are new
records for Malaysia. Identification and confirmation of the snails was done using
the reference collection at the British Natural History Museum in London.
Gyliotrachela hungerfordiana was found to be the most common Vertiginidae
species in Langkawi having been found in ten sampling locations.
This study also revealed that the morphological variations within vertiginids
species at Langkawi Islands might be caused by the geological separation of the
limestone formation. Pearson correlation coefficient showed that the abundance of
vertiginids showed moderate correlation (rW = 0.614 and rD = 0.537 at 95%
significance level) with the light intensity during wet and dry sampling season, while
the species diversity of vertiginids showed moderate correlation with relative air
humidity (r = 0.654 at 99% significance level) and ambient temperature (r = 0.515 at
95% significance level) during the wet season. Non-metric multidimensional scaling
(NMDS) analysis showed no apparent relationship between other environmental
parameters (orientation and condition of limestone wall on which the snails are
found. and plant canopy coverage) with the abundance of vertiginids in the sampling
location.
Description
Keywords
Diversity and distribution of microsnails , in Langkawi, Kedah