Morphometric Study of Some Caecilians in Thailand
Abstract
Six species of the caecilian genus Ichthyophis have been reported in Thailand. At present, besides the numbers of teeth, there is no unambiguous criteria, which can be used in the classification and identification of the caecilians in Thailand. We used 4 species of caecilians which were identified as Ichthyophis acuminatus, I. larutensis, I. supachaii, and I. kohtaoensis (2, 2, 10 and 43 specimens, respectively). Thirty-eight externally morphometric characters were examined. Principal component and hierarchical cluster analyses were conducted. The results showed that 1) the juveniles of I. kohtaoensis could be separated from I. supachaii. 2) the adult samples of I. acuminatus could be separated from I. larutensis without using the criterion of the splenial teeth as previously reported and 3) the adult specimens of I. supachaii and I. kohtaoensis were not conclusively classified, which was different to the previous identification. Since the pattern of lateral stripe and teeth, the important characters of Ichthyophis identification, of most adult I. kohtaoensis and I. supachaii specimens were unusable, we therefore suggest that molecular analysis is required to confirm species all of specimens first. Next, morphological data of this study will be added to all species descriptions to fulfill the species variations. Finally, molecular and morphological data will be used for the key of Thai caecilians.
Keywords : Ichthyophis acuminatus, Ichthyophis larutensis, Ichthyophis supachaii, Ichthyophis kohtaoensis,
external morphology
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