New Distributional Record and Intra-Specific Variation Of Cerberus schneiderii In Iyam River, Lucena City, Quezon, Philippines

Abstract

Cerberus is a genus of semi-aquatic snakes that inhabit a wide range of aquatic habitats including estuarine environments. There are two species belonging to this genus known to occur in the Philippines. However, its distributional record is still not well established since only limited areas are surveyed despite of its wide distributional range in the coastal habitats of the country. This study primarily aims to document the occurrence of Cerberus in Iyam River, Lucena City. The scalation patterns and metric characters were also described to determine the range of individual variability among the species. Samples were collected from different habitat types in the sampling area by systematic transect walking. By close examination, it was revealed that the samples exhibit the established morphological description of Cerberus schneiderii. Moreover, population exhibit high variability in scalation pattern such as anal plate, anterior chin shield, lower labials at the first chin shield, type of scale, prefrontal plate, upper labials at loreal, and ocular ring; and metric characters such as total length, tail length, snout-vent length (SVL) and Tail:SVL ratio (H’ = 0.67-1.0). Statistical analysis further showed a strong significant correlation (P = <0.01) between total length and SVL, total length and weight, SVL and weight, and total length and tail length. The occurrence of different morphotypes is very important in understanding the extent of intra-specific variation within Cerberus schneiderii and the possible role of local adaptations and habitat use.