Occurrence of the tropical eels Anguilla bengalensis bengalensis and Anguilla bicolor bicolor in Peninsular Malaysia and implications for eel taxonomy

Abstract

The anguillid eels found in Peninsular Malaysia were identified using a morphological analysis and that identification was further validated as Anguilla bengalensis bengalensis and Anguilla bicolor bicolor by an analysis of the eels' mitochondrial cytochrome oxidase subunit I (COI) sequences. Because of the difficulty of accurately identifying tropical eels solely on morphological analyses, previous studies had reported the occurrence of the tropical eel species Anguilla marmorata in Peninsular Malaysia. This study suggests the occurrence of Anguilla bengalensis bengalensis in Malaysian waters, confirmed by both morphological and molecular genetic analyses. Anguilla bicolor is further confirmed as the subspecies of Anguilla bicolor bicolor by molecular genetic analyses. The present study also suggests that accurate tropical eel species identification requires validation by molecular genetic analysis after a morphological observation.