Morphological differentiation of suckermouth armored catfish, genus Pterygoplichthys (Siluriformes: Loricariidae) in Sri Lankan freshwaters

This study documents the occurrence of the exotic Suckermouth armoured catfishes (Loricariidae) of the genus Pterygoplichthys spp. in the Sri Lankan reservoirs. As little is known about the taxonomic status of the alien Pterygoplichthys spp. in Sri Lankan inland waters, this study was conducted based on the specimens collected in four distinct reservoirs in Kala Oya basin, North central province of Sri Lanka. The different morphometric measurements and meristic counts of current study reveals that suckermouth armored catfish, previously reported as Pterygoplichthys multiradiatus (Orinoco sailfin catfish), actually belong to the two different species- Pterygoplichthys disjunctivus (Vermiculated sailfin catfish) and Pterygoplichthys pardalis (Amazon sailfin catfish). Although the current examination describes two different species as above, some wild populations may probably be hybrids. In recent past there is a high concern on these species due to rapid range expansion and the effects on native ichthyofauna and inland fisheries resources. Therefore, implementations of effective management options of these species are highly recommended in native condition.