A report of the Four-lined tonguesole, Cynoglossus quadrilineatus (Bleeker, 1851) and Lachner's tonguesole, Cynoglossus lachneri Menon, 1977 from the Andaman and Nicobar Islands, India

Abstract

This study reports the occurrence of Cynoglossus quadrilineatus (Four-lined tonguesole) and Cynoglossus lachneri (Lachner's tonguesole) from the Andaman and Nicobar Islands, India, extending their known distribution range. Notably, C. lachneri is recorded from the Andaman Sea for the first time. Three specimens of C. quadrilineatus and one specimen of C. lachneri were collected from the vicinity of the South Andaman Islands. Cynoglossus quadrilineatus is characterised by 12 caudal fin rays and two lateral lines on each side of the body, while C. lachneri is identified by 10 caudal fin rays, two lateral lines, and 15 interlinear scales. Species identification was further validated through partial cytochrome coxidase I (COI) gene sequencing. The genetic distance analysis using the Kimura-2-parameter model revealed no overlap among closely related species within the family Cynoglossidae. This study also provides the first COI gene sequence for C. lachneri, contributing to the assessment of phylogenetic diversity in future research.