Journal of the Marine Biological Association of India

Taxonomic revision of six species of the genus Thryssa from Indian waters: A step towards diversity assessment

Volume 67 Issue 1

Ashly Gopinath, E. M. Abdussamad, N. S. Jeena and Elizabeth Tomy

doi:10.6024/jmbai.2025.67.1.2562-06

Abstract

Anchovies belonging to the genus Thryssa (family:Engraulidae) are common pelagic fishes that constitute a significant fishery resource along the Indian coast. A total of 314 specimens belonging to six species of the genus Thryssa were collected to generate data for exact field identification and species-specific molecular signatures. The specimens were identified by morphometric and meristic characters, along with COI-based DNA barcodes. This integrative study also aimed to reconstruct a phylogeny to clarify the evolutionary relationships among the species. The morpho-meristic results indicated that maxilla length, number of belly scutes, number of lower gill-rakers, and anal fin ray count were the main characteristics for identifying Thryssa species . The nucleotide content of each species was examined, and the genetic distance was calculated. The interspecific genetic distance (K2P) ranged from 13% to 22%, with the highest distance observed between T. baelama and T. cuvierii (22%) and the lowest between T. mystax and T. polybranchialis (13%). The average genetic distance within the genus was 19%. The topology of the phylogenetic tree showed that all the species in this study formed separate clades with a common ancestor. This work provides the first COI-barcode of the least investigated T. polybranchialis from the Indian coast, and establishes the relationship between T. mystax and T. polybranchialis. Further morphological and molecular studies are recommended to elucidate the relationship between all extant species within this genus.

Keywords

Anchovy, barcode, COI, Engraulidae, India, phylogenetic tree

Date : 10-06-2025