Morphological identification and molecular validation of anchovies (Engraulidae) in the Persian Gulf and Oman Sea

Abstract

Validation of species using independent lines of evidence is sometimes desirable when their identification using only one approach is difficult or questionable. The identification of anchovies (Engraulidae) are often challenging based on morphology because closely related species exhibit only slight morphological differentiation. This study utilized morphological characteristics and DNA barcodes for identification and validation of anchovies in the Persian Gulf and Oman Sea. Based on morphology, we identified eight species: Thryssa hamiltonii, T. setirostris, T. vitrirostris, T. whiteheadi, T. dussumieri, Encrasicholina punctifer, E. pseudoheteroloba and Stolephorus indicus. A 658 bp region of mitochondrial cytochrome oxidase subunit I (COI) was generated for 53 specimens from these eight species. From these sequences, we built a Maximum Likelihood phylogenetic tree. In this tree, each species forms a monophyletic group confirming our initial morphological identification. In addition, we provided (and registered in GenBank) the first barcode sequences for T. whiteheadi, an endemic species of this region. Interspecies genetic distances were comprised between 0.168 to 0.275. The largest genetic distance was found between T. vitrirostris and S. indicus and the smallest between T. dussumieri and T. whiteheadi. This study successfully identified eight species of anchovies in the Persian Gulf and Oman Sea based on both morphological and molecular characters.