Background and Objectives: The aim of this study was to investigate the morphology and molecular identification of oyster knife Solen dactylus. Razor clams are edible bivalve molluscs that fetch high prices in international markets.

Methods: For this purpose, sampling of this species was performed from the designated station in Khowr-e Guban, south of Shadegan wetland. Morphological identification was first performed using valid identification keys. Then, to ensure assurance, molecular identification of the species was performed using amplification of mitochondrial COI region. The resulting genomic sequences were analyzed using Chromas, BioEdit, and Mega 7 software. Blast sequences were also identified in NCBI and phylogenetic tree was constructed.
Findings: The results showed that the Solen strictus species and the Solen marginatus species and the present study species (Solen sp.) are in a sister clade and derived from a common ancestor. The sequence of amplified gene fragments with specific COI primers showed 83% similarity to S. strictus, while the two species are similar in appearance, but in morphological studies and the use of identification keys specifications such as palliative tentacles on the front of the foot, small teeth, and measurement of oyster length and width, which are characteristic of S. dactylus and do not exist in S. strictus and S. marginatus species.
Conclusion: Therefore, according to morphological and molecular results, Solen sp. species is probably the same as S. dactylus. This species was registered in the NCBI database with the acceptance code QGL52628.