Morphological analysis and DNA barcoding confirm presence of a cryptic fish species, the blotched triplefin, Enneapterygius ventermaculus (Teleostei: Blenniiformes: Tripterygiidae), at Qeshm Island, Persian Gulf

The small, cryptic, blotched triplefin, Enneapterygius ventermaculus (Tripterygiidae), is reported based on 10 specimens collected at the Qeshm Island, Persian Gulf, Iran, in February 2021. The identification was confirmed using integrated morphological and molecular methods. Enneapterygius ventermaculus is characterized by its dorsal-fin rays III+XII-XIII+9-10; anal-fin rays I,17; pectoral-fins rays 14; lateral line with 13 pored and 22-26 notched scales, starting from the second scale row below the end of the pored series; total lateral scale rows 35-39; transverse scale rows 2+1+6; mandibular pores 3+1+3. Enneapterygius ventermaculus is distinguished from the similar species, E. pusillus by having a lower total number of anal-fin soft rays (17 vs. 20-21), a higher number of total lateral scale rows (35-39 vs. 29-30), a higher number of transverse scale rows (2/6 vs. 2/4), and a different number of mandibular pores (3+1+3 vs. 2+2+2). The morphological identification was confirmed by a molecular analysis based on mitochondrial COI barcode region sequences. Enneapterygius ventermaculus showed a sister-group relationship to E. pusillus. An average K2P genetic distance of 21.5% also supported the closer phylogenetic relationship of the two species.