Integrative taxonomy reveals a new species of Didimacar (Bivalvia, Noetiidae) from Kuwait

Didimacar bajelaopsis sp. nov . is described from Kuwait in the northern Arabian Gulf using morphological and mitochondrial DNA barcode evidence. Nine cox1 sequences from Kuwaiti specimens were deeply divergent from East Asian sequences deposited as D. tenebrica , with only 82.5% sequence identity to the closest BLASTn match (OL877284, Korea). Maximum - likelihood analysis recovered the Kuwaiti specimens as a distinct clade. The shell and anatomy of D. bajelaopsis are described in detail and compared with the syntypes of D. tenebrica and additional material from across the Indo-West Pacific. Subtle differences in shell shape, sculpture and hinge morphology are insufficient to differentiate D. bajelaopsis from D. tenebrica and its many varieties. Comparative material from Pakistan and southern India shows additional geographic variation, but sequence data are required to clarify the taxonomic identity of these populations and as an interim it is suggested to label the varieties under D. tenebrica agg.