Reallocation of the magnificent catshark Proscyllium magnificum Last & Vongpanich, 2004 to the genus Ctenacis Compagno, 1973 (Carcharhiniformes: Proscylliidae).

The magnificent catshark Proscyllium magnificum was described in 2004 based off five specimens collected in the Andaman Sea off Myanmar. It was originally allocated to the genus Proscyllium, but recent molecular analyses suggested it was more closely related to the harlequin catshark Ctenacis fehlmanni from the western Indian Ocean. This study incorporated meristics and external and internal morphology, together with molecular data to reclassify the magnificent catshark as Ctenacis magnificum and provides revised diagnoses for the genera Ctenacis and Proscyllium. Ctenacis consists of two allopatric Indian Ocean species, while Proscyllium is monotypic genus confined to the northwest Pacific. The revised Ctenacis can be distinguished from Proscyllium in having a broader and longer head (head length 21%-23% vs. 16%-18% of total length), distance between pectoral and pelvic bases shorter than head length (vs. greater than head length), more teeth (upper jaw with 80-86 vs. 46-62 tooth files), and a complex colour pattern of dark reddish-brown blotches and saddles (vs. colour pattern of small black spots). A revised key to the genera of proscylliids and species of Ctenacis is provided.