Morphology and Identity of the Holotype of <em>Megaptera indica</em> H.-P. Gervais, 1883

In 1883 a baleen whale stranded at ‘baie de Bassora’ (Basrah Bay), in the Chat-el-Arab river delta, Iraq, at the northwestern corner of the Persian/Arabian Gulf. Gervais obtained the complete specimen for the national museum in Paris (MNHN), and described it as a new humpback whale species Megaptera indica H.-P. Gervais, 1883. The authors studied the incomplete and slightly damaged holotype skull, measured and estimated craniometrics, and concluded that M. indica is a junior synonym of Megaptera novaeangliae (Borowski, 1781). No postcranial bones were found. Importantly, two cranial features suggest that M. indica nests between Atlantic humpback whales and other large Balaenopteridae. Megaptera novaeangliae has the widest skull index, i.e. breadth skull at squamosals relative to condylobasal length (57–66.9%, n=8), higher than M. indica which scored 54.9%, and considerably higher than other Balaenopteridae. Also the ratio of the width of skull at postorbitals (frontale) versus rostrum width at base in M. indica is smaller and barely overlaps with Atlantic humpback whales (n=4), again suggesting taxonomic significance. Gervais also reported several postcranial differences, presently unverifiably. Cranial findings support subspecific status, Megaptera novaeangliae indica (H.-P. Gervais, 1883), proposed also by Amaral et al. (submitted) for the Arabian Sea (cum Persian/Arabian Gulf) humpback whale population, based on mtDNA control region analysis.The reported pachyostosis in the Iraqi whale is suggested a possible example of phenotypic plasticity, an adaptation to the unusually high-salinity, high-density habitat of the Gulf, as to reduce buoyancy and avoid insolation.