Geographical variation in Hector's dolphin: Recognition of new subspecies of Cephalorhynchus hectori

Abstract

The endemic New Zealand dolphin Cephalorhynchus hectori has been shown through genetic analyses to consist of four regional populations separated to various degrees both geographically and reproductively. A morphological study of skull and mandible features was undertaken to examine variation between the most genetically distinct population, occurring on the west coast of the North Island, and the populations around the South Island. Univariate and principal component analyses demonstrate that the North Island population can be differentiated from the southern populations on the basis of several skeletal characters. These characters, plus the genetic evidence of haplotype differences and absence of gene-flow between populations, enable us to formally describe the North Island population of Hector's dolphin as a new subspecies, C. hectori maui, and the nominate South Island populations as C. hectori hectori.