Comments: Eastern Pacific populations of Chelonia are regarded by some authors as a distinct species, the black turtle, C. agassizii (King and Burke 1989); other authors (e.g., Ernst and Barbour 1989) retain agassizii as a subspecies of C. mydas (Kamezaki and Matsui 1995) or do not recognize it taxonomically at all (Crother et al. 2000). Phylogenetic analyses of mtDNA data by Bowen et al. (1992) yielded no evidence of matrilineal distinctiveness of agassizii. See Karl and Bowen (1999), Pritchard (1999), Grady and Quattro (1999), Shrader-Frechette and McCoy (1999), and Bowen and Karl (1999) for further debate about the taxonomic status of the black turtle.
The Australian flatback turtle, formerly known as Chelonia depressa, has been removed to its own genus, Natator (Zangerl et al. 1988, Limpus et al. 1988). MtDNA data indicate a fundamental phylogenetic split distinguishing all green turtles in the Atlantic-Mediterranean from those in the Indian-Pacific oceans (Bowen et al. 1992).
Most regional populations of Chelonia mydas are genetically distinct (Bowen et al. 1992). Florida population is characterized by unusually high mtDNA diversity (Allard et al. 1994).