This name is problematic in that the type specimen actually represents Chelonoidis denticulata;[2] however, this was discussed and petitioned before the ICZN[3] and accepted: the name Aldabrachelys is therefore the correct name for this genus.
Taxonomy
Within Testudinidae, Aldabrachelys is most closely related to Astrochelys and Pyxis, which are also native to Madagascar, suggesting that they share a common origin on the island. Within the genus, Aldabrachelys abrupta is more closely related to A. gigantea than it is to A. grandidieri, but A. abrupta and A. gigantea are relatively genetically divergent, suggesting that they are not synonymous as had sometimes been previously proposed, and that they diverged from each other several million years ago. The proposed subspecies of A. gigantea show relatively little genetic differentiation from each other.[4]
References
^ abLoveridge A, Williams EE (1957). "Revision of the African tortoises and turtles of the suborder Cryptodira". Bull. Mus. Comp. Zool. Harvard115: 163–557.
^Bour R (2006). "Identity of Testudo gigantea Schweigger, 1812 and rediscovery of the type specimen". Emys13 (4): 12–23.
^Frazer J (2009). "Testudo gigantea Schweigger, 1812 (currently Geochelone (Aldabrachelys) gigantea; Reptilia, Testudines): proposed conservation of usage of the specific name by maintenance of a designated neotype, and suppression of Testudo dussumieri Gray, 1831 (currently Dipsochelys dussumieri)". Bulletin of Zoological Nomenclature66 (1):Case:3463[permanent dead link]