Relationships within the Elephantinae using hyoid characters

Results are based on ten hyoid characters of seven proboscidean taxa; four belong to the subfamily Elephantinae. Using PAUP we generated six equally parsimonious trees. The consensus tree yields two polytomies: in the basal polytomy the relationships among Mammut, gomphotheres, Stegodon, and Loxodonta are not resolved; in the other polytomy Palaeoloxodon, Mammuthus, and Elephas are grouped in a cluster. The joining of Palaeoloxodon and Mammuthus has not been suggested previously, and there are ample non-hyoid data of grouping Loxodonta, Elephas, and Mammuthus. For this reason and since a major focus of this study has been to test relationships among Loxodonta, Elephas, and Mammuthus, we relied on studies of other workers and rearranged the consensus cladogram to unite Loxodonta with other members of Elephantinae (Palaeoloxodon, Elephas, and Mammuthus). The hypothesis that Mammuthus is more closely related to Elephas than to Loxodonta is more parsimonious (by two evolutionary steps) than when Loxodonta joins Mammuthus. This finding is provisional and should be retested with additional data, especially with taxa with small sample size, and with specimens of extinct Elephantinae taxa. Results also corroborate other findings that Palaeoloxodon is a bona fide elephant genus; we classify it in the new subtribe Palaeoloxodontina Zhang and Zong [1983. Genus Palaeoloxodon of China. Vertebrata PalAsiatica 21(4), 301–312].