Reassessment of the phylogenetic relationships of the late Miocene apes Hispanopithecus and Rudapithecus based on vestibular morphology

Reconstructing the phylogenetic relationships of extinct apes is challenging due to their fragmentary fossil record and the recurrent independent evolution of morphological features. Given the relevance of the phylogenetic signal of the bony labyrinth, here we assess the phylogenetic affinities of the late Miocene great apes Hispanopithecus and Rudapithecus by studying their inner ear morphology. Our results are consistent with the distinct generic status of these dryopiths, which further differ from the derived condition of orangutans and most closely resemble African apes. However, the latter appear largely primitive (similar to the last common ancestor of great apes and humans). Hence, our results do not conclusively favor a closer relationship with African apes as opposed to great apes as a whole.