Inner ear morphology and great ape evolution

The inner ear morphology of fossil apes sheds light on hominid evolution, according to a study. Untangling the relationships between extinct and extant apes remains a challenge due to a fragmentary fossil record and the fact that certain morphological features evolved multiple times independently. Recent work has shown that the morphology of the inner ear’s bony labyrinth reflects the evolutionary relationships among apes, monkeys, and humans. Alessandro Urciuoli, David Alba, and colleagues used microcomputed tomography scans to examine the inner ear morphology of two extinct European apes from the late Miocene epoch, Hispanopithecus laietanus and Rudapithecus hungaricus, and compared them to that of extant and fossil hominoids. Volumetric proportions of the semicircular canals in Hispanopithecus and Rudapithecus resembled those of extant great apes and humans, and significantly differed from those of lesser apes. Detailed shape analysis indicated that the inner ears of the two extinct apes were distinct from each other, supporting their classification into separate genera. Among extant apes, both Hispanopithecus and Rudapithecus most closely resembled African apes, particularly chimpanzees and bonobos, and also closely resembled the reconstructed last common ancestor of extant hominids. The results suggest that Hispanopithecus and Rudapithecus belong to the hominid lineage but do not conclusively establish their relationship to extant hominid groups, according to the authors.

Article #20-15215: “Reassessment of the phylogenetic relationships of the late Miocene apes Hispanopithecus and Rudapithecus based on vestibular morphology,” by Alessandro Urciuoli et al.

MEDIA CONTACT: Alessandro Urciuoli, Miquel Crusafont Catalan Institute of Paleontology, Sabadell, SPAIN; tel: +34-935868603; email: <

[email protected]

>; David M. Alba, Miquel Crusafont Catalan Institute of Paleontology, Sabadell, SPAIN; tel: +34-653674030; email:

[email protected]

###