The ICP researcher, Sergio Almécija, published an article this week in the Journal of Human Evolution confirming that the species known as Hispanopithecus laietanus, the most famous specimen of which is popularly known as Jordi, walked in a particular way that has not been observed in other apes. Analysis of the distal part of the tibia of Jordi has confirmed that H. laietanus combined the ability to climb vertically with the ability to walk on all fours among the trees.
The locomotion of Hispanopithecus laietanus was fairly well known before, thanks to the skeleton of Jordi and, especially, to the abundant remains of the hand. These indicate that H. laietanus not only had an orthograde plan (with an erect torso) suitable for climbing vertically up the trunks and adaptations to suspend from the branches, as most of extant hominids do (especially orangutans and chimpanzees), but also retained similar adaptations to the extant arboreal monkeys to allow it to move on all fours above the branches. This combination of suspension and arboreal quadrupedalism has not been documented in any other extant or fossil hominid.
In the article published online this week in the Journal of Human Evolution, the researchers analyzed and described in detail a lower limb, specifically the distal part of the tibia of Jordi’s skeleton. This is the closest part to the ankle and is of great value in making inferences on locomotion in fossils because it reflects both the extent and the type of mobility of the foot. The research has been carried out by the ICP researcher, Sergio Almécija, together with Melissa Tallman (project leader) from Grand Valley State University (USA) and other researchers at the University of Central Lancashire (UK) and the ICP.
The study has compared this area of the tibia of Hispanopithecus with the equivalent area of 181 other primates belonging to 17 different species among fossil hominoids (such as Proconsul and Sivapithecus), apes such as gorillas, orangutans, chimpanzees and gibbons and Old World monkeys such as macaques or proboscis monkeys. Numeric comparisons were made using three-dimensional geometric morphometrics, which makes it possible to compare morphologies among different individuals using three-dimensional homologous coordinates.
This study supports the hypothesis that locomotor repertoires in Miocene apes were different than any other extant primate and, in the case of Hispanopithecus, combined above-branch quadrupedalism and suspension. Furthermore, the results indicate that the evolution of the great apes occurred in mosaic, with small changes in different parts of the skeleton, causing morphological combinations unlike that of any hominoid extant today.
+info Tallman, M., Almécija, S., Reber, S.L., Alba, D.M., Moyà-Solà, S.(2013). "The distal tibia of Hispanopithecus laietanus: more evidence for mosaic evolution in Miocene apes." Journal of Human Evolution 64: 319-327. http://dx.doi.org/10.1016/j.jhevol.2012.07.009