Catalan fossils a key element to the evolution of hominoids

An article by the Catalan Institute of Palaeontology published in PNAS provides relevant data to the chronology of hominoids in Eurasia and demonstrates the large value of Miocene fossil records in Catalonia, the most important in the world from this period, for the study of the evolution of hominoids, which includes the human species.

23/03/2011

In the article "Updated chronology for the Miocene hominoid radiation
in Western Eurasia" authors offer a critical vision of the dating of hominoids from the Miocene period (from 23 to 5 million years ago) in Western Eurasia, with the addition of unedited results of specimens found recently in Hostalets de Pierola, in the Anoia region. Authors of the study are ICP researchers Isaac Casanovas, David M. Alba, Josep M. Robles and Salvador Moyà, and Miguel Garcés of the University of Barcelona.

According to the study, 12 to 9 million years ago in Europe and particularly in Catalonia a large number of hominoid species existed, a far larger number in group diversity than at present. The majority of these forms are included in the extinct subfamily of dryopithecins, restricted to the Eurasian Miocene. Some Catalan dryopithecins present advanced characteristics, such as adaptations for tree climbing while maintaining an upright position, or hanging from trees with the use of their arms. Among today's anthropomorphes these characteristics can be found in pongines (orangutans) and hominids (gorillas, chimpanzees and humans).

The study also improves the dating of European sites containing remains of kenyapithecins, a group which appeared in Africa some 20 million years ago and invaded Eurasia 14 million years ago, giving way to the origin of dryopithecins.

The study concludes that it is very probable that climbing trees while maintaining an upright position and hanging from branches using only their arms were adaptations which evolved independently in dryopithecins and hominids. Orangutans are thought to be descendents of dryopithecins, and would have inherited these adaptations from them. The same adaptations would have appeared independently in hominids (chimpanzees, gorillas and humans) in Africa with the kenyapithecins. However, it cannot be discarded that in the case of hominids these adaptations could well be related to European forms.

According to Salvador Moyà, director of ICP and co-author of the article, "Catalan fossil records cover the first part of the evolution of hominids and is the most complete and of highest quality in the world. That is why it is essential when trying to understand the origin of our family." Of the thirteen hominoid species from the Miocene period described in Eurasia, five have been found in Catalonia. The densest fossil record is located in the Vallès-Penedès Basin, in the province of Barcelona, and is the result of continuous work and scientific discoveries made by ICP.

All species found in Catalonia are grouped into the dryopithecin subfamily, a scientific name derived from Greek which means apes of the forest and which evolved from kenyapithecins. Dryopithecins show a series of common advanced characteristics with pongines (modern day orangutans) and hominids (chimpanzees, gorillas and humans).

According to what is known presently, pongines could have originated from dryopithecins. It must still be confirmed whether African hominids also are related to these European hominoids or whether they evolved separately in Africa. Regardless of which scenario is correct, understanding the origin of the evolutionary line which gave rise to humans includes understanding better the evolution of Catalan hominoids.

The giant rabbit of Minorca
Another study carried out by ICP, published on the cover and as featured article in the Journal of Vertebrate Paleontology, describes a giant rabbit of the Neogene period discovered in Minorca. Nuralagus Rex, the scientific name of this giant rabbit, existed some 5 million years ago. It weighed between 12 and 15 kg and walked with the palm of its front legs flat on the ground, characteristic of plantigrade animals such as bears and some primates.

ICP
ICP was created as a foundation in November 2006, sponsored by the Government of Catalonia and Universitat Autònoma de Barcelona, and includes the former Institut de Paleontologia Miquel Crusafont, founded in 1969 by palaeontologist Miquel Crusafont Pairó.