Oreopithecus Research Articles

A NEW FIND OF OREOPITHECUS (MAMMALIA, PRIMATES) IN THE BACCINELLO BASIN (GROSSETO, SOUTHERN TUSCANY)

A mandible of Oreopithecus cf. bambolii was found in Miocene sediments of the Baccinello basin (Grosseto, Tuscany). It confirms, unequivocally, the occurrence of this peculiar primate in the V2 mammal fauna of the basin. This find allows some comments on the correlation among the Miocene sites with endemic vertebrate faunas in southern Tuscany.

Palynology of the late Miocene Oreopithecus-bearing lignite from Baccinello, Italy

This paper presents the results of an analysis of pollen and spores in 7 lignite samples from the vertebrate-bearing V1 lignite at Baccinello, Italy. The aim of the study is to reconstruct the vegetation associated with the vertebrate fauna, and to integrate this evidence with data from geological, paleontological and paleobotanical research in order to provide an improved understanding of the paleoenvironmental context. The V1 lignite, consisting of a 3 m seam near the base of the local geological sequence, is late Miocene (Tortonian) in age. It is dated at 8.5–9.0 Ma (European Mammal Zone MN 12) based on faunal correlations and on radiometric age determinations of an overlying tuffaceous layer. The fossil fauna comprises a small number of species, many of which are unique to the coal deposits of Tuscany, including the controversial hominoid, Oreopithecus bambolii. The high level of endemism, low taxonomic diversity, preponderance of ruminants, tendency for gigantism among some of the micromammals, and absence of cursorial carnivores, all point to an insular environment. Evidence from structural geology confirms that a tectonically unstable island arc bordered the eastern side of the Tyrrhenian Sea during the late Miocene. By a combination of island sweepstake events and ephemeral land connections, intermittent migrations of mammals from continental Europe and Africa led to the development of a unique fauna on islands of the northern Tethys Sea. The reconstructed vegetation is of lowland mixed mesophytic forest. The community of broad-leaved deciduous angiospermous and evergreen gymnospermous trees contained a rich understory of small trees and shrubs and an herbaceous ground cover. The abundance of aquatic seed plants and algae, as well as the preponderance of ferns and arboreal taxa that commonly grow on moist substrates, suggest that the lowland areas were poorly drained. Upland or montane habitats appear to have been present, but were located at some distance from the depositional basin. The rarity of grasses and chenopods indicates that extensive tracts of open country were of limited occurrence. The closest modern analogue to the vegetation is the mixed mesophytic forest of the Yangtze River Valley of east central China. It seems reasonable to infer that comparable warm temperate to subtropical conditions with high precipitation, especially in the summer months, characterized the late Miocene climate at Baccinello.

New fossil anthropoids from the middle Miocene of East Africa and their bearing on the origin of the oreopithecidae.

Recent paleontological collections at the middle Miocene locality of Maboko Island in Kenya, dated at 15-16 million years, have yielded numerous new specimens belonging to at least five species of fossil anthropoids. The most common species of ape at the site, a medium-sized primate with a very distinctive dental morphology, clearly represents a previously undescribed taxon. When compared with other Miocene anthropoids from East Africa, it has its closest affinities with the poorly known species Rangwapithecus vancouveringi from the early Miocene locality of Rusinga Island. The species from Maboko Island is described here as belonging to a new genus of fossil anthropoid, to which "Rangwapithecus" vancouveringi is also referred. The new genus has a highly distinctive suite of derived characters of its molars and premolars, which it shares with Oreopithecus bambolii from the late Miocene of Europe. These synapomorphies indicate a close phyletic relationship between the East African species and Oreopithecus and form the basis for the inclusion of these taxa in a single family, the Oreopithecidae Schwalbe, 1915. In many respects, however, the East African forms are more conservative than Oreopithecus, and in a general sense they can be regarded as an intermediate grade between Oreopithecus and the more generalized early Miocene catarrhines, the proconsuloids. There is, therefore, good fossil evidence to indicate that the origins of the Oreopithecidae can be traced back to the early Miocene of Africa.

Chronological and paleogeographical background to the study of Oreopithecus bambolii

Oreopithecus bambolii belongs to a unique faunal assemblage found only in Tuscany. Six localities have yiclded specimens of this Maremma Local Fauna, which at Baccinello can be seen to occur in two horizons: V2, dated to about 8·5 Ma, and the older V1. The Casteani faunule corresponds to the latter, while Monte Bamboli (type locality of O. Bambolii ) is similar to V2. Updated faunal lists for the two horizons are provided. Several rodents and a charophyte indicate European affinities for part of the assemblage, while two bovids and Oreopithecus are of African origin. Although the paucity of species (especially carnivores) and the presence of “giant” rodents suggested an insular environment to Hurzeler and Engesser, the lack of any concomitant reduction in size of the large mammals does not support this view. Faunal and floral considerations indicate that although open country may have occurred nearby, Oreopithecus probably inhabited a swampy forest. Analysis of the regional paleogeography suggests that a tectonically folded passageway may have permitted the one-way “filter-bridge” migration of terrestrial mammals from northern Africa and from continental Europe into Tuscany, but probably at different times.

Cranial Anatomy of Oreopithecus

Reexamination of the 1958 skull of the late Miocene Oreopithecus bambolii revealed a cranial anatomy different from that widely accepted for this taxon. There is a sagittal crest, a high nuchal crest, a large gonial angle, and alpha high, rather vertical, occiput. This catarrhine was not a very large brained primate compared to known advanced hominoids.

OREOPITHECUS BAMBOLII

<i>OREOPITHECUS BAMBOLII</i>