Oreopithecus

One of the most controversial fossil primates known, Oreopithecus bambolii has generated substantial debate since its original discovery in the 1870s. Although only distantly related to humans, this Miocene hominoid shows several features that later evolved in parallel in the earliest human ancestors, including potential bipedalism and hand grasping ability. While its taxonomic placement and phylogenetic affinities have garnered controversy, scientists recognizeOreopithecus bambolii as an important species in understanding the evolution of certain human characteristics.

The first Oreopithecus specimens were discovered in the early 1870s in the lignite mines of Tuscany. In 1872, noted French anatomist and paleontologist Paul Gervais named these fossils Oreopithecus, which he described as similar to both gorillas and macaques. Much debate over the phylogenetic position of Oreopithecus soon followed, with some scientists arguing that the species was perhaps ancestral to modern humans and others pushing for a close linkage to the Cercopithecidae. A cache of additional specimens, including a complete skeleton of a young adult male, was unearthed near Baccinello, Italy, in 1958. Originally studied by Johannes Hürzeler, these specimens have settled much of the taxonomic debate. Although Oreopithecus “jumps around” in many modern cladograms, most researchers agree that this genus is a primitive hominoid closely related to Dryopithecus. Depending on which classification one follows, Oreopithecus may be placed in the Hominidae, but is far removed from humans.

Although known only from Italy and possibly Moldova, Oreopithecus is the best represented European fossil hominoid. Its fossils have been found in the Late Miocene sediments of Tuscany and Sardinia, which have been dated to 7–9 million years ago. During the Late Miocene, this region is thought to have been an island, and the insular environment of Oreopithecus is often cited as the source of many of its unusual features.

Oreopithecus was a relatively large-bodied primate, reaching sizes of 30–35 kilograms. Chief among its distinguishing features were a small brain, extremely short face, small postcanine and canine teeth, gracile carpals, and robust facial bones that indicate strong chewing muscles. The primitive and conservative [Page 1790]postcranium of Oreopithecus has often been described as similar to the ancestral hominid morphology, and several studies have shown similarities in dentition between this genus and modern hominids. Additionally, the strong chewing muscles and small brain of Oreopithecus suggest a strongly folivorous diet, although some scientists have disagreed with this conclusion.

Also controversial is the notion that Oreopithecuswas a habitual biped with human-like hand-grasping abilities. Based on a study of the internal bone structure of the pelvis, along with an examination of leg and foot morphology, it has been suggested that Oreopithecus was bipedal, perhaps as a consequence of its insular environment. The development of bipedalism freed the hands of Oreopithecus from locomotion, which enabled the evolution of an improved grasping ability similar to that seen in modern humans. Although unrelated in an evolutionary sense, these features make Oreopithecus an important species for understanding human bipedalism and grasping abilities. However, the hypotheses of bipedality and grasping in Oreopithecus have not been met with total acceptance. Other scientists have argued that Oreopithecus was an arboreal form, and that its unique hand and hip morphology reflect ape-like power, grasping, and suspension, not bipedalism.

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