Dryopithecus taxonomy has been the subject of much turmoil, with new specimens being the basis of a new species or genus based on minute differences, resulting in several now-defunct species. In 1965, English palaeoanthropologist David Pilbeam and American palaeontologist Elwyn L. Simons separated the genus–which included specimens from across the Old World at the time–into three subgenera: Dryopithecus in Europe, Sivapithecus in Asia, and Proconsul in Africa. Afterwards, there was discussion over whether each of these subgenera should be elevated to genus. In 1979, Sivapithecus was elevated to genus, and Dryopithecus was subdivided again into the subgenera Dryopithecus in Europe, and Proconsul, Limnopithecus, and Rangwapithecus in Africa. Since that time, several more species were assigned and moved, and by the 21st century, the genus included D. fontani, D. brancoi, D. laietanus, and D. crusafonti. However, the 2009 discovery of a partial skull of D. fontani caused many of them to be split off into different genera, such as the newly erected Hispanopithecus, because part of the confusion was caused by the fragmentary nature of the Dryopithecus holotype with vague and incomplete diagnostic characteristics. Based on dental development in chimpanzees, it was 6 to 8 years old, and several diagnostic characteristics made from the holotype would be lost in mature D. fontani; A partial left humerus arm bone, an additional mandible (MNHNP 1872-2), a left lower jaw and five isolated teeth are also known from the site.
- A male partial face, IPS35026, and femur, IPS41724, from Vallès Penedès in Catalonia, Spain.
Dryopithecus is classified into the namesake great ape tribe Dryopithecini, along with Hispanopithecus, Rudapithecus, Ouranopithecus, Anoiapithecus, and Pierolapithecus, though the latter two may belong to Dryopithecus, Dryopithecini is either regarded as an offshoot of orangutans (Ponginae), an ancestor to African apes and humans (Homininae), or its own separate branch (Dryopithecinae).
Dryopithecus was a part of an adaptive radiation of great apes in the expanding forests of Europe in the warm climates of the Miocene Climatic Optimum, possibly descending from early or middle Miocene African apes which diversified in the proceeding Middle Miocene disruption (a cooling event). It is possible great apes first evolved in Europe or Asia, and then migrated down into Africa.
Description
Based on measurements of the femoral head of the Spanish IPS41724, the living weight for a male Dryopithecus was estimated to be . The femoral neck, which connects the femoral head to the femoral shaft, is not very long nor steep; the femoral head is positioned low to the greater trochanter; and the lesser trochanter is positioned more towards the backside. All these characteristics are important in the mobility of the hip joint, and indicate a quadrupedal mode of locomotion rather than suspensory. Dental wearing indicates Dryopithecus ate both soft and hard food, which could either indicate they consumed a wide array of different foods, or they ate harder foods as a fallback. Nonetheless, its unspecialized teeth indicate it had a flexible diet, and large body size would have permitted a large gut to aid in the processing of less-digestible food, perhaps stretching to include foods such as leaves (folivory) in times of famine like in modern apes. Unlike modern apes, Dryopithecus likely had a high carbohydrate, low fibre diet.
Paleoecology
thumb|300px|A map of late Miocene Europe
The remains of Dryopithecus are often associated with several large mammals, such as proboscideans (e. g., though not limited to, Gomphotherium), rhinoceroses (e. g., Lartetotherium), suids (e. g., Listriodon), bovids (e. g., Miotragocerus), equids (e. g., Anchitherium), hyaenids (e. g., Protictitherium), and felids (e. g., Pseudaelurus). Other associated primates are the great apes Hispanopithecus, Anoiapithecus, and Pierolapithecus; and the pliopithecid ape Pliopithecus. These fauna are consistent with a warm, forested, paratropical wetland environment, and it may have lived in a seasonal climate. For the Austrian Dryopithecus, plants such as Prunus, grapevines, black mulberry, strawberry trees, hickory, and chestnuts may have been important fruit sources; and the latter two, oak, beech, elm, and pine honey sources.