Propliopithecus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of ape

Ape

Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea. The apes are native to Africa and South-east Asia, although in relatively recent times humans have spread all over the world...

.

The 40 cm (1 ft 4 in) long creature resembled today's gibbon

Gibbon

Gibbons are apes in the family Hylobatidae . The family is divided into four genera based on their diploid chromosome number: Hylobates , Hoolock , Nomascus , and Symphalangus . The extinct Bunopithecus sericus is a gibbon or gibbon-like ape which, until recently, was thought to be closely related...

s. Its eye

Eye

Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...

s faced forwards, giving it stereoscopical vision. Propliopithecus was most likely an omnivore

Omnivore

Omnivores are species that eat both plants and animals as their primary food source...

. It is possible that Propliopithecus is the same creature as Aegyptopithecus

Aegyptopithecus

Aegyptopithecus zeuxis means “linking Egyptian ape”. It was discovered by E. Simons in 1965. There is controversy over whether or not Aegyptopithecus should be a genus on its own or whether it should be moved into the genus Propliopithecus. If Aegyptopithecus is placed in its own genus, then there...

. If that would be the case the name Propliopithecus would take precedence over Aegyptopithecus according to ICZN

International Code of Zoological Nomenclature

The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...

rules, because it was coined earlier.