Palaeomastodon_beadnelli
Palaeomastodon
Extinct genus of proboscid
Palaeomastodon ("ancient mastodon") is an extinct genus within the elephant order Proboscidea. Its fossils have been extracted from Oligocene strata conventionally dated to 33.9-23.03 million years old. Usually considered an ancestor or near-ancestor of elephants or mastodons as a member of Elephantiformes[1] it lived in marshes and fluvial-deltaic environments of what is now Egypt, Ethiopia, Libya, and Saudi Arabia.
Few postcranial remains are known, but based on the reported 875 mm length of one P. beadnelli femur, a recent study estimated an adult shoulder height of about 2.2 metres (7.2 ft) with a mass over 2.5 tonnes (2.8 short tons).[2]
Palaeomastodonts possessed both maxillary and mandibular tusks. The mandibular tusks projected anteriorly and were generally flat and scoop-like. They were probably used to scrape the bark off trees and uproot various plants. By contrast, the sharp maxillary tusks primarily functioned as defensive weapons.[3] Unlike later proboscideans belonging to Elephantimorpha, the teeth erupted vertically rather than horizontally, as shared with other "paleomastodonts" like Phiomia.[4]
The form, size, and capabilities of palaeomastodont nasal structures have long been debated. Though often depicted with a relatively small, prehensile proboscis, Osborn 1909 argued that wear patterns on the lower tusks better favored the presence of a large, retractile upper lip.
