Phiomia (after the Greek phiom "lake", an ancient name for the Fayum),[1][2] is an extinct genus of basal elephantiform proboscidean that lived in what is now Northern Africa during the Late Eocene to Early Oligocene some 37–30 million years ago.

A retracted naris (nasal cavity) with strong muscle attachment sites, long snout and protruding mandible all suggest that Phiomia was among the first proboscideans to possess a true trunk.

The type specimen of Phiomia, a partial left mandible (lower jaw), was recovered from strata belonging to the Jebel Qatrani Formation, part of the Eocene-age Fayum fossil deposits of Egypt.

[3] In 1902, the mandible was described by Charles William Andrews and Hugh John Llewellyn Beadnell, as part of a paper naming several mammal genera from the Fayum.

[5] Andrews and Beadnell were uncertain of Phiomia's relationships, though, believing it to have been carnivorous, tentatively suggested that it was a highly specialised member of the now-disused order Creodonta.

[8] An additional Phiomia species, P. major, was described in 2004 by William J. Sanders, John Kappelman, and D. Tab Rasmussen, based on teeth from the Chilga district of Ethiopia.

[1] In Pascal Tassy's 1988 paper on the phylogeny of proboscideans, wherein he erected the suborder Elephantiformes, he classified Phiomia as a basal member of the group, intermediate between Palaeomastodon and the later Hemimastodon.

[8] The environment of the Jebel Qatrani Formation, from which Phiomia serridens originates, has been described as a subtropical to tropical lowland plain by Bown, who further suggests the presence of streams and ponds.

[18] Based on the occurrence of birds that are associated with water (such as ospreys, early flamingos, jacanas, herons, storks, cormorants and shoebills), Rasmussen and colleagues inferred that the environment featured slow-moving freshwater with a substantial amount of aquatic vegetation, which matches the prior hypothesis.

Although lithology suggests that most fossils were deposited on sandbanks after being transported by currents, the authors argue that swamps could have easily formed along the banks of the river that was present during the Oligocene and may account for the mudstone found in certain quarries.

[20] In a 2001 paper Rasmussen et al. argued that the sandstone and mudstone of the formation likely formed as sediments were aggraded by a system of river channels that emptied towards the west into the Tethys.

[21] Overall this indicates that this region was a part of an extensive belt of tropical forest that stretched across what is now northern Africa, which would gradually give rise to open woodland and even steppe the further one was to travel inland.