[2] There is some scientific debate as to whether any Desmatophoca species may have been present in the Oligocene, but without fossil samples obtained from this era, this is based primarily on conjecture.

[1] All samples of fossil Desmatophoca were found in marine deposits in Washington and Oregon, in the USA, which could indicate a geographic range of what is now the Pacific Northwest.

[4] The thickness of the mandible is especially important, as it provides both high bite force and increased surface area for muscular attachment between the jaws, which allows for stronger mastication.

[8] All members of Phocoidea, including Desmatophoca, share large orbits, bulbous cheektooth crowns, and expanded contact between the squamosal and the jugal.

[8] It was described and classified based solely off of a skull and partial jaw, and at the time, it helped shed light on the relationship between modern pinnipeds and other terrestrial carnivores.

[3] By comparing morphologies of D. oregonensis with extant terrestrial carnivores, it was determined that Desmatophoca shares a most recent common ancestor with bears and mustelids.

[3] This fossil sample also helped throw out the theory that seals share their most recent common ancestor with dogs and other canines, which was a popular thought at the time.

[3] The second species of Desmatophoca, D. brachycephala was discovered in 1987 by Barnes, in the late Miocene layer of the Astoria Formation that jetted into southwest Washington state.