Mustela, Potamotherium, Enhydra, Enhydriodon, Lontra, Neotherium and Puijilla

Mustela lutreola (Linneaus 1761; up to 43cm in length) is the extant European mink, a fast and agile animal related to weasels and polecats. Mustela lives in a burrow, but it also swims and dives skilfully. It is able to run along stream beds, and stay underwater for one to two minutes. Mustela is basal to otters.

Lontra canadensis (von Schreber 1777, Gray 1843; 84cm in length) is the extant river otter, nesting between the mink and sea otter.

Enhydra lutris (Fleming 1828, originally Mustela lutris Linneaus 1758) is the extant sea otter. Here it nests with Mustela and the river otter, Lontra. Uniquely it is often found floating on its back. The sea otter opens mollusc shells by hitting them with rocks held between their hands. Note the large flat feet with longer lateral toes.

Enhydriodon sivalensis (Falconer 1868, Geraads et al. 2011, Grohé et al 2022, Miocene and Pliocene, Ethiopia) This is the largest known river otter. The naris and orbit have mirgrated dorsally. The jugal appears to rise nearly closing off the orbit.

Potamotherium valletoni (Geoffroy 1833, Miocene, 1.5m long) is a traditional member of the otters and weasels, as it is in the LRT. Note the three premolars and two molars.

Puijila darwini (Rybczynski, Dawson and Tedford 2009; Late Oligocene 23 mya;1m in length) was originally considered an extinct species of seal based chiefly on skull and tooth traits. Here it nests with sea otters not releated to seals. Note the elevation of the large orbits. Puijila lived in and near high Arctic lakes.

Neotherium mirum (Kellogg 1931; Middle Miocene) was originally considered a small, tuskless walrus, but here nests with otters like Puijila. The molars are premolarized.

Fleming J 1828. A history of British animals, exhibiting the descriptive characters and systematic arrangement of the genera and species of quadrupeds, birds, reptiles, fishes, Mollusca, and Radiata of the United Kingdom; including the indigenous, extirpated, and extinct kinds, together with periodical and occasional visitants. - pp. i-xxxii [= 1-23], 1-565, [1]. Edinburgh. (Bell & Bradfute).

Grohé C et al 2022. Lutrinae Bonaparte 1838 (Carnivora, Mustelidae) from the Plio-Pleistocene of the Lower Omo Valley, southwestern Ethiopia: systematics and new insights into the paleoecology and paleobiogeography of the Turkana otters, Comptes Rendus Palevol 21(30):681–705. DOI: 10.5852/cr-palevol2022v21a30

Geraads D, Alemseged Z, Bobe R and Reed D 2011. Enhydriodon dikikae, sp. nov. (Carnivora: Mammalia), a gigantic otter from the Pliocene of Dikika, Lower Awash, Ethiopia. Journal of Vertebrate Paleontology. 31: 447–453.

Gray JE 1843. XXI.—Descriptions of some new genera and species of Mammalia in the British Museum Collection'

Kellogg AR 1931. Pelagic mammals of the Temblor Formation of the Kern River region, California. Proceedings of the California Academy of Science 19(12):217-397.

Linneaus C von 1761. Fauna Suecica sistens Animalia Sueciae Regni: Mammalia, Aves, Amphibia, Pisces, Insecta, Vermes. Distributa per Classes, Ordines, Genera, Species, cum Differentiis Specierum, Synonymis Auctorum, Nominibus Incolarum, Locis Natalium, Descriptionibus insectorum. Editio altera, auctior. Stockholmiae: L. Salvii, 48 + 578 pp.

Rybczynsk Ni, Dawson MR and Tedford RH 2009. A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia. Nature Letter 458:1021–1023. doi:10.1038/nature0798

von Schreber JCD 1777. Die Säugethiere, 3(18): pl. 126.B[1776], see also text:3(26):457, 588(index)[1777]).

wiki/Mustela
wiki/Sea_otter
wiki/North_American_river_otter
wiki/Lontra
wiki/Enhydriodon
wiki/Puijila
wiki/Potamotherium
wiki/Neotherium