Pantolestidae ("all robbers") is a paraphyletic family of placental mammals from extinct order Pantolesta, that lived in North America, Asia and Europe from the early Paleocene to middle Oligocene. They first appear in North America, whence they spread to Europe and Asia.
Description The pantolestids were a small to moderate in size, omnivorous, semi-fossorial mammals. Members of this family formed grade towards families Paroxyclaenidae and Pentacodontidae, with representatives of subfamily Dyspterninae, aswell genus Entomodon, were anatomically most similar to them. Oldest known pantolestids were north american genera Bessoecetor, Leptonysson and Paleotomus, while youngest known pantolestid was european genus Kochictis.
Members of subfamily Pantolestinae were semiaquatic, otter-like mammals, with a body length of about and a tail about long. The anatomy of these archaic "insectivorous" mammals is best known through well-preserved Middle Eocene specimens from genus Buxolestes found at Messel in Germany, and a few other less complete specimens, such as the Palaeosinopa found at Fossil Butte in Wyoming, estimated to have reached body weights of up to , making them relatively large early mammals. They had moderately strong canines and multi-cusped cutting teeth supported by the strong jaw muscles to which cranial cavities were adapted. This combination of dentition and muscles has been interpreted as an early adaptation to a hard diet such as clams and snails. Freely articulated forearm bones (radius and ulna) permitted their powerful forelimbs wide rotational movements, while their digits had large bony claws indicating they could dig and build underground dens. Their powerful hind limbs could not be rotated in the same way, but the prominent transverse processes of the first tail vertebra suggest that they used their powerful tails to propel through the water like modern otters. In later pantolestins there is a prominent cranial crest combined with strong spinal processes, indicating the presence of strong neck muscles needed by swimmers that constantly hold their heads above the water surface.
Classification Taxonomy Family: †Pantolestidae (paraphyletic family) Genus: †Aatotomus †Aatotomus placochton Genus: †Amaramnis †Amaramnis gregoryi Genus: †Chadronia †Chadronia margaretae †Chadronia sp. (BADL 16917) Genus: †Entomodon †Entomodon comptus Genus: †Paleotomus †Paleotomus carbonensis †Paleotomus junior †Paleotomus milleri †Paleotomus radagasti †Paleotomus senior Subfamily: †Dyspterninae Genus: †Cryptopithecus †Cryptopithecus alcimonensis †Cryptopithecus major †Cryptopithecus sideroolithicus Genus: †Dyspterna †Dyspterna woodi Genus: †Euhookeria †Euhookeria hopwoodi Genus: †Galethylax †Galethylax brainvillei Genus: †Gobiopithecus †Gobiopithecus khan Genus: †Kiinkerishella †Kiinkerishella zaisanica Genus: †Kochictis †Kochictis centennii Genus: †Oboia †Oboia argillaceous Subfamily: †Pantolestinae Genus: †Bessoecetor †Bessoecetor krausei †Bessoecetor pilodontus †Bessoecetor septentrionalis †Bessoecetor thomsoni Genus: †Bouffinomus †Bouffinomus lamaudi Genus: †Buxolestes †Buxolestes hammeli †Buxolestes minor †Buxolestes piscator Genus: †Leptonysson †Leptonysson basiliscus †Leptonysson orthius Genus: †Pagonomus †Pagonomus dionysi Genus: †Palaeosinopa †Palaeosinopa aestuarium †Palaeosinopa didelphoides †Palaeosinopa dorri †Palaeosinopa incerta †Palaeosinopa lacus †Palaeosinopa lutreola †Palaeosinopa nunavutensis †Palaeosinopa osborni †Palaeosinopa reclusum †Palaeosinopa russelli Genus: †Pantolestes †Pantolestes densus †Pantolestes longicaudus †Pantolestes natans †Pantolestes sabatieri Genus: †Premontrelestes †Premontrelestes duchaussoisi Genus: †Thelysia †Thelysia artemia Genus: †Zhigdenia †Zhigdenia nemegetica Incertae sedis: †Pantolestinae sp. (CMN 30947)
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