| Pantolestidae | |
|---|---|
| | |
| reconstruction of Palaeosinopa didelphoides | |
| | |
| part of lower jaw of Paleotomus senior | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Clade: | Eutheria |
| Order: | † Pantolesta |
| Family: | † Pantolestidae Cope, 1884 [1] |
| Type genus | |
| † Pantolestes Cope, 1872 | |
| Genera | |
[see classification] | |
| Synonyms | |
synonyms of family:
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Pantolestidae ("all robbers") is an extinct paraphyletic family of placental mammals from extinct order Pantolesta, that lived in North America, Asia and Europe from the early Paleocene to middle Oligocene. [5] [6] [7] [8] [9] They first appear in North America, whence they spread to Europe and Asia. [10]
The pantolestids were a small to moderate in size, omnivorous, semi-fossorial mammals. Members of subfamily Dyspterninae, aswell genus Entomodon , were anatomically similar to family Paroxyclaenidae, [11] while subfamily Pantolestinae and genera Aatotomus and Paleotomus were similar to family Pentacodontidae. 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 50 centimetres (20 in) and a tail about 35 centimetres (14 in) 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, [12] such as the Palaeosinopa found at Fossil Butte in Wyoming, estimated to have reached body weights of up to 1,400 grams (3 lb), making them relatively large early mammals. [10] They had moderately strong canines and multi-cusped cutting teeth supported by the strong jaw muscles [12] 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. [10] 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. [12] 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. [10]
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