Pantodont
| Pantodonta Temporal range: Paleocene - Eocene, 63–34 Ma |
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| Barylambda | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Subphylum: | Vertebrata |
| Class: | Mammalia |
| Infraclass: | Eutheria |
| Order: | †Cimolesta |
| Suborder: |
†Pantodonta Cope 1873 |
| Subgroups | |
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Pantodonta is an extinct suborder (or, according to some, an order) of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve after the end of the Cretaceous.
Pantodonta include some of the largest mammals of their time, but were a diversified group, with some primitive members weighing less than 10 kg (22 lb) and the largest more than 500 kg (1,100 lb).
The earliest and most primitive pantodonts, Bemalambda (with a 20 cm (7.9 in) skull probably the size of a dog) and Hypsilolambda, appear in the early Paleocene Shanghuan Formation in China. All more derived families are collectively classified as Eupantodonta. The pantodonts appear in North America in the middle Paleocene, where Coryphodon survived into the middle Eocene. Pantodont teeth have been found in South America (Alcidedorbignya) and Antarctica, and footprints in a coal mine on Svalbard.
The pantodonts varied considerably in size: the small Archaeolambda, of which there is a complete skeleton from the Late Palaeocene of China, was probably arboreal, while the North American, ground sloth-like Barylambda was massive, slow-moving ("") and probably browsed on high vegetation.
The pantodonts have a primitive dental formula (3.1.4.33.1.4.3) with little or no diastemata. Their most important synapomorphy are the (V-shaped ectoloph opening towards lip) P3–4 and (except in the most primitive families) (W-shaped ectoloph) upper molars. Most pantodonts lacked a hypocone (fourth cusp) and had small conules (additional small cusps). The incisors are small but the canines large, occasionally sabertooth-like. On P3-M3 there is normally an ectoflexus (indentation on the outer side). Asian families can typically be distinguished from the American because their paracone and metacone (bottom of W on side of tongue) tend to be closer together.
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