Dryolestoidea Temporal range: Middle Jurassic–Early Paleocene |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Subclass: | Theriiformes |
(unranked): | Cladotheria |
Superorder: | †Dryolestoidea Butler, 1939 |
Orders | |
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Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a coronoid and splenial, but the Cretaceous forms lack these. Another primitive feature is the presence of a Meckelian groove (the Cretaceous forms have a reduced version). Dryolestoids are known from the Jurassic through Early Cretaceous of the Northern Hemisphere (North America, Eurasia, and North Africa) and from the Late Cretaceous through Paleocene of South America.
Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo, Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure (New York: Columbia University Press, 2004), 14, 375, 379-380.