Skeleton of Repenomamus giganticus, from Hu et al. (2005).

Belongs within: Cynodontia.
Contains: Mammalia.

The Mammaliaformes has been defined as the most exclusive group containing both crown mammals and the early Jurassic Sinoconodon. This represents the total group including fossil taxa generally considered as 'mammals'.

Synapomorphies (from Luo et al. 2002): Craniomandibular joint comprised of dentary condyle and squamosal glenoid; petrosal promontorium present; extensive development of a petrosal floor for the cavum epiptericum housing the trigeminal ganglion; separate tympanic aperture for prootic canal containing the prootic vein; fenestra vestibuli lacking thickened rim; hypoglossal foramen (cranial nerve XII) separated from the jugular foramen (cranial nerves IX, X, XI).


Hu, Y., J. Meng, Y. Wang & C. Li. 2005. Large Mesozoic mammals fed on young dinosaurs. Nature 433: 149-152.

Luo, Z.-X., Z. Kielan-Jaworowska & R. L. Cifelli. 2002. In quest for a phylogeny of Mesozoic mammals. Acta Palaeontologica Polonica 47: 1-78.

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