The skull of Morganucodon

Morganucodontans are sampled as early mammaliaforms outside narrower crown Mammalia in the cited broad character analysis; this placement is a higher-taxon convention and topology, not evidence that Morganucodonta is the direct ancestor of living mammals.

The primary skull study describes Lower Jurassic Morganucodon watsoni from Wales and M. oehleri from China; these two source localities are representative material, not a complete geographic distribution for Morganucodonta.

The described Morganucodon skulls have teeth differentiated into incisors, canines, premolars and molars, but the study does not directly observe diet, habitat, locomotion or behaviour for Morganucodonta as a whole.

Kermack and colleagues describe a 26 mm Morganucodon watsoni skull and a slightly larger M. oehleri skull, with a squamosal–dentary contact while the articular–quadrate joint is retained; this is one anatomical mosaic, not a linear transition or direct ancestry claim.