Mammaliaformes

Mammaliaformes is a clade comprising crown mammals and extinct relatives more closely related to mammals than to tritylodontids. Its members are distinguished by mammalian jaw and ear transformations.

Mammalia: Mammalia is the crown group comprising the last common ancestor of living mammals and all its descendants. Mammaliaformes includes this living-anchored group and its extinct stem relatives.
Mammalian middle ear evolution: Mammalian middle ear evolution is the transition of jaw-associated bones into structures that transmit sound. Fossils document this transformation across successive mammaliaform forms.
Cynodont: Cynodonts are a group of synapsids that includes mammaliaforms and several extinct non-mammalian lineages. Mammaliaforms arose within cynodont diversity.
Docodon: Docodon is a Jurassic docodont mammaliaform known especially from its distinctive molars. Its teeth illustrate the specialized food processing found among docodonts.
Mammaliaform jaw joint: The mammalian jaw articulation formed between the dentary and squamosal bones. This joint marks a major anatomical transition within mammaliaform evolution.
Tribosphenic molar: A tribosphenic molar combines shearing and crushing surfaces, including a basin on the lower molar. This tooth design expanded food-processing abilities in early therians.
Tritylodontidae: Tritylodontidae is an extinct family of herbivorous cynodonts generally placed outside Mammaliaformes. The gloss’s boundary distinguishes mammaliaforms from this neighboring cynodont lineage.
Castorocauda: Castorocauda is a Jurassic docodont mammaliaform with adaptations for swimming. Its fossils show that some mammaliaforms occupied aquatic niches.
Dentary: The dentary is the principal tooth-bearing bone of the lower jaw in vertebrates. Mammaliaforms increasingly relied on this bone as the sole lower-jaw element.
Tooth replacement: Tooth replacement is the process by which a tooth is shed and replaced during an animal’s life. Patterns of replacement help distinguish mammaliaform groups and illuminate their development.

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