Triassic Mammal (Morganucodon) Teeth - Very Rare!

This is a very rare and unusual offering, it's a set of 5 teeth from one of the earliest, true mammals, Morganucodon watsoni. These five teeth come in a riker mount display case picture. Morganucodon was a small, shrew-looking animal which was about 4 inches (10cm in length).

The teeth were trapped during the Triassic when silt filled fissures and caves in Carboniferous limestone, concentrating small vertebrate bones and teeth. The remains of these fissures is then acid prepared and sorted under microscope to reveal the teeth.



There is currently controversy about whether or not to classify Morganucodon as a mammal or as a non-mammalian mammaliaform. Some researchers limit the term "mammal" to the crown group mammals, which would not include Morganucodon and its relatives. Others, however, define "mammals", as a group, by the possession of a special, secondarily evolved jaw joint between the dentary and the squamosal bones, which has replaced the primitive one between the articular and quadrate bones in all modern mammalian groups. Under this definition, Morganucodon would be a mammal. Nevertheless, its lower jaw retains some of the bones found in its non-mammalian ancestors in a very reduced form rather than being composed solely of the dentary. Furthermore, the primitive reptile-like jaw joint between the articular and quadrate bones, which in modern mammals has moved into the middle ear and become part of the ear ossicles as malleus and incus, is still to be found in Morganucodon. Morgunacodon also suckled (it may have been the earliest animal to do so), had only two sets of teeth and grew rapidly to adult size and stopped growing thereafter, all typical mammalian traits