Late Triassic (Norian)

Pant Quarry, Fissure Fill

Near Brigend, South Glamorgan, Wales

Excellent 1mm tooth of one of earliest mammals mounted on a standard microfossil slide

Mammal,

Morganucodon is the genus considered the earliest known mammal by many paleontologists while others contend it belongs to a group closely-related to early mammals.  Unlike most Mesozoic mammals, other parts of the Morganucodon skeleton are known and there appears to be evidence it had fur and the females produced milk for their offspring which would qualify it as a mammal.