Kunminia
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Morganucodon Temporal range: Late Triassic–Middle Jurassic |
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| Restoration of M. watsoni | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | Therapsida |
| Suborder: | Cynodontia |
| Family: | †Morganucodontidae |
| Genus: | †Morganucodon |
| Type species | |
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Morganucodon watsoni Kühne, 1949 |
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Morganucodon ("Glamorgan tooth") is an early mammaliaform genus that lived during the late Triassic period. It first appeared about 205 million years ago. Unlike many other early mammals, Morganucodon is well represented by abundant and well preserved, though in the vast majority of cases disarticulated, material. Most of this comes from Glamorgan in Wales (Morganucodon watsoni), but fossils have also been found in Yunnan Province in China (Morganucodon oehleri) and various parts of Europe and North America. Some at least closely related animals (Megazostrodon) are known from exquisite fossils from South Africa.
The name comes from a Latinization of Morganuc, "South Glamorgan in the Domesday Book", the county where it was discovered by Walter Georg Kühne, so it means "Glamorgan tooth". It has acquired the nickname Morgie in the Smithsonian National Museum of Natural History.
Morganucodon was a small, plantigrade animal. The tail was moderately long. According to Kemp (2005), "the skull was 2-3 cm in length and a presacral body length of about 10 cm [4 inches]. In general appearance, it would have looked like a shrew or mouse". There is evidence that it had specialized glands used for grooming, which may indicate that, like present day mammals, it had fur.
Like present day mammals of similar size and presumed habit, Morganucodon was likely nocturnal and spent the day in a burrow. There is no direct fossil evidence, but several lines of evidence point to a nocturnal bottleneck in the evolution of the mammal class, and almost all modern mammals of similar size to Morganucodon are still nocturnal. Likewise, burrowing was widespread both in the cynodonts and in primitive mammals. The logics of phylogenetic bracketing would make Morgunacodon nocturnal and burrowing too. Plant material from the conifer Hirmeriella was also found in the fissure fills, indicating Morganucudon lived in, or near, a forested area.
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Wikipedia