Moros (dinosaur)
| Moros | ||||||||||||
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Diagram (scale 1 m), which highlights known skeletal elements |
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous ( Cenomanium ) | ||||||||||||
| 96.4 to 93 million years | ||||||||||||
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| Scientific name | ||||||||||||
| Moros | ||||||||||||
| Zanno , Tucker , Canoville , Avrahami , Gates , Makovicky , 2019 | ||||||||||||
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Moros was a Tyrannosauroiden - genus that in the upper Cretaceous period on the territory of the present United States occurred. The only species is Moros intrepidus .
description
Moros intrepidus is known from two specimens: The holotype (NCSM 33392) is formed by a right hind leg. The thigh bone , the lower leg bone , the second and fourth metatarsal bones and the third and fourth phalanx of the fourth toe are preserved. Its skull length is estimated at 352 mm, its hind leg length at 1.2 m and its body mass at 78 kg. A histological analysis shows that the specimen was growing slowly at the time of death. It follows that the individual came close to the calculated adult age of 6-7 years. Larger tyrannosauroids underwent exponential growth at the same age. The foot bones are very narrow. Their proportions are more similar to those of ornithomimids than those of other tyrannosauroids, indicating special adaptations for walking. Two paratypes (NCSM 33393 and NCSM 33276) are only known from isolated teeth. The calculated skull length of the former is 309 mm.
Surname
The generic name refers to the Greek god Moros ( Greek Μόρος Móros , German 'fate, fate' ), who is the embodiment of approaching disaster. The approaching disaster in this case are the tyrannosauroids, whose arrival on the North American continent Moros embodies. The species name comes from the Latin word intrepidus (dt. Fearless), which refers to the supposed intra-continental distribution of Moros and his relatives at that time.
Systematics
Prior to the discovery of Moros , there was a 70 million year gap in the fossil record of the Tyrannosauroidea. The oldest undisputed finds of tyrannosauroids in North America were previously around 81 million years old. Moros shifts the origin of this group on the continent by about 15 million years.
According to a phylogenetic analysis from the first description, Moros was closely related to taxa such as Xiongguanlong , which inhabited Asia during the Middle Cretaceous. The analysis supports the hypothesis that tyrannosauroids immigrated from Asia to North America before the Cenomanian and lived there as small and nimble predators in the shadow of the allosauroids . It was only when these became extinct that the tyrannosaurs were able to develop into top predators .
literature
- Lindsay E. Zanno, Ryan T. Tucker, Aurore Canoville, Haviv M. Avrahami, Terry A. Gates, Peter J. Makovicky: Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record . In: Communications Biology . tape 2 , 2019, p. 1-12 , doi : 10.1038 / s42003-019-0308-7 .