Siats

Siats
speculative life reconstruction
Temporal occurrence
Upper Cretaceous ( Cenomanium )
100.5 to 93.9 million years
Locations
North America ( Utah )
Systematics
Theropoda Carnosauria Allosauroidea Neovenatoridae Megaraptora Siats
Scientific name
Siats
Zanno & Makovicky , 2013
Art
Siats meekerorum

Siats is an extinct genus theropod dinosaur that lived around 100 to 94 million years ago during the Early Upper Cretaceous ( Cenomanium ) in what is now Utah - and thus the first neovenatoride whose remains were found in North America.

features

The fossils found indicate that Siats are two-legged carnivores. The remains described are assigned to a young animal due to non- fused vertebral arches . The taxon can be characterized by seven diagnostic features (including four autapomorphies ). These include the short (about half as high as the vertebral body ) and wide spinous processes of the vertebrae and the triangular cross-section of some cervical vertebrae.

Discovery and naming

The first bone of a Siat was discovered in 2008 by an expedition of the Field Museum of Natural History at the base of Cedar Mountain. In the following two years, other remains were found in the same place, including what is believed to be a second specimen.

The genus was named after a man-eating monster from a legend of the Ute , Native Americans , whose settlement area once extended across Utah , among other places . The only species and type species described so far is Siats meekerorum . The species name honors the geologist John Caldwell Meeker and his daughter Lis, who worked as a research assistant on the project.

Systematics

Siats is classified in the Neovenatoridae family within the Carnosauria . Within this family, Siats together with Aerosteon , Megaraptor , Australovenator and Fukuiraptor form the group Megaraptora . However, the exact location of Siats in this group is not certain because the remains are too fragmentary. The following is a cladogram according to Zanno & Makovicky (2013):

Neovenatoridae	Neovenator      Chilantaisaurus   Megaraptora    Siats      Australovenator      Fukuiraptor      Aerosteon      Megaraptor

Individual evidence

1. ^ ^{A b c} Lindsay E. Zanno, Peter J. Makovicky : Neovenatorid theropods are apex predators in the Late Cretaceous of North America. In: Nature Communications. 4, Article number: 2827, November 2013, ISSN  2041-1723 , doi : 10.1038 / ncomms3827 .
2. ^ Chicago Tribune: New dinosaur discovered by Field Museum expedition rivaled T. rex , accessed August 2, 2014.