Dynamo terror
| Dynamo terror | ||||||||||||
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Part of the holotype of Dynamoterror dynastes : right frontal in ventral (A, B) and dorsal (C, D) view with the diagnostic features of the species |
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| Temporal occurrence | ||||||||||||
| Lower Campanium ( Upper Cretaceous ) | ||||||||||||
| 83.6 to 80.6 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Dynamo terror | ||||||||||||
| McDonald et al., 2018 | ||||||||||||
Dynamoterror is a genus of theropod dinosaur in the Tyrannosauridae family thatlivedin what is now New Mexico about 80 million years ago in the Late Cretaceous Period . The type species and only species of the genus is Dynamoterror dynastes . It is one of the oldest tyrannosaurids ever discovered.
etymology
The generic name is a compound from a derivation of the Greek word δύναμις dynamis 'force' and the Latin word terror 'fear'. The epithet of the type species is the Greek word δυνάστης dynástes , which means something like 'ruler'.
features
The first description of Dynamoterror dynastes is based on a few, partly fragmentary fossil bones, which probably come from the same individual. This holotype specimen (UMNH VP 28348) includes in detail the two frontalia as the only cranial elements as well as four vertebral fragments, several rib fragments, a fragment of the right ilium (part above the acetabulum ), some fragments of the arm or leg bones that cannot be determined in detail right second metacarpal and two phalanges of the fourth toe of the left foot as postcranial elements.
Nevertheless, these few remains were sufficient for an assignment to the tyrannosaurids, and according to McDonald et al. (2018) they showed enough anatomical deviations from previously known tyrannosaurid material to be able to establish a new genus and species for them. As diagnostic for or as autapomorphic features of Dynamoterror and D. dynastes are given in the first description:
- The prefrontolacrimal and prefrontonasal processes at the front end of the upper (dorsal) part of the frontal are close together and only separated from each other by a shallow notch.
- The rear (caudal), approximately rectangular part of the suture area of the frontal to the postorbital is separated from the anterior (rostral) part of this suture area in the ventral (ventral) view by a deep notch.
Hardly any concrete statements can be made about the general appearance. It can only be estimated from the dimensions of the individual bones (e.g. right frontal almost 10 cm rostrocoaudal length) that Dynamo Terror was around 9 meters long during its lifetime.
Find location
The holotype specimen (see above ) - the only known fossil remains of Dynamoterror - were discovered in 2012 during an expedition in the Juans Lake Strata in the upper part of the Allison subformation of the Menefee Formation in San Juan County in northwest New Mexico found. It is currently in the collection of the Museum of Natural History of Utah (UMNH) in Salt Lake City .
The relative age of the find layer was based on the findings of the ammonite Baculites perplexus in the overlying Cliff House sandstone, using radiometric dating of a bentonite near the upper end of the Menefee Formation (both based on an absolute age of these layers of around 78 million years suggestive) and the relative position of the Juans Lake strata within the Menefee Formation, estimated at Lower Campanium (83.6 to 80.6 mya ). Dynamoterror is thus one of the oldest tyrannosaurids to be discovered alongside Lythronax .
The Nodosaurid Invictarx , which has also only been handed down in fragments, also comes from the Juans Lake strata and probably also from the same area or even the same locality .
Systematics
On the basis of a cladistic relationship analysis that was carried out in the context of the first description, Dynamoterror is considered a representative of the subfamily Tyrannosaurinae within the family Tyrannosauridae . As a result of the analysis, it stands within an extensive polytomy together with other massively built genera of the Tyrannosaurinae. A better resolution of Dynamoterror's relationship with these genres is currently not possible because of the fragmentary nature of its remains.
Web links
Individual evidence
- ↑ a b c d e f g Andrew T. McDonald, Douglas G. Wolfe, Alton C. Dooley Jr: A new tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Menefee Formation of New Mexico. PeerJ. Vol. 6, 2018, item no. e5749, doi: 10.7717 / peerj.5749 .
- ^ Riley Black: Newly Discovered Tyrant Dinosaur Stalked Ancient New Mexico. In: Smithsonian.com. October 9, 2018, accessed April 19, 2019 .
- Jump up ↑ Andrew T. McDonald, Douglas G. Wolfe: A new nodosaurid ankylosaur (Dinosauria: Thyreophora) from the Upper Cretaceous Menefee Formation of New Mexico. PeerJ. Vol. 6, 2018, item no. e5435, doi: 10.7717 / peerj.5435 .