[Paleontology • 2018] Dynamoterror dynastes • A New Tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Menefee Formation of New Mexico

Dynamoterror dynastes 

McDonald​, Wolfe & Dooley, 2018

Invictarx zephyri  

McDonald​ & Wolfe, 2018

 DOI:  10.7717/peerj.5749 twitter.com/WesternCenter 

Art by Brian Engh  twitter.com/GreyGriffon 

Abstract
The giant tyrannosaurids were the apex predators of western North America and Asia during the close of the Cretaceous Period. Although many tyrannosaurid species are known from numerous skeletons representing multiple growth stages, the early evolution of Tyrannosauridae remains poorly known, with the well-known species temporally restricted to the middle Campanian-latest Maastrichtian (∼77–66 Ma). The recent discovery of a new tyrannosaurid, Lythronax argestes, from the Wahweap Formation of Utah provided new data on early Campanian (∼80 Ma) tyrannosaurids. Nevertheless, the early evolution of Tyrannosauridae is still largely unsampled. We report a new tyrannosaurid represented by an associated skeleton from the lower Campanian Allison Member of the Menefee Formation of New Mexico. Despite fragmentation of much of the axial and appendicular skeleton prior to discovery, the frontals, a metacarpal, and two pedal phalanges are well-preserved. The frontals exhibit an unambiguous autapomorphy and a second potential autapomorphy that distinguish this specimen from all other tyrannosaurids. Therefore, the specimen is made the holotype of the new genus and species Dynamoterror dynastes. A phylogenetic analysis places Dynamoterror dynastes in the tyrannosaurid subclade Tyrannosaurinae. Laser-scanning the frontals and creation of a composite 3-D digital model allows the frontal region of the skull roof of Dynamoterror to be reconstructed.

 Reconstructed frontal complex of Dynamoterror dynastes.

 Missing elements reconstructed based upon Teratophoneus curriei (UMNH VP 16690) (Loewen et al., 2013). 

 Dynamoterror dynastes & Invictarx zephyri 

Art by Brian Engh 

twitter.com/WesternCenter 

 twitter.com/GreyGriffon 

Dinosauria Owen, 1842, sensu Baron, Norman & Barrett, 2017
Theropoda Marsh, 1881, sensu Baron, Norman & Barrett, 2017
Coelurosauria Huene, 1914, sensu Sereno, McAllister & Brusatte, 2005

Tyrannosauroidea Osborn, 1906,

 sensu Walker, 1964; Sereno, McAllister & Brusatte, 2005

Tyrannosauridae Osborn, 1906,

 sensu Sereno, McAllister & Brusatte, 2005

Tyrannosaurinae Osborn, 1906,

sensu Matthew & Brown, 1922; Sereno, McAllister & Brusatte, 2005

Dynamoterror dynastes gen. et sp. nov.

Holotype: UMNH VP 28348, incomplete associated skeleton including the left and right frontals, four fragmentary vertebral centra, fragments of dorsal ribs, right metacarpal II, supraacetabular crest of the right ilium, unidentifiable fragments of long bones, phalanx 2 of left pedal digit IV, and phalanx 4 of left pedal digit IV.

Etymology: Dynamoterror is derived from the transliterated Greek word dynamis (“power”) and the Latin word terror. The specific name, dynastes, is a Latin word meaning “ruler.” The intended meaning of the binomen is “powerful terror ruler.” The name also honors the binomen “Dynamosaurus imperiosus” (Osborn, 1905), a junior synonym of Tyrannosaurus rex (Osborn, 1905, 1906), but a particular childhood favorite of the lead author.

Locality: UMNH VP 28348 was collected in San Juan County, New Mexico, on land administered by the US BLM. Precise locality data are on file at UMNH and the BLM.

Horizon: UMNH VP 28348 was collected from outcrops of the Juans Lake Beds (Miller, Carey & Thompson-Rizer, 1991), upper part of the Allison Member, Menefee Formation; lower Campanian, Upper Cretaceous. Lucas et al. (2005) produced a radioisotopic date of 78.22 ± 0.26 Ma from a bentonite layer near the top of the Menefee Formation in the Gallina hogback in the eastern part of the San Juan Basin. In the part of the San Juan Basin where UMNH VP 28348 was collected, the overlying Cliff House Sandstone contains fossils of the ammonoid Baculites perplexus (Siemers & King, 1974), corresponding to between 78.0 and 78.5 Ma (Molenaar et al., 2002). According to the regional stratigraphic correlation chart of Molenaar et al. (2002), the Menefee Formation spans approximately 84.0–78.5 Ma, based upon correlations with marine biostratigraphic zones. This age range corresponds to uppermost Santonian—middle Campanian (Cohen et al., 2013).

Specific diagnosis (as for genus by monotypy): tyrannosaurine tyrannosaurid distinguished by two autapomorphies on the frontals: (1) prefrontonasal and prefrontolacrimal processes are in close proximity, separated only by a shallow notch; and (2) subrectangular, concave, laterally projecting caudal part of the postorbital suture, separated from the rostral part by a deep groove. The second autapomorphy should be treated as provisional, given the ontogenetic variation observed in this region of the frontal in other tyrannosaurids (Carr & Williamson, 2004) (see description of the lateral surface of the frontal below). In the context of the phylogenetic analysis of Carr et al. (2017), which is used herein, UMNH VP 28348 exhibits a feature that supports its affinities among derived tyrannosauroids (1561, “frontal, dorsotemporal fossa, medial extension, dorsal view: meets opposing fossa at the midline”; also present in Timurlengia euotica, Xiongguanlong baimoensis, B. sealeyi, and Tyrannosauridae), and a feature identified by Carr et al. (2017) as an unambiguous synapomorphy of “derived tyrannosaurines” (1571, “frontal, sagittal crest, form, dorsal and lateral views: present and pronounced (dorsoventrally tall), single structure”).
....

Conclusions: 

The description of Dynamoterror dynastes from the lower Campanian Allison Member of the Menefee Formation provides additional data on the morphology and diversity of early tyrannosaurines in Laramidia. However, additional discoveries are needed to elucidate the paleobiogeographic history of tyrannosaurines.





Andrew T. McDonald​, Douglas G. Wolfe and Alton C. Dooley Jr. 2018. A New Tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Menefee Formation of New Mexico. PeerJ. 6:e5749.  DOI:  10.7717/peerj.5749

 twitter.com/Hippodraco/status/1049634324729872385

 twitter.com/WesternCenter/status/1049632730361679873
Newly Discovered Tyrant Dinosaur Stalked Ancient New Mexico 
po.st/IteAl4 via @SmithsonianMag

Andrew T. McDonald​ and Douglas G. Wolfe. 2018. A New Nodosaurid Ankylosaur (Dinosauria: Thyreophora) from the Upper Cretaceous Menefee Formation of New Mexico. PeerJ. 6:e5435.  DOI:  10.7717/peerj.5435

   

[Paleontology • 2017] Daspletosaurus horneri • A New Tyrannosaur with Evidence for Anagenesis and Crocodile-like Facial Sensory System

Daspletosaurus horneri 

 Carr, Varricchio, Sedlmayr, Roberts & Moore, 2017 

Holotype (MOR 590). Illustration: Dino Pulerà.
 DOI: 10.1038/srep44942  

Abstract

A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond. We studied the excellent fossil record of the tyrannosaurid to test that hypothesis. Phylogenetic analysis places this new taxon as the sister species to Daspletosaurus torosus. However, given their close phylogenetic relationship, geographic proximity, and temporal succession, where D. torosus (~76.7–75.2 Ma) precedes the younger new species (~75.1–74.4 Ma), we argue that the two forms most likely represent a single anagenetic lineage. Daspletosaurus was an important apex predator in the late Campanian dinosaur faunas of Laramidia; its absence from later units indicates it was extinct before Tyrannosaurus rex dispersed into Laramidia from Asia. In addition to its evolutionary implications, the texture of the facial bones of the new taxon, and other derived tyrannosauroids, indicates a scaly integument with high tactile sensitivity. Most significantly, the lower jaw shows evidence for neurovasculature that is also seen in birds.

Figure 1: Skull and jaws of the holotype (MOR 590) of Daspletosaurus horneri sp. nov.;
 (A) photograph and, (B) labeled line drawing of skull and jaws in left lateral view; (C) photograph and, (D) labeled line drawing of occiput and suspensorium in caudal view; (E) photograph and, (F) labeled line drawing of skull in dorsal view. Scale bars equal 10 cm. Abbreviations: MOR, Museum of the Rockies. 

Figure 2: Phylogenetic position and synapomorphies of Daspletosaurus, based on parsimony analysis.
 (A) Phylogenetic relationships of tyrannosaurines calibrated to geological time. Full consensus trees in Extended Data. Synapomorphies of the Daspletosaurus lineage from: (B) maxilla of MOR 1130; (C) lacrimal of MOR 1130; (D) postorbital of CMN 11594; (E) vomer of MOR 590; (F) palatine of MOR 1130; and (G) frontoparietal complex of MOR 590. Abbreviations: AMNH FARB, American Museum of Natural History, Fossil Amphibians, Reptiles, and Birds; As, Asia CMN, Canadian Museum of Nature; K/Pg, Cretaceous-Paleogene; LA, Laramidia; MOR, Museum of the Rockies. 

Figure 3: The growth series of Daspletosaurus horneri sp. nov., based on parsimony analysis.
 Unambiguously optimized derived phylogenetic characters were recovered as synontomorphies at two of the five growth stages, which are labeled at the corresponding numbers. Scale bar equals 10 cm. Abbreviations: AMNH FARB, American Museum of Natural History, Fossil Amphibians, Reptiles, and Birds; MOR, Museum of the Rockies. 

Theropoda Marsh, 1881

Tyrannosaurinae Matthew and Brown, 1922 (sensu Sereno et al., 2005)

Daspletosaurus Russell, 1970

Daspletosaurus. All species more closely related to Daspletosaurus torosus than to Tyrannosaurus rex.

Daspletosaurus horneri sp. nov.

Etymology: Horneri, Latinized form of Horner, in honor of Jack Horner, in recognition of his successful field program in the Two Medicine Formation that has recovered many new species of dinosaurs that are critical for our understanding of the palaeobiology of dinosaurs in Laramidia, support in the preparation and curation of these specimens, and to acknowledge that his mentoring efforts have launched many professional scientific careers.

Figure 4: The craniofacial epidermis of Daspletosaurus horneri sp. nov., based on comparison with its closest living relatives, crocodylians and birds. Figure 4 Bone texture indicates large zones of large, flat scales and subordinate regions of armor-like skin and cornified epidermis; integumentary sense organs occur on the flat scales that cover the densest regions of neurovascular foramina. The region outside of the crocodylian-like skin is reconstructed with small scales after fossilized skin impressions of tyrannosaurids.

 Illustration: Dino Pulerà.  

Thomas D. Carr, David J. Varricchio, Jayc C. Sedlmayr, Eric M. Roberts and Jason R. Moore. 2017. A New Tyrannosaur with Evidence for Anagenesis and Crocodile-like Facial Sensory System.
 Scientific Reports. 7, 44942 (2017). DOI: 10.1038/srep44942 

[Paleontology • 2016] Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany

The Theropods of northern Germany 

by Hyrotrioskjan  Hyrotrioskjan.DeviantART.com
DOI: 10.1371/journal.pone.0158334  

Abstract

Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A—R) could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A) and Abelisauridae (morphotype K). This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q) differ only in some probably size-related characteristics from larger morphotypes (B and C) and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America.

The Theropods of northern Germany 

  by Hyrotrioskjan  Hyrotrioskjan.DeviantART.com

Conclusions

This study reveals ecologic sympatry of several major clades of Theropoda in the Late Jurassic of Northern Germany. Basal Tyrannosauroidea, Allosauroidea, Megalosauridae and probably Ceratosauria can be established with a high probability. The presence of Dromaeosauridae could not be confirmed by DFA and cladistic analysis, pending more complete material of this clade. The smaller teeth of our study show no similarities with the only slightly younger theropod fauna of Southern Germany. Results of recent screen-washing activities at the Langenberg Quarry seem to confirm this interpretation. However, this may be due to sampling bias as the teeth of Sciurumimus, Compsognathus and Juravenator are small and could easily be overlooked when embedded in matrix. The theropod fauna from Northern Germany shares many similarities with specimens described from Portugal (morphotype B, E, F, G, K and N) and the North American Morrison Formation (morphotype J). This could imply that at least some faunal exchange via temporary land connections between these localities existed in the Late Jurassic.

Oliver Gerke and Oliver Wings. 2016. Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany. PLoS ONE.  11(7): e0158334. DOI: 10.1371/journal.pone.0158334

"The Theropods of northern Germany" by Hyrotrioskjan

  http://Hyrotrioskjan.DeviantART.com/art/The-theropods-of-northern-Germany-620388847

In their recent paper Oliver Gerke and Oliver Wings describe a number of teeth of theropod dinosaurs from the late Jurassic.

The analysis of these rare finds reveal a surprising diversity in this part of Europe, some of them come from the same locality as Europasaurus. Beside the expected allosaur like teeth the collection includes Torvosaurus and Marshosaurus like forms, but also ceratosaur teeth (here represented with a Ceratosaurus-like theropod, which isn't really correct)

and one or two morphotypes associated with basal tyrannosaurs.

Here some art for the press release and are normally five single pictures they are just glued together here.

[Paleontology • 2016] Timurlengia euotica • New Tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies Evolution of Giant Body Sizes and Advanced Senses in Tyrant Dinosaurs

Timurlengia euotica 

 Brusatte, Averianov, Sues, Muir & Butler, 2016
DOI:   10.1073/pnas.1600140113 

Significance

Tyrannosaurs — the iconic group of dinosaurian carnivores that includes Tyrannosaurus rex —dominated latest Cretaceous ecosystems with their colossal sizes and sophisticated senses. A gap in the mid-Cretaceous fossil record between these giant apex predators and their older, smaller relatives makes it difficult to understand how the characteristic body size and ecological habits of T. rex and kin developed. A new species from Uzbekistan fills this gap. This horse-sized animal shows that tyrannosaurs had yet to achieve huge size at this time but had already evolved key brain and sensory features of the gigantic latest Cretaceous species. Tyrannosaurs apparently developed giant body size rapidly, late in the Cretaceous, and their success may have been enabled by their early-evolving keen senses.

Abstract

Tyrannosaurids — the familiar group of carnivorous dinosaurs including Tyrannosaurus and Albertosaurus — were the apex predators in continental ecosystems in Asia and North America during the latest Cretaceous (ca. 80–66 million years ago). Their colossal sizes and keen senses are considered key to their evolutionary and ecological success, but little is known about how these features developed as tyrannosaurids evolved from smaller basal tyrannosauroids that first appeared in the fossil record in the Middle Jurassic (ca. 170 million years ago). This is largely because of a frustrating 20+ million-year gap in the mid-Cretaceous fossil record, when tyrannosauroids transitioned from small-bodied hunters to gigantic apex predators but from which no diagnostic specimens are known. We describe the first distinct tyrannosauroid species from this gap, based on a highly derived braincase and a variety of other skeletal elements from the Turonian (ca. 90–92 million years ago) of Uzbekistan. This taxon is phylogenetically intermediate between the oldest basal tyrannosauroids and the latest Cretaceous forms. It had yet to develop the giant size and extensive cranial pneumaticity of T. rex and kin but does possess the highly derived brain and inner ear characteristic of the latest Cretaceous species. Tyrannosauroids apparently developed huge size rapidly during the latest Cretaceous, and their success in the top predator role may have been enabled by their brain and keen senses that first evolved at smaller body size.

Keywords: dinosaur, Tyrannosauroidea, Uzbekistan, phylogenetics, evolution

Fig. 1. Skeletal reconstruction of Timurlengia euotica, with known bones colored in red. Individual bones come from different individuals, as they were surfacecollected as isolated specimens in the Bissekty Formation of Uzbekistan. The proportions of the skeleton are based on an intermediate body type between Xiongguanlong and Tyrannosaurus but should be considered provisional until associated material is found.
Bones are as follows: A, left frontal, ZIN PH 2330/ 16; B, holotypic braincase, ZIN PH 1146/16; C, cervical vertebra, ZIN PH 671/16; D, cervical vertebra, USNM (National Museum of Natural History) 538131; E, dorsal neural arch, USNM 538132; F, dorsal vertebra, CCMGE (Chernyshev’s Central Museum of Geological Exploration) 432/12457; G, anterior caudal vertebra, ZIN PH 951/16; H, middle caudal vertebra, ZIN PH 120/16; I, distal caudal vertebra, ZIN PH 507/16; J, pedal ungual, USNM 538167; K, manual ungual, ZIN PH 619/16; L, right articular and surangular (reversed), ZIN PH 1239/16; M, left quadrate, ZIN PH 2296/16; N, right dentary, ZIN PH 15/16; and O, right maxilla (reversed), ZIN PH 676/16. (Individual scale bars, 2 cm.)

Skeletal drawing courtesy of Todd Marshall.

A fossil tooth (front and back) of the newly discovered dinosaur. The blade-like teeth, says Hans Sues, were well-suited for "slicing through meat."

smithsonianmag.com

Systematic Paleontology
Dinosauria Owen, 1842; Theropoda Marsh, 1881;
Coelurosauria Huene, 1914; Tyrannosauroidea Osborn, 1905;

Timurlengia euotica  gen. et sp. nov.

Holotype: ZIN PH (Paleoherpetological Collection, Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia) 1146/16, a well-preserved braincase missing only the paroccipital processes and much of the parabasisphenoid (Figs. 1 and 2 and Figs. S1−S3).

Etymology Timurlengia, in reference to the fourteenth-century Central Asian ruler Timurleng (English: Tamerlane), and euotica, meaning “well eared” in reference to the large inner ear of the holotype.

Horizon and Locality: Dzharakuduk, central Kyzylkum Desert, Navoi Viloyat, Uzbekistan. Bissekty Formation, Upper Cretaceous, Middle-Upper Turonian (ca. 90–92 million years ago)

A reconstruction of the horse-sized tyrannosaur Timurlengia euotica, named for the charismatic Central Asian ruler Tamerlane, shows the species' long, slender legs, large head and teeth built sharp like a steak knife.

NMNH, Original painting by Todd Marshall 

Fig. 3. Phylogenetic relationships of Timurlengia euotica among theropod dinosaurs. Strict consensus of 99,999 most parsimonious trees (length = 3,367, consistency index = 0.322, retention index = 0.777) recovered from cladistic analysis in which T. euotica is scored based on the holotypic braincase and series of referred specimens. Numbers next to nodes are Bremer/jackknife support values, thick lines next to each taxon depict temporal range (which in most cases is age uncertainty and not true range), colors of lines denote geographic areas, and silhouettes are in relative proportion and scaled to total body length (T. rex = 13 m).

Geographic silhouettes are from Loewen et al. (3), and taxon silhouettes are courtesy of phylopic.org (Kileskus, T. M. Keesey; Guanlong, S. Hartman; Juratyrant, S. Hartman, T. M. Keesey; Eotyrannus, S. Hartman; Dryptosaurus, T. M. Keesey; Albertosaurus, C. Dylke; Daspletosaurus, S. O’Connor, T. M. Keesey; Tyrannosaurus, S. Hartman).

Conclusions

Timurlengia is a long-awaited diagnostic tyrannosauroid from the middle part of the Cretaceous. It indicates that these predators were still far from giants during this time, but had already evolved signature brain and sensory features that may have been tied to the extraordinary success of the last-surviving, latest Cretaceous species like Tyrannosaurus. However, Timurlengia remains a single data point from a still murky interval in dinosaur history, and future discoveries from this gap will undoubtedly lead to a better understanding of how tyrannosauroids rose from marginal creatures into some of the largest terrestrial predators in Earth history.

 Stephen L. Brusatte, Alexander Averianov, Hans-Dieter Sues, Amy Muir and Ian B. Butler. 2016. New Tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies Evolution of Giant Body Sizes and Advanced Senses in Tyrant Dinosaurs. Proceedings of the National Academy of Sciences of the United States of America. in press. DOI:   10.1073/pnas.1600140113

The discovery of a tiny Tyrant set the stage for the evolution of T. rex
http://po.st/TSbHav via @SmithsonianMag @NMNH #PreRex
 Behold Timurlengia—the Elusive Missing Link in Tyrannosaur Evolution
http://gizmodo.com/behold-timurlengia-the-elusive-missing-link-in-tyrannos-1764749916

Timurlengia euotica: Distant relative of T-rex shows how dinosaur became giant
  http://ibt.uk/A6V4r  via @IBTimesUK #dinosaurevolution