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[dinosaur] North American tyrannosaur papers + hadrosaur sacrum from Oregon + dinosaur taphonomy at Tianyuan, Zhuzhou (China) (free pdfs)

Ben Creisler

Some recent dinosaur papers with free pdfs.
Many thanks to Vahe Demirjian for passing this on theÂNew Mexico MuseumÂpdf links!

Sebastian G. Dalman, Spencer G. Lucas and D. Edward Malinzak (2018)
Tyrannosaurid teeth from the Upper Cretaceous (Campanian) Two Medicine Formation of Montana.Â
Lucas, S.G. and Sullivan, R.M., eds., 2018, Fossil Record 6. New Mexico Museum of Natural History and Science 79: 125-140
pdf link:

Several isolated teeth of tyrannosaurid dinosaurs from the Upper Campanian Two Medicine Formation of Montana are described. The teeth were found at the Flaming Cliffs, the Landslide Butte, and the Willow Creek Anticline localities. Some teeth are incomplete, whereas others are nearly complete. Extensive wear facets are preserved on most teeth. The majority of the wear facets that have smooth, elliptical-shaped surfaces are interpreted as the result of tooth-to-tooth contact during feeding, whereas others with spalled surfaces are interpreted as tooth-and-hard tissue (bone) contact. The location of the wear facets on the teeth may be a helpful tool to identify the maxillary and dentary teeth. The teeth most likely belong to either Daspletosaurus or Gorgosaurus, the skeletal remains of which have been recovered from the Two Medicine Formation. Both genera are also present in the Campanian deposits of the Dinosaur Park Formation of Alberta and in the Judith River Formation of north-central Montana. The genus Daspletosaurus also occurs in the Oldman Formation of Alberta. However, it may be difficult to separate quantitatively the isolated teeth of Daspletosaurus from those of Gorgosaurus, because of the temporal co-occurrence of these taxa and the striking morphologic similarities of their teeth. Therefore, the assignment of the teeth to Tyrannosauridae indeterminate is appropriate.Â


Sebastian G. Dalman & Spencer G. Lucas (2018)
New evidence for predatory behavior in tyrannosaurid dinosaurs from the Kirtland Formation (Late Cretaceous, Campanian), northwestern New Mexico.Â
Lucas, S.G. and Sullivan, R.M., eds., 2018, Fossil Record 6. New Mexico Museum of Natural History and Science 79: 113-124Â
pdf link:

A nearly complete skull of a chasmosaurine ceratopsian from the late Campanian of the Kirtland Formation of northwestern New Mexico shows evidence of an attack by a large tyrannosaurid dinosaur. The right maxilla, the right epijugal, the proximal end of the right squamosal and the left premaxilla exhibit several bite traces. The bite traces on the premaxilla, maxilla and the squamosal are full penetrations, whereas those on the epijugal are partial penetrations. Remodeled bone surface around the largest bite trace on the right maxilla demonstrates that the ceratopsian dinosaur survived the attack. The lack of bone remodeling around the other identified bite traces on the right squamosal and the left premaxilla suggests that this biting most likely occurred postmortem. Furthermore, based on the position of the bite traces and their concentration on the right side of the ceratopsian dinosaur skull the tyrannosaurid attacked from the right side. This ceratopsian specimen adds new information about active predation by a tyrannosaurid dinosaur.ÂÂ


Sebastian G. Dalman & Spencer G. Lucas (2018)
Tyrannosaurid dinosaurs (Theropoda: Tyrannosauridae) from the Upper Cretaceous (early Campanian) Allison Member of the Menefee Formation, New Mexico: Implications for the origin of Tyrannosauridae in North America.Â
Lucas, S.G. and Sullivan, R.M., eds., 2018, Fossil Record 6. New Mexico Museum of Natural History and Science 79: 99-112Â
pdf link:

We report on tyrannosaurid skeletal fossil remains from the early Campanian deposits of the Allison Member of the Menefee Formation in New Mexico. The skeletal fossil remains described here, which were found at several localities in the Menefee Formation include the left postorbital, isolated lateral tooth, thoracic rib shaft, anterior right scapula, and partial right metatarsal II. Overall morphology of the isolated skeletal remains resembles that of albertosaurine tyrannosaurids from younger Upper Cretaceous deposits of Alberta and Montana. At present the taxonomic identity of the Menefee tyrannosaurid cannot be ascertained because other skeletal elements are unknown, including the diagnostic cranial bones. Among the bones described here the postorbital exhibits a distinct morphology. The lateral surface of the postorbital has a prominent rugosity that extends along the anterolateral margin of the ventral postorbital ramus. The rugosity forms a characteristic sinuous flange-like structure, which then slightly extends into- and covers a small portion of the orbit and is best seen in lateral and anterior views. The flange-like structure is angled at 30 angle with respect to the ventral ramus. The characteristic position of the flange-like structure results in the formation of an elongated shallow fossa. However, the relatively small size the bones suggests that they belong to juvenile animals. The presence of tyrannosaurids in the Menefee Formation marks one the earliest occurrences of these iconic theropods in southwestern part of North America and adds to the previous assumption of the origin of Tyrannosauridae in this continent. Â


David G. Taylor and Spencer G. Lucas (2018)
A Late Cretaceous (Campanian) hadrosaur sacrum from the Cape Sebastian Sandstone, Curry County, Oregon.Â
Lucas, S.G. and Sullivan, R.M., eds., 2018, Fossil Record 6. New Mexico Museum of Natural History and Science 79: 695-702.Â
pdf link:

This paper describes a partial dinosaur sacrum of Campanian age from the shallow marine Cape Sebastian Sandstone in Curry County, Oregon. It is the first dinosaur fossil from the State. The specimen is from a hadrosaurid because it possesses at least eight sacral vertebrae and has lamellar sacral ribs characteristic of hadrosaurs. The morphology of the sacral ribs suggests a hadrosaurine.  Â


HUANG Leqing,TANG Ying,TONG Qianming, HUANG Jianzhong, LI Guang &HU Nengyong (2018)Â
Geological records of fossils layer and death process and taphonomy of dinosaurs in Cretaceous in Tianyuan, Zhuzhou.Â
Geology in China 45(5): 1023-1038 (in Chinese with English abstract).

Based on the study of regional geological data, the authors recognized 3 sedimentary events in the Upper Cretaceous formation for the first time, with the 3 geological records being exposure geological record, flood geological record and earthquake geological record. In addition, on the basis of lots of scientific statistics of gravels, the authors discussed the paleocurrent direction as well as provenance of the lake basins in Tianyuan of Zhuzhou systematically. The authors found that dinosaurs lived on the west bank of a long narrow NE-SW distributed lake in the south part of the Zhuzhou lake basin. Based on the results obtained, the authors infer that local volcano (?), earthquake, landslide and pluvial events are the reasons for paleocimate change and animals' death as well as the main reasons for the death of dinosaurs in the palaeoenvironment with dry weather and scarce forest vegetation. The burial process was closely related to the delta deposit system from channel alluvial.



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