Ben Creisler
Some recent non-dino papers:
Highlights
A new basal turtle, from the Lower Cretaceous of Europe, is defined.
Aragochersis lignitesta gen. et sp. nov. is an helochelydrid.
It is represented by the two most complete skeletons of this lineage in Europe.
New anatomical information about this relatively poorly known lineage is provided.
ABSTRACT
Two partial skeletons attributable to a single basal turtle taxon (i.e., Testudinata not belonging to the crown group Testudines) are studied here. These specimens come from the lower Albian (Lower Cretaceous) of the lignite coal mine of Santa MarÃa, in AriÃo (Teruel Province, Aragon, northeastern Spain). They are identified as belonging to a new member of the clade of terrestrial turtles Helochelydridae, Aragochersis lignitesta gen. et sp. nov. Both specimens represent the most complete skeletons of this lineage so far identified in Europe. The skull and mandible of the new taxon, but also the shell, several vertebrae, and numerous elements of the appendicular skeleton, are preserved. New anatomical information about this relatively poorly known group of basal turtles is provided.
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Orientalosuchus naduongensis gen. et sp. nov.Â
During systematic paleontological surveys in the Na Duong Basin in North Vietnam between 2009 and 2012, well-preserved fossilized cranial and postcranial remains belonging to at least 29 individuals of a middle to late Eocene (late Bartonian to Priabonian age (39â35 Ma)) alligatoroid were collected. Comparative anatomical study of the material warrants the diagnosis of a new taxon, Orientalosuchus naduongensis gen. et sp. nov. The combined presence of an enlarged fifth maxillary tooth, prominent preorbital ridges, a large supraoccipital exposure on the skull table, a palatine-pterygoid suture anterior to the posterior end of the suborbital fenestra, and a pterygoid forming a neck surrounding the choana is unique to this species. Unlike previous phylogenies, our parsimony analysis recovers a monophyletic Late Cretaceous to Paleogene East to Southeastern Asian alligatoroid group, here named Orientalosuchina. The group includes Orientalosuchus naduongensis, Krabisuchus siamogallicus, Eoalligator chunyii, Jiangxisuchus nankangensis and Protoalligator huiningensis, all of them sharing a medial shifted quadrate foramen aerum. The recognition of this clade indicates at least two separate dispersal events from North America to Asia: one during the Late Cretaceous by Orientalosuchina and one by the ancestor of Alligator sinensis during the Paleogene or Neogene, the timing of which is poorly constrained.
News:
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Michael R. Rampino, Yoram Eshet-Alkalai, Athanasios Koutavas & Sedelia Rodriguez (2019)
End-Permian stratigraphic timeline applied to the timing of marine and non-marine extinctions.
Palaeoworld (advance online publication)
doi:
https://doi.org/10.1016/j.palwor.2019.10.002 https://www.sciencedirect.com/science/article/pii/S1871174X19301040A latest Permian timeline (251.9âMa) can be constructed from the perspectives of: a global nickel spike attributed to emissions from the coeval Siberian flood-basalt eruptions, the correlative end-Permian marine mass extinction (EPME), a transition from reversed to normal paleomagnetism, and a negative anomaly in Î13Ccarb and Î13Corg. In a number of marine and non-marine localities, this timeline is also correlated (to within â30âky) with palynological evidence for the latest Permian destruction of terrestrial vegetation and the accompanying short-lived global fungal (Reduviasporonites) event. This correlation suggests that devastation in marine and non-marine environments was essentially coeval at a time marked by hyperthermal conditions and anoxic oceans.
We utilized this proposed timeline to estimate the relative timing of the extinction of latest Permian vertebrates in the Karoo Basin of South Africa. In several sections in the Karoo, the LAD of the therapsid Dicynodon, is correlated with the proposed timeline. In the Carlton Heights section in the Karoo we estimate that the palynological changes and the fungal event occurred within â 30 ky of the LAD of Dicynodon. Further sampling in the Karoo and other PermianâTriassic non-marine basins would help to clarify the relative timing of the global marine extinctions, plant devastation and the disappearance of non-marine vertebrates.
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Free pdf:
https://giw.utahgeology.org/index.php/giw/article/view/36/60The outcrop belt of the Upper Jurassic Morrison Formation in the northeastern Uinta Basin and southeastern flank of the Uinta Mountains is particularly rich in dinosaurian and non-dinosaurian faunas, as well as in fossil plants. The discovery of several well-preserved, relatively intact, fossil logs at several locations in Rainbow Draw and one location in Miners Draw, both near Dinosaur National Monument (Utah), has provided an opportunity to study the local paleobotany, stratigraphy, and sedimentology of the Morrison Formation in northeastern Utah. The Morrison Formation in northeastern Utah consists of four members. In ascending chronostratigraphic order, they are the Windy Hill, Tidwell, Salt Wash, and Brushy Basin Members. The lithology (including the presence of glauconite grains) and fossil assemblage of the lower two members (Windy Hill and Tidwell) indicate a marine to marginal marine (coastal plain) depositional environment, whereas the lithology, fossil flora and faunaassemblage of the upper two members (Salt Wash and Brushy Basin) indicate a fluvialâlacustrine depositional environment. At least 10 fossil log sites in Rainbow Draw have been documented so far, and geologic mapping indicates that the logs and wood all occur in the same stratigraphic interval within the Salt Wash Member, approximately 17 to 27 m above the base of the member. The unit containing the logs and wood is about 11 m thick and consists of very fine to fine-grained sandstone and siltstone with indistinct bedding and no discernible sedimentary features.
The logs are siliceous, some have a coaly exterior, and they range in exposed length from 0.5 to 11 m and reach diameters up to 1.1 m. In the Miners Draw area, a single siliceous log is documented in the upper part of the Salt Wash Member within a silty sandstone unit that is 4 m thick; its exposed length is about 6 m. Although the correlation of the Miners Draw log-bearing interval to the interval in Rainbow Draw is uncertain, both units are lithologically similar and both occur in the upper part of the Salt Wash Member. The logs have been identified as araucariaceous conifers that pertain to the same taxon originally described as Araucarioxylon hoodii Tidwell et Medlyn 1993 from Mt. Ellen in the Henry Mountains of southern Utah. Concurrent systematic work will prompt a nomenclatural transfer of this species to the genus Agathoxylon. Based on the abundance of large fossil logs and wood in the same stratigraphic interval in Rainbow Draw, we hypothesize that the area was covered by stands of moderately large trees of araucariaceous conifers. The sedimentological evidence suggests that the trees were not transported far from their original site of growth before they were deposited in a low-energy floodplain environment.