scholarly journals A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7562
Author(s):  
Tobias Massonne ◽  
Davit Vasilyan ◽  
Márton Rabi ◽  
Madelaine Böhme
Keyword(s):  
Late Cretaceous ◽  
Anatomical Study ◽  
Late Eocene ◽  
New Taxon ◽  
Maxillary Tooth ◽  
Asian Clade ◽  
Postcranial Remains ◽  
Alligator Sinensis ◽  
North Vietnam ◽  
Dispersal Events

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 (39–35 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.

scholarly journals A new southern Laramidian ankylosaurid, Akainacephalus johnsoni gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, USA

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5016 ◽  
Author(s):  
Jelle P. Wiersma ◽  
Randall B. Irmis
Keyword(s):  
Late Cretaceous ◽  
First Record ◽  
Multiple Time ◽  
New Taxon ◽  
Postcranial Skeleton ◽  
Surface Textures ◽  
Close Phylogenetic Relationship ◽  
Biogeographic Provinces ◽  
Dispersal Events ◽  
Upper Campanian

A partial ankylosaurid skeleton from the upper Campanian Kaiparowits Formation of southern Utah is recognized as a new taxon, Akainacephalus johnsoni, gen. et sp. nov. The new taxon documents the first record of an associated ankylosaurid skull and postcranial skeleton from the Kaiparowits Formation. Preserved material includes a complete skull, much of the vertebral column, including a complete tail club, a nearly complete synsacrum, several fore- and hind limb elements, and a suite of postcranial osteoderms, making Akainacephalus johnsoni the most complete ankylosaurid from the Late Cretaceous of southern Laramidia. Arrangement and morphology of cranial ornamentation in Akainacephalus johnsoni is strikingly similar to Nodocephalosaurus kirtlandensis and some Asian ankylosaurids (e.g., Saichania chulsanensis, Pinacosaurus grangeri, and Minotaurasaurus ramachandrani); the cranium is densely ornamented with symmetrically arranged and distinctly raised ossified caputegulae which are predominantly distributed across the dorsal and dorsolateral regions of the nasals, frontals, and orbitals. Cranial caputegulae display smooth surface textures with minor pitting and possess a distinct conical to pyramidal morphology which terminates in a sharp apex. Character analysis suggests a close phylogenetic relationship with N. kirtlandensis, M. ramachandrani, Tarchia teresae, and S. chulsanensis, rather than with Late Cretaceous northern Laramidian ankylosaurids (e.g., Euoplocephalus tutus, Anodontosaurus lambei, and Ankylosaurus magniventris). These new data are consistent with evidence for distinct northern and southern biogeographic provinces in Laramidia during the late Campanian. The addition of this new ankylosaurid taxon from southern Utah enhances our understanding of ankylosaurid diversity and evolutionary relationships. Potential implications for the geographical distribution of Late Cretaceous ankylosaurid dinosaurs throughout the Western Interior suggest multiple time-transgressive biogeographic dispersal events from Asia into Laramidia.

scholarly journals Coal petrology analysis and implications in depositional environments from upper Cretaceous to Miocene: a study case in the Eastern Cordillera of Colombia

2021 ◽  
Author(s):  
Clara Guatame ◽  
Marco Rincón
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Late Eocene ◽  
Depositional Environments ◽  
Estuarine System ◽  
Eastern Cordillera ◽  
Stratigraphic Position ◽  
San Fernando ◽  
Coal Facies ◽  
Oil Sector

AbstractThe Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

scholarly journals An early bothremydid (Testudines, Pleurodira) from the Late Cretaceous (Cenomanian) of Utah, North America

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2502 ◽  
Author(s):  
Walter G. Joyce ◽  
Tyler R. Lyson ◽  
James I. Kirkland
Keyword(s):  
Phylogenetic Analysis ◽  
Late Cretaceous ◽  
New Taxon ◽  
The Novel ◽  
Depositional Settings ◽  
Near Shore ◽  
Phylogenetic Hypotheses ◽  
North And South America ◽  
North And South ◽  
Early Late

BackgroundBothremydidae is a clade of extinct pleurodiran turtles known from the Cretaceous to Paleogene of Africa, Europe, India, Madagascar, and North and South America. The group is most diverse during the Late Cretaceous to Paleogene of Africa. Little is known, however, about the early evolution of the group.MethodsWe here figure and describe a fossil turtle from early Late Cretaceous deposits exposed at MacFarlane Mine in Cedar Canyon, southwestern Utah, USA. The sediments associated with the new turtle are utilized to infer its stratigraphic provenience and the depositional settings in which it was deposited. The fossil is compared to previously described fossil pleurodires, integrated into a modified phylogenetic analysis of pelomedusoid turtles, and the biogeography of bothremydid turtles is reassessed. In light of the novel phylogenetic hypotheses, six previously established taxon names are converted to phylogenetically defined clade names to aid communication.ResultsThe new fossil turtle can be inferred with confidence to have originated from a brackish water facies within the late Cenomanian Culver Coal Zone of the Naturita Formation. The fossil can be distinguished from all other previously described pleurodires and is therefore designated as a new taxon,Paiutemys tibertgen. et. sp. nov. Phylogenetic analysis places the new taxon as sister to the EuropeanPolysternon provinciale,Foxemys trabantiandFoxemys mechinorumat the base of Bothremydinae. Biogeographic analysis suggests that bothremydids originated as continental turtles in Gondwana, but that bothremydines adapted to near-shore marine conditions and therefore should be seen as having a circum-Atlantic distribution.

scholarly journals A second peirosaurid crocodyliform from the Mid-Cretaceous Kem Kem Group of Morocco and the diversity of Gondwanan notosuchians outside South America

2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Cecily S. C. Nicholl ◽  
Eloise S. E. Hunt ◽  
Driss Ouarhache ◽  
Philip D. Mannion
Keyword(s):  
South America ◽  
Late Cretaceous ◽  
North Africa ◽  
Lateral Surface ◽  
Middle Jurassic ◽  
Tooth Enamel ◽  
Phylogenetic Analyses ◽  
Late Eocene ◽  
South American ◽  
Early Late

Notosuchians are an extinct clade of terrestrial crocodyliforms with a particularly rich record in the late Early to Late Cretaceous (approx. 130–66 Ma) of Gondwana. Although much of this diversity comes from South America, Africa and Indo-Madagascar have also yielded numerous notosuchian remains. Three notosuchian species are currently recognized from the early Late Cretaceous (approx. 100 Ma) Kem Kem Group of Morocco, including the peirosaurid Hamadasuchus rebouli . Here, we describe two new specimens that demonstrate the presence of at least a fourth notosuchian species in this fauna. Antaeusuchus taouzensis n. gen. n. sp. is incorporated into one of the largest notosuchian-focused character-taxon matrices yet to be compiled, comprising 443 characters scored for 63 notosuchian species, with an increased sampling of African and peirosaurid species. Parsimony analyses run under equal and extended implied weighting consistently recover Antaeusuchus as a peirosaurid notosuchian, supported by the presence of two distinct waves on the dorsal dentary surface, a surangular which laterally overlaps the dentary above the mandibular fenestra, and a relatively broad mandibular symphysis. Within Peirosauridae, Antaeusuchus is recovered as the sister taxon of Hamadasuchus . However, it differs from Hamadasuchus with respect to several features, including the ornamentation of the lateral surface of the mandible, the angle of divergence of the mandibular rami, the texture of tooth enamel and the shape of the teeth, supporting their generic distinction. We present a critical reappraisal of the non-South American Gondwanan notosuchian record, which spans the Middle Jurassic–late Eocene. This review, as well as our phylogenetic analyses, indicate the existence of at least three approximately contemporaneous peirosaurid lineages within the Kem Kem Group, alongside other notosuchians, and support the peirosaurid affinities of the ‘trematochampsid’ Miadanasuchus oblita from the Maastrichtian of Madagascar. Furthermore, the Cretaceous record demonstrates the presence of multiple lineages of approximately contemporaneous notosuchians in several African and Madagascan faunas, and supports previous suggestions regarding an undocumented pre-Aptian radiation of Notosuchia. By contrast, the post-Cretaceous record is depauperate, comprising rare occurrences of sebecosuchians in north Africa prior to their extirpation.

An ornithurine bird coracoid from the Late Cretaceous of Alberta, Canada

2020 ◽  
pp. 1-7
Author(s):  
Sydney R. Mohr ◽  
John H. Acorn ◽  
Gregory F. Funston ◽  
Philip J. Currie
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Ct Scans ◽  
Micro Ct ◽  
Internal Structures ◽  
Postcranial Remains ◽  
Dinosaur Park Formation ◽  
Upper Campanian

The Cretaceous birds of Alberta are poorly known, as skeletal elements are rare and typically consist of fragmentary postcranial remains. A partial avian coracoid from the upper Campanian Dinosaur Park Formation of Alberta, Canada, can be referred to the Ornithurae, and is referred to here as Ornithurine G (cf. Cimolopteryx). Its structure is similar to previously described ornithurine coracoids from Alberta and other localities in North America, particularly those belonging to the genus Cimolopteryx. A comparison of these elements indicates that the new coracoid is distinct; however, its preservation prevents complete diagnosis. As other Cimolopteryx are Maastrichtian in age, Ornithurine G (cf. Cimolopteryx) also represents the earliest occurrence of a Cimolopteryx-like anatomy. A pneumatized coracoid is a diagnostic trait of Neornithes, identified by the presence of a pneumatic foramen. Ornithurine G (cf. Cimolopteryx) does not preserve this feature. CT and micro-CT scans of both pneumatic and apneumatic coracoids of modern birds show similar internal structures to Ornithurine G (cf. Cimolopteryx), indicating that pneumaticity of the coracoid cannot be determined in the absence of an external pneumatic foramen. A comparison between members of Cimolopterygidae, including Cimolopteryx and Lamarqueavis, raises questions about the assignment of Lamarqueavis to the Cimolopterygidae, and the validity of this family as a whole.

scholarly journals Ruminants reveal Eocene Asiatic palaeobiogeographical provinces as the origin of diachronous mammalian Oligocene dispersals into Europe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bastien Mennecart ◽  
Manuela Aiglstorfer ◽  
Yikun Li ◽  
Chunxiao Li ◽  
ShiQi Wang
Keyword(s):  
Central Asia ◽  
New Taxa ◽  
Late Eocene ◽  
Eastern Asia ◽  
Large Mammal ◽  
Southern Province ◽  
The North ◽  
Grande Coupure ◽  
Dispersal Events ◽  
North And South

AbstractFaunal provincialism between the North and South parts of Eastern Asia is shown to have been in place since the late Eocene. This provincialism structured the mammalian dispersals across Eurasia for millions of years and provides insights into both palaeonvironments and palaeoclimate zonation. In addition, this study reveals the oldest record of a crown ruminant (Iberomeryx from Shinao, China). Ecologically, as well as economically, ruminant artiodactyls are one of the most important large mammal groups today. The revision of the ruminants from the Shinao Formation, from the Caijiachong marls and Xiaerhete, resulted in two new taxa and shows that the different provinces were populated by distinct taxa living in different environments, dominated by the monsoon in the South and drier conditions in the North. Evaluating this result in a Eurasian context demonstrates that the dispersals from Asia to Europe was complex. These results confirm that there were at least two dispersal events, distinct in space and time: the Grande-Coupure from Northern and Central Asia along the North ca. 34 Mya and the Bachitherium dispersal event from the Southern province along a southerly route ca. 31 Mya.

Two-stage development of the Late Cretaceous to Late Eocene Darende Basin: implications for closure of Neotethys in central eastern Anatolia (Turkey)

2012 ◽  
Vol 372 (1) ◽  
pp. 385-419 ◽  
Author(s):  
Matthew G. Booth ◽  
Alastair H. F. Robertson ◽  
Kemal Tasli ◽  
Nurdan İnan ◽  
Ulvi Can Ünlügenç ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Late Eocene ◽  
Eastern Anatolia ◽  
Two Stage ◽  
Stage Development ◽  
Central Eastern

scholarly journals New turtle remains from the Late Cretaceous of Monte Alto-SP, Brazil, including cranial osteology, neuroanatomy and phylogenetic position of a new taxon

PalZ ◽  
2018 ◽  
Vol 92 (3) ◽  
pp. 481-498 ◽  
Author(s):  
Gabriel S. Ferreira ◽  
Fabiano V. Iori ◽  
Guilherme Hermanson ◽  
Max C. Langer
Keyword(s):  
Late Cretaceous ◽  
Phylogenetic Position ◽  
New Taxon ◽  
Cranial Osteology

scholarly journals A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China

Zootaxa ◽  
2010 ◽  
Vol 2403 (1) ◽  
pp. 1 ◽  
Author(s):  
XING XU ◽  
JONAH N. CHOINIERE ◽  
MICHAEL PITTMAN ◽  
QINGWEI TAN ◽  
DONG XIAO ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Inner Mongolia ◽  
Upper Cretaceous ◽  
Systematic Position ◽  
Sister Taxon ◽  
New Taxon ◽  
Salient Features

We describe a new dromaeosaurid theropod from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia. The new taxon, Linheraptor exquisitus gen. et sp. nov., is based on an exceptionally well-preserved, nearly complete skeleton. This specimen represents the fifth dromaeosaurid taxon recovered from the Upper Cretaceous Djadokhta Formation and its laterally equivalent strata, which include the Wulansuhai Formation, and adds to the known diversity of Late Cretaceous dromaeosaurids. Linheraptor exquisitus closely resembles the recently reported Tsaagan mangas. Uniquely among dromaeosaurids, the two taxa share a large, anteriorly located maxillary fenestra and a contact between the jugal and the squamosal that excludes the postorbital from the infratemporal fenestra. These features suggest a sister-taxon relationship between L. exquisitus and T. mangas, which indicates the presence of a unique dromaeosaurid lineage in the Late Cretaceous of Asia. A number of cranial and dental features seen in L. exquisitus and T. mangas, and particularly some postcranial features of L. exquisitus, suggest that these two taxa are probably intermediate in systematic position between known basal and derived dromaeosaurids. The discovery of Linheraptor exquisitus is thus important for understanding the evolution of some salient features seen in the derived dromaeosaurids.

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