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[dinosaur] Dinosaur precursors and early dinosaurs from Argentina + Spanish nothosaur + more free pdfs





Ben Creisler
bcreisler@gmail.com

A number of recent (and not so recent) papers that are available in open access or through Research Gate:




in open access (from last year):

S. Figueiredo, P. Rosina & L. Figuti (2015)
Dinosaurs and other vertebrates from the Papo-Seco Formation (Lower Cretaceous) of southern Portugal.
Journal of Iberian Geology 41 (3) : 301-314
doi: http://dx.doi.org/10.5209/rev_JIGE.2015.v41.n3.47828
http://revistas.ucm.es/index.php/JIGE/article/view/47828
http://revistas.ucm.es/index.php/JIGE/article/view/47828/48053


New vertebrate remains reported from the Papo-Seco Formation (Lower Barremian, Lower Cretaceous) of Areias do Mastro, in Cabo Espichel, SW Portugal, south of Lisbon. The marine, lagoonal, and estuarine limestones, marls, sands and gravels have yielded remains of dinosaurs and other reptiles since the 19th century. Recent paleontological prospecting produced several vertebrate remains, including turtle shell fragments, crocodilian teeth, fish and pterosaurs. Research identified both bones and teeth of fish, crocodiles, dinosaurs Baryonyx and iguanodontian, as well as a ctenochasmatoid pterosaur, and a possible ornithocheirid pterosaur. These new disclosures are an important contribution to the knowledge of vertebrate diversity from the Portuguese Cretaceous. Faunal species combination proven to be similar to other faunal associations of Barremian formations in the Iberian Peninsula.

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in open access:

C. de Miguel Chaves, S. García-Gil, F. Ortega, J. L. Sanz, A. Pérez-García
First Triassic tetrapod (Sauropterygia, Nothosauridae) from Castilla y León: evidence of an unknown taxon for the Spanish record.
Journal of Iberian Geology 42 (1): 29-38
doi: http://dx.doi.org/10.5209/rev_JIGE.2016.v42.n1.51210
http://revistas.ucm.es/index.php/JIGE/article/view/51210
http://revistas.ucm.es/index.php/JIGE/article/view/51210/48543
http://pendientedemigracion.ucm.es/info/estratig/JIG/vol_content/vol%2042_1/JIG_42_1_Miguel_29_38.pdf

Several vertebrae of a sauropterygian specimen have been recovered in Fuencaliente de Medinaceli (Soria Province, Castilla y León, Spain). The remains come from late Middle Triassic levels (late Ladinian) of the upper Muschelkalk Facies. This finding represents the first documented evidence of a Triassic tetrapod in Castilla y León. The vertebrae belong to Nothosaurus, a sauropterygian genus found in Europe, Middle East, North of Africa and China. This genus is poorly-known in the Iberian record. The new remains constitute the first evidence of the species Nothosaurus giganteus, or a related taxon, in the Iberian Peninsula, being referred as Nothosaurus cf. giganteus. This study reveals the occurrence of at least two species of the sauropterygian Nothosaurus in the Iberian record.

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online through Research Gate:

Martin Ezcurra and Ricardo N Martinez (2016)
Dinosaur precursors and early dinosaurs of Argentina.
Historia Evolutiva y Paleobiogeografía de los Vertebrados de América del Sur; Contribuciones del MACN (Editors: F. Agnolíin, G.L. Lio, F. Brissón Egli, N.R. Chimento, F. Novas) 6: 97 -107
https://www.researchgate.net/publication/304038241_Dinosaur_precursors_and_early_dinosaurs_of_Argentina

Dinosaurs include two main branches, Ornithischia and Saurischia, with a minimum divergence time of approximately 231 Ma (late Carnian) based on the age of the oldest known members of the group. Argentinean non-dinosaurian dinosauromorphs are known from the Upper Triassic Chañares, Ischigualasto and Quebrada del Barro formations, including five or six nominal species and an unnamed form. The non-dinosaurian dinosauromorph assemblage of Chañares is the most diverse worldwide and has been crucial to understand the origin of the group. The Ischigualasto Formation preserves a formidable fossil record and has provided the most comprehensive source of information about the oldest known dinosaurs. Eight valid dinosaur species are known from this unit and represent the three principal dinosaurian subgroups—Ornithischia, Sauropodomorpha, and Theropoda. The anatomical knowledge or understanding of the evolution of character-states in some of these early dinosaurs (e.g. Pisanosaurus, Herrerasaurus) still prompts considerable debate about their phylogenetic position.


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Spencer G. Lucas, Robert M. Sullivan, Asher J. Lichtig, Sebastian G. Dalman and Steven E. Jasinski (2016)
Late Cretaceous dinosaur biogeography and endemism in the Western Interior basin, North America: A critical re-evaluation.
in Khosla, A. and Lucas, S.G., eds., 2016, Cretaceous Period: Biotic Diversity and Biogeography. New Mexico Museum of Natural History and Science Bulletin 71: 195-213
https://www.researchgate.net/publication/223692413_Late_Maastrichtian_paleoenvironments_and_dinosaur_biogeography_in_the_Western_Interior_of_North_America_Palaeogeogr_Palaeoclimatol_Palaeoecol

North-south provinciality among Campanian and/or Maastrichtian vertebrates, especially dinosaurs, in the Western Interior basin of North America (specifically, between West Texas and southern Alberta, Canada) has been accepted by many vertebrate paleontologists for about 30 years. However, a critical review indicates that the case for provinciality based on non-dinosaurian vertebrates is weak to nonexistent, and that the case based on dinosaurs is problematic, resting solely on a few taxa of dinosaurs, most notably the chasmosaurine ceratopsids, which have also been used to identify extreme dinosaur endemism. Paleobiogeographic provinces can be rejected because of: (1) problems and biases in sampling; (2) the lack of topographic barriers in the Western Interior basin that would divide provinces; (3) the lack of significant climatic or vegetational differences and/or gradients to provincialize vertebrates; (4) how taxonomic (largely cladotaxonomic) decisions have been intimately involved in the perception of endemism and provinciality; (5) how the demonstrable diachroneity of most fossil assemblages undermines the ability to include them in biogeographic analyses; and (6) how the non-uniformitarian conclusions of those who argue for dinosaur provinciality and endemism undermine their own arguments. Not only do we demonstrate the biological and geological implausibility of dinosaur-based biogeographic provinces and high degrees of endemism in the Western Interior basin during the Late Cretaceous, but the arguments and analyses that have been marshalled to support such concepts are questionable. Consequently, there is no compelling evidence that there was any discrete biogeographic separation of the Campanian (or Maastrichtian) dinosaur-dominated vertebrate assemblages from north to south beteen Texas and Alberta in the Western Interior basin. Also, there is no compelling evidence of high degrees of dinosaur endemism in the Western Interior basin during the Campanian.  
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