Ben CreislerSome recent preprint papers that have not been peer-reviewed but have free pdfs:==Jing-Shan Zhao, Yaser Saffar Talori & Jingmai Kathleen O'Connor (2018)Kinematics of wings from Caudipteryx to modern birds.bioRxiv (preprint) (not peer-reviewed)This study seeks to better quantify the parameters that drove the evolution of flight from non-volant winged dinosaurs to modern birds. In order to explore this issue, we used fossil data to model the feathered forelimb of Caudipteryx, the most basal non-volant maniraptoran dinosaur with elongate pennaceous feathers that could be described as forming proto-wings. In order to quantify the limiting flight factors, we created three hypothetical wing profiles for Caudipteryx representing incrementally larger wingspans, which we compared to the actual wing morphology as what revealed through fossils. These four models were analyzed under varying air speed, wing beat amplitude, and wing beat frequency to determine lift, thrust potential and metabolic requirements. We tested these models using theoretical equations in order to mathematically describe the evolutionary changes observed during the evolution of modern birds from a winged terrestrial theropod like Caudipteryx. Caudipteryx could not fly, but this research indicates that with a large enough wing span Caudipteryx-like animal could have flown, the morphology of the shoulder girdle would not actually accommodate the necessary flapping angle and metabolic demands would be much too high to be functional. The results of these analyses mathematically confirm that during the evolution of energetically efficient powered flight in derived maniraptorans, body weight had to decrease and wing area/wing profile needed to increase together with the flapping angle and surface area for the attachment of the flight muscles. This study quantifies the morphological changes that we observe in the pennaraptoran fossil record in the overall decrease in body size in paravians, the increased wing surface area in Archaeopteryx relative to Caudipteryx, and changes observed in the morphology of the thoracic girdle, namely the orientation of the glenoid and the enlargement of the sternum.=====Michel Laurin & Graciela Pineiro (2018)A Reassessment of the Taxonomic Position of Mesosaurs Based on Two Data Matrices.bioRxiv (preprint) (not peer-reviewed)The Early Permian mesosaurs are the oldest known primarily aquatic amniotes. Despite the interest that they have generated over time, their affinities remain controversial. Recently, two hypotheses have been supported, in which mesosaurs are either the sister-group of all other sauropsids, or the sister-group of other parareptiles. We recently upheld the former hypothesis, but in the latest study on mesosaur affinities, MacDougall et al. published a study highly critical of our work, while upholding the hypothesis that mesosaurs are basal parareptiles. We expect that the debate about mesosaur affinities will continue in the foreseeable future, but we wish to respond to the two central comments published by MacDougall et al. in 2018, who argue that variability in the temporal fenestration of early sauropsids, combined with the omission of several recently-described parareptile taxa, explain the differences in topologies between their study and ours. Reanalyzing our data matrix and theirs without characters linked with temporal fenestration, and removing from their matrix the parareptile taxa that they added (and that we omitted) does not alter the resulting topologies. Thus, their main conclusions are false; the differences in taxonomic position of mesosaurs must result from character choice and scoring differences.======================NOTE: These are additional papers from a forthcoming publication by a privately run museum in Austria. The papers apparently are not peer-reviewed. I recently posted another paper describing Wachtlerosaurus, identified as an avemetatarsalian, which various people have questioned.Michael Wachtler (2018)Megachirella wachtleri - The history of discovery.In: Thomas Perner; Michael Wachtler. Some new and exciting Triassic Archosauria from the Dolomites (Northern Italy).ÂDolomythos Museum, Innichen, South Tyrol, Italy; Oregon Institute of Geological Research, Portland, OR, (USA)https://www.researchgate.net/publication/326834623_ Megachirella_wachtleri_-_The_ history_of_discovery In 1999, Michael Wachtler recovered a partially preserved reptile-skeleton from the KÃh-wiesenkopf (Prà della Vacca) in the Pragser Dolomites. It was described by Silvio Renesto and Renato Posenato in 2003 as Megachirella wachtleri. Immediately, the importance of this fossil was recognized as pertaining to the crown group of squamata and also the lepidosauromorpha. But only in 2018, a group of scientists under the overall control of Tiago SimÅes were able to classify Megachirella wachtleri as the oldest known stem squamate by using the new high-resolution microfocus X-ray computed tomography data. This paper deals with the exciting found-history of Megachirella and the chronological course of research.=====Michael Wachtler (2018)The marine reptile Neusticosaurus from the Eastern Alps.In: Thomas Perner; Michael Wachtler. Some new and exciting Triassic Archosauria from the Dolomites (Northern Italy).ÂDolomythos Museum, Innichen, South Tyrol, Italy; Oregon Institute of Geological Research, Portland, OR, (USA)Whereas nothosaurians are a common element in the Middle Triassic of Monte San Giorgio (Western Alps, Switzerland-Italy) in the Eastern Alps till now only scanty remains were recovered. Recently substantial marine reptiles findings in the Carinthian Dolomites especially of the genus Neusticosaurus enlarge our knowledge considerably. It can be stated that in addition to the well-known Neusticosaurus pusillus and Neusticosaurus peyeri from Swiss-Italian Monte San Giorgio we encounter in the Eastern Alps with Neusticosaurus toeplitschi another interesting small-sized marine sauropterygia. It dominated the beach-near deep water and anaerobic abysses of this part of the ancient Tethys-Ocean, now conserved as dark and bituminous well-layered sediments.=====Michael Wachtler (2018)Early-Middle Triassic vertebrate tracksites from the Dolomites (Northern Italy).In: Thomas Perner; Michael Wachtler. Some new and exciting Triassic Archosauria from the Dolomites (Northern Italy).ÂDolomythos Museum, Innichen, South Tyrol, Italy; Oregon Institute of Geological Research, Portland, OR, (USA)The Dolomites are rich in Paleozoic-Mesozoic ichno-associations, which can be followed in the rock-sediments from the Early Permian till the Middle Triassic. Several well-preserved Anisian footprints were analysed and brought in the context to its paleoecosystem. In addition to the dominant Rhynchosauroides tirolicus imprints, the attention focuses especially on the larger-sized tracks from suggested archosaurs like Isochirotherium delicatum, Chirotherium barthiii, Brachychirotherium parvum, and especially on the only known ichno-species from the Dolo-mites-Sphingopus ladinicus. Mainly, all tracks evidence a clear tendency towards bipedalism with a functionally three-toed pes as is possible in the synapomorphies of basal dinosaurs.