The first paper for CoeruleodracoÂÂis now free at this pdf link:
On Fri, Jan 11, 2019 at 4:43 PM Ben Creisler <bcreisler@gmail.com> wrote:
Ben CreislerA new paper:Coeruleodraco jurassicus gen. et sp. nov.,ÂÂÂRyoko Matsumoto, Liping Dong, Yuan Wang & Susan E. Evans (2019)The first record of a nearly complete choristodere (Reptilia: Diapsida) from the Upper Jurassic of Hebei Province, Peopleâs Republic of China.Journal of Systematic Palaeontology (advance online publication)ÂChoristodera are freshwater aquatic reptiles known from the Middle Jurassic to the Miocene. Their fossil record shows a peak in diversity in the Early Cretaceous of eastern Asia, most notably in the Jehol Biota of China but also in Japan and Mongolia. However, until now, the only Jurassic records from Asia have been rare disarticulated elements from Middle Jurassic microvertebrate sites in Transbaikalian Siberia, with a possible jaw fragment from the Late Jurassic of Xinjiang, China. Here we describe Coeruleodraco jurassicus gen. et sp. nov., a new, fully articulated choristodere skeleton from the Tiaojishan Formation of China, which is considered to be of Late Jurassic (Oxfordian) age. As such, the new specimen represents the first complete Jurassic choristodere recovered worldwide, and also provides important information on the pre-Cretaceous history of the group in eastern Asia. In its proportions and postcranial characters the new taxon resembles previously described Asian taxa such as Philydrosaurus, but it is distinct in possessing several apparently plesiomorphic characters, including a short antorbital region, paired external nares and an open lower temporal fenestra. Phylogenetic analysis places the new choristodere as the sister taxon of a non-neochoristoderan clade comprising Asian and European taxa, whereas the European Jurassic Cteniogenys becomes the sister taxon to all other Choristodera.Â=====Qing He, Qin Jiang, Lida Xing, Shukang Zhang, Wenjing Pang, Hui Hu, Shuo Lu & Qifeng Yin (2019)Geochemical characteristics of newly discovered Elongatoolithidae eggs from the Upper Cretaceous of Jiangxi Province, southern China: Palaeoenvironmental and palaeoclimatic inferences.Cretaceous Research (advance online publication)
HighlightsThe newly discovered dinosaur eggs from Yudu area, Jiangxi Province can be referred to Macroolithus rugustus.Four trace elements (Sr, Ir, As and Pb) of Macroolithus rugustus reach a high level which suggest these trace elements in the study area near the K/Pg boundary might be abnormal.The carbon and oxygen isotopic compositions of Macroolithus rugustus show the microenvironment with C3 plants with relatively high CO2 concentration, low MAP, and relatively low humidity.The relatively higher elemental and isotopic compositions of Macroolithus rugustus samples in the Yudu area suggest a drier climate during the Late Cretaceous compared with other known dinosaur-egg-bearing sites.AbstractWe analyzed identified oospecies and associated geochemical characteristics of newly discovered dinosaur eggs from the Cretaceous Hekou Formation in Yudu District, Jiangxi Province, China. Results reveal that the Yudu eggs can be identified as representatives of the known oospecies Macroolithus rugustus within Elongatoolithidae based on external shape, size, ornamentation, and internal microstructure between the columnar and cone layers. The major element found in Macroolithus rugustus shells is Ca, while trace elements mainly include Sr, Ba, As, Cr, Mn, Pb, Cd, La, and Ir, characterised by Ir and Sr abnormalities, as well as the toxic elements As and Pb. Enrichment of trace elements in shells might be due to the diet of dinosaurs and subsequent deposition in eggs, consistent with global Ir anomalies and the regional enrichment of trace elements. Î13C values for Macroolithus rugustus ranging between -8.81â and -7.65â are indicative of C3 plants with relatively high CO2 concentration and low mean annual precipitation (MAP), while Î18O values ranging between -8.51â and 3.14â indicate relatively low humidity and the alteration of water sources of female dinosaur. The Sr and Ca contents as well as Î18O values of eggshells could be associated with the drinking water and food materials together with dissolved bone apatite. In light of the red-brown colour of surrounding rocks, high Fe composition revealed by macroelement analysis, and the presence of a C3 vegetation with low MAP, the palaeoenvironment of Yudu dinosaur nesting area was most likely to have been fluvial and the palaeoclimate was semi-arid to arid, which is conducive to the preservation of eggs.