Some recent or not yet mentioned non-dino papers:
Free pdf:
Pan-Chelidae (Testudines, Pleurodira) is a group of side-necked turtles with a currently disjointed distribution in South America and Australasia and characterized by two morphotypes: the long-necked and the short-necked chelids. Both geographic groups include both morphotypes, but different phylogenetic signals are obtained from morphological and molecular data, suggesting the monophyly of the long-necked chelids or the independent evolution of this trait in both groups. In this paper, we addressed this conflict by compiling and editing available molecular and morphological data for Pan-Chelidae, and performing phylogenetic and dating analyses over the individual and the combined datasets. Our total-evidence phylogenetic analysis recovered the clade Chelidae as monophyletic and as sister group of a clade of South American extinct chelids; furthermore Chelidae retained inside the classical molecular structure with the addition of extinct taxa in both the Australasian and the South American clades. Our dating results suggest a Middle Jurassic origin for the total clade Pan-Chelidae, an Early Cretaceous origin for Chelidae, a Late Cretaceous basal diversification of both geographic clades with the emergence of long-necked lineages, and an Eocene diversification at genera level, with the emergence of some species before the final breakup of Southern Gondwana and the remaining species after this event.
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Free pdf:
Raman spectroscopy has been widely used in micropaleontology and organic geochemistry to identify carbonaceous materials and evaluate their thermal maturity in fossils or metasedimentary rocks. Meanwhile, fossil egg researches have mostly focused on biomineralized calcite, but preserved carbonaceous (or possibly organic) materials inside the eggshells have been usually neglected until recently. Here we report an enigmatic egg from the Wido Volcanics (Upper Cretaceous) of South Korea that was analyzed using diverse methods including polarized light microscope, scanning electron microscope, electron probe microanalyzer, electron backscatter diffraction, and Raman spectroscopy. The eggshell not only shows the crystallography of archosaurian eggshells but also contains peculiar dark bands, which were previously known as the trait of fossil and modern Crocodyliformes eggshells. Raman spectroscopic analysis showed that the dark bands are mainly due to amorphous carbon, as evidenced by the clear graphite (G) and disordered (D) bands. The deconvolution of amorphous carbon peaks and resultant parameters made it possible to infer the paleotemperature inscribed in the eggshell. The result suggests that preserved amorphous carbon in the fossil eggshells can be identified using Raman spectroscopy and Raman parameters may make it possible to compare the thermal maturity of spatiotemporally diverse fossil eggshells. The biogenicity of the dark band is not clear because Raman spectroscopic analysis is not sufficient to confirm biogenicity. However, overall distribution of the dark band may imply the biogenic origin. It is apparent that the material of this study is not a dinosaur egg but might belong to a crocodyliform or choristoderan egg, and even other non-dinosaur archosaur can be a candidate as well.
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Rebecca J. Lakin, Paul M. Barrett, Colin Stevenson, Robert J. Thomas & Matthew A. Wills (2020)
First evidence for a latitudinal body mass effect in extant Crocodylia and the relationships of their reproductive characters.
Biological Journal of the Linnean Society, blz208
doi:
https://doi.org/10.1093/biolinnean/blz208https://academic.oup.com/biolinnean/advance-article-abstract/doi/10.1093/biolinnean/blz208/5713003 Relationships between distribution patterns and body size have been documented in many endothermic taxa. However, the evidence for these trends in ectotherms generally is equivocal, and there have been no studies of effects in crocodylians specifically. Here, we examine the relationship between latitudinal distribution and body mass in 20 extant species of crocodylians, as well as the relationships between seven important reproductive variables. Using phylogenetically independent contrasts to inform generalized linear models, we provide the first evidence of a latitudinal effect on adult female body mass in crocodylians. In addition, we explore the relationships between reproductive variables including egg mass, hatchling mass and clutch size. We report no correlation between egg mass and clutch size, upholding previously reported within-species trends. We also find no evidence of a correlation between measures of latitudinal range and incubation temperature, contrasting with the trends found in turtles.
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