Some recent non-dino papers:
Free pdf:
Geoffrey Ruaux, Sophie Lumineau and Emmanuel de Margerie (2020)
The development of flight behaviours in birds.
Proceedings of the Royal Society B: Biological Sciences 287(1929): 20200668.
doi:
https://doi.org/10.1098/rspb.2020.0668https://royalsocietypublishing.org/doi/10.1098/rspb.2020.0668Free pdf:
https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2020.0668Flight is a unique adaptation at the core of many behaviours in most bird species, whether it be foraging, migration or breeding. Birds have developed a wide diversity of flight modes (e.g. flapping, gliding, soaring, hovering) which involves very specialized behaviours. A key issue when studying flight behaviours is to understand how they develop through all the ontogenetic stages of birds, from the embryo to the flying adult. This question typically involves classical debates on animal behaviour about the importance of maturation and experience. Here, we review the literature available on the development of flight behaviours in birds. First, we focus on the early period when young birds are not yet capable of flight. We discuss examples and show how endogenous processes (e.g. wing flapping in the nest, flight development timing) and environmental factors (e.g. maternal stress, nutritional stress) can influence the development of flight behaviours. Then, we review several examples showing the different processes involved in the development of flight in flight-capable juveniles (e.g. practice, trial and error learning, social learning). Despite the lack of experimental studies investigating this specific question at different developmental stages, we show that several patterns can be identified, and we anticipate that the development of new tracking techniques will allow us to study this question more thoroughly in more bird species.
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Free pdf:
Christian PÃntener, JÃrÃmy Anquetin and Jean-Paul Billon-Bruyat (2020)
New material of "Eurysternidae" (Thalassochelydia, Pan-Cryptodira) from the Kimmeridgian of the Swiss Jura Mountains.
Palaeovertebrata 43 (1)-e2.
doi: 10.18563/pv.43.1.e2
https://www.palaeovertebrata.com/Articles/view/379Â
The region of Porrentruy (Swiss Jura Mountains) is known for its rich and diverse assemblage of Late Jurassic coastal marine turtles (Thalassochelydia). Dominated by the "Plesiochelyidae", this assemblage also includes representatives of the two other thalassochelydian groups, the "Thalassemydidae" and "Eurysternidae." In this study, we present new shell-based material from Porrentruy referable to eurysternids. One specimen represents a juvenile individual or a relatively small taxon, and is notably characterized by a well fenestrated plastron exhibiting a wider than long central plastral fontanelle. Two other specimens are much larger and possibly represent the largest eurysternids known to date. The fourth specimen is characterized by a unique plastral morphology otherwise only known in very small juveniles. This is the first time this unique plastral morphology is known to persist in an adult or subadult. The new material described herein represents at least three distinct taxa, all of them probably new. However, we refrain from naming new species based on this incomplete material in order to avoid adding confusion to an already complex taxonomical situation. This study provides new insights into the great diversity of eurysternids during the Late Jurassic.Â
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Free pdf:
Chunpeng He, Tingyu Han, Xin Liao, Rui Guan, Zuhong Lu, J.-Y. Chen, Kimberly D. Tremblay & Zuhong Lu (2020)
On the origin of vertebrate body plan: Insights from the endoderm using the hourglass model.
Gene _expression_ Patterns Article 119125
doi:
https://doi.org/10.1016/j.gep.2020.119125https://www.sciencedirect.com/science/article/pii/S1567133X19302054The vertebrate body plan is thought to be derived during the early Cambrian from a worm-like chordate ancestor. While all three germ layers were clearly involved in this innovation, the role of the endoderm remains elusive. According to the hourglass model, the optimal window for investigating the evolution of vertebrate endoderm-derived structures during cephalochordate development is from the Spemann's organizer stage to the opening of the mouth (Stages 1â7, described herein). Regulatory gene _expression_, examined during these stages, illustrate that the cephalochordate endoderm is patterned into 12 organ primordia. Early vertebrates inherited at least a portion of 6 of these primordia, while the remainder were lost. Of those that were preserved, we demonstrate that the vertebrate symmetric mouth was built on a vestige of the anterior pre-oral pit, that the pre-existing pharyngeal pouch in this chordate ancestor laid the foundation for the new neural crest cell (NCC)-derived vertebrate-type pharyngeal arches, that the thyroid evolved from the posterior endostyle primordim, that the pancreas was derived from the Pdx1-expressing diverticulum primordium, and the small and large intestines originated with the Cdx1-expressing hindgut rudiments. This investigation uncovers the evolutionary foundations of vertebrate endoderm-derived structures, and demonstrates that the number of organ primordia were reduced during evolution.
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Robert A. Gastaldo, Kaci Kus, Neil Tabor & Johann Neveling (2020)
Calcic Vertisols in the upper Daptocephalus Assemblage Zone, Balfour Formation, Karoo Basin, South Africa: Implications for Late Permian Climate
Journal of Sedimentary Research 90 (6): 609-628
doi:
https://doi.org/10.2110/jsr.2020.32https://pubs.geoscienceworld.org/sepm/jsedres/article-abstract/90/6/609/587564/Calcic-Vertisols-in-the-upper-DaptocephalusÂ
The fully continental succession of the Beaufort Group, Karoo Basin, South Africa, has been used in the development of environmental models proposed for the interval that spans the contact between the Daptocephalus to Lystrosaurus Assemblage Zones, associated by some workers with the end-Permian extinction event. An aridification trend is widely accepted, yet geochemical data indicate that the majority of in situ paleosols encountered in this interval developed in waterlogged environments. To date, the presence of calcic paleosols in the latest Permian can be inferred only from the presence of calcite-cemented pedogenic nodules concentrated in fluvial channel-lag deposits. Here, we report on the first empirical evidence of in situ calcic Vertisols found in the upper Daptocephalus Assemblage Zone near Old Wapadsberg Pass, one of eight classic localities in which the vertebrate turnover is reported in the Karoo Basin. Seven discrete intervals of calcic Vertisols, exposed over a very limited lateral extent, occur in an ~25 m stratigraphic interval. Estimates of mean annual temperature and mean annual precipitation are calculated from geochemical measurements of one paleosol, and these estimates indicate that the prevailing climate at the time of pedogenesis was seasonally cold and humid. Correlation with adjacent stratigraphic sections indicates that the late Permian landscape experienced poorly drained and better-drained phases, interpreted to reflect a climate that varied between episodically dry and episodically wet. In contrast to a paleoenvironmental reconstruction of unidirectional aridification from strata in the Wapadsberg Pass region, this study provides new evidence for a wetting trend towards the Daptocephalus-Lystrosaurus Assemblage-Zone boundary.