Some recent non-dino papers:
Free pdf:
Valentina Rossi, Maria E. McNamara, Sam M. Webb, Shosuke Ito, and Kazumasa Wakamatsu (2019)
Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates.
Proceedings of the National Academy of Sciences (advance online publication)
doi: https://doi.org/10.1073/pnas.1820285116
https://www.pnas.org/content/early/2019/08/13/1820285116
Free pdf:
https://www.pnas.org/content/pnas/early/2019/08/13/1820285116.full.pdf
Significance
Valentina Rossi, Maria E. McNamara, Sam M. Webb, Shosuke Ito, and Kazumasa Wakamatsu (2019)
Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates.
Proceedings of the National Academy of Sciences (advance online publication)
doi: https://doi.org/10.1073/pnas.1820285116
https://www.pnas.org/content/early/2019/08/13/1820285116
Free pdf:
https://www.pnas.org/content/pnas/early/2019/08/13/1820285116.full.pdf
Significance
Recent reports of nonintegumentary melanosomes in fossils hint at functions for melanin beyond color production, but the biology and evolution of internal melanins are poorly understood. Our results show that internal melanosomes are widespread in diverse fossil and modern vertebrates and have tissue-specific geometries and metal chemistries. Tissue-specific chemical signatures can persist in fossils despite some diagenetic overprint, allowing the reconstruction of internal soft-tissue anatomy in fossil vertebrates, and suggest that links between melanin and metal regulation have deep evolutionary origins in vertebrates.
Abstract
Recent discoveries of nonintegumentary melanosomes in extant and fossil amphibians offer potential insights into the physiological functions of melanin not directly related to color production, but the phylogenetic distribution and evolutionary history of these internal melanosomes has not been characterized systematically. Here, we present a holistic method to discriminate among melanized tissues by analyzing the anatomical distribution, morphology, and chemistry of melanosomes in various tissues in a phylogenetically broad sample of extant and fossil vertebrates. Our results show that internal melanosomes in all extant vertebrates analyzed have tissue-specific geometries and elemental signatures. Similar distinct populations of preserved melanosomes in phylogenetically diverse vertebrate fossils often map onto specific anatomical features. This approach also reveals the presence of various melanosome-rich internal tissues in fossils, providing a mechanism for the interpretation of the internal anatomy of ancient vertebrates. Collectively, these data indicate that vertebrate melanins share fundamental physiological roles in homeostasis via the scavenging and sequestering of metals and suggest that intimate links between melanin and metal metabolism in vertebrates have deep evolutionary origins.
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JÃrÃme Fuchs, ÂPer AlstrÃm, ÂReuven Yosef Â& Urban Olsson (2019)
Miocene diversification of an openâhabitat predatorial passerine radiation, the shrikes (Aves: Passeriformes: Laniidae).
Zoologica Scripta (advance online publication)
doi: https://doi.org/10.1111/zsc.12363
https://onlinelibrary.wiley.com/doi/10.1111/zsc.12363
Miocene diversification of an openâhabitat predatorial passerine radiation, the shrikes (Aves: Passeriformes: Laniidae).
Zoologica Scripta (advance online publication)
doi: https://doi.org/10.1111/zsc.12363
https://onlinelibrary.wiley.com/doi/10.1111/zsc.12363
Diversification of avifaunas associated with savannah and steppes appears to correlate with open habitats becoming available, starting in the Miocene. Few comparative analyses exist for families for which all species are predominantly adapted to these habitats. One such group is Laniidae (Passeriformes), which are smallâ to mediumâsized predatory passerines known for their distinctive behaviour of impaling prey. We used multispecies coalescentâbased and concatenation methods to provide the first complete speciesâlevel phylogeny for this group, as well as an estimate of the timing of diversification. Our analyses indicate that Laniidae as currently delimited is not monophyletic, as the genus Eurocephalus is not closely related to the remaining species. The two species currently assigned to the monotypic genera Urolestes and Corvinella are part of the same clade as the Lanius species, and we propose that they are included in the genus Lanius, making Laniidae monogeneric. The initial diversification of the clade is inferred to have occurred very rapidly, starting about 7.2-9.1 million years ago, timing depending on calibration method, but in either case coinciding with the expansion of C4 grasses. An African origin is inferred in the biogeographic analysis. In the redefined Laniidae, cooperative breeding is inferred to be restricted to a single clade, characterized by gregarious behaviour and rallying. Migratory behaviour evolved multiple times within the family.
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Sol RodrÃguezâMartÃnez Â& Ismael GalvÃn (2019)
Juvenile pheomelaninâbased plumage colouration has evolved more frequently in carnivorous species.
Ibis (advance online publication)
doi: Âhttps://doi.org/10.1111/ibi.12770
https://onlinelibrary.wiley.com/doi/10.1111/ibi.12770
Juvenile pheomelaninâbased plumage colouration has evolved more frequently in carnivorous species.
Ibis (advance online publication)
doi: Âhttps://doi.org/10.1111/ibi.12770
https://onlinelibrary.wiley.com/doi/10.1111/ibi.12770
Distinctive pheomelaninâbased plumage colouration in juvenile birds has been proposed as a signal of immaturity to avoid aggression by older conspecifics, but recent findings suggest a detoxifying strategy. Pheomelanin synthesis implies the consumption of cysteine, a semiâessential amino acid that is necessary for the synthesis of the antioxidant glutathione (GSH) but that may be toxic if in excess in the diet. As the nestling stage probably represents a lowâstress period with limited requirement for GSH protection, the synthesis of pheomelanin in developing birds may help maintain cysteine homeostasis, particularly in species with a high content of protein in the diet (i.e. carnivores). Here we confirm this hypothesis showing that, among 53 species of Western Palearctic birds, juvenile pheomelaninâbased colouration has evolved more frequently in strictly carnivorous species than in species with other diets.
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Gennady Cherepanov (2019)
Morphogenetic and constructional differences of the carapace of aquatic and terrestrial turtles and their evolutionary significance.
Journal of Morphology (advance online publication)
doi: https://doi.org/10.1002/jmor.21050
https://onlinelibrary.wiley.com/doi/10.1002/jmor.21050
Morphogenetic and constructional differences of the carapace of aquatic and terrestrial turtles and their evolutionary significance.
Journal of Morphology (advance online publication)
doi: https://doi.org/10.1002/jmor.21050
https://onlinelibrary.wiley.com/doi/10.1002/jmor.21050
The postembryonic development of the turtle carapace was studied in the aquatic Ðmys orbicularis and the terrestrial Ðestudo graeca. Differences in the structure of the bony shell in aquatic and terrestrial turtles were shown to be associated with varying degrees of development of epidermal derivatives, namely, the thickness of the scutes and the depth of horny furrows. Sinking of the horny furrows into the dermis causes local changes in the structure of the collagen matrix, which might precondition the acceleration of the ossification. Aquatic turtles possess a relatively thin horny cover, whose derivatives are either weakly developed or altogether absent and thus make no noticeable impact on the growth dynamics of bony plates. Carapace plates of these turtles outgrow more or less evenly around the periphery, which results in uniform costals, relatively narrow and partly reduced neurals, and broad peripherals extending beyond the marginal scutes. In terrestrial turtles (Testudinidae), horny structures are much more developed and exert a considerable impact on the growth of bony elements. As a result, bony plates outgrow unevenly in the dermis, expanding fast in the zones under the horny furrows and slowly outside these zones. This determines the basic features of the testudinid carapace: alternately cuneate shape of costals, an alternation of broad octagonal and narrow tetragonal neurals, and the limitation of the growth of peripherals by pleuroâmarginal furrows. The evolutionary significance of morphogenetic and constructional differences in the turtle carapace, and the association of these differences with the turtle habitats are discussed.
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Also may be of interest (they're free...)
Free pdf:
Dmitry D. Sokoloff, ÂMargarita V. Remizowa, ÂElena S. El, ÂPaula J. Rudall Â& Richard M. Bateman (2019)
Supposed Jurassic angiosperms lack pentamery, an important angiospermâspecific feature.
New Phytologist (advance online publication)
doi: https://doi.org/10.1111/nph.15974
https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.15974
Free pdf:
https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/nph.15974
The question of whether any angiosperms existed before the Cretaceous period is of key importance for understanding seedâplant evolution. Most authorities suggest that the earliest unequivocal microfossil and macrofossil records of flowering plants date from the Early Cretaceous (reviewed by Herendeen et al., 2017; Coiro et al., 2019). However, recent indirect evidence from molecular dating analyses suggests that angiosperms began to diversify into living clades (the crown group) before this time, during the Jurassic, Triassic or even Permian (Foster et al., 2017; Salomo et al., 2017; BarbaâMontoya et al., 2018). The latest detailed molecular study dated the origin of the crown angiosperms to the Late Triassic (Li et al., 2019). It is therefore unsurprising that the range of claims for preâCretaceous, especially Jurassic, angiosperm fossils has accelerated in recent years. Several Jurassic fossils from China have been described and attributed to angiosperms, including Euanthus, Juraherba, Nanjinganthus, Solaranthus, Yuhania and Xingxueanthus (Wang et al., 2007; Wang, 2010, 2018; Wang & Wang, 2010; Zheng & Wang, 2010; Han et al., 2016; Liu & Wang, 2016, 2017; Fu et al., 2018). The taxonomic attribution of these potentially pivotal fossils has been widely discussed and often directly criticized (Herendeen et al., 2017; Coiro et al., 2019).
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Free pdf:
Pupa U. P. A. Gilbert, Susannah M. Porter, Chang-Yu Sun, Shuhai Xiao, Brandt M. Gibson, Noa Shenkar, and Andrew H. Knoll (2019)
Biomineralization by particle attachment in early animals.
Proceedings of the National Academy of Sciences (advance online publication)
doi: https://doi.org/10.1073/pnas.1902273116
https://www.pnas.org/content/early/2019/08/13/1902273116
Proceedings of the National Academy of Sciences (advance online publication)
doi: https://doi.org/10.1073/pnas.1902273116
https://www.pnas.org/content/early/2019/08/13/1902273116
The mechanisms by which organisms form mineralized skeletons have been a major research focus for the last 50 y and remain so today. Among the most surprising discoveries is the recent observation that different animals use the same mechanisms, and precisely the same amorphous precursors, to form biomineralized structures as diverse as coral skeletons, molluscan shells, and sea urchin spines. In living animals, skeletal biomineralization from amorphous precursors correlates with a distinctive nanoparticulate texture that can be preserved in fossils, enabling us to probe mechanisms of skeletal formation in early animals. We document nanoparticulate texture in some of the oldest known carbonate skeletons, which strongly suggests that skeletons formed from amorphous precursors throughout the recorded history of animals.
Abstract
Crystallization by particle attachment (CPA) of amorphous precursors has been demonstrated in modern biomineralized skeletons across a broad phylogenetic range of animals. Precisely the same precursors, hydrated (ACC-H2O) and anhydrous calcium carbonate (ACC), have been observed spectromicroscopically in echinoderms, mollusks, and cnidarians, phyla drawn from the 3 major clades of eumetazoans. Scanning electron microscopy (SEM) here also shows evidence of CPA in tunicate chordates. This is surprising, as species in these clades have no common ancestor that formed a mineralized skeleton and appear to have evolved carbonate biomineralization independently millions of years after their late Neoproterozoic divergence. Here we correlate the occurrence of CPA from ACC precursor particles with nanoparticulate fabric and then use the latter to investigate the antiquity of the former. SEM images of early biominerals from Ediacaran and Cambrian shelly fossils show that these early calcifiers used attachment of ACC particles to form their biominerals. The convergent evolution of biomineral CPA may have been dictated by the same thermodynamics and kinetics as we observe today.