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Free pdf:
https://www.nature.com/articles/s41598-020-59528-9.pdfBiofluorescence is the absorption of electromagnetic radiation (light) at one wavelength followed by its reemission at a lower energy and longer wavelength by a living organism. Previous studies have documented the widespread presence of biofluorescence in some animals, including cnidarians, arthropods, and cartilaginous and ray-finned fishes. Many studies on biofluorescence have focused on marine animals (cnidarians, cartilaginous and ray-finned fishes) but we know comparatively little about the presence of biofluorescence in tetrapods. We show for the first time that biofluorescence is widespread across Amphibia, with a focus on salamanders (Caudata), which are a diverse group with a primarily Holarctic distribution. We find that biofluorescence is not restricted to any particular family of salamanders, there is striking variation in their fluorescent patterning, and the primary wavelengths emitted in response to blue excitation light are within the spectrum of green light. Widespread biofluorescence across the amphibian radiation is a previously undocumented phenomenon that could have significant ramifications for the ecology and evolution of these diverse and declining vertebrates. Our results provide a roadmap for future studies on the characterization of molecular mechanisms of biofluorescence in amphibians, as well as directions for investigations into the potential impact of biofluorescence on the visual ecology and behavior of biofluorescent amphibians.
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Most amphibians can glow in the dark, scientists report
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Augà Marc Louis & Brizuela Santiago (2020)
Transient presence of a teiid lizard in the European Eocene suggests transatlantic dispersal and rapid extinction.
Palaeobiodiversity and Palaeoenvironments (advance online publication)
doi:
https://doi.org/10.1007/s12549-019-00414-2https://link.springer.com/article/10.1007/s12549-019-00414-2Several teiid specimens (frontal, vertebra, maxillae) are described from the late Eocene of Europe (MP17, Phosphorites du Quercy). The results of phylogenetic analyses confirm that these European Eocene fossils belong to teiid lizards and more specifically to the subfamily Tupinambinae. So far, the Paleogene record of teiids is limited to South America and no occurrence of crown teiids is known in Europe. This disjunct distribution of teiids during the Eocene suggests transatlantic dispersal and this possibility is discussed. The presence of teiids in the European fossil record is brief (limited to standard level MP17). The circumstances that prevented the persistence of an invading clade in Europe are examined. Ecological (e.g. biotic interactions) and/or demographic (Allee effect) processes may have been involved.
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H. Jonas Barthel, Denis Fougerouse, Thorsten Geisler & Jes Rust (2020)
Fluoridation of a lizard bone embedded in Dominican amber suggests open-system behavior.
PLoS ONE 15(2): e0228843
doi:
https://doi.org/10.1371/journal.pone.0228843https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0228843Free pdf:
https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0228843&type=printableVertebrate fossils embedded in amber represent a particularly valuable paleobiological record as amber is supposed to be a barrier to the environment, precluding significant alteration of the animalsâ body over geological time. The mode and processes of amber preservation are still under debate, and it is questionable to what extent original material may be preserved. Due to their high value, vertebrates in amber have never been examined with analytical methods, which means that the composition of bone tissue in amber is unknown. Here, we report our results of a study on a left forelimb from a fossil Anolis sp. indet. (Squamata) that was fully embedded in Miocene Dominican amber. Our results show a transformation of the bioapatite to fluorapatite associated with a severe alteration of the collagen phase and the formation of an unidentified carbonate. These findings argue for a poor survival potential of macromolecules in Dominican amber fossils.
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The gomphotheres were a diverse and widespread group of proboscideans occupying Eurasia, North America, and South America throughout the Neogene. Their decline was temporally and spatially heterogeneous, and the gomphotheres ultimately became extinct during the late Pleistocene; however, the genus Cuvieronius is rarely represented in late Pleistocene assemblages in North America. Two alternative hypotheses have been invoked to explain this phenomenon: (1) competitive exclusion by sympatric mammoths and mastodons or (2) ecologic displacement due to an environmental transition from closed forests to open grasslands. To test whether competition for resources contributed to the demise of North American Cuvieronius, we present herein a large collection of stable isotope and dental microwear data from populations occupying their Pleistocene refugium in the Atlantic Coastal Plain. Results suggest that Cuvieronius consumed a wide range of resources with variable textural and photosynthetic properties and was not specialized on either grasses or browse. Further, we document evidence for the consumption of similar foods between contemporaneous gomphotheres, mammoths, and mastodons. The generalist feeding strategy of the gomphotheres likely facilitated their high Miocene abundance and diversity. However, this âjack of all trades and master of noneâ feeding strategy may have proved challenging following the arrival of mammoths and likely contributed to the extirpation of Cuvieronius in North America.