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Mitochondrial DNA diversity and evolution of the Pleistocene cave bear complex
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Cave bears are among the most well known extinct Pleistocene mammals. Their biogeography and taxonomy, along with the factors that led to their extinction, have been subject to long-standing controversy. Here, we reconstruct the phylogeography as well as the temporal and spatial population dynamics of cave bears across their range using mitochondrial DNA control region sequences from 77 published as well as 65 new cave bear samples, Our analyses reveal a dramatic loss of genetic diversity in cave bear populations after 30,000 years before present and provide evidence for a range decline from east to west towards the onset of the last glacial maximum. Our results also suggest that the three major haplogroups within cave bears, which may correspond to distinct species, were previously more widespread, with relict populations in remote and alpine areas still harbouring haplotypes that have disappeared from most of their previous range. Applying a phylogenetic dating approach, we estimated the age of the oldest of our samples, originating from the Yana River region in north-eastern Siberia, to be around 178,000 years, which confirms a previous estimate of a Middle Pleistocene age based on its stratigraphic position. Our results extend our knowledge about the evolutionary history of cave bears, but they also show that to unravel the complexities of cave bear evolution future ancient DNA studies on this Pleistocene species will need to go beyond short mitochondrial DNA fragments, including full mitochondrial genomes as well as nuclear DNA sequences.
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RBINS Staff Publications
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Shaking the wings and preening feathers with the beak help a bird to recover its ruffled feather vane
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The feather of a bird consists of barbs which again comprise numerous barbules with micro-hooklets. This hierarchically organized feather structure provides a smooth vane to bear the load from the airflow; however, the feather vane is vulnerable to disruption by external pulling forces during collision with the branches of a tree and hitting some small obstacles in flight or strong turbulence. The feather is unable to carry the weight of the bird's body if the vane could not be recovered immediately. Here we discovered that the feather vane can be re-established easily by birds themselves. A bird can always recover its feather vane from ruffled state by shaking its wings and preening its feathers with its beak because of the cascaded geometries of barbs and barbules. This biophysical mechanism of self-healing suggests that the hierarchical vane structure can be used to design artificial feathers for a flapping robot.
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RBINS Staff Publications 2019
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The oldest freshwater crabs: claws on dinosaur bones
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With approximately 1,500 extant species, freshwater crabs (Decapoda: Brachyura) are among the most diverse decapod crustaceans. nevertheless, their fossil record is extremely limited: only potamidae, potamonautidae and trichodactylidae are reported up to the eocene of the neotropics so far. this work documents unusually large decapod claws from the Upper Cretaceous (Campanian) continental deposits of Velaux and vicinity (southern France), in close association with large vertebrate remains. In addition to (1) the systematic assignment of these claws, the study addresses (2) the salinity trends in the deposit environment from its faunal assemblage and the elementary chemical patterns of fossils, and (3) the likely scenario for their auto/allochthony in the Velaux fuvial system. These claws belong to a new taxon, Dinocarcinus velauciensis n. gen. n. sp., referred to as Portunoidea sensu lato, a group of “true” crabs nowadays linked to marine systems. However, the faunal assemblage, the claw taphonomy and the carbonates Y/Ho signatures support their ancient freshwater/terrestrial ecology, making them the oldest reported continental brachyurans and extending the presence of crabs in freshwater environments by 40 Ma. Either as primary or as secondary freshwater crabs, the occurrence of these portunoids in Velaux is an evidence for the independent colonizations of continental environments by multiple brachyuran clades over time, as early as the campanian.
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RBINS Staff Publications 2019
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L’herpétofaune du site Ramsar des Monts Birougou (Gabon) : catalogue illustré des espèces.
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RBINS Staff Publications 2018
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The pan-and-tilt hyperspectral radiometer system (PANTHYR) for autonomous satellite validation measurements – prototype design and testing
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RBINS Staff Publications 2019
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Pterosaur melanosomes support signalling functions for early feathers
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RBINS Staff Publications 2022
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Radial porosity profiles: a new bone histological method for comparative developmental analysis of diametric limb bone growth
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RBINS Staff Publications 2022
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The common morphospecies Cypridopsis vidua (O.F. MÜLLER, 1776) (Crustacea, Ostracoda) is not an obligate parthenogen
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The common non-marine ostracod Cypridopsis vidua (O.F. Müller, 1776) is used as a proxy in various biological disciplines, such as (palaeo-)ecology, evolutionary biology, ecotoxicology and parasitology. This morphospecies was considered to be an obligate parthenogen. We report on the discovery of the first population of C. vidua with males from Woods Hole (MA, USA) and determine that it is a population with mixed reproduction. We describe the morphology of the males and of the sexual and asexual females. We illustrate a copula of a male and a sexual female as well insemination in a sexual female, showing that males are functional. Therefore, Cypridopsis vidua is a morphospecies with mixed reproduction, not a full apomictic parthenogen. We use, for the first time, polychromatic polarization microscope technology to illustrate soft parts of ostracods. In addition, we compare the sexual species C. bisexualis, C. okeechobei, C. howei and C. schwartzi and conclude that these species, especially the latter three, are morphologically very close to C. vidua.
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RBINS Staff Publications 2023
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Using molecular techniques to identify organisms of policy concern: Some examples from the BopCo project
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RBINS Staff Publications 2016
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Constructing a DNA barcode database of Belgian rove beetles (Staphylinidae) and its application in forensic cases
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RBINS Staff Publications 2016
