15 research outputs found

    Exposure to UV radiance predicts repeated evolution of concealed black skin in birds

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    Plumage is among the most well-studied components of integumentary colouration. However, plumage conceals most skin in birds, and as a result the presence, evolution and function of skin colour remains unexplored. Here we show, using a database of 2259 species encompassing >99% of bird genera, that melanin-rich, black skin is found in a small but sizeable percentage (5%) of birds, and that it evolved over 100 times. The spatial distribution of black skin follows Gloger's rule, which states that pigmentation of endothermic animals increases towards the equator. Furthermore, most black-skinned birds inhabit high irradiation regions, and tend to be bald and/or have white feathers. Thus, taken together, our results suggest that melanin-rich, black skin helps to protect birds against ultraviolet irradiation. More generally, our results illustrate that feathered skin colour varies taxonomically, ontogenetically and temporally, providing an additional dimension for avian colour research

    The evolution and function of integumentary melanin

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    Trait-based range expansion aided in the global radiation of Crocodylidae

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    Aim: Almost half of the extant species of Crocodylia (nine genera, sensu Benton & Clark) belong to the genus Crocodylus, which originated in the Miocene. Today, this genus has a circumtropical distribution, with representatives found in Asia, Oceania, Africa and the Neotropics. However, its geographical origin and the historical events behind its rapid diversification and global radiation are still debated. Here, we inferred the evolution of a set of life traits that aid in dispersal and how they influenced the biogeography of Crocodylus.N.J.M. was supported by the Australian Research Council's Discovery Early Career Researcher Award #DE150101773, by The Australian National University and by the University of Auckland and Marsden Grant #16‐UOA‐277

    Anomaloglossus meansi sp. n., a new Pantepui species of the Anomaloglossus beebei group (Anura, Aromobatidae)

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    Recent extinctions and drastic population declines have been documented in the Guiana Shield endemic frog genus Anomaloglossus, hence the importance to resolve its alpha-taxonomy. Based on molecular phylogenies, the literature has long reported the occurrence of an undescribed species in the Pakaraima Mountains of Guyana in the Pantepui region. We here describe this new taxon and demonstrate that in addition to divergence at the molecular level the new species differs from congeners by a unique combination of morphological characters, notably a small size (maximum SVL in males 18.86 mm, maximum SVL in females 21.26 mm), Finger I = Finger II when fingers adpressed, Finger III swollen in breeding males, fringes on fingers absent, toes basally webbed but lacking fringes, in life presence of a thin dorsolateral stripe from tip of snout to tip of urostyle, and a black throat in preserved males (immaculate cream in females). Virtually nothing is known about the ecology of the new species. We suggest the new species to be considered as Data Deficient according to IUCN standards

    First observation of a brood patch on a male sunbird (Chalcomitra amethystina)

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    Nest care and brooding in sunbirds (Nectariniidae) is thought to be performed exclusively by females. Here, we provide the first evidence that male sunbirds might help with brooding. During a ringing session in Hoekwil, South Africa, we observed one male Amethyst Sunbird (Chalcomitra amethystina) with a brood patch. Its sex was confirmed using molecular methods, and our observation suggests that nest care in sunbirds may at least in some cases be biparental
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