32 research outputs found

    A taxonomic bibliography of the South American snakes of the Crotalus durissus complex (Serpentes, Viperidae)

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    Thoracotomy and esophageal surgery: Key points to preserve the possibilities of flaps

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    International audienceAnastomotic leakage frequently complicates esophagectomy and can trigger a rare life- threatening complication, a tracheoesophageal fistula. No guideline has yet addressed this complication. Plastic surgeons play a crucial role for salvage surgery. When a re-operation is chosen the possibilities of flap interposition depend on how the thoracotomy was initially performed. This study tried to identify key techniques in order help thoracic or general surgeons to preserve all the local flaps available for TEF if it occurs. These techniques improve flap conservation, helping plastic surgeons when a later transposition flap is required

    Concealed weapons: erectile claws in African frogs

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    Vertebrate claws are used in a variety of important behaviours and are typically composed of a keratinous sheath overlying the terminal phalanx of a digit. Keratinous claws, however, are rare in living amphibians; their microstructure and other features indicate that they probably originated independently from those in amniotes. Here we show that certain African frogs have a different type of claw, used in defence, that is unique in design among living vertebrates and lacks a keratinous covering. These frogs have sectorial terminal phalanges on their hind feet that become functional by cutting through the skin. In the resting state, the phalanx is subdermal and attached to a distal bony nodule, a neomorphic skeletal element, via collagen-rich connective tissue. When erected, the claw breaks free from the nodule and pierces the ventral skin. The nodule, suspended by a sheath attached to the terminal phalanx and supported by collagenous connections to the dermis, remains fixed in place. While superficially resembling the shape of claws in other tetrapods, these are the only vertebrate claws known to pierce their way to functionality
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