The wing of Archaeopteryx as a primary thrust generator

Article Abstract:

The idea that birds evolved from bipedal and predominantly terrestrial maniraptoriform dinosaurs is broadly accepted. However the cursorial model of flight origins has not been as successful as the arboreal model, due to the gap between the estimated running speed of Archaeopteryx and its estimated minimum flying speed, and the problems of flight stroke. The take off run of Archaeopteryx through lift-off is analyzed and the importance of combining functional and aerodynamic considerations with phylogeny is emphasized. A solution to the velocity gap problem is provided.

Archaeopteryx

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Argentinian unhatched pterosaur fossil

Article Abstract:

The study describes an embryonic fossil of a different pterosaur from the Early Cretaceous lacustrine deposits of Loma del Pterodaustro in central Argentina. It concluded that pterosaurs shared with extant archasaurs and chelonians an eggshell composed of a single layer of juxtaposed carbonatic crystals, but they differed from chelonians in that they laid calcitic eggs with blade-shaped crystals.

Science & research, Argentina, Reptiles, Fossil, Fossil reptiles

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Foot posture in a primitive pterosaur

Article Abstract:

Pelvis and femur material from Pterodactyloidea has been studied and the movements possible at the hip have been resolved, although examination of all of the movements possible in the foot was prevented by the lack of three-dimension, articulated pterosaur feet. Examination of a partial skeleton showed that a digitigrade posture was not possible without separating most of the joints.

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