Wing phalanges of a ?thalassodromine pterosaur from the Aptian–Albian Antlers Formation of Texas, USA

Abstract

Fragmentary pterosaurian wing phalanges from the Aptian-Albian Antlers Formation of north-central Texas, USA are described. Wing phalanges 1 and 2 have suboval shafts with thickened bone at the leading and trailing edges, whereas the third wing phalanx has a flattened airfoil-like cross-section with greatly thickened bone at the leading and trailing edges and a small subrectangular medullary cavity. The cortical bone exhibits an unusual coarse surface texture, and bone thin sections reveal extensive Haversian remodeling and endosteal lamellar bone. The morphology of the wing phalanges differs from that of dsungaripterids, pteranodontoids, and azhdarchids, so the specimen is not a North American record of the Dsungaripteridae as some have stated; whereas based on comparisons to a roughly contemporaneous indeterminate thalassodromine pterosaur specimen from the Romualdo Formation of Brazil, the specimen is tentatively interpreted as an indeterminate thalassodromine with an estimated wingspan of ∼3.5 m.