Lamarqueavis is an extinct genus of ornithuran dinosaurs from the family Cimolopterygidae known from Late Cretaceous-aged rocks from Argentina, Canada, and the United States. The type species, L. australis, was named in 2010 and is based on the holotype MML 207, a partial right coracoid found in the Allen Formation, Argentina. Two other species, L. minima, based on the holotype UCMP 53976, a right coracoid found in the Lance Formation, Wyoming,Brodkorb, P. (1963). Birds from the Upper Cretaceous of Wyoming. Proceedings of the XIII International Ornithological Congress 55-70 and L. petra, based on the holotype AMNH 21911, a left coracoid also found in the Lance Formation, Wyoming,Hope, S. (2002). The Mesozoic radiation of Neornithes. Mesozoic Birds: Above the Heads of Dinosaurs. University of California Press, Berkeley 339-388 were transferred over from Cimolopteryx to Lamarqueavis in 2010. A third unnamed species is known from the Dinosaur Park Formation of Alberta, Canada.
Lamarqueavis autralis and Lamarqueavis sp. were placed in Cimolopterygidae based on the family's traits; a humeral articular facet that's ventrally oriented, a sternally extended procoracoid process that developed into a thin lamina, and a large ventrally positioned supracoracoid nerve foramen. Despite these family traits, they were found to be unique to Lamarqueavis, while not present in Cimolopteryx. References