The second taxon of alvarezsaurid theropod dinosaurs from the Late Cretaceous Khulsan locality in Gobi Desert, Mongolia

Abstract

ABSTRACT Khulsanurus magnificus gen. et sp. nov., is described based on a partial skeleton, including cervical and caudal vertebrae, scapulocoracoids, humerus, and pubis from the Late Cretaceous (Campanian) Barungoyot Formation at Khulsan locality in Gobi Desert, Mongolia. The new taxon differs from other alvarezsaurids by a combination of characters that include cervicals lacking pleurocoels, carotid processes, and epipophyses, dorsoventrally thick and subtriangular in cross-section transverse process of the anterior caudals, prominent infrapostzygapophyseal fossa on the transverse process of anterior caudals, short and mostly anteriorly directed prezygapophyses of anterior caudals, neural arch of anterior caudal lacking the interzygapophyseal ridges and having a prominent dorsal depression around the anterior end of the neural spine. The new taxon retains a number of plesiomorphic traits: slightly convex posterior centrum condyle of anterior caudals, prominent anterior, and posterior bumps at the neurocentral junction in anterior caudals, neural arch of anterior caudals extending for the entire length of the centrum, and pubic foot and apron. Khulsanurus shares with Shuvuuia the deltopectoral crest of humerus that is continuous with the humeral head. The phylogenetic analysis placed Khulsanurus in the Parvicursorinae in a polytomy with Mononykus, Shuvuuia, Albinykus, and Xixianykus.