Catherine A. Forster, Patrick M. O’Connor, Luis M. Chiappe & Alan H. Turner, 2020
The osteology of the Late Cretaceous paravian Rahonavis ostromi from Madagascar
Palaeontologia Electronica. 23 (2): Article number 23(2):a29. doi:10.26879/793
Rahonavis ostromi, a paravian from the Maastrichtian Maevarano Formation, Mahajanga Basin, northwestern Madagascar, preserves morphology germane to understanding the character transformations present among paravian theropods, and in particular, among those non-avialan theropods most closely related to birds. The holotype specimen consists of a partial axial column (including cervicodorsal, dorsal, sacral, and caudal vertebrae and chevrons), most of the hind limbs and pelvis, and a partial forelimb (scapula, ulna, radius). Additional isolated elements referred to Rahonavis include distal humeri, a partial dentary, and a second right ulna; the duplicate right ulna demonstrates that at least two individuals of Rahonavis are present in the collection. All specimens of Rahonavis were recovered from the same level in quarry MAD 93-18 in 1995. All elements are described in detail and illustrated in multiple views, including CT slices of select elements to demonstrate internal morphology. Recent phylogenetic analyses place Rahonavis either within the non-avialan Unenlagiinae, an early-diverging clade within Dromaeosauridae, or at the base of Avialae. Rahonavis is one of the best represented and preserved Gondwanan paravians, and remains a pivotal taxon for understanding the evolution and biogeography of paravians.