Diuqin lechiguanae. Image credit: Porfiri et al 2024
The fossil record of basal paravians in Gondwana is restricted to a relatively small number of taxa. South American paravians are included within the clade Unenlagiidae. The group was erected by Bonaparte aiming to include Argentinean Unenlagia and the Malagasy Rahonavis. Unenlagiines have been interpreted as dromaeosaurids, troodontids, as well as the sister group of Avialae. The clade is important to improve our understanding on bird origins and the phylogenetic relationships among Avialae. Unfortunately, most taxa are represented by fragmentary materials.
Diuqin lechiguanae is a new unenlagiine from the Upper Cretaceous (Santonian) Bajo de la Carpa Formation of the Neuquén Basin of Neuquén Province in northern Patagonia, Argentina. The holotype (MUCPv 1401) comprises the posteriormost sacral vertebral neural arch, an anterior caudal vertebral neural arch, the nearly complete left humerus, and four unidentified fragments (at least two of which may be small pieces of vertebrae). The new specimen fills a significant temporal hiatus in the fossil record of Unenlagiinae in Argentina. The generic name is derived from the Mapuzungun language meaning “bird of prey”. The specific name, lechiguanae, is dervied from Lechiguana, the witch in the 1975 film Nazareno Cruz y el Lobo (directed by Argentinian filmmaker Leonardo Favio).
Left humerus of Diuqin lechiguanae. Scale bar = 5 cm. From Porfiri et al. 2024.
Diuqin lechiguanae exhibits a last sacral vertebra with an accessory lamina between the spinopostzygapophyseal laminae, and distinctive paired foramina on the posteriormost sacral and anterior caudal neural arches. The humerus o is the most omplete bone (missing only parts of the proximal end and deltopectoral crest), and it appears intermediate between those of geologically older unenlagiines from the Neuquén Basin (e.g., Unenlagia spp. from the Turonian–Coniacian Portezuelo Formation) and that of the stratigraphically younger, larger-bodied Austroraptor cabazai from the Campanian–Maastrichtian Allen Formation.
Tooth marks on distal end of lateral surface of humerus of Diuqin lechiguanae. Scale bar = 5 centimeters. From : Porfiri et al., 2024.
The humerus also shows two conical tooth marks. These are one and two millimeters deep and five and four millimeters in maximum diameter, respectively. Some bones of the Buitreraptor holotype (MPCA 245) have similar marks that have been termed ‘punctures’ and are attributed to crocodyliform or mammalian trace makers. However, it has no been discount the possibility that another unenlagiine individual produced the punctures seen on the Diuqin humerus.
References:
Porfiri, J.D., Baiano, M.A., dos Santos, D.D. et al. Diuqin lechiguanae gen. et sp. nov., a new unenlagiine (Theropoda: Paraves) from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous) of Neuquén Province, Patagonia, Argentina. BMC Ecol Evo 24, 77 (2024). https://doi.org/10.1186/s12862-024-02247-w
Letters from Gondwana. 