A new unenlagiine (Theropoda, Dromaeosauridae) from the Upper Cretaceous of Brazil

Abstract

The record of unenlagiines in Brazil, except for one dorsal vertebra, is still under debate based on isolated teeth. Here, we describe Ypupiara lopai gen. et sp. nov., the first dromaeosaurid species from Brazil, from the Maastrichtian of the Bauru Group, Paran a Basin. The specimen consists of a partial right maxilla (with three teeth in loci) and a right dentary. Ypupiara is characterized by a restricted number of neurovascular foramina on the lateral surface of the maxilla, a rectangular and anteroposteriorly expanded interdental plate, and a labiolingual compression of the teeth, which have a labiolingual diameter more than 3/5 of the rostrocaudal diameter. Our phylogenetic analysis recovers Ypupiara as an unenlagiine based on the fluted teeth and places it as the sister taxon of Austroraptor due to the ratio of the labiolingual and mesiodistal diameters of the teeth being more than 3/5. We also erect the new group Unenlagiinia, which includes Unenlagiinae and Halszkaraptorinae. Ypupiara nests within Unenlagiinia based on the widely spaced teeth and the lack of mesial and distal carinae in the maxillary teeth. The morphology of the teeth is similar to Buitreraptor, although the proportions are markedly distinct. The teeth and comparisons with other Unenlagiinia also support fish being part of the diet for Ypupiara. We also performed a parsimony analysis of endemicity, which suggested that the presence of unenlagiines in Brazilian Upper Cretaceous outcrops is explained by dispersion or extinction events. The new species provides new information on the evolution of Gondwanan dromaeosaurids, and its preserved teeth provide new data to enable the assignment of isolated dromaeosaurid teeth from the Bauru Group.

Elemgasem nubilus: a new brachyrostran abelisaurid (Theropoda, Ceratosauria) from the Portezuelo Formation (Upper Cretaceous) of Patagonia, Argentina

“…2020; Brum et al . 2021). This scenario supports the absence of carcharontosaurids after the Turonian (e.g.…”

“…2012; Brum et al . 2021). Except for carcharodontosaurids, which are widespread across Gondwana at least until the Cenomanian–Turonian and disappear after this interval (e.g.…”

A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria

“…Patagonykus , Bonapartenykus ; Novas, 1996; Agnolín et al., 2012) and dromaeosaurids (e.g. Unenlagia , Neuquenraptor , Pamparaptor , Austroraptor , Ypupiara ; Novas and Puerta, 1997; Calvo et al., 2004; Novas and Pol, 2005; Novas et al., 2009; Porfiri et al., 2011; Brum et al., 2021).…”

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

“…Unenlagiines are Gondwanan (Southern Hemisphere) predatory dinosaurs that are nested within Paraves, the clade that includes birds and their closest non-avian theropod relatives. The unenlagiine fossil record comes predominantly from Argentina, where the greatest number of specimens and the most complete skeletons have been found, although other materials at least tentatively assigned to Unenlagiinae have also been recovered from Brazil [1][2][3], Chile [4], Colombia [5], and Antarctica [6][7][8]. The small-bodied, potentially volant Madagascan theropod Rahonavis ostromi [9,10] has also been frequently regarded as an unenlagiine, depending on the specific phylogenetic hypothesis employed [10][11][12][13][14].…”