Osteology of<i>Unenlagia comahuensis</i>(Theropoda, Paraves, Unenlagiidae) from the Late Cretaceous of Patagonia

Novas, Fernando E.; Agnolín, Federico; Motta, Matías J.; Egli, Federico Brissón

doi:10.1002/ar.24641

Cited by 11 publications

(25 citation statements)

References 127 publications

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“…2A and C and 5A) are not observed in any of the preserved sacral vertebrae of Buitreraptor or U. comahuensis, although in the latter taxon the sacrals are poorly preserved. However, in the anteriormost sacral vertebra of U. comahuensis, there are bilateral foramina located more lateral to the neural spine, which are similar to those present in the posteriormost dorsal vertebra of this species [66]. In Rahonavis, the sacral neural arches lack foramina [10].…”

Section: Comparisons With Other Paraviansmentioning

confidence: 65%

“…The following Patagonian Late Cretaceous unenlagiine taxa and specimens were examined firsthand during the course of this study: ). Morphological and/or taphonomic observations were supplemented using the following literature sources for the Gondwanan Late Cretaceous paravian taxa in question: Austroraptor [23,56,57]; Buitreraptor [11,15,18,[58][59][60][61][62]; Imperobator antarcticus [6,7]; Neuquenraptor [21,63]; Overoraptor chimentoi [24]; Pamparaptor [22,57]; Rahonavis ostromi [9,10]; U. comahuensis [19,57,[64][65][66]; U. paynemili [20,57]; Ypupiara lopai [2].…”

Section: Methodsmentioning

confidence: 99%

“…3a), especially in that the postzygapophyses are situated close to the sagittal midline. In addition, the neural spine is not fused to that of the preceding sacral vertebra, as in the posteriormost sacrals of Rahonavis ostromi [10] and possibly Unenlagia comahuensis [66], although the preservation of the sacrum of the latter species is too poor to be certain of this feature. The neurocentral suture is open (Fig.…”

Section: Descriptionmentioning

confidence: 99%

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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

Porfiri,

Baiano,

dos Santos

et al. 2024

BMC Ecol Evo

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Background Unenlagiine paravians are among the most relevant Gondwanan theropod dinosaur clades for understanding the origin of birds, yet their fossil record remains incomplete, with most taxa being represented by fragmentary material and/or separated by lengthy temporal gaps, frustrating attempts to characterize unenlagiine evolution. Results and conclusions Here we describe Diuqin lechiguanae gen. et sp. nov., a new unenlagiine taxon from the Upper Cretaceous (Santonian) Bajo de la Carpa Formation of the Neuquén Basin of Neuquén Province in northern Patagonia, Argentina that fills a substantial stratigraphic gap in the fossil record of these theropods. Although known only from a very incomplete postcranial skeleton, the preserved bones of Diuqin differ from corresponding elements in other unenlagiines, justifying the erection of the new taxon. Moreover, in several morphological aspects, the humerus of Diuqin 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. Consequently, the morphology of the new taxon appears to indicate a transitional stage in unenlagiine evolution. Phylogenetic analysis recovers Diuqin as a paravian with multiple plausible systematic positions, but the strongest affinity is with Unenlagiinae. The humerus of the new form exhibits subcircular punctures near its distal end that are interpreted as feeding traces most likely left by a conical-toothed crocodyliform, mammal, or theropod, the latter potentially corresponding to a megaraptorid or another unenlagiine individual. Thus, in addition to filling important morphological and temporal gaps in unenlagiine evolutionary history, the new taxon also offers information relating to the paleoecology of these theropods.

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Section: Comparisons With Other Paraviansmentioning

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

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

Porfiri,

Baiano,

dos Santos

et al. 2024

BMC Ecol Evo

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“…In Buitreraptor MCPA 245 and MPCN-PV-598, the scapula and coracoid are tightly articulated as in Sinornithosaurus IVPP V12811, with marked rugosities that indicate ongoing fusion on the coracoidal articular surface ( Brochu, 1995 ; Parsons & Parsons, 2015 ; Gianechini et al, 2018 ; Novas et al, 2018 ). A similarly rugose articular surface is also observed on the scapula of Unenlagia MCF PVPH 78 ( Novas et al, 2021a ). The only exception is the smooth coracoid facet on the scapula of Rahonavis UA 8656 ( Forster et al, 2020 ), which suggests a derived avian-like coracoscapular joint that is apomorphic in Rahonavis and may be related to flight capabilities in this taxon.…”

Section: Compare Of Pennaraptoran Pectoral Girdlementioning

confidence: 77%

Transformation of the pectoral girdle in pennaraptorans: critical steps in the formation of the modern avian shoulder joint

Wu,

O’Connor,

Wang

et al. 2024

PeerJ

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Important transformations of the pectoral girdle are related to the appearance of flight capabilities in the Dinosauria. Previous studies on this topic focused mainly on paravians yet recent data suggests flight evolved in dinosaurs several times, including at least once among non-avialan paravians. Thus, to fully explore the evolution of flight-related avian shoulder girdle characteristics, it is necessary to compare morphology more broadly. Here, we present information from pennaraptoran specimens preserving pectoral girdle elements, including all purportedly volant taxa, and extensively compare aspects of the shoulder joint. The results show that many pectoral girdle modifications appear during the evolution from basal pennaraptorans to paravians, including changes in the orientation of the coracoid body and the location of the articulation between the furcula and scapula. These modifications suggest a change in forelimb range of motion preceded the origin of flight in paravians. During the evolution of early avialans, additional flight adaptive transformations occur, such as the separation of the scapula and coracoid and reduction of the articular surface between these two bones, reduction in the angle between these two elements, and elongation of the coracoid. The diversity of coracoid morphologies and types of articulations joining the scapula-coracoid suggest that each early avialan lineage evolved these features in parallel as they independently evolved more refined flight capabilities. In early ornithothoracines, the orientation of the glenoid fossa and location of the acrocoracoid approaches the condition in extant birds, suggesting a greater range of motion in the flight stroke, which may represent the acquisition of improved powered flight capabilities, such as ground take-off. The formation of a new articulation between the coracoid and furcula in the Ornithuromorpha is the last step in the formation of an osseous triosseal canal, which may indicate the complete acquisition of the modern flight apparatus. These morphological transitions equipped birds with a greater range of motion, increased and more efficient muscular output and while at the same time transmitting the increased pressure being generated by ever more powerful flapping movements in such a way as to protect the organs. The driving factors and functional adaptations of many of these transitional morphologies are as yet unclear although ontogenetic transitions in forelimb function observed in extant birds provide an excellent framework through which we can explore the behavior of Mesozoic pennaraptorans.

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“…The ilium is 64% of the femoral length. The preacetabular process is longer than the postacetabular process of the ilium, a feature shared with Halszkaraptor , Tianyuraptor and Unenlagia among dromaeosaurids 6 , 9 , 29 , and comparable to Rahonavis and most avialans 30 . As in other dromaeosaurids 5 , the postacetabular process is gradually declined caudoventrally but does not extend below the level of the ischial peduncle.…”

Section: Resultsmentioning

confidence: 94%

Intestinal preservation in a birdlike dinosaur supports conservatism in digestive canal evolution among theropods

Wang

Cau²,

Guo

et al. 2022

Sci Rep

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Dromaeosaurids were bird-like dinosaurs with a predatory ecology known to forage on fish, mammals and other dinosaurs. We describe Daurlong wangi gen. et sp. nov., a dromaeosaurid from the Lower Cretaceous Jehol Biota of Inner Mongolia, China. Exceptional preservation in this specimen includes a large bluish layer in the abdomen which represents one of the few occurrences of intestinal remnants among non-avian dinosaurs. Phylogenetically, Daurlong nests among a lineage of short-armed Jehol Biota species closer to eudromaeosaurs than microraptorines. The topographic correspondence between the exceptionally preserved intestine in the more stem-ward Scipionyx and the remnants in the more birdlike Daurlong provides a phylogenetic framework for inferring intestine tract extent in other theropods lacking fossilized visceral tissues. Gastrointestinal organization results conservative among faunivorous dinosaurs, with the evolution of a bird-like alimentary canal restricted to avialan theropods.

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Osteology ofUnenlagia comahuensis(Theropoda, Paraves, Unenlagiidae) from the Late Cretaceous of Patagonia

Cited by 11 publications

References 127 publications

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

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

Transformation of the pectoral girdle in pennaraptorans: critical steps in the formation of the modern avian shoulder joint

Intestinal preservation in a birdlike dinosaur supports conservatism in digestive canal evolution among theropods

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