A new small deinonychosaur (Dinosauria: Theropoda) from the Late Cretaceous of Patagônia, Argentina

Porfiri, Juan D.; Calvo, Jorge O.; Santos, Domenica Dos

doi:10.1590/s0001-37652011000100007

Cited by 27 publications

(15 citation statements)

References 13 publications

(12 reference statements)

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“…However, in the case of Neuquenraptor the features of its hindlimb indicate that velocity was probably important to obtain its prey. Only scarce hindlimb remains are known for U. comahuensis and U. paynemili, including the phalanges of digit II, which are very similar to those of the other unenlagiines (Novas and Puerta, 1997;Calvo et al 2004;Porfiri et al 2011). Accordingly, mainly due to the lack of skull and metatarsus remains, as well as of most of the pedal phalanges, it is more difficult to infer locomotor and predatory habits of U. comahuensis and U. paynemili.…”

Section: Locomotor and Predatory Habits Of Buitreraptor And Other Umentioning

confidence: 99%

Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies

2020

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Tetrapod limbs morphology is a reliable proxy of locomotor capacities. Beyond this, other aspects of life habits, such as predation abilities, can also be relevant to determine main morphofunctional appendicular properties, which ultimately reflect a compromise between different factors of the biological role. Dromaeosauridae is a dinosaur clade belonging to Theropoda, a group of bipedal predators. Dromaeosaurids represent an interesting study case, in which the hindlimbs have been proposed to be involved in both locomotion and predation activity. A peculiar feature characterizing all dromaeosaurids is a modified second pedal digit, which is typically related to predation. This theropod group is closely related to birds and diversified during the Cretaceous Period, mainly in the Northern Hemisphere (Laurasia). However, a subclade of dromaeosaurids, the Unenlagiinae, was recently recognized for Gondwana.Nevertheless, there are morphological differences between derived Laurasian dromaeosaurids (eudromaeosaurs) and unenlagiines. Such differences are observed in the proportions between hindlimb bones and in the presence of a subarctometatarsalian condition in unenlagiines, which is mainly characterized by a proximally constricted metatarsal III. To evaluate the function of these divergent morphologies, we conducted morphometric analyses and comparisons of qualitative morphological aspects, encompassing unenlagiines, other dromaeosaurids, as well as taxa from other theropod groups, including extant birds. The former approach consisted of two phylogenetic principal component analyses, one based on the main measurements of the hindlimb, and the other focused on the lengths of the pedal phalanges. The first analysis drew the unenlagiines close to taxa with long tibiae, as well as long and slender metatarsi. Instead, eudromaeosaurs are closer to taxa with shorter tibiae, and shorter and wider metatarsi. The second analysis showed that eudromaeosaurs and unenlagiines have similar phalangeal proportions, including the elongation of distal phalanges. However, the shorter second phalanx of the pedal digit II of eudromaeosaurs could have increased the force generated by this digit, which was the main predatory tool of the autopodium. This, together with a shorter and wider metatarsus, and a marked hinge-like morphology of the articular surfaces of metatarsals | 773 GIANECHINI Et Al.

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Section: Locomotor and Predatory Habits Of Buitreraptor And Other Umentioning

confidence: 99%

Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies

2020

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“…Currently, the only taxa widely accepted as belonging to Unenlagiidae are South American forms, namely Unenlagia comahuensis, Buitreraptor gonzalezorum, and Austroraptor cabazai (Novas and Puerta, 1997;Makovicky et al, 2005;Novas et al, 2009Novas et al, , 2018Gianechini et al, 2011bGianechini et al, , 2017Gianechini et al, , 2018Currie and Paulina Carabajal, 2012) together with less completely known taxa such as Neuquenraptor argentinus, "Unenlagia" paynemili, and Pamparaptor micros (Calvo et al, 2004;Novas and Pol, 2005;Gianechini and Apesteguía, 2011;Porfiri et al, 2011;Brissón Egli et al, 2017). Agnolin et al (2010), following Bonaparte (1999), proposed that Timimus hermani from the Early Cretaceous of Australia may belong to Unenlagiidae.…”

Section: Unenlagiidaementioning

confidence: 99%

Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview

et al. 2019

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Recent years witnessed the discovery of a great diversity of early birds as well as closely related non-avian theropods, which modified previous conceptions about the origin of birds and their flight. We here present a review of the taxonomic composition and main anatomical characteristics of those theropod families closely related with early birds, with the aim of analyzing and discussing the main competing hypotheses pertaining to avian origins. We reject the postulated troodontid affinities of anchiornithines, and the dromaeosaurid affinities of microraptorians and unenlagiids, and instead place these groups as successive sister taxa to Avialae. Aiming to evaluate previous phylogenetic analyses, we recoded unenlagiids in the traditional TWiG data matrix, which resulted in a large polytomy at the base of Pennaraptora. This indicates that the TWiG phylogenetic scheme needs a deep revision. Regarding character evolution, we found that: (1) the presence of an ossified sternum goes hand in hand with that of ossified uncinate processes; (2) the presence of foldable forelimbs in basal archosaurs indicates widespread distribution of this trait among reptiles, contradicting previous proposals that forelimb folding driven by propatagial and associated tendons was exclusive to the avian lineage; (3) in basal paravians and avialans (e.g., Archaeopteryx, Anchiornis) the wings are relatively large and wide, with relatively short rectricial feathers, a rounded alar contour, and a convex leading margin. These taxa exhibit restricted forelimb folding capability with respect to more derived birds, their hands being preserved at angles of flexion (with respect to the radius/ulna) of no less than 90 • . In more derived birds, however, the rectrices are notably elongate and the angle between the hand and forearm is much less than 90 • , indicating not only increased forelimb folding capability but also an increased variety of wingbeat movements during flight. Because of the strong similarities in pectoral girdle configuration between ratites and basal avialans and paravians, it is possible to infer that the main forelimb movements were similar in all these taxa, lacking the complex dorsoventral wing excursion characteristic of living neognathans.

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“…The Patagonian record of unenlagiines currently includes five taxa, three of which preserve only postcranial remains: Unenlagia comahuensis , Unenlagia paynemili and Neuquenraptor argentinus and two species with cranial remains, i.e., B. gonzalezorum and Austroraptor cabazai . Recently, a fragmentary coelurosaur represented only by hindlimb remains, but with possible deinonychosaurian affinities was described as Pamparaptor micros ( Porfiri, Calvo & Dos Santos, 2011 ). Its potential relationships with unenlagiines have not yet been thoroughly evaluated.…”

Section: Introductionmentioning

confidence: 99%

Postcranial skeletal anatomy of the holotype and referred specimens ofBuitreraptor gonzalezorumMakovicky, Apesteguía and Agnolín 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia

Gianechini

Makovicky

Apesteguı́a

et al. 2018

PeerJ

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Here we provide a detailed description of the postcranial skeleton of the holotype and referred specimens of Buitreraptor gonzalezorum. This taxon was recovered as an unenlagiine dromaeosaurid in several recent phylogenetic studies and is the best represented Gondwanan dromaeosaurid discovered to date. It was preliminarily described in a brief article, but a detailed account of its osteology is emerging in recent works. The holotype is the most complete specimen yet found, so an exhaustive description of it provides much valuable anatomical information. The holotype and referred specimens preserve the axial skeleton, pectoral and pelvic girdles, and both fore- and hindlimbs. Diagnostic postcranial characters of this taxon include: anterior cervical centra exceeding the posterior limit of neural arch; eighth and ninth cervical vertebral centra with lateroventral tubercles; pneumatic foramina only in anteriormost dorsals; middle and posterior caudal centra with a complex of shallow ridges on lateral surfaces; pneumatic furcula with two pneumatic foramina on the ventral surface; scapular blade transversely expanded at mid-length; well-projected flexor process on distal end of the humerus; dorsal rim of the ilium laterally everted; and concave dorsal rim of the postacetabular iliac blade. A paleohistological study of limb bones shows that the holotype represents an earlier ontogenetic stage than one of the referred specimens (MPCA 238), which correlates with the fusion of the last sacral vertebra to the rest of the sacrum in MPCA 238. A revised phylogenetic analysis recovered Buitreraptor as an unenlagiine dromaeosaurid, in agreement with previous works. The phylogenetic implications of the unenlagiine synapomorphies and other characters, such as the specialized pedal digit II and the distal ginglymus on metatarsal II, are discussed within the evolutionary framework of Paraves.

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A new small deinonychosaur (Dinosauria: Theropoda) from the Late Cretaceous of Patagônia, Argentina

Cited by 27 publications

References 13 publications

Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies

Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies

Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview

Postcranial skeletal anatomy of the holotype and referred specimens ofBuitreraptor gonzalezorumMakovicky, Apesteguía and Agnolín 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia

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