Osteology of Deinonychus antirrhopus, an Unusual Theropod from the Lower Cretaceous of Montana

Ostrom, John H.

doi:10.12987/9781933789408

Cited by 20 publications

(75 citation statements)

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“…19), and isolated phalanges. In all elements, the manual morphology corresponds closely to that of other dromaeosaurids such as Velociraptor mongoliensis (IGM 100/982), Deinonychus antirrhopus (Ostrom, 1969b), Zhenyuanlong suni (Li and Brusatte, 2015), and Microraptor zhaoianus (Xu et al, 2003). The semilunate carpal is large and complete, capping most of metacarpal I and all of metacarpal II.…”

Section: Forelimbsupporting

confidence: 52%

“…It compares favorably with C3 and C4 in Tsaagan mangas (IGM 100/1015) and Shri devi (IGM 100/980), so we tentatively identify it as C3/4. The centrum is strongly anterodorsally inclined, as is characteristic for dromaeosaurids (Ostrom, 1969b). The transverse processes are present as poorly developed projections.…”

Section: Vertebraementioning

confidence: 92%

“…Dorsal 5 is poorly exposed, but clearly shows the characteristic pediculate parapophysis of dromaeosaurids (Norell and Makovicky, 1997). The parapophysis appears to be below the level of the transverse process, unlike Velociraptor mongoliensis (IGM 100/986) but like Shri devi (IGM 100/980) and Deinonychus antirrhopus (Ostrom, 1969b;Turner et al, 2021). Dorsal 5 lacks a hypapophysis, but has a keeled ventral margin of the centrum.…”

Section: Vertebraementioning

confidence: 98%

“…14) is less completely preserved, but a cast of a now-missing second posterior caudal is present, and preserves the missing pre-and postzygapophyses. The prezygapophyses are elongate, as is typical for eudromaeosaurs and exemplified by Deinonychus antirrhopus (Ostrom, 1969b) and Velociraptor mongoliensis (Norell and Makovicky, 1999). There is no trace of a neural spine, save for a faint ridge along the dorsal surface of the neural arch, which is continuous with a faint sulcus between the postzygapophyses, which are elongate and overhang the posterior extent of the centrum.…”

Section: Vertebraementioning

confidence: 98%

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A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia

Napoli

Ruebenstahl

Bhullar

et al. 2021

American Museum Novitates

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Dromaeosaurid theropods represent a rare but important clade of nonavialan dinosaurs. Their close evolutionary relationship to modern birds has placed them at the center of paleontological research for the last several decades. Herein we describe a new species of dromaeosaurid-Kuru kulla, gen. et sp. nov.-based on a partial skeleton from the Late Cretaceous Khulsan locality (Barun Goyot Formation) of Mongolia. This species is diagnosed by several autapomorphies within Dromaeosauridae, including a sharp groove anterior and ventral to the narial fossa on the premaxilla, a posterolaterally directed hornlet on the posterodorsal process of the lacrimal, a deep surangular bearing two surangular foramina, and anteriorly displaced pleurocoels on the dorsal centra. The taxon is further characterized by a unique combination of characters, including a mediolaterally narrow metatarsal II, serrations on both carinae of the dentary teeth, hyposphenes that are widely separated but joined by a web of bone, and a lacrimal with a poorly developed boss on its lateral surface. Phylogenetic analysis finds Kuru kulla to be the sister taxon of Adasaurus mongoliensis, from the slightly later Nemegt Formation, with which it is united by three synapomorphies: a posterior surangular foramen that is ~30% the depth of the surangular, absence of a fourth trochanter of the femur, and thoracic centra that are markedly longer than their midpoint widths. The recognition of this taxon has important implications for common assumptions of Mesozoic terrestrial ecosystem structure and adds new data to a recently recognized pattern in dromaeosaurid faunal composition among Late Cretaceous localities in Mongolia and Inner Mongolia (Nei Mongol Autonomous Region, China).

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Section: Forelimbsupporting

confidence: 52%

Section: Vertebraementioning

confidence: 92%

Section: Vertebraementioning

confidence: 98%

Section: Vertebraementioning

confidence: 98%

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A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia

Napoli

Ruebenstahl

Bhullar

et al. 2021

American Museum Novitates

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“…As in ornithomimosaurs, the posterior process of the proximal articular surface is slightly more extended proximally than the anterior process in lateral view (Fig 7D4), which is in contrast to the tyrannosaurids condition of subequal development of processes. In anterior view, the anterior process is pointed proximally as in most ornithomimosaurs and dromaeosaurids, such as D. antirrhopus [111]; this differs from the rounded condition in tyrannosaurids. However, MMNS VP-7119 can be differentiated from D. antirrhopus by its asymmetrical and relatively straight shaft mediolaterally.…”

Section: Resultsmentioning

confidence: 99%

Large-bodied ornithomimosaurs inhabited Appalachia during the Late Cretaceous of North America

Chinzorig

Cullen

Phillips

et al. 2022

Preprint

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Reconstructing the evolution, diversity, and paleobiogeography of North America’s Late Cretaceous dinosaur assemblages requires spatiotemporally contiguous data; however, there remains a spatial and temporal disparity in dinosaur data on the continent. The rarity of vertebrate-bearing sedimentary deposits representing Turonian–Santonian ecosystems, and the relatively sparse record of dinosaurs from the eastern portion of the continent, present persistent challenges for studies of North American dinosaur evolution. Here we describe an assemblage of ornithomimosaurian materials from the Santonian Eutaw Formation of Mississippi. Morphological data coupled with osteohistological growth markers suggest the presence of two taxa of different body sizes, including one of the largest ornithomimosaurians known worldwide. The regression predicts a femoral circumference and a body mass of the Eutaw individuals similar to or greater than that of large-bodied ornithomimosaurs, Beishanlong grandis and Gallimimus bullatus . The paleohistology of MMNS VP-6332 demonstrates that the individual was at least 11 years of age (similar to B. grandis [~375 kg, 13–14 years old at death]). Additional pedal elements share some intriguing features with ornithomimosaurs yet suggest a larger-body size closer to Deinocheirus mirificus . The presence of a large-bodied ornithomimosaur in this region during this time is consistent with the relatively recent discoveries of early-diverging, large-bodied ornithomimosaurs from mid-Cretaceous strata of Laurasia ( Arkansaurus fridayi and B. grandis ). The smaller Eutaw taxon is represented by a tibia preserving seven growth cycles, with osteohistological indicators of decreasing growth, yet belongs to an individual with near reaching somatic maturity of the larger taxon, suggesting the co-existence of medium- and large-bodied ornithomimosaur taxa during the Late Cretaceous Santonian of North America. The Eutaw ornithomimosaur materials provide key information on the diversity and distribution of North American ornithomimosaurs and Appalachian dinosaurs and fit with broader evidence of multiple cohabiting species of ornithomimosaurian dinosaurs in Late Cretaceous ecosystems of Laurasia.

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Tail Weaponry in Ankylosaurs and Glyptodonts: An Example of a Rare but Strongly Convergent Phenotype

Arbour

Zanno

2019

The Anatomical Record

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The unusual clubbed tails of glyptodonts among mammals and ankylosaurines among dinosaurs most likely functioned as weapons of intraspecific combat or interspecific defense and are characterized by stiffening of the distal tail and, in some taxa, expansion of the distal tail tip. Although similarities in tail weaponry have been noted as a potential example of convergent evolution, this hypothesis has not been tested quantitatively, particularly with metrics that can distinguish convergence from long‐term stasis, assess the relative strength of convergence, and identify potential constraints in the appearance of traits during the stepwise, independent evolution of these structures. Using recently developed metrics of convergence within a phylomorphospace framework, we document that convergence accounts for over 80% of the morphological evolution in traits associated with tail weaponry in ankylosaurs and glyptodonts. In addition, we find that ankylosaurs and glyptodonts shared an independently derived, yet constrained progression of traits correlated with the presence of a tail club, including stiffening of the distal tail as a precedent to expansion of the tail tip in both clades. Despite differences in the anatomical construction of the tail club linked to lineage‐specific historical contingency, these lineages experienced pronounced, quantifiable convergent evolution, supporting hypotheses of functional constraints and shared selective pressures on the evolution of these distinctive weapons. Anat Rec, 303:988–998, 2020. © 2019 Wiley Periodicals, Inc.

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Osteology of Deinonychus antirrhopus, an Unusual Theropod from the Lower Cretaceous of Montana

Cited by 20 publications

References 0 publications

A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia

A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia

Large-bodied ornithomimosaurs inhabited Appalachia during the Late Cretaceous of North America

Tail Weaponry in Ankylosaurs and Glyptodonts: An Example of a Rare but Strongly Convergent Phenotype

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