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Osteology of Archaeornithomimus asiaticus (Upper Cretaceous, Iren Dabasu Formation, People's Republic of China)
Journal of Verterbrate Paleontology
Abstract
The remains of the omithomimid dinosaur Archaeomithomimus asiaticus from the Upper Cretaceous of the People's Republic of China are described and comparisons made with the bones of Elaphrosaurus, Gallimimus, Struthiomimus, Ornithomimus, Dromiceiomimus, Deinocheirus, and Allosaurus. The diagnosis of the Ornithomimidae of Russell (1972) is expanded to include the characters of Elaphrosaurus and Archaeomithomimus. Some of the remains from the Arundel Formation of Maryland that have been referred to Archaeomithomimus affinis are probably ornithomimid but are generically and specifically indeterminate.
... The phylogenetic analysis by Sues and Averianov (2016a) found the Bissekty ornithomimid as an early-diverging member of Ornithomimidae, more derived than Archaeornithomimus from the Turonian-Santonian Iren Dabasu Formation of Inner Mongolia, China (Gilmore, 1933;Smith & Galton, 1990;Watanabe et al., 2015). The same result was subsequently obtained by Yao et al. (2022) and Hattori et al. (2023). ...
... Russell (1972) did not provide a diagnosis for Archaeornithomimus but enumerated a suite of differences between it and other ornithomimids known at that time, thus fulfilling the requirements of ICZN Article 13.1.1. Smith and Galton (1990) first presented a formal diagnosis. The characters listed in their diagnosis are either identical with those for or unknown for Dzharacursor. ...
... This specimen could be a third dorsal vertebra. The hypapophysis is absent or poorly developed on the anterior dorsals of Archaeornithomimus, Gallimimus, Garudimimus, Harpymimus, Ornithomimus, Pelecanimimus, Sinornithomimus, and Struthiomimus (Cuesta et al., 2022;Kobayashi & Barsbold, 2005a, 2005bKobayashi & Lü, 2003;Osmólska et al., 1972;Smith & Galton, 1990;Watanabe et al., 2015). Aside from Dzharacursor, the hypapophysis is pronounced on the anterior dorsals of Deinocheirus and Nqwebasaurus (Choiniere et al., 2012;Lee et al., 2014). ...
... However, ornithomimids are rare in the Maastrichtian faunas of western North America (DeCourten and Russell, 1985;Claessens and Loewen, 2015). In Asia, ornithomimids were common in pre-Campanian strata of Uzbekistan and China (Gilmore, 1933;Smith and Galton, 1990;Kobayashi and Lü, 2003;Sues and Averianov, 2016;Yao, Sullivan, Tan, and Xu, 2022), but are rare in the Campanian of Mongolia (Chinzorig et al., 2017). However, the greatest taxonomic diversity of ornithomimosaurs is known from the Maastrichtian Nemegt Formation of Mongolia (Osmólska and Roniewicz, 1970;Osmólska, Roniewicz, and Barsbold, 1972;Barsbold, 1988;Kobayashi and Barsbold, 2006;Bronowicz, 2011;Lee et al., 2014;Chinzorig et al., 2018). ...
A fragmentary tibia of an actively growing sub-adult individual from the Upper Cretaceous (Maastrichtian) Udurchukan Formation at Kundur, Amur oblast, Far East, Russia, is similar to the tibia of Qiupalong henanensis from the Maastrichtian of Henan Province, China, in bearing a weak posteromedial ridge at the distal end and equally projecting distal malleoli. Qiupalong had a transcontinental distribution and likely originated in North America. Similarly, lambeosaurine hadrosaurids from the Udurchukan Formation have American affinities and their ancestors may had dispersed from North America to East Asia together with a Qiupalong-like ornithomimid. Q. henanensis and Ornithomimidae indet. from Kundur are the only records of the Maastrichtian Ornithomimidae in Asia outside Gobi Desert.
... Cullen et al., 2013, Figs. 2 and 3; Sues & Averianov, 2016, Fig. 24; Claessens & Loewen, 2015, Figs. 5, 6 and 8;McFeeters et al., 2016); and deep and distinct collateral ligament fossae(Smith & Galton, 1990;Kobayashi & Barsbold, 2005; Shapiro et al., 2003, Fig. 1). ...
We report here the first dinosaur skeletal material described from the marine Fox Hills Formation (Maastrichtian) of western South Dakota. The find consists of two theropod pedal phalanges: one recovered from the middle part of the Fairpoint Member in Meade County, South Dakota; and the other from the Iron Lightning Member in Ziebach County, South Dakota. Comparison with pedal phalanges of other theropods suggests strongly that the Fairpoint specimen is a right pedal phalanx, possibly III-2, from a large ornithomimid. The Iron Lightning specimen we cautiously identify as an ornithomimid left pedal phalanx II-2. The Fairpoint bone comes from thinly bedded and cross-bedded marine sandstones containing large hematitic concretions and concretionary horizons. Associated fossils include osteichthyan teeth, fin spines and otoliths, and abundant teeth of common Cretaceous nearshore and pelagic chondrichthyans. Leaf impressions and other plant debris, blocks of fossilized wood, and Ophiomorpha burrows are also common. The Iron Lightning bone comes from a channel deposit composed of fine to coarse sandstone beds, some of which contain bivalves, and a disseminated assemblage of mammal teeth, chondrichthyan teeth, and fragmentary dinosaur teeth and claws. We interpret the depositional environment of the two specimens as marginal marine. The Fairpoint bone derives from a nearshore foreset setting, above wave base subject to tidal flux and storm activity. The Iron Lightning specimen comes from a topset channel infill probably related to deposition on a tidal flat or associated coastal setting. The taphonomic history and ages of the two bones differ. Orthogonal cracks in the cortical bone of the Fairpoint specimen suggest post-mortem desiccation in a dryland coastal setting prior to transport and preservation in the nearby nearshore setting described above. The pristine surface of the Iron Lightning specimen indicates little transport before incorporation into the channel deposit in which it was found. The Fairpoint bone bed most probably lies within the Hoploscaphites nicolletii Ammonite Zone of the early late Maastrichtian, and would therefore have an approximate age of 69 Ma. The Iron Lightning bone is from the overlying H. nebrascensis Ammonite Zone, and is thus about one million years younger.
A small-bodied ornithomimosaur, Kinnareemimus khonkaenensis Buffetaut, Suteethorn, and Tong 2009, from the Lower Cretaceous Sao Khua Formation of northeastern Thailand was first reported in 1995, then named in 2009. It is the only report of this group in Southeast Asia and was concluded to be a member of Ornithomimosauria, more derived than Harpymimus and Garudimimus but more basal than Archaeornithomimus. Since then, a few published studies have analyzed the phylogenetic position of Kinnareemimus but failed to find it within the clade Ornithomimosauria. Here, the phylogenetic analyses for assessing the relationships of Kinnareemimus within Ornithomimosauria were performed. The results suggested it might be a basal ornithomimosaur or belongs to the subclade Deinocheiridae. Kinnareemimus shares with deinocheirids the proximally projected cnemial crest and the shape of the fibula in proximal view. Its metatarsal III shows subarctometatarsalian condition with metatarsal III pinched between II and IV but visible in anterior view proximally, which might have evolved independently from other ornithomimids. However, the basal position of Kinnareemimus could also be due to the immaturity and the incomplete nature of this animal.
Ornithomimosauria consists of the ostrich-mimic dinosaurs, most of which showing cursorial adaptations, that often exhibit features indicative of herbivory. Recent discoveries have greatly improved our knowledge of their evolutionary history, including the divergence into Ornithomimidae and Deinocheiridae in the Early Cretaceous, but the early part of their history remains obscured because their fossil remains are scarce in the Aptian–Albian sediments. In recent years, many isolated ornithomimosaur remains have been recovered from the Aptian Kitadani Formation of Fukui, central Japan. These remains represent multiple individuals that share some morphological features common to them but unknown in other ornithomimosaurs, suggesting a monospecific accumulation of a new taxon. As a result of the description and phylogenetic analysis, the Kitadani ornithomimosaur is recovered as a new genus and species Tyrannomimus fukuiensis, the earliest definitive deinocheirid that complements our knowledge to understand the early evolutionary history of Ornithomimosauria. Due to its osteological similarity to Tyrannomimus, a taxon previously considered an early tyrannosauroid based on fragmentary specimens, namely Aviatyrannis jurassica, may represent the earliest ornithomimosaur from the Upper Jurassic of Europe, significantly expanding the temporal and biogeographic range of Ornithomimosauria. This finding fills a 20-million-year ghost lineage of Ornithomimosauria implied by the presence of the oldest fossil record of Maniraptora from the Middle Jurassic and is consistent with the hypothesis that their biogeographic range was widespread before the Pangaean breakup in the Kimmeridgian.
This Doctoral Thesis presents an exhaustive review of the Patagonian alvarezsaurids (Dinosauria, Theropoda). It includes a detailed osteological description of specimens of Patagonykus puertai (Holotype, MCF-PVPH-37), cf. Patagonykus puertai (MCF-PVPH-38), Patagonykinae indet. (MCF-PVPH-102), Alvarezsaurus calvoi (Holotype, MUCPv-54), Achillesaurus manazzonei (Holotype, MACN-PV-RN 1116), Bonapartenykus ultimus (Holotype, MPCA 1290), and cf. Bonapartenykus ultimus (MPCN-PV 738). A phylogenetic analysis and a discussion about the taxonomic validity of the recognized species and the taxonomic assignment of the materials MCF-PVPH-38, MCF-PVPH-102 and MPCN-PV 738 are presented. Different evolutionary and paleobiological studies were carried out in order to elucidate functional and behavioral aspects.
Alvarezsaurus calvoi (MUCPv-54), Achillesaurus manazzonei (MACN-PV-RN 1116), Patagonykus puertai (MCF-PVPH-37) and Bonapartenykus ultimus (MPCA 1290) are valid species due to the presence of many autapomorphies. In this sense, the hypothesis proposed by P. Makovicky and collaborators that Achillesaurus manazzonei is a junior synonym of Alvarezsaurus calvoi is rejected. Likewise, certain morphological evidence allows hypothesizing that Alvarezsaurus calvoi represents a growth stage earlier than skeletal maturity. Specimen MCF-PVPH-38 is referable as cf. Patagonykus puertai, while MCF-PVPH-102 is considered an indeterminate Patagonykinae. In turn, MPCN-PV 738 is assigned as cf. Bonapartenykus ultimus based on the little overlapping material with the Bonapartenykus ultimus holotype.
The results obtained from the mineralogical characterization through the X-ray diffraction method of specimens MPCN-PV 738 and the holotype of Bonapartenykus ultimus (MPCA 1290), allow to suggest that both specimens come from the same geographical area and stratigraphic level.
The phylogenetic analysis, which is based upon the matrix of Gianechini and collaborators of 2018 with the inclusion of proper characters, and the database of Xu and collaborators of 2018, recovered the South American members of Alvarezsauria, such as Alnashetri cerropoliciensis (Candeleros Formation; Cenomanian), Patagonykus puertai (Portezuelo Formation, Turonian-Coniacian), Alvarezsaurus calvoi and Achillesaurus manazzonei (Bajo de La Carpa Formation, Coniacian-Santonian), and Bonapartenykus ultimus (Allen Formation, Campanian-Maastrichtian), nesting within the family Alvarezsauridae. In this sense, the forms that come from the Bajo de La Carpa Formation (Coniacian-Santonian) are recovered at the base of the Alvarezsauridae clade, while Alnashetri cerropoliciensis nests as a non-Patagonykinae alvarezsaurid. Regarding the type specimens of Patagonykus puertai and Bonapartenykus ultimus, they are recovered as members of the Patagonykinae subclade, a group that is recovered as a sister taxon of Parvicursorinae, both nested within the Alvarezsauridae. In addition, the topology obtained allows discerning the pattern, rhythm and time of evolution of the highly strange and derived alvarezsaurian skeleton, concluding in a gradual evolution. The Bremer and Bootstrap supports of the nodes (Haplocheirus + Aorun), [Bannykus + (Tugulusaurus + Xiyunykus)], and Patagonykinae, show indices that represent very robust values for these nodes. Likewise, these values suggest that two endemic clades originated early in Asia, while one endemic clade is observed in Patagonia, i.e., Patagonykinae.
The analysis of the directional trends of the Alvarezsauria clade, tested by means of a own database on body masses based on the Christiansen and Fariña method, subsequently calibrated with the group's phylogeny using the R software, shows two independent miniaturization events in the alvarezsaurid evolution, namely the former originating from the base of the Alvarezsauridae (sustained by Alvarezsaurus), and the latter within the Parvicursorinae. Analysis of the Alvarezsauria dentition reveals possible dental synapomorphies for the Alvarezsauria clade that should be tested in an integrative phylogenetic analysis. The general characterization of the forelimb and a partial reconstruction of the myology of alvarezsaurs demonstrate different configurations for Patagonykinae and Parvicursorinae. The multivariate analyzes carried out from the databases of Elissamburu and Vizcaíno, plus that of Cau and collaborators, show that the Patagonykinae would have had ranges of movements greater than those observed in Parvicursorinae, although the latter would have had a greater capacity to carry out more strenuous jobs. The morphometric analysis of the hindlimb and the use of the Snively and collaborators equations, show that the configuration of this element in Alvarezsauria is indicative of a highly cursorial lifestyle, as well as possible particular strategies for more efficient locomotion. The topology obtained in the phylogenetic analysis that was carried out in this Doctoral Thesis, allowed clarifying the ontogenetic changes observed in the ontogenetic series of the manual ungueal element II-2 within the clade Alvarezsauridae. In addition, the multivariate analysis carried out from the manual phalanx II-2 allows us to infer that alvarezsaurs could have performed functions such as hook-and-pull and piercing, where the arm would function as a single unit. The anatomy and myology of the alvarezsaurian tail show that the caudal vertebrae of alvarezsaurians exhibit a combination of derived osteological features that suggests functions unique among theropods, such as considerable dorsal and lateral movements, as well as exceptional abilities to support distal loading of their long tail without compromising stability and/or mobility.
A newly identified ornithomimosaurian pelvis and sacrum from the Upper Cretaceous Erlian Formation of Nei Mongol, China is described in detail in this paper. This specimen is distinguished from previously described taxa by the presence of a combination of features that is unique among Ornithomimosauria: sacrum comprising five vertebrae with neural spines fused into a continuous plate, iliac posterior end rectangular, pubic shaft distally straight, ischial boot not broadened transversely, and ischial shaft proximally straight, distally curved, and 80 percent as long as the pubis. This specimen differs from at least some material assigned to the sympatric Archaeornithomimus asiaticus, showing that two distinct ornithomimosaurian taxa are present in this Late Cretaceous fossiliferous rock unit. A phylogenetic analysis places LH-02-01 in a relatively early-diverging position within Ornithomimosauria, outside the two major clades Deinocheiridae and Ornithomimidae, but its relationships with other early-diverging ornithomimosaurs remain unresolved. The primitive nature of LH-02-01 adds to the evidence from fossil vertebrates that the Erlian Formation correlates with the Turonian Bissekty Formation of Uzebekistan, while the biostratigraphic evidence from non-vertebrates instead indicates a Campanian to Maastrichtian age for the Erlian Formation. This apparent contradiction remains unresolved, pending future research aimed at reconciling the seemingly incompatible lines of evidence.
Despite an abundance of ornithomimid fossils from the Late Cretaceous of Alberta, Canada, only isolated elements are known from the upper Maastrichtian Scollard Formation. Ornithomimus velox and Struthiomimus sedens are the two taxa recognized from penecontemporaneous formations in the U.S.A., but the incomplete nature of these specimens and the lack of contemporary material from Alberta creates a gap in our understanding of ornithomimid diversity during the late Maastrichtian of North America. Here, I describe the first diagnostic ornithomimid fossils from the upper Maastrichtian Scollard Formation of central Alberta, Canada, providing new information about the taxonomic composition of North American ornithomimids during the late Maastrichtian. The first fossil, an articulated forelimb, exhibits metacarpal ratios and features of the manual unguals that support its referral to the genus Ornithomimus. The second fossil, an associated hind limb, belongs to a large-bodied ornithomimid, and based on characteristics of the pedal unguals is assigned to the genus Struthiomimus. Based on these taxonomic designations, the stratigraphic ranges of both Ornithomimus and Struthiomimus are extended from the upper Campanian Dinosaur Park Formation through to the upper Maastrichtian Scollard Formation of Alberta, which constitutes more than 10 million years of time. These specimens offer new knowledge on the taxonomic composition of ornithomimids in Alberta, but the unusually long stratigraphic range coupled with the difficulty in diagnosing either specimen to species underscores the need for review of North American ornithomimid taxonomy.
A humerus from the Morrison Formation (Upper Jurassic) of western North America is referred toElaphrosaurus which is represented by a skeleton from the Tendaguru Beds of Tanzania, East Africa. The referral ofCoelurus agilis Marsh (Morrison Formation, western U.S.A.) andTeinurosaurus sauvagei (Huene) (Kimmeridgian, France) toElaphrosaurus is incorrect. The recognition ofElaphrosaurus from North America provides additional evidence for a Morrison-Tendaguru land connection sometime during the Late Jurassic.Elaphrosaurus is referred to the family Ornithomimidae because the form of the humerus, slender and straight with a low deltopectoral crest,
is diagnostic of this family.Deinocheirus from the Upper Cretaceous of Mongolia is a giant ornithomimid.
Ein Humerus aus der oberjurassischen Morrison-Formation des westlichen Nordamerika wird zuElaphrosaurus gestellt, der durch ein Skelett aus den Tendaguru-Schichten von Tanzania in Ostafrika bekannt ist. Die Zuweisung vonCoelurus agilis Marsh aus der Morrison-Formation und vonTeinurosaurus sauvagei (Huene) aus dem französischen Kimméridgien ist nicht richtig. Der Nachweis vonElaphrosaurus in Nordamerika liefert ein weiteres Zeugnis einer Morrison-Tendaguru-Landverbindung in der spaten Jurazeit.Elaphrosaurus läßt sich den Ornithomimidae zuordnen, für die der schlanke und gestreckte, mit niedrigem Deltopectoralkamm versehene Humerus
charakteristisch ist.Deinocheirus aus der Oberkreide der Mongolei ist ein riesiger Ornithomimide.