Qiupalong

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Qiupalong
Temporal range: Late Cretaceous
~72 to 66 Ma - Maastrichtian
The holotype specimen on display in China
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: †Ornithomimosauria
Family: †Ornithomimidae
Genus: †Qiupalong
Xu et al., 2011
Type species
†Qiupalong henanensis
Xu et al., 2011

Qiupalong (meaning "dragon from the Qiupa Formation") is an

theropod that was discovered in the Late Cretaceous Qiupa Formation of Henan, China. The genus contains a single species, Q. henanensis, the specific epithet for which was named for the province of Henan.[1] Uniquely, Qiupalong is one of the few Late Cretaceous non-avian dinosaurs known from both Asia and Laramidia. Specimens from Russia and Alberta have been referred to the genus without being assigned to the type species.[2][3]

Discovery

A map of the Qiupa Formation with a corresponding stratigraphic chart

The

dinosaurs.[5]

The Qiupa Formation preserves a wide variety of dinosaur eggs, many of which have been named as

Henan Geological Museum and was given the designation HGM 41HIII-0106.[1]

The Dinosaur Park Formation, where the remains of Qiupalong sp. were discovered

In 2017, another team of researchers including

ornithomimid remains from the Belly River Group in Alberta, Canada. These included the specimens UALVP 53595 and UALVP 52861 from the Dinosaur Park Formation and CMN 8902. The latter specimen was discovered in 1921 before the delineation between the Dinosaur Park and Oldman formations was erected, and the precise locality from which it was collected is not certain. Therefore, the specimen's precise age is also uncertain.[2]

When these newer specimens were described, the authors noted that they bore significant morphological similarities to the holotype of Qiupalong. The foot claws of the new specimens in particular were nearly identical to those of the holotype. As a result, they referred these new remains to the genus, but they did not assign it to the type species. The significance of this referral was noted by the authors. It extended the temporal range of Qiupalong from the middle Campanian to the latest Maastrichtian - a span of roughly 10 million years. This would also make Qiupalong the only genus of ornithomimid known from both Asia and Laramidia.[2]

In 2023, the

hadrosaurs of North American affinities. They hypothesized that it was from an animal very similar to Qiupalong which may have participated in a faunal dispersal from North America to Asia. However, Averianov and colleagues did not refer the remains to any specific genus within ornithomimidae.[3]

Description

Life restoration
of Qiupalong

Qiupalong was very similar to derived North American

metatarsals as 320 millimetres (13 in), 384 millimetres (15.1 in), and 233 millimetres (9.2 in) respectively.[1] They did not give an estimate for the animal's overall size,[1] but Rubén Molina-Pérez and Asier Larramendi suggested a length of 2.85 metres (9.4 ft) and a mass of 63 kilograms (139 lb).[6]

Xu and colleagues diagnosed the genus by the following

synapomorphic traits shared with other ornithomimids.[1]

Holotype

A diagram of the metatarsals of several ornithomimosaur species, including Qiupalong

The

metatarsals, a phalanx, and a pedal ungual from the right hindlimb. These bones are not confidently assigned to a single animal, but the size of the bones relative to one another suggests that they come from a minimum of two similarly-sized animals.[1]

The taphonomic conditions vary for the different bones of the holotype. The pelvic elements are crushed and not completely preserved, and the right side of these bones are more intact than those of the left side. The leg bones are mostly complete and several of the ankle elements were partially articulated.[1]

In comparison to other ornithomimids, Qiupalong has a mix of derived and plesiomorphic features. The toe claws are curved downwards, which resembles the condition seen in basal ornithomimosaurs and is unlike other derived ornithomimids from Asia. The metatarsals display the

arctometatarsalian condition, and they are almost identical to the other derived ornithomimids including Ornithomimus, Struthiomimus, and Gallimimus. The shape of the pubis is also more similar to ornithomimids from North America than it is to non-ornithomimid ornithomimosaurs like Shenzhousaurus and Harpymimus.[1]

In their description of the holotype, Xu and colleagues made numerous comparisons to the holotype of the

coelurosaurs, the specific morphology of Qiupalong clearly identifies it as an ornithomimosaur.[1]

Referred material

  • Pubic bones of CMN 8902 from multiple views
    Pubic bones of CMN 8902 from multiple views
  • CMN 8902 (A) compared with other ornithomimosaurs (B-F)
    CMN 8902 (A) compared with other ornithomimosaurs (B-F)
  • Caudal vertebrae of CMN 8902
    Caudal vertebrae of CMN 8902
  • UALVP 53595 (A-F) compared to Ornithomimus (G-H) and Struthiomimus (I)
    UALVP 53595 (A-F) compared to Ornithomimus (G-H) and Struthiomimus (I)
  • UALVP 52861 compared to outlines of the holotype of Qiupalong henanensis
    UALVP 52861 compared to outlines of the holotype of Qiupalong henanensis

Several

ornithomimosaur specimens recovered from the Belly River Group in Alberta had not been assigned to any particular genus on their initial discovery. In 2017, a team of authors led by Bradly McFeeters revisited these specimens and referred several of them to the recently described genus, Qiupalong. These specimens included CMN 8902 (vertebrae, ribs, scapulocoracoid, partial limb bones, and hip bones), UALVP 53595 (an ankle bone), UALVP 52861 (pedal ungual).[2]

The UALVP specimens were from the

Charles M. Sternberg before the Dinosaur Park and Oldman formations were split into two distinct geological units, and the notes he gave were not sufficient to identify exactly from which locality he collected CMN 8902.[2]

These specimens were referred to Qiupalong sp. because they were not diagnostic to the species level, but they strongly resembled some of the bones of the holotype of Q. henanensis. In particular, UALVP 52861 (a pedal ungual) was noted to be almost identical in morphology to those known from the holotype. However, McFeeters and colleagues noted that several of the bones of CMN 8902 were not able to be compared with the holotype of Qiupalong because the specimen consists of bones that are not present in the holotype (the vertebrae and bones of the arm). The authors also note that the morphology of these elements is broadly similar to other North American ornithomimosaurs and if CMN 8902 is an individual of Qiupalong, it supports a close relationship with Struthiomimus and Ornithomimus.[2]

Proximal view of the tibia from CMN 9802, showing the notch on the medial posterior process

McFeeters and colleagues also remark that one of the listed

autapomorphies for the type species of Qiupalong (a notch on the medial posterior process of the tibia) may not be a true autapomorphy because a similar condition is present in the specimen TMP 1994.012.1010, which has not been referred to any particular species. They also remark that, because of the poor preservation conditions of many ornithomimosaur fossils, it is difficult to determine whether or not other taxa possessed this trait.[2]

Most recently, in

hadrosaur fossils, including the Olorotitan and Kundurosaurus.[3]

The specimen itself, AEIM 2/1045, was sectioned for histological study to determine its ontogenetic age. Averianov and colleagues suggested, based on the presence of active secondary remodeling and the lack of an external fundamental system, that the individual was a young adult which was still actively growing when it died. They do not specifically refer it to Qiupalong, but they do remark that it bears the most similarity to it out of all ornithomimids.[3]

Classification

Articulated skeletons of Struthiomimus (top) and Ornithomimus (bottom), which were both close relatives of Qiupalong

In their description of the

tyrannosaurids as outgroups.[1]

They recovered Qiupalong in a clade with Struthiomimus and Ornithomimus, which they refer to as the "North American clade" (after Kobiyashi and Lü who recovered the same clade). This clade is diagnosed by a very acute angle between pubic shaft and boot and a tip of anterior extension of the pubic boot. They also comment on the discovery of some material from the Dinosaur Park Formation, that may also belong to this clade.[1] This material would later be described and referred to "Qiupalong sp.".[2]

Ornithomimosauria

More recent phylogenetic analyses have recovered mostly similar positions for Qiupalong (i.e. in a derived position closely-related to North American taxa). Examples of such analyses include Brusatte and colleagues (2014),[8] Serrano-Brañas and colleagues (2020),[9] and Hattori and colleagues (2023).[10]

Averianov and Dieter-Sues recovered a slightly different phylogeny

sister taxon of Ornithomimus and Struthiomimus as being the most basal member of this clade. The results of their analysis are shown below.[11]

Ornithomimidae

Paleoecology

Diet

The skull of Qiupalong is not known, although it is assumed that it was likely similar to other

edentulous and having a beak.[1][2] As such, no concrete hypotheses of the animal's diet have been made, although Cullen and colleagues suggested that it probably had a similar diet to other ornithomimids like Ornithomimus and Struthiomimus and may have even coexisted alongside them with minimal competition.[13]

Evolution and dispersal

North America and Asia were sporadically connected during the Cretaceous Period

Although the first remains of Qiupalong to be described were from

Bering Land Bridge, which has its origins in the Cretaceous.[3]

Qiupalong is not the only genus to exist on both continents. Both Saurolophus and Parasaurolophus (or possibly Charonosaurus) are known to have migrated from North America to Asia. Furthermore, it has been suggested that animals like Sinoceratops, Olorotitan, and Tarbosaurus are the descendants of animals which immigrated to Asia during this period. The exact time that this migration occurred is uncertain because the geochronology of Cretaceous Asia has not been studied as thoroughly as the geochronology of North America.[3][14]

Paleoenvironment

A map of the world during the Late Cretaceous
Belly River Group

The exact age of the North American specimens of Qiupalong is not confidently known. However the ages of the Oldman Formation and the Dinosaur Park Formation as a whole is relatively confidently known to have been deposited between 79.50 and 75.46 million years ago.[14]

The Dinosaur Park and Oldman formations are composed of sediments that were derived from the erosion of the mountains to the west. They were deposited on an alluvial to coastal plain by river systems that flowed eastward and southeastward to the Bearpaw Sea, a large inland sea that was part of the Western Interior Seaway. That sea gradually inundated the adjacent coastal plain, depositing the marine shales of the Bearpaw Formation on top of the Dinosaur Park Formation, which is in turn on top of the Oldman Formation.[15]

Qiupa Formation

The

Cretaceous Period.[16]

Contemporary fauna

Belly River Group
A herd of Centrosaurus, one of the most common animals in the lower Dinosaur Park Formation, crossing a river

The earliest record of Qiupalong is from either the

ornithomimosaurs.[13]

The remains of Qiupalong are from differing localities, some of which are unknown, but most of the material that is confidently assigned to individual localities are from the lower half of the Dinosaur Park Formation, about 20 meters above the contact with the Oldman Formation.[1] This corresponds to what has been called "Megaherbivore Assemblage Zone 1", the "Sandy zone", or the "Centrosaurus-Corythosaurus zone". This faunal stage would have obviously included Centrosaurus and Corythosaurus, but other animals from this time period included Euoplocephalus, Dyoplosaurus, Panoplosaurus, Chasmosaurus, Lambeosaurus, and Parasaurolophus.[14][17] These herbivores would have been preyed upon by the tyrannosaurids Gorgosaurus and Daspletosaurus, which are known to have coexisted.[18]

Small dinosaurs in general appear to have overlapped in their temporal distribution much more significantly. Most remains from small theropods are from the lower half of the Dinosaur Park Formation, where the remains of Qiupalong are believed to have originated. Qiupalong is believed to have coexisted with

bovids in Africa today. Qiupalong also likely coexisted with the three known caenagnathids from the area, Citipes, Chirostenotes, and Caenagnathus.[13]

Qiupa Formation
Some of the fauna of the Nemegt Formation, which was close in both space and time to the Qiupa Formation

The

Yulong.[20]

This environment was also home to a variety of other animals. These would have included

edentulous enantiornithine Yuornis.[4][21]

See also

References

  1. ^
    doi:10.1016/j.cretres.2010.12.004
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  2. ^
    doi:10.1139/facets-2016-0074
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  3. ^
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    doi:10.1007/s11430-011-4186-1
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  5. PMID 36122246
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  6. ISBN 978-0691180311
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  7. ^ Kobayashi, Yoshitsugu; Lü, Jun−Chang (2003). "A new ornithomimid dinosaur with gregarious habits from the Late Cretaceous of China". Acta Palaeontologica Polonica. 48 (2): 235–259.
  8. S2CID 8879023
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  9. S2CID 218968100
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  10. PMID 37679444
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    doi:10.1016/j.cretres.2015.07.012
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  12. doi:10.1016/j.jafrearsci.2012.05.005
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  13. ^
    doi:10.1139/cjes-2020-0145
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  14. ^
    PMID 29166406
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  15. ISBN 0-253-34595-2
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  16. ^ a b Alroy, John; Carrano, Matthew; Benson, Roger; Mannion, Philip (2021). "Qiupa, Luanchuan Basin (Cretaceous of China)". The Paleobiology Database.
  17. doi:10.1016/j.palaeo.2012.06.024
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  18. S2CID 85665879
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  19. doi:10.31035/cg2018005
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  20. PMID 23314810
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  21. doi:10.1017/S0016756821000807
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