Sinocalliopteryx

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Sinocalliopteryx
Temporal range: Early Cretaceous, 124.6  Ma
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Holotype of Sinocalliopteryx gigas.png
Holotype specimen JMP-V-05-8-01
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Compsognathidae
Genus: Sinocalliopteryx
Ji et al., 2007
Species:
S. gigas
Binomial name
Sinocalliopteryx gigas
Ji et al., 2007

Sinocalliopteryx (meaning 'Chinese beautiful feather') is a genus of carnivorous compsognathid theropod dinosaurs from the Lower Cretaceous Yixian Formation of China (Jianshangou Beds, dating to 124.6 Ma).

While similar to the related Huaxiagnathus , Sinocalliopteryx were larger. The type specimen, at 2.37 meters (7.78 ft) in length, in 2007 was the largest known compsognathid exemplar. In 2012 an even larger specimen was reported.

Discovery

Assigned specimen CAGS-IG-T1 Sinocalliopteryx.png
Assigned specimen CAGS-IG-T1

The type species Sinocalliopteryx gigas was named and described in 2007 by Ji Shu'an, Ji Qiang, Lü Junchang and Yuan Chongxi. The generic name is derived from Sinae, Latin for the Chinese and Greek καλός, kalos, "beautiful", and πτέρυξ, pteryx, "feather". The large size of this "giant compsognathid" lent Sinocalliopteryx its specific name, gigas, meaning 'giant'. [1]

The holotype, JMP-V-05-8-01, was discovered at Hengdaozi, in Sihetun, in Liaoning Province, from the Jianshangou Beds of the Yixian Formation dating from the Barremian-Aptian, about 125 million years old. It consists of a nearly complete skeleton with skull, compressed on a single plate, of an adult individual. Extensive remains of protofeathers have been preserved. [1] In 2012 a second specimen was described, CAGS-IG-T1, of an individual larger than the holotype. The skull was about 10% longer, the feet about a third, a difference explained by positive allometry. The specimen consists of a partial skull, tail, hands, feet and ribcage. It shows filaments on the tail. [2]

Description

Sinocalliopteryx was a bipedal predator. The preserved length of the holotype specimen is 237 centimetres. Its weight was estimated by Gregory S. Paul in 2010 at twenty kilogrammes. [3] Sinocalliopteryx is distinguished from Huaxiagnathus, as well as other compsognathids, by its relatively long hands in relation to its arms. The arms and hindlimbs were also longer overall than in other compsognathids, a feature possibly related to its size. [1]

Life restoration Sinocalliopteryx gigas.jpg
Life restoration

Sinocalliopteryx had an elongated head with a pointed snout, showing a convex upper profile. There were four teeth in the premaxilla which were small but exceptionally had denticles on their front edges. Only six, larger, teeth were present in the maxilla of the holotype specimen but the number of its tooth positions could not be adequately determined. Specimen CAGS-IG-T1 preserves ten maxillary tooth sockets with room for one or two more in damaged areas. The jugal was a strongly built element with a high-rising front branch that formed part of the lower front edge of the eye socket. The lower jaw lacked an opening in its outer side. [1] [2]

The vertebral column consisted of eleven cervical, twelve dorsal, five sacral and at least forty-nine caudal vertebrae. The point of the tail is missing. In the tail, the spines and chevrons strongly inclined to the back. The gastralia had very short lateral segments. [1]

The arm had a short humerus and also the lower arm was short and elegant with an ulna showing only a weakly developed olecranon process on its back upper end. The hand was very elongated though, as long as the ulna and upper arm combined. The second metacarpal was expanded at the top at the side of the first metacarpal, making the entire metacarpus more compact. The second claw was elongated, as long as the thumb claw. The third metacarpal was rather short and carried a thin, third, finger. [1]

In the pelvis there was a little notch in the front edge of the ilium. The relatively long shaft of the ischium curved downwards. The hindlimb was elongated, largely because of a long lower leg, having 90% of the length of the thighbone. The foot was also long, especially in the metatarsus. [1]

Like many other theropods of the Yixian Formation, Sinocalliopteryx was preserved with "protofeathers," simple filamentous integument (hairlike structures covering the skin), very similar to that found in Sinosauropteryx . The integument of Sinocalliopteryx differ in length across the body, with the longest protofeathers covering the hips, base of the tail, and back of the thighs. These longest protofeathers measured up to ten centimeters (4 in) in length. Protofeathers were also found on the metatarsus (upper part of the foot). While these were not nearly as long or modern as the corresponding feathers of "four-winged" dinosaurs such as Microraptor and Pedopenna , they do indicate that foot-feathers or similar structures first arose in dinosaurs much more basal or "primitive" than previously known. [1]

Classification

Sinocalliopteryx feeding on Sinornithosaurus Sinocalliopteryx gigas feeding on the dromaeosaur Sinornithosaurus - journal.pone.0044012.g008.png
Sinocalliopteryx feeding on Sinornithosaurus

Sinocalliopteryx was by its describers assigned to the Compsognathidae. [1]

This cladogram shows the position of Sinocalliopteryx in the Compsognathidae according to a study by dal Sasso & Maganuco in 2011: [4]

Tyrannoraptora

Here is a simplified version of Cau (2024) with Sinocalliopteryx in bold.

Tetanurae

The large size of Sinocalliopteryx compared to its relatives is also notable, and may indicate a trend towards large size among compsognathids (a group well known for their small size compared to other, giant theropod dinosaurs), similar to the trends towards larger sizes in other dinosaurian lineages. [1]

In 2024, Andrea Cau published a study on the phylogenetics of Compsognathids that called the assessment of Sinocalliopteryx into question. The paper recovered the taxon, along with four other proposed Compsognathids in a polytomy within basal Coelurosauria. This polytomy notably did not include Composognathus proper, which would make none of the these species Compsognathids. [5]

Paleobiology

Diet and feeding

Abdominal contents of Sinocalliopteryx JMP-V-05-8-01.png
Abdominal contents of the holotype
Undigested integument within the abdominal cavity of Sinocalliopteryx JMP-V-05-8-01.png
Undigested integument within the abdominal cavity of the holotype

The well-preserved skeleton of the Sinocalliopteryx holotype contained the partial leg of a dromaeosaurid within the abdominal cavity, comprising a complete lower leg and foot with toes and claws in their natural, articulated position. [2] While the leg part, about one foot long, is very large in relation to the abdominal cavity, it is clearly situated within it, lying between the ribs. Ji and colleagues in 2007 suggested that this could indicate it preyed upon the smaller, bird-like dinosaur. This discovery indicated that Sinocalliopteryx may have been an agile, active, "fierce" predator, especially since other compsognathids have been found with (presumably fast-moving) lizards and small mammals in their abdominal cavities. [1] In 2012 the dromaeosaurid was tentatively identified as an individual of Sinornithosaurus with a length of 1.2 metres (3.9 ft). The 2012 study also reported newly discovered remains of prey animals. Above the dromaeosaurid leg, feathers are visible. Below it two clusters of digested food can be seen. It was suggested that the feathers had belonged to a bird and were with the leg still present in the stomach. The digested food would, using the preserved digestive tract of Scipionyx as a reference, have been positioned in the duodenum. [2] The C-shaped abdominal contents of this specimen appear to reflect of the original contour of the digestive tract. [6]

Sinocalliopteryx feeding on Confuciusornis Sinocalliopteryx gigas feeding on the primitive bird Confuciusornis - journal.pone.0044012.g008.png
Sinocalliopteryx feeding on Confuciusornis

In addition to the dromaeosaurid leg, four irregularly-shaped stones with a diameter between fifteen and twenty millimetres were found in the abdomen, with no similar stones present in any other portions of the skeleton or embedded in the surrounding rock. The authors interpreted these as gastroliths (gizzard stones) similar to those found with Nqwebasaurus and Baryonyx . Other theropods, such as Caudipteryx and a Mongolian ornithomimid, were also found with gastroliths, though in those cases the stones were much more numerous and smaller in size. Ji and colleagues speculated that, since the later two dinosaurs were probably primarily herbivores, the number and size of gastroliths may correspond with diet; that is, herbivores ingested many small stones, while carnivores ingested only a few larger stones to aid in digestion. [1] However, the 2012 study could find no gastroliths with the second specimen and therefore concluded that the stones with the holotype were swallowed by accident. In any case no special gizzard would have been present. [2]

The second specimen, CAGS-IG-T1, also preserves the remains of several meals. Disarticulated bones were found, in front of the lower ischia, identified as belonging to at least two individuals of Confuciusornis sanctus, a basal bird that is very common in the formation. Also a 13.5 centimetres long scapula was discovered, belonging to some 1.5 metres (4.9 ft) long herbivorous ornithischian, perhaps Yueosaurus or a Psittacosaurus species. The bone surface of the scapula looked as if it had been etched by stomach acid for about thirteen days, leading to the conclusion the birds were swallowed later and in quick succession. This again would indicate a high metabolism for Sinocalliopteryx, necessitating a regular food intake. [2]

Stomach contents of CAGS-IG-T1 Abdominal contents of Sinocalliopteryx CAGS-IG-T1.png
Stomach contents of CAGS-IG-T1

That the second specimen in a short period of time caught two birds, together with the bird feather remains in the holotype stomach, might be an indication that Sinocalliopteryx specialised in such prey. Even the Sinornithosaurus might conform to this pattern as the authors considered it a possibly volant form. In 2011 a specimen of Microraptor was reported with a bird in its stomach and seen as proof that the former were arboreal. The 2012 study denied the relevance of flying prey for this issue as Sinocalliopteryx was in all likelihood cursorial, or ground-dwelling, and yet apparently quite capable of catching birds, e.g. by using stealth attack, a method employed by many modern cursorial predators of fowl. [2]

Related Research Articles

<i>Compsognathus</i> Genus of dinosaurs

Compsognathus is a genus of small, bipedal, carnivorous theropod dinosaur. Members of its single species Compsognathus longipes could grow to around the size of a chicken. They lived about 150 million years ago, during the Tithonian age of the late Jurassic period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany in the 1850s and the second in France more than a century later. Today, C. longipes is the only recognized species, although the larger specimen discovered in France in the 1970s was once thought to belong to a separate species and named C. corallestris.

<i>Caudipteryx</i> Genus of oviraptorosaur dinosaurs

Caudipteryx is a genus of small oviraptorosaur dinosaurs that lived in Asia during the Early Cretaceous, around 124.6 million years ago. They were feathered and extremely birdlike in their overall appearance, to the point that some paleontologists suggested it was a bird. Two species have been described: C. zoui, in 1998, and C. dongi, in 2000.

<i>Sinosauropteryx</i> Extinct genus of dinosaurs

Sinosauropteryx is a compsognathid dinosaur. Described in 1996, it was the first dinosaur taxon outside of Avialae to be found with evidence of feathers. It was covered with a coat of very simple filament-like feathers. Structures that indicate colouration have also been preserved in some of its feathers, which makes Sinosauropteryx the first non-avialian dinosaurs where colouration has been determined. The colouration includes a reddish and light banded tail. Some contention has arisen with an alternative interpretation of the filamentous impression as remains of collagen fibres, but this has not been widely accepted.

<span class="mw-page-title-main">Coelurosauria</span> Clade of dinosaurs

Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.

<i>Beipiaosaurus</i> Extinct genus of dinosaurs

Beipiaosaurus is a genus of therizinosauroid theropod dinosaurs that lived in Asia during the Early Cretaceous in the Yixian Formation. The first remains were found in 1996 and formally described in 1999. Before the discovery of Yutyrannus, Beipiaosaurus were among the heaviest dinosaurs known from direct evidence to be feathered. Beipiaosaurus is known from three reported specimens. Numerous impressions of feather structures were preserved that allowed researchers to determine the feathering color which turned out to be brownish.

<i>Sinornithosaurus</i> Extinct genus of dinosaurs

Sinornithosaurus is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaur genus discovered by 1999. The original specimen was collected from the Sihetun locality of western Liaoning. It was found in the Jianshangou beds of the Yixian Formation, dated to 124.5 million years ago. Additional specimens have been found in the younger Dawangzhangzi bed, dating to around 122 million years ago.

<i>Bambiraptor</i> Extinct genus of dinosaurs

Bambiraptor is a Late Cretaceous, 72-million-year-old, bird-like dromaeosaurid theropod dinosaur described by scientists at the University of Kansas, Yale University, and the University of New Orleans.

<i>Jinfengopteryx</i> Theropod dinosaur genus

Jinfengopteryx is a genus of maniraptoran dinosaur. It was found in the Qiaotou Member of the Huajiying Formation of Hebei Province, China, and is therefore of uncertain age. The Qiaotou Member may correlate with the more well-known Early Cretaceous Yixian Formation, and so probably dates to around 122 Ma ago.

<i>Yixianosaurus</i> Extinct genus of dinosaurs

Yixianosaurus is a maniraptoran theropod dinosaur genus from the Early Cretaceous of China.

<span class="mw-page-title-main">Microraptoria</span> Extinct clade of dinosaurs

Microraptoria is a clade of basal dromaeosaurid theropod dinosaurs. The first microraptorians appeared 125 million years ago in China. Many are known for long feathers on their legs and may have been semiarboreal powered fliers, some of which were even capable of launching from the ground. Most microraptorians were relatively small; adult specimens of Microraptor range between 77–90 centimetres long (2.53–2.95 ft) and weigh up to 1 kg (2.2 lb), making them some of the smallest known nonavialan dinosaurs.

<i>Scipionyx</i> Extinct genus of dinosaurs

Scipionyx was a genus of theropod dinosaur from the Early Cretaceous of Italy, around 113 million years ago.

<i>Juravenator</i> Extinct genus of dinosaurs

Juravenator is a genus of small coelurosaurian theropod dinosaur, which lived in the area which would someday become the top of the Franconian Jura of Germany, about 151 or 152 million years ago. It is known from a single, juvenile specimen.

<i>Huaxiagnathus</i> Extinct genus of dinosaurs

Huaxiagnathus is a genus of theropod dinosaur from the Lower Cretaceous of China. It was a compsognathid, large for that group at about half a meter longer than Compsognathus and larger specimens of Sinosauropteryx, with the largest specimen about 1.8 meters in length.

<i>Graciliraptor</i> Extinct genus of dinosaurs

Graciliraptor is a genus of theropod dinosaur from the early Cretaceous Period. It is a microraptorine dromaeosaurid.

<span class="mw-page-title-main">Compsognathidae</span> Extinct family of dinosaurs

Compsognathidae is a family of coelurosaurian theropod dinosaurs. Compsognathids were small carnivores, generally conservative in form, hailing from the Jurassic and Cretaceous Periods. The bird-like features of these species, along with other dinosaurs such as Archaeopteryx inspired the idea for the connection between dinosaur reptiles and modern-day avian species. Compsognathid fossils preserve diverse integument — skin impressions are known from four genera commonly placed in the group, Compsognathus, Sinosauropteryx, Sinocalliopteryx, and Juravenator. While the latter three show evidence of a covering of some of the earliest primitive feathers over much of the body, Juravenator and Compsognathus also show evidence of scales on the tail or hind legs. "Ubirajara jubatus", informally described in 2020, had elaborate integumentary structures on its back and shoulders superficially similar to the display feathers of a standardwing bird-of-paradise, and unlike any other non-avian dinosaur currently described.

<i>Tianyuraptor</i> Extinct genus of dinosaurs

Tianyuraptor is a genus of short-armed dromaeosaurid dinosaur that lived during the Early Cretaceous, about 122 million years ago. Its remains have been found in western Liaoning, China. It was similar to other dromaeosaurids found in Liaoning, with the exception of being somewhat more primitive. The type specimen, formally named in 2009, shows features not seen in previously known Northern Hemisphere (Laurasian) dromaeosaurids, but present in Southern Hemisphere (Gondwanan) species and early birds. Because of this, the scientists who first studied Tianyuraptor described it as a "transitional species", bridging the gap between northern and southern types of dromaeosaurid. Tianyuraptor also differs from previously known dromaeosaurids in that it possesses a relatively small furcula ("wishbone"), and unusually short forelimbs.

<i>Zhenyuanlong</i> Extinct genus of dinosaurs

Zhenyuanlong is a genus of dromaeosaurid dinosaur from the Yixian Formation of Liaoning, China. It lived during the Aptian age of the early Cretaceous period, approximately 125 million years ago. It is known from a single specimen belonging to the species Zhenyuanlong suni. This type specimen preserved a nearly complete skeleton that contains traces of feathers, including long tail feathers and large wings. In addition to further complicating diversity of Liaoning dromaeosaurids, this specimen provides the first direct evidence of well-developed pennaceous feathers in a large, non-flying dromaeosaur, raising the question of what function such wings would serve.

"Beipiaognathus" is a dubious genus of coelurosaurian theropod from the Early Cretaceous Yixian Formation of Liaoning, China. The type species is "Beipiaognathus jii" and it was named and described by Hu et al. in 2016.

<i>Zhongjianosaurus</i> Extinct genus of reptiles

Zhongjianosaurus is a genus of dromaeosaurid belonging to the Microraptoria. Believed to hail from the Yixian Formation, specifically the middle of the Jehol Biota, it is the smallest known microraptorine thus far discovered and one of the smallest non-avian theropod dinosaurs.

<i>Xunmenglong</i> Extinct genus of dinosaurs

Xunmenglong is a genus of compsognathid theropod dinosaur from the Huajiying Formation from Hebei Province in China. The type and only species is Xunmenglong yinliangis. The holotype material consists of a pelvis, tail base and hindlimbs that had previously been part of a chimera containing three different animals. The animal is described as being the smallest known member of Compsognathidae, being about the size of the sub-adult Scipionyx holotype specimen or approximately 0.5 meters in length.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 Ji, S., Ji, Q., Lu J., and Yuan, C. (2007). "A new giant compsognathid dinosaur with long filamentous integuments from Lower Cretaceous of Northeastern China." Acta Geologica Sinica, 81(1): 8-15
  2. 1 2 3 4 5 6 7 Lida Xing, Phil R. Bell, W. Scott Persons IV, Shuan Ji, Tetsuto Miyashita, Michael E. Burns, Qiang Ji, Philip J. Currie, 2012, "Abdominal Contents from Two Large Early Cretaceous Compsognathids (Dinosauria: Theropoda) Demonstrate Feeding on Confuciusornithids and Dromaeosaurids", PLoS ONE7(8): e44012. doi : 10.1371/journal.pone.0044012
  3. Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 121
  4. Cristiano dal Sasso & Simone Maganuco, 2011, Scipionyx samniticus (Theropoda: Compsognathidae) from the Lower Cretaceous of Italy — Osteology, ontogenetic assessment, phylogeny, soft tissue anatomy, taphonomy and palaeobiology. Memorie della Società Italiana de Scienze Naturali e del Museo Civico di Storia Naturale di MilanoXXXVII(I): 1-281
  5. Cau, Andrea (2024). "A Unified Framework for Predatory Dinosaur Macroevolution" (PDF). Bollettino della Società Paleontologica Italiana. 63: 1-19. doi:10.4435/BSPI.2024.08.
  6. Dal Sasso C, Maganuco S (2011) Scipionyx samniticus (Theropoda: Compsognathidae) from the Lower Cretaceous of Italy; osteology, ontogenetic assessment, phylogeny, soft tissue anatomy taphonomy and palaeobiology. Memorie 37: 1–281. doi : 10.1080/08912963.2012.654705.