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Caihong juji
Jurassic Carnivore

Rainbow with a big crest

Caihong juji

"rainbow with a big crest"

Period
Jurassic · Oxfordiano
Lived
161–160 Ma
Length
up to 0.4 m
Estimated weight
0.475 kg
Country of origin
China
Described in
2018 by Hu, D., Clarke, J.A., Eliason, C.M., Qiu, R., Li, Q., Shawkey, M.D., Zhao, C., D'Alba, L., Jiang, J., Xu, X.

About this species

Caihong juji is a small paravian theropod from the Late Jurassic of China whose name comes from Mandarin and means rainbow with a big crest. It measures about 40 centimeters in length and weighs approximately 475 grams, placing it among the smallest known non-avian dinosaurs. The holotype PMoL-B00175, a nearly complete skeleton preserved on slab and counterslab, was found by a local farmer in 2014 in rocks of the Tiaojishan Formation, in the Qinglong Manchu Autonomous County, Hebei Province, and formally described in 2018 by an international team led by Dongyu Hu and Julia Clarke, with Xing Xu, Matthew Shawkey, and other Chinese, American, and European co-authors. Its surprising anatomy includes an elongated bony crest on the snout, formed by expanded lacrimal bones, combined with long asymmetrical pennaceous feathers on the forelimbs and along the entire tail, a morphological package without parallel in the Jurassic record. This geometry suggests Caihong already displayed elaborate ornamental surfaces long before it was capable of sustained powered flight. The most remarkable feature was revealed by scanning electron microscopy: thousands of fossilized melanosomes in feathers of the neck, chest, and base of the tail show a platelet shape, a nanostructure virtually identical to that found in living hummingbirds. In modern birds, this arrangement produces structural iridescence that shifts with the angle of incident light, so that the same individual may appear metallic green, blue, or red with subtle movements. Applying the same principle to the fossil, the authors concluded that parts of Caihong's body shimmered in metallic tones, likely in blue, green, and reddish bands, indeed recalling the rainbow that gives the genus its name. This is the first direct evidence of iridescent plumage in a non-avian dinosaur, pushing back the minimum record of this kind of coloration by roughly 40 million years, which had previously been known only in the Early Cretaceous Microraptor. The simultaneous presence of a bony crest and ornamental feathers indicates that complex visual signals, most likely linked to sexual display or species recognition, were already established at the base of Paraves. Positioned phylogenetically as an anchiornithid close to Anchiornis, Xiaotingia, and Aurornis, Caihong reinforces the idea that the origin of birds was not a linear sequence of aerodynamic innovations, but a parallel evolutionary experiment with multiple small, feathered, visually striking lineages across the Jurassic of Asia. The find also consolidates the Qinglong and Liaoning region as a global epicenter of soft-tissue paleobiology, thanks to exceptional preservation in the volcanic tuffs of the Yanliao Biota, where periodic ashfalls blanketed anoxic lakes and locked feathers, melanosomes, and even subcellular nanostructures into the sediment. For science, Caihong juji marks the moment when we stopped imagining dinosaurs in faded earth tones and began to recognize that some of them competed for mates and chased off rivals by flashing optical sparks very similar to those that today glint on the chests of hummingbirds.

Geological formation & environment

The Tiaojishan Formation is a volcaniclastic sequence from the Middle to Late Jurassic (Callovian to Oxfordian, roughly 165 to 156 million years ago), spanning Hebei, Liaoning, and Inner Mongolia in northeastern China. It is the core unit of the Yanliao Biota, a lacustrine ecosystem with exceptional soft-tissue preservation driven by periodic ashfalls over anoxic lakes. Its fauna is rich in small paravians, salamanders, insects, pterosaurs, and early modern mammals, and has produced some of the most relevant fossils for understanding the origin of birds, including Anchiornis, Xiaotingia, Eosinopteryx, Aurornis, and Caihong juji.

Image gallery

Ecology and behavior

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Habitat

Caihong juji inhabited temperate to subtropical forests along the margins of volcanic lakes in what is now northeastern China during the Oxfordian of the Late Jurassic, about 161 million years ago. The Tiaojishan Formation is part of the Yanliao Biota, a lacustrine ecosystem well preserved in volcanic tuffs and shales, with dense gymnosperm forests. The same context hosted other small paravians such as Anchiornis, Xiaotingia, and Eosinopteryx, pterosaurs like Darwinopterus, salamanders like Jeholotriton, diverse insects, and small basal mammals.

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Feeding

Its small, numerous, serrated teeth, combined with a diminutive 40-centimeter body, indicate a diet composed mainly of insects and small vertebrates such as lizards, amphibians, and occasional nests of other paravians. Limb proportions suggest active hunting on the forest floor and among low vegetation, with probable climbing ability on trunks and branches.

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Behavior and senses

The combination of an elongated bony snout crest, long asymmetrical feathers on wings and tail, and iridescent plumage on neck, chest, and base of tail suggests strongly developed visual display behavior, likely linked to sexual selection or species recognition. Despite aerodynamically sophisticated feathers, limb morphology and the lack of robust sternal adaptations indicate Caihong juji did not yet engage in sustained powered flight; at most it may have performed short glides or cushioned leaps between low branches.

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Physiology and growth

The density and quality of feathers throughout the body point to endothermic metabolism, typical of small paravians. The most extraordinary finding is structural: platelet-shaped melanosomes, statistically identical to those of modern hummingbirds, were identified in feathers of the neck, chest, and base of the tail. In living birds this geometry produces structural iridescence that shifts from green to blue to red depending on the angle of light. Caihong juji is therefore the oldest known record of this type of nanostructure, pushing the origin of iridescence in dinosaurs to at least 161 million years ago.

Paleogeography

Continental configuration

Mapa paleogeográfico do Jurassic (~90 Ma)

Ron Blakey · CC BY 3.0 · Jurassic, ~90 Ma

During the Oxfordiano (~161–160 Ma), Caihong juji inhabited the fragmenting Pangea. North America and Europe were still close, and the North Atlantic was just beginning to open. Climate was warm and humid globally, with no polar ice caps.

Bone Inventory

Estimated completeness 92%

The holotype PMoL-B00175 is a nearly complete articulated skeleton preserved on slab and counterslab, with pennaceous feather impressions on the forelimbs, hindlimbs, and tail. The skull preserves the diagnostic lacrimal crest, and platelet-shaped melanosomes were identified in feathers of the neck, chest, and base of the tail. It is the only known specimen of the species.

Found (15)
Inferred (2)
Esqueleto de dinossauro — theropod
Wikimédia Commons / Scott Hartman CC BY-SA 3.0

Found elements

skulllower_jawvertebraeribsfurculascapulahumerusradiusulnahandpelvisfemurtibiafibulafoot

Inferred elements

complete_skinsoft_tissue

Scientific Literature

15 papers in chronological order — from the original description to recent research.

2018

A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution (parte 1: osteologia e holótipo)

Hu, D., Clarke, J.A., Eliason, C.M., Qiu, R., Li, Q., Shawkey, M.D., Zhao, C., D'Alba, L., Jiang, J., Xu, X. · Nature Communications

In this first part of the founding paper, Hu and colleagues present the holotype PMoL-B00175 and detail the overall anatomy of the new taxon. The skeleton is articulated, with the skull preserving the diagnostic lacrimal crest, long and tall, which gives the species its name. The authors describe vertebral morphology, pectoral girdle, and limbs, highlighting proportions typical of small paravians. The combination of bony crest, serrated teeth, and limb proportions justifies the erection of a new genus distinct from other anchiornithids known from the region.

Holotype PMoL-B00175 of Caihong juji on slab and counterslab, with interpretive drawing of preserved elements. Figure 1 of Hu et al. (2018).

Holotype PMoL-B00175 of Caihong juji on slab and counterslab, with interpretive drawing of preserved elements. Figure 1 of Hu et al. (2018).

Vertebral column of the holotype, highlighting the morphology of cervical and dorsal vertebrae. Figure 2 of Hu et al. (2018).

Vertebral column of the holotype, highlighting the morphology of cervical and dorsal vertebrae. Figure 2 of Hu et al. (2018).

Caihong juji holotype specimen (PMoL-B00175). Photographs of the slab (a) and counter slab (b) and line drawing (c) of the specimen based on both

Caihong juji holotype specimen (PMoL-B00175). Photographs of the slab (a) and counter slab (b) and line drawing (c) of the specimen based on both

Photographs of the pectoral girdle and limbs of Caihong juji. a Right scapula and coracoid in medial and proximal views; b right forelimb; c left manus;

Photographs of the pectoral girdle and limbs of Caihong juji. a Right scapula and coracoid in medial and proximal views; b right forelimb; c left manus;

2018

A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution (parte 2: cintura peitoral, membros e penas)

Hu, D., Clarke, J.A., Eliason, C.M., Qiu, R., Li, Q., Shawkey, M.D., Zhao, C., D'Alba, L., Jiang, J., Xu, X. · Nature Communications

The second part of the paper describes in detail the pectoral girdle, the hand, and the distribution of feathers. Wing feathers are pennaceous and asymmetrical, with a curved rachis, and are aligned on both forelimbs and legs. The entire tail is covered by long rectrices. The presence of an alula-like structure, a small group of feathers on the first digit, indicates that aerodynamic elements appeared before the origin of powered flight. The contrast between ornamental crest, asymmetrical wings, and feathered tail suggests strong sexual selection pressure on visual surfaces.

Pectoral girdle and limbs of Caihong juji, including details of the hand and foot. Figure 3 of Hu et al. (2018).

Pectoral girdle and limbs of Caihong juji, including details of the hand and foot. Figure 3 of Hu et al. (2018).

Preserved feathers on neck, chest, forelimbs (remiges and alula), hindlimbs, and tail (rectrices). Figure 4 of Hu et al. (2018).

Preserved feathers on neck, chest, forelimbs (remiges and alula), hindlimbs, and tail (rectrices). Figure 4 of Hu et al. (2018).

2018

A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution (parte 3: iridescência e filogenia)

Hu, D., Clarke, J.A., Eliason, C.M., Qiu, R., Li, Q., Shawkey, M.D., Zhao, C., D'Alba, L., Jiang, J., Xu, X. · Nature Communications

The third part of the paper presents the central finding: highly organized platelet-shaped melanosomes were identified in feathers of the neck, chest, and base of the tail. These nanostructures are statistically comparable to those of modern hummingbirds, whose iridescent coloration ranges from metallic green to vivid red through shades of blue. This is the first evidence of iridescent plumage in a non-avian dinosaur, preceding earlier records in Microraptor by roughly 40 million years. The phylogenetic analysis, based on a strict consensus of 192 equally parsimonious trees, places Caihong juji close to other anchiornithids, near the base of Paraves, alongside lineages that would give rise to modern birds.

Comparison between platelet-shaped nanostructures preserved in Caihong juji and melanosomes of modern iridescent birds, highlighting hummingbirds. Figure 5 of Hu et al. (2018).

Comparison between platelet-shaped nanostructures preserved in Caihong juji and melanosomes of modern iridescent birds, highlighting hummingbirds. Figure 5 of Hu et al. (2018).

Diversity of nanostructure shapes in fossil and extant feathers, combined with a cladogram of coelurosaurs showing the position of Caihong juji at the base of Paraves. Figure 6 of Hu et al. (2018).

Diversity of nanostructure shapes in fossil and extant feathers, combined with a cladogram of coelurosaurs showing the position of Caihong juji at the base of Paraves. Figure 6 of Hu et al. (2018).

2011

An Archaeopteryx-like theropod from China and the origin of Avialae

Xu, X., You, H., Du, K., Han, F. · Nature

Xu and colleagues describe Xiaotingia zhengi, a small paravian from the Tiaojishan Formation, and propose a reorganization of the phylogeny of early birds that places Archaeopteryx outside Avialae, grouped with dromaeosaurids. The analysis is relevant to Caihong juji because it shares the same geological context and the same debate about which taxa are the direct ancestors of birds. In the 2018 description of Caihong, Xiaotingia appears as one of its closest relatives within Anchiornithidae.

Comparative image: Xiaotingia zhengi, an anchiornithid from the same Tiaojishan Formation and one of the closest relatives of Caihong juji according to Xu et al. (2011).

Comparative image: Xiaotingia zhengi, an anchiornithid from the same Tiaojishan Formation and one of the closest relatives of Caihong juji according to Xu et al. (2011).

Comparative image: Aurornis, a basal paravian close to Anchiornis and Caihong, is part of the phylogenetic debate reorganized by Xu et al. (2011).

Comparative image: Aurornis, a basal paravian close to Anchiornis and Caihong, is part of the phylogenetic debate reorganized by Xu et al. (2011).

2010

Plumage color patterns of an extinct dinosaur

Li, Q., Gao, K.Q., Vinther, J., Shawkey, M.D., Clarke, J.A., D'Alba, L., Meng, Q., Briggs, D.E.G., Prum, R.O. · Science

First study to reconstruct the complete coloration pattern of a Mesozoic dinosaur, Anchiornis huxleyi, using the shape and density of melanosomes preserved in the feathers. The authors show it is possible to infer color in fossils when nanostructure geometry is compared to a database of modern birds. This methodological framework paved the way for later iridescence studies in Microraptor and Caihong juji, both analyzed by the same team.

Comparative image: peacock plumage, a classic example of structural coloration in modern birds, useful as a visual reference for the melanosome studies applied by Li et al. (2010).

Comparative image: peacock plumage, a classic example of structural coloration in modern birds, useful as a visual reference for the melanosome studies applied by Li et al. (2010).

Comparative image: Magnificent Hummingbird, whose iridescence is produced by platelet-shaped melanosomes analogous to those found in Caihong juji, the methodology initiated by Li et al. (2010).

Comparative image: Magnificent Hummingbird, whose iridescence is produced by platelet-shaped melanosomes analogous to those found in Caihong juji, the methodology initiated by Li et al. (2010).

2008

The colour of fossil feathers

Vinther, J., Briggs, D.E.G., Prum, R.O., Saranathan, V. · Biology Letters

Seminal paper that for the first time demonstrates structures previously interpreted as bacteria in fossil feathers are in fact preserved melanosomes. Vinther and colleagues opened the field of paleobiology of structural and pigmentary color. Without this foundational work, inferring iridescence in Caihong juji in 2018 would not have been possible.

Comparative image: the rainbow, an optical phenomenon that inspires the name Caihong and illustrates the idea of angle-dependent coloration, central to the structural color studies initiated by Vinther et al. (2008).

Comparative image: the rainbow, an optical phenomenon that inspires the name Caihong and illustrates the idea of angle-dependent coloration, central to the structural color studies initiated by Vinther et al. (2008).

Comparative image: modern hummingbird, a direct reference used in fossil color studies following the foundational work of Vinther et al. (2008).

Comparative image: modern hummingbird, a direct reference used in fossil color studies following the foundational work of Vinther et al. (2008).

2010

Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds

Zhang, F., Kearns, S.L., Orr, P.J., Benton, M.J., Zhou, Z., Johnson, D., Xu, X., Wang, X. · Nature

Zhang and colleagues infer, from Sinosauropteryx melanosomes, that this feathered dinosaur had a color pattern with reddish tail bands. The method applied to Sinosauropteryx is the same that, combined with the advance by Li et al. (2010) on Anchiornis, allowed the diagnosis of iridescence in Caihong juji in 2018.

Comparative image: Serikornis, a paravian with preserved feathers from the Upper Jurassic of China, illustrates the type of fossil material analyzed by studies derived from Zhang et al. (2010).

Comparative image: Serikornis, a paravian with preserved feathers from the Upper Jurassic of China, illustrates the type of fossil material analyzed by studies derived from Zhang et al. (2010).

Comparative image: Jinfengopteryx, a basal feathered troodontid from China, one of many taxa whose feathers were reassessed following the techniques introduced by Zhang et al. (2010).

Comparative image: Jinfengopteryx, a basal feathered troodontid from China, one of many taxa whose feathers were reassessed following the techniques introduced by Zhang et al. (2010).

Figure 1: Melanosomes in an isolated pennaceous feather (IVPP V15388B).

Figure 1: Melanosomes in an isolated pennaceous feather (IVPP V15388B).

Figure 2: Melanosomes in feathers of the bird Confuciusornis (IVPP V13171).

Figure 2: Melanosomes in feathers of the bird Confuciusornis (IVPP V13171).

Figure 3: Melanosomes in the integumentary filaments of the dinosaur Sinosauropteryx (IVPP V14202).

Figure 3: Melanosomes in the integumentary filaments of the dinosaur Sinosauropteryx (IVPP V14202).

Figure 4: Melanosomes in the integumentary filaments of the dinosaur Sinornithosaurus (IVPP V12811).

Figure 4: Melanosomes in the integumentary filaments of the dinosaur Sinornithosaurus (IVPP V12811).

2012

Reconstruction of Microraptor and the evolution of iridescent plumage

Li, Q., Gao, K.Q., Meng, Q., Clarke, J.A., Shawkey, M.D., D'Alba, L., Pei, R., Ellison, M., Norell, M.A., Vinther, J. · Science

Before Caihong juji, Microraptor was the only non-avian dinosaur with evidence of iridescent plumage, identified by Li and colleagues in 2012. The authors showed that narrow, organized melanosomes revealed iridescent black coloration. The discovery in Caihong six years later pushes back the minimum record of dinosaur iridescence by roughly 40 million years, from the Early Cretaceous to the Late Jurassic.

Comparative image: Inkayacu paracasensis, a fossil penguin whose plumage was reconstructed with a method analogous to that applied by Li et al. (2012) to Microraptor.

Comparative image: Inkayacu paracasensis, a fossil penguin whose plumage was reconstructed with a method analogous to that applied by Li et al. (2012) to Microraptor.

Comparative image: Juravenator, a small theropod from the Late Jurassic of Germany with preserved integumentary tissues, the same type of material investigated by Li et al. (2012).

Comparative image: Juravenator, a small theropod from the Late Jurassic of Germany with preserved integumentary tissues, the same type of material investigated by Li et al. (2012).

2010

Fossil evidence for evolution of the shape and color of penguin feathers

Clarke, J.A., Ksepka, D.T., Salas-Gismondi, R., Altamirano, A.J., Shawkey, M.D., D'Alba, L., Vinther, J., DeVries, T.J., Baby, P. · Science

Clarke and colleagues describe Inkayacu paracasensis, a fossil penguin from the Eocene of Peru, and use preserved melanosomes to show that its plumage was gray and reddish-brown, in contrast to the black-and-white pattern of modern species. The work expands the use of melanosome signatures as a proxy for coloration and involves members of the same team that would later describe iridescence in Caihong juji.

Comparative image: Scansoriopteryx, a paravian with climbing and gliding adaptations, illustrates the morphological diversity in which Clarke et al.'s (2010) methodology is embedded.

Comparative image: Scansoriopteryx, a paravian with climbing and gliding adaptations, illustrates the morphological diversity in which Clarke et al.'s (2010) methodology is embedded.

Comparative image: Epidexipteryx, a scansoriopterygid with four long ornamental tail feathers, another Jurassic example of visual display studied by the same methodological group as Clarke et al. (2010).

Comparative image: Epidexipteryx, a scansoriopterygid with four long ornamental tail feathers, another Jurassic example of visual display studied by the same methodological group as Clarke et al. (2010).

2006

Anatomy, physics, and evolution of structural colors

Prum, R.O. · Bird Coloration, volume 1 (Harvard University Press)

Classic chapter in which Richard Prum formalizes the physical theory behind structural coloration in birds, including angle dependence and the nanoscale organization of structures that produce iridescence. This is the theoretical framework used by Hu et al. (2018) to infer that the platelet-shaped melanosomes of Caihong juji produced iridescent coloration analogous to that of hummingbirds.

Comparative image: Epidexipteryx hui, a Jurassic paravian used as a case study in the discussion of visual display in basal theropods, a central theme of Prum's (2006) chapter.

Comparative image: Epidexipteryx hui, a Jurassic paravian used as a case study in the discussion of visual display in basal theropods, a central theme of Prum's (2006) chapter.

Comparative image: Sinornithosaurus millenii, a Chinese feathered dromaeosaurid, a recurring reference in discussions of structural color in paravians applied by Prum (2006).

Comparative image: Sinornithosaurus millenii, a Chinese feathered dromaeosaurid, a recurring reference in discussions of structural color in paravians applied by Prum (2006).

2009

A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin

Xu, X., Zhao, Q., Norell, M.A., Sullivan, C., Hone, D., Erickson, G., Wang, X., Han, F., Guo, Y. · Chinese Science Bulletin

Redescription of Anchiornis huxleyi based on additional specimens from the Tiaojishan Formation, consolidating the genus as a central piece in the dinosaur-bird transition. The same geological context would later yield the holotype of Caihong juji, indicating that the Qinglong/Liaoning region preserved a genuine epicenter of paravian diversity during the Late Jurassic.

Comparative image: Sinornithoides youngi, a troodontid close to Anchiornis in phylogenetic discussions, part of the same methodological context as Xu et al. (2009).

Comparative image: Sinornithoides youngi, a troodontid close to Anchiornis in phylogenetic discussions, part of the same methodological context as Xu et al. (2009).

Comparative image: Jinfengopteryx elegans, a small feathered Chinese paravian, illustrates the core morphological group in Xu et al. (2009) and not far from Caihong juji.

Comparative image: Jinfengopteryx elegans, a small feathered Chinese paravian, illustrates the core morphological group in Xu et al. (2009) and not far from Caihong juji.

2012

A review of dromaeosaurid systematics and paravian phylogeny

Turner, A.H., Makovicky, P.J., Norell, M.A. · Bulletin of the American Museum of Natural History

Comprehensive monograph on the systematics of Dromaeosauridae and the phylogeny of Paraves. The cladogram produced by Turner and colleagues provided much of the character matrix that Hu et al. (2018) used, with modifications, to place Caihong juji at the base of Paraves, within Anchiornithidae.

Comparative image: Jianianhualong, a feathered Chinese troodontid with asymmetrical rectrices, an example of the phylogenetic diversity analyzed by Turner et al. (2012).

Comparative image: Jianianhualong, a feathered Chinese troodontid with asymmetrical rectrices, an example of the phylogenetic diversity analyzed by Turner et al. (2012).

Comparative image: Balaur bondoc, a European Late Cretaceous paravian with unusual anatomy, reassessed within the phylogenetic scheme proposed by Turner et al. (2012).

Comparative image: Balaur bondoc, a European Late Cretaceous paravian with unusual anatomy, reassessed within the phylogenetic scheme proposed by Turner et al. (2012).

2014

A new long-tailed basal bird from the Lower Cretaceous of north-eastern China

Lefèvre, U., Hu, D., Escuillié, F., Dyke, G., Godefroit, P. · Biological Journal of the Linnean Society

Work that describes Jianianhualong and revisits the phylogenetic position of Eosinopteryx and Aurornis, raising the hypothesis of synonymy with Anchiornis. This debate about the taxonomic integrity of Anchiornithidae is directly relevant to Caihong juji, which remains a distinct genus thanks to its bony crest, a unique character in the group.

Comparative image: Jeholopterus, a feathered anurognathid pterosaur from the Chinese Jurassic, shares environments with anchiornithids discussed by Lefèvre et al. (2014).

Comparative image: Jeholopterus, a feathered anurognathid pterosaur from the Chinese Jurassic, shares environments with anchiornithids discussed by Lefèvre et al. (2014).

Comparative image: Darwinopterus, a transitional pterosaur from the same geological interval as the Tiaojishan Formation, part of the Yanliao biota in which Caihong juji was found.

Comparative image: Darwinopterus, a transitional pterosaur from the same geological interval as the Tiaojishan Formation, part of the Yanliao biota in which Caihong juji was found.

2014

New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers

Foth, C., Tischlinger, H., Rauhut, O.W.M. · Nature

Foth and colleagues describe the eleventh specimen of Archaeopteryx, preserving feathers all over the body. The authors argue that extensive pennaceous plumage evolved initially for visual display and was only later co-opted for flight. This hypothesis is reinforced by Caihong juji, which already shows long asymmetrical ornamental feathers associated with a bony crest, with no evidence of active flight capability.

Comparative image: Archaeopteryx, the Jurassic European avialan, the central reference in the discussions of pennaceous feather evolution led by Foth et al. (2014).

Comparative image: Archaeopteryx, the Jurassic European avialan, the central reference in the discussions of pennaceous feather evolution led by Foth et al. (2014).

Comparative image: Caudipteryx, an oviraptorosaur with pennaceous feathers on wings and tail, a classic case used to discuss plumage evolution with ornamental function, in line with Foth et al. (2014).

Comparative image: Caudipteryx, an oviraptorosaur with pennaceous feathers on wings and tail, a classic case used to discuss plumage evolution with ornamental function, in line with Foth et al. (2014).

2013

A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds

Godefroit, P., Cau, A., Hu, D., Escuillié, F., Wu, W., Dyke, G. · Nature

Godefroit and colleagues describe Aurornis xui and include Eosinopteryx in their analysis, proposing a revised phylogeny in which Archaeopteryx returns to Avialae and anchiornithids occupy a nearby position. This phylogenetic matrix is one of the bases used by Hu et al. (2018) to place Caihong juji, consolidating Anchiornithidae as a critical group for understanding the base of birds.

Comparative image: Eosinopteryx, a Chinese Jurassic paravian included by Godefroit et al. (2013) as a possible close relative of Caihong juji and other anchiornithids.

Comparative image: Eosinopteryx, a Chinese Jurassic paravian included by Godefroit et al. (2013) as a possible close relative of Caihong juji and other anchiornithids.

Comparative image: Zhenyuanlong, a feathered Early Cretaceous Chinese dromaeosaurid, illustrates the continuity of long-feather display documented since the Jurassic by Godefroit et al. (2013).

Comparative image: Zhenyuanlong, a feathered Early Cretaceous Chinese dromaeosaurid, illustrates the continuity of long-feather display documented since the Jurassic by Godefroit et al. (2013).

Figure 1: Aurornis xui YFGP-T5198.

Figure 1: Aurornis xui YFGP-T5198.

Figure 2: Selected skeletal elements of Aurornis xui YFGP-T5198.

Figure 2: Selected skeletal elements of Aurornis xui YFGP-T5198.

Figure 3: Phylogenetic relationships of Aurornis xui among coelurosaurian theropods.

Figure 3: Phylogenetic relationships of Aurornis xui among coelurosaurian theropods.

Famous museum specimens

PMoL-B00175 (holótipo) — Paleontological Museum of Liaoning, Shenyang

Wikimedia Commons, CC BY-SA 4.0

PMoL-B00175 (holótipo)

Paleontological Museum of Liaoning, Shenyang

Completeness: esqueleto quase completo com impressões de penas
Found in: 2014
By: fazendeiro local

Slab and counterslab preserving the articulated skeleton, the diagnostic lacrimal bony crest, and pennaceous feather impressions on the forelimbs, hindlimbs, and tail. Platelet-shaped melanosomes were identified in feathers of the neck, chest, and base of the tail, supporting the inference of iridescent plumage. Only known specimen of the species.

Classification

Dinosauria
└ Saurischia
└ Theropoda
└ Coelurosauria
└ Paraves
└ Anchiornithidae
└ Caihong

Discovery

First fossil
2014
Discoverer
fazendeiro local
Formal description
2018
Described by
Hu, D., Clarke, J.A., Eliason, C.M., Qiu, R., Li, Q., Shawkey, M.D., Zhao, C., D'Alba, L., Jiang, J., Xu, X.
Formation
Formação Tiaojishan
Region
Hebei (Condado Autônomo Manchu de Qinglong)
Country
China
📄 Original description paper

Fun fact

First evidence of iridescent plumage in a non-avian dinosaur, the preserved platelet-shaped melanosomes are analogous to those of modern hummingbirds, suggesting Caihong displayed vivid rainbow-like colors that inspired its name.