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In Living Color (Maybe)

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With the increasing number of studies on the emerging field of fossil color, a guide to our current tally of fossil dinosaurs with known coloration is likely of interest. With the exception of Borealopelta, this guide only includes colors inferred from direct examination of preserved melanosomes, thus color patterns on Archaeopteryx (Manning et al., 2013) and Confuciusornis (Wogelius et al., 2011) inferred from distribution of trace metals (a method criticized by Vinther, 2015) were excluded. This guide also excludes very recent feather fossils in which the original colors are still discernible without melanosome analysis, such as those of Apteribis (Dove and Olson, 2011) and moa (Rawlence et al., 2009). Color patterns in some fossil dinosaurs have also been suggested based on changes in scale morphology observed in skin impressions (e.g., Bell, 2012), but were excluded on the grounds that the colors themselves cannot be inferred. Preserved coloration in amber-trapped specimens has been reported (e.g., Xing et al., 2016), but are currently not included here as it is uncertain how much these colors have been taphonomically altered. This guide also does not include inferred eggshell coloration (Wiemann et al., 2017; Wiemann et al., 2018). For a more comprehensive list that includes all proposed evidence for coloration in prehistoric animals, see this list by Zhejiangopterus.

The dinosaurs are not to scale. Coloration is restricted to body regions that have been sampled for melanosomes.

Anchiornis (coloration inferred by Li et al., 2010)
Body feathers were black and/or dark gray. Wing and hindlimb feathers were black and white. Feathers on the top of the head (possibly forming a crest) were reddish brown. Flecks of reddish brown were also present on the face. Coloration of tail feathers unknown, as the specimen examined did not preserve a tail.

Inkayacu (coloration inferred by Clarke et al., 2010)
Secondary wing feathers and an isolated body feather were brown, whereas preserved covert and tertiary wing feathers were gray.

Archaeopteryx (coloration inferred by Carney et al., 2012 and Carney et al., 2020)
The isolated holotype feather (possibly a covert wing feather) was black. Note that Kaye et al. (2019) questioned the referral of this feather to Archaeopteryx, though their arguments were disputed by Carney et al. (2020).

Microraptor (coloration inferred by Li et al., 2012)
Feathers sampled across the body were iridescent. Their exact hue is unknown, but the most conservative possibility is that they were glossy black.

Eocypselus (coloration inferred by Ksepka et al., 2013)
Feathers on the top of the head (possibly forming a crest) were glossy black. Melanosomes were also found in the wing feathers, but have not been interpreted as representing any particular color.

Caudipteryx (coloration inferred by Li et al., 2014)
Feathers sampled across the body were black. Tail feathers preserve a visible banding pattern.

Messelornis (coloration inferred by Colleary et al., 2015)
The paper is unclear about exactly where the sample was taken, but appears to have been a wing feather based on their figured photo of the specimen. The feather was iridescent. No exact hue was suggested, but I've given the primary wing feathers the same conservative coloration as inferred for Microraptor.

Pellornis (coloration inferred by Colleary et al., 2015)
A tail feather was brown. This specimen was not identified to species level by Colleary et al., but was later assigned to Pellornis by Musser et al. (2019).

Changzuiornis (coloration inferred by Huang et al., 2016)
Preserved wing and tail (or leg?) feathers were black.

CUGB P1202 (coloration inferred by Peteya et al., 2017)
An unnamed enantiornithean. Feathers from the nape, head, and body were iridescent. Their exact hue is unknown, but I've given them the same conservative coloration as inferred for Microraptor. Melanosomes were also found in a wing feather, but had degraded too much to determine what colors they might have produced.

Eoconfuciusornis (coloration inferred by Zheng et al., 2017 and Pan et al., 2022)
Feathers making up the wing coverts, nape, and tail were black. A dark spotted pattern is visible on the secondary wing feathers. Feathers on the hindlimb and top of the head were gray. Feathers on the throat were brown. A subsequent study also found evidence for iridescence on the top of the head. The specimen examined may have been a female, as evidenced by the putative presence of preserved ovaries.

Caihong (coloration inferred by Hu et al., 2018)
Feathers on the tail, wings, and hindlimbs were mostly black. A few isolated samples were inferred to be brown, including small patches on the wings, head, chest, and the tips of the feathers at the end of the tail. Feathers on the head, neck, chest, base of the tail, leading edges of the wings, and the front of the hindlimbs were mostly iridescent. The exact hue of iridescence is unknown, but I have colored it differently from "basic" iridescence (e.g., in Microraptor) to reflect the more specialized melanosome morphology of the iridescent feathers in Caihong. However, please note that the morphology of iridescence-producing melanosomes has not been correlated with the production of specific colors.

Iteravis (coloration inferred by Wang et al., 2018)
Feathers on the chest and wing were black.

Primotrogon (coloration inferred by Nordén et al., 2019)
Wing feathers were mostly gray, but one sample taken near the wrist was iridescent. Take note: the authors point out that the gray feathers could potentially represent down (the preservation of the examined specimen isn't sufficient to allow identification of individual feathers), in which case they probably wouldn't have been so visible in life.

Scaniacypselus (coloration inferred by Nordén et al., 2019)
Feathers near the neck, base of the wings, and wrist were gray. One sample taken from the leading edge of the wing was brown. As with Primotrogon, the authors caution that the gray feathers could potentially represent down.

Eocoracias (coloration inferred by Babarović et al., 2019)
Feathers on the tail, rump, and part of the nape were black. Those on the belly, chest, back, throat, and back of the head were inferred to be structurally colored (but not iridescent). Two samples were also taken from the wing feathers but failed to recover melanosomes. The authors note that they were unable to distinguish melanosomes involved in producing non-iridescent structural colors from those that produce gray based on morphology alone; thus, non-iridescent structural coloration can only be confidently inferred through phylogenetic bracketing, as in this case.

Calciavis (coloration inferred by Eliason and Clarke, 2020)
Feathers on the head, tail, and primary wing feathers were iridescent, possibly glossy black. Another sample taken from the wing feathers was black; this may represent the primaries or primary coverts. Due to the disarticulated nature of the specimens studied, there is some uncertainty about the position of the sampled feathers in general.

Protopteryx (coloration inferred by O'Connor et al., 2020)
The tip of a primary wing feather was black.

Yuanchuavis (coloration inferred by Wang et al., 2021)
The elongated central pair of tail feathers was black, whereas shorter tail feathers were gray.

Wulong (coloration inferred by Croudace et al., 2023)
Feathers on the hindlimbs and wings were iridescent, whereas those on the hips and an uncertain region of the forelimb were gray. A sample that may represent feathers from either the underside or the forelimb exhibited a range of different melanosome types that might indicate a mixture of colors from gray to iridescence to possibly brown. Samples were also taken from the tail feathers and near the head but failed to recover melanosomes.

Li et al. (2014) argued based on examination of melanosomes in modern animals that direct inference of colors from melanosome morphology is only reliable for pennaraptors and (to a lesser degree) mammals. As a result, coloration inferred for the following taxa may be less secure.

Sinosauropteryx (coloration inferred by Zhang et al., 2010 and Smithwick et al., 2017)
Feathers sampled from the tail were reddish brown. Though no other samples were examined, a banding pattern is preserved along the tail and likely reflects distribution of melanosomes. More detailed examination of preserved feather distribution across several specimens suggests a countershaded pattern on the body and a "bandit mask" on the face.

Beipiaosaurus (coloration inferred by Li et al., 2014)
Feathers sampled from the neck were brown.

Psittacosaurus (coloration inferred by Vinther et al., 2016)
Scales sampled across the body were likely brown. Variation in the density of pigmentation is suggestive of a countershaded body pattern with darker dorsal coloration and a lighter underside. The face, ankle, ischial region, cloacal region, and some large scales on the shoulder were particularly heavily pigmented. Vinther et al. were able to document these variations in staggering detail, much more than is easily summarized here, so those interested in finding out more are highly encouraged to consult the original paper.

Borealopelta (coloration inferred by Brown et al., 2017)
No preserved melanosomes were found, but chemical signatures suggest high concentrations of pheomelanin, which produce reddish brown coloration. According to Jakob Vinther (one of the authors on the study), the sacral shield was the main region directly examined for melanin samples, but broad-scale methods of investigation such as fluorescence imaging suggest that coloration was consistent across most of the dorsal surface of the body, with lighter coloration on the shoulder spine. Consistent lack of melanin preserved on the ventral surface suggests a countershaded pattern.

Preserved melanosomes have also been found in the feathers of Confuciusornis, Sinornithosaurus, Pedopenna, Yixianosaurus, Gansus, Yi, Cruralispennia, and Ambopteryx, as well as in the scales of a hadrosaur specimen, but have not yet been interpreted as representing particular colors.* In addition, visible color patterns have been identified in the preserved plumage of Hassiavis, Plesiocathartes, Messelirrisor, Cratoavis, and Confuciusornis.

*Roy et al. (2020) claim otherwise regarding Confuciusornis and Sinornithosaurus, citing Zheng's The Origin of Birds and Li et al. (2018) for the former and Zhang et al. (2010) for the latter. I have not been able to find a copy of The Origin of Birds, but it appears to be a popular, non-peer-reviewed book and is thus disregarded here, whereas Li et al. (2018) state that colors cannot be confidently reconstructed for the Confuciusornis specimen they examined due to its preservational state. As far as I can tell, Zhang et al. (2010) only report that Sinornithosaurus preserves evidence of "significantly different colour tones" across its plumage but do not attempt to infer what those colors would have been.

I recommend Vinther (2015), Roy et al. (2020), and Vinther (2020) as reviews of our current understanding of fossil color. Unsurprisingly for a newly-developed field of research, much uncertainty remains. Can we infer the coloration of all fossil melanosomes with equal confidence (as discussed by Li et al., 2014)? Melanosomes are not the only way to color integument; can we find evidence of other types of pigmentation in fossils and use them to inform life restorations (e.g., McNamara et al., 2016)? How well can we account for taphonomic distortion of melanosomes (e.g., McNamara et al., 2013)? There is much work to be done.

Thanks to Jakob Vinther for suggestions that improved this guide! This graphic was cited in Roy et al. (2023).

Bibliography
    • Vinther, J., R. Nicholls, S. Lautenschlager, M. Pittman, T.G. Kaye, E. Rayfield, G. Mayr, and I.C. Cuthill. 2016. 3D camouflage in an ornithischian dinosaur. Current Biology 26: 2456–2462. doi: 10.1016/j.cub.2016.06.065
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    Atlantis536's avatar

    You should add Wulong after Croudace et al. (2023).


    Also, I noticed you depicted Caudipteryx with no secondary feathers. Is there any particular reason why?