Small theropod remains from Upper Cretaceous Nenjiang Formation in China + pterosaur pycnofibers with iridescent coloration (free pdfs)
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Ben Creisler
May 16, 2026, 5:53:30 PM (8 hours ago) May 16
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Ben Creisler
Zelin Wu, Liliana D'ALba, Zhou Chang-Fu, Julia Clarke, Jinhua Li, Matthew Shawkey & Quanguo Li (2026)
Iridescence in pterosaur pycnofibers and the evolution of integumentary coloration
bioRxiv 2026.05.06.723168 (preprint)
doi: https://doi.org/10.64898/2026.05.06.723168
https://www.biorxiv.org/content/10.64898/2026.05.06.723168v1
The bodies of pterosaurs, the first flying vertebrates, are covered with integumentary filaments (pycnofibres) thought to be homologous to feathers in dinosaurs, but their coloration remains unknown. Here, we report a layered internal arrangement of melanosomes containing a photonic nanostructure within the monofilaments in a previously undescribed specimen of tapejarid pterosaur Sinopterus dongi from the Early Cretaceous Jehol Biota. Optical simulations showed that this structure reflects green to magenta iridescent coloration, confirming the presence of melanosome-based iridescent coloration previously thought to be unique to birds. This finding deepens our understanding of structure/color gamut relationships in amniotes, while supporting further shared characteristics associated with derived genetic and regulatory shifts in archosaurs.
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Recent papers not yet mentioned:
Yuqi HUANG, Wenhao WU, Bolotsky Ivan & Kaifeng YU (2026)
Additional small theropod remains from the Upper Cretaceous Nenjiang Formation in Songliao Basin, Northeast China
Global Geology 29(1): 1-12
DOI: 10.3969/j.issn.1673-9736.2026.01.01
https://www.sciopen.com/article/10.3969/j.issn.1673-9736.2026.01.01
Free pdf:
https://www.sciopen.com/article/pdf/10.3969/j.issn.1673-9736.2026.01.01.pdf
Five new small theropod teeth and one manual ungual have recently been recovered from the Upper Cretaceous Nenjiang Formation in the Songliao Basin. The specimens were examined for their morphological characteristics, leading to the identification of four distinct taxa. The first taxon consists of three foliodont teeth characterized by a pronounced basal constriction and large hook-like distal denticles, which can be attributed to Troodontidae. The second taxon is represented by an elongated tooth featuring prominent longitudinal ridges, allowing for its assignment to Paronychodon. The third taxon is a blade-like tooth with notably small distal denticles, corresponding to Richardoestesia. The fourth taxon comprises a manual ungual characterized by a transversely wide and nearly symmetrical proximal articular surface, fully enclosed ventral foramina, a flattened ventral surface, and the absence of a flexor tubercle, resembling Alvarezsauridae. These specimens significantly enhance the known dinosaur diversity of the Nenjiang Formation and provide crucial insights for understanding the terrestrial ecosystem in Northeast Asia during the Late Cretaceous.
Free pdf:
Yuqi HUANG, Wenhao WU, Bolotsky Ivan & Kaifeng YU (2026)
Additional small theropod remains from the Upper Cretaceous Nenjiang Formation in Songliao Basin, Northeast China
Global Geology 29(1): 1-12
DOI: 10.3969/j.issn.1673-9736.2026.01.01
https://www.sciopen.com/article/10.3969/j.issn.1673-9736.2026.01.01
Free pdf:
https://www.sciopen.com/article/pdf/10.3969/j.issn.1673-9736.2026.01.01.pdf
Five new small theropod teeth and one manual ungual have recently been recovered from the Upper Cretaceous Nenjiang Formation in the Songliao Basin. The specimens were examined for their morphological characteristics, leading to the identification of four distinct taxa. The first taxon consists of three foliodont teeth characterized by a pronounced basal constriction and large hook-like distal denticles, which can be attributed to Troodontidae. The second taxon is represented by an elongated tooth featuring prominent longitudinal ridges, allowing for its assignment to Paronychodon. The third taxon is a blade-like tooth with notably small distal denticles, corresponding to Richardoestesia. The fourth taxon comprises a manual ungual characterized by a transversely wide and nearly symmetrical proximal articular surface, fully enclosed ventral foramina, a flattened ventral surface, and the absence of a flexor tubercle, resembling Alvarezsauridae. These specimens significantly enhance the known dinosaur diversity of the Nenjiang Formation and provide crucial insights for understanding the terrestrial ecosystem in Northeast Asia during the Late Cretaceous.
===
Free pdf:
Zelin Wu, Liliana D'ALba, Zhou Chang-Fu, Julia Clarke, Jinhua Li, Matthew Shawkey & Quanguo Li (2026)
Iridescence in pterosaur pycnofibers and the evolution of integumentary coloration
bioRxiv 2026.05.06.723168 (preprint)
doi: https://doi.org/10.64898/2026.05.06.723168
https://www.biorxiv.org/content/10.64898/2026.05.06.723168v1
The bodies of pterosaurs, the first flying vertebrates, are covered with integumentary filaments (pycnofibres) thought to be homologous to feathers in dinosaurs, but their coloration remains unknown. Here, we report a layered internal arrangement of melanosomes containing a photonic nanostructure within the monofilaments in a previously undescribed specimen of tapejarid pterosaur Sinopterus dongi from the Early Cretaceous Jehol Biota. Optical simulations showed that this structure reflects green to magenta iridescent coloration, confirming the presence of melanosome-based iridescent coloration previously thought to be unique to birds. This finding deepens our understanding of structure/color gamut relationships in amniotes, while supporting further shared characteristics associated with derived genetic and regulatory shifts in archosaurs.
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