Mesozoic mammaliaforms

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Time: Jurassic, Cretaceous

Region: China

Formation: Jehol and Yanliao Biotas

Coloration Data

In Li et al. (2025), pelage coloration was investigated across six Mesozoic mammal species: the Jurassic taxa Arboroharamiya fuscus, Vilevolodon diplomylos, and Megaconus mammaliaformis, as well as Cretaceous docodonts and a eutherian. Despite phylogenetic divergence and differing ecological lifestyles, all six taxa exhibited uniform, unpatterned dark-brown coats. This uniformity is explained by an absence of morphological diversity in their hair melanosomes and aligns with the nocturnal bottleneck hypothesis, reflecting a lack of chromatic sexual dimorphism or intraspecific visual signaling.

Method: Scanning electron microscopy (SEM).

Publications

• Ruoshuang Li, Liliana D’Alba, Gerben Debruyn, Jessica L. Dobson, Chang-Fu Zhou, Julia A. Clarke, Jakob Vinther, Quanguo Li, Matthew D. Shawkey (2025)
  A study of the coloration of Mesozoic mammaliaforms.

Documents and files

• Li_et_al_2025.pdf (PDF)
  Study of coloration in Mesozoic mammaliaforms.

Reconstructions

Fossils