Osteoderms in a mammal the spiny mouse Acomys and the independent evolution of dermal armor

Malcolm Maden; Trey Polvadore; Arod Polanco; W Brad Barbazuk; Edward Stanley

doi:10.1016/j.isci.2023.106779

Osteoderms in a mammal the spiny mouse Acomys and the independent evolution of dermal armor

iScience. 2023 May 24;26(6):106779. doi: 10.1016/j.isci.2023.106779. eCollection 2023 Jun 16.

Authors

Malcolm Maden¹, Trey Polvadore¹, Arod Polanco¹, W Brad Barbazuk¹, Edward Stanley²

Affiliations

¹ Department of Biology & UF Genetics Institute, University of Florida, Gainesville, FL 32611, USA.
² Florida Museum of Natural History, University of Florida, Museum Road, Gainesville, FL 32611, USA.

Abstract

Osteoderms are bony plates found in the skin of vertebrates, mostly commonly in reptiles where they have evolved independently multiple times, suggesting the presence of a gene regulatory network that is readily activated and inactivated. They are absent in birds and mammals except for the armadillo. However, we have discovered that in one subfamily of rodents, the Deomyinae, there are osteoderms in the skin of their tails. Osteoderm development begins in the proximal tail skin and is complete 6 weeks after birth. RNA sequencing has identified the gene networks involved in their differentiation. There is a widespread down-regulation of keratin genes and an up-regulation of osteoblast genes and a finely balanced expression of signaling pathways as the osteoderms differentiate. Future comparisons with reptilian osteoderms may allow us to understand how these structures have evolved and why they are so rare in mammals.

Keywords: Comparative anatomy; Developmental biology; Evolutionary biology; Zoology.