100-million-year-old conifer tissues in Cretaceous amber

Terrestrial plant remains in fossilised tree resin are relatively common. However, histology and preservation of plants entombed in Cretaceous ambers remain poorly known. In this paper, the structure of a conifer’s leafy axis (Glenrosa carentonensis) is revealed in 100-million-year-old opaque amber from Western France.

PPC-SRμCT, 3D renderings of the leafy axis of Glenrosa carentonensis, specimen IGR.BUZ-7.
PPC-SRμCT, 3D renderings of the leafy axis of Glenrosa carentonensis, specimen IGR.BUZ-7. (A–C) Lateral view; (D–F) top view; (G–I) bottom view. From left to right, external cast of the leafy axis (A, D, G) is progressively and virtually eroded in order to expose only the cuticle (C, F, I). Scale bars = A–C, 5 mm; D–I, 2 mm. Voxel size, 14·92 μm

Moreau et al. examined the fossil using a high-resolution 3D imaging technique and with synchrotron microtomography, allowing for unprecedented resolution and views of the cuticle, which are preserved in three dimensions down to the cellular level as well as of the majority of the inner tissues. The study highlights the complexity of taphonomic processes that can occur in resin inclusions and the importance of microtomography for palaeobotanical studies focussed on the preservation of soft-bodied plants in Cretaceous amber.

Reference

Moreau, J.-D., Néraudeau, D., Perrichot, V., & Tafforeau, P. (2016). 100-million-year-old conifer tissues from the mid-Cretaceous amber of Charente (western France) revealed by synchrotron microtomography. Annals of Botany, 119(1), 117–128. https://doi.org/10.1093/aob/mcw225