Internal anatomy through deep time

In addition to non-biomineralized body fossils, Konservat-Lagerstätten also provide valuable information on the internal anatomy of extinct organisms. Although digestive tracts and gut glands are by far the most commonly fossilized internal organs, recent discoveries indicate that the central nervous system can also be preserved under truly exceptional circumstances in Cambrian Burgess Shale type deposits. Combined with the study of extant animals, these data offer unique insights into the ancestral organization of the non-exoskeletal morphology of panarthropods, and an improved understanding of the conditions necessary for the preservation of these labile tissues.


Exceptional preservation of the central nervous system in the soft-bodied artiopodan Houghtonites gracilis from the middle Cambrian Burgess Shale in Canada. Illumination alternates between reflected light, polarized light, and polarized light under water in order to highlight internal organs. (Image by Javier Ortega–Hernández).

Representative publications:

- Ortega–Hernández, J., Fu, D.J., Zhang, X.L. & Shu, D. 2018. Gut glands illuminate trunk segmentation in Cambrian fuxianhuiids. Current Biology 28: R146–R147.

- Yang. J., Ortega–Hernández, J., Butterfield, N.J., Liu, Y., Boyan, G., Tian, L., Hou, J.-B., & Zhang, X.-G. 2016. Fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda. Proceedings of the National Academy of Sciences 113: 2988-2993.

- Ortega–Hernández, J. & Budd, G.E. 2016. The nature of non-appendicular anterior paired projections in Palaeozoic total-group Euarthropoda. Arthropod Structure & Development 45: 185-199. 

- Ortega–Hernández, J. 2015. Homology of head sclerites in Burgess Shale euarthropods. Current Biology 25: 1625-1631.