Discovery of Early Eocene amber in Belgium

Fossil resins from the Early Eocene period are relatively scarce, with the majority of specimens being found in the Vastan and Tadkeshwar mines in Gujarat province, India. The Cambay amber, which is dated to approximately 54.5 million years ago (Ma), is a notable example. The ambers from the Fushun Mine in Liaoning Province, China, are slightly younger, dated to c. 53-50 Ma, while the amber from the Hat Creek Formation in British Columbia, Canada, is slightly older, dated to c. 52-51 Ma. The parent plants of these fossil resins are also different. The amber from India was formed by trees of the family Dipterocarpaceae, while the amber from Fushun and the amber from Hat Creek are derived from trees of the family Cupressaceae. In Europe, early Eocene amber was known from the Paris Basin area, from the Oise region. This amber was derived from trees of the family Fabaceae-Detariae (or Combretaceae). The palaeobotanical collection of the Royal Belgian Institute of Natural Sciences in Brussels contains fossil resin specimens from three localities in Belgium, originating from the two geographical areas of Leval-Trahegnies and Orp-le-Grand. Physico-chemical studies utilizing Fourier transform infrared spectroscopy (FTIR) have indicated a close chemical relationship between Belgian amber and early Eocene amber from the Paris Basin. The results also pointed the potential impact of weathering on the chemical composition of the amber. The amber originated from a similar botanical source as the Oise amber, but from different depositional basins. Two sites from Leval-Trahegnies yielded samples that exhibited various stages of weathering (highly cracked and cracked, darkened) and no inclusions. The amber from the Orp-le-Grand site was observed to be the least weathered, with one piece containing two inclusions: a mite and a new genus and species of true bug, described in the publication as a new genus and species in the family Miridae – Cativolcus uebruum Szwedo, 2024. The other specimen exhibited the imprint of an undesignated insect on the surface. The researches on amber from Belgium were conducted by an international team, including University of Gdańsk Professor Jacek Szwedo, from the Laboratory of Evolutionary Entomology and the Museum of Amber Inclusions. The findings were published in the journal Scientific Reports: Seyfullah L.J., Szwedo J., Schmidt A.R., Prestianni C. 2024. Fossiliferous amber from the early Eocene of Belgium. Scientific Reports 14, 13705, 1–12+[122]+1–6. [Published online 14 June 2024] https://doi.org/10.1038/s41598-024-64286-z.

A. Fossil resin sites in Belgium; B. Cativolcus uebruum Szwedo, 2024 (Heteroptera: Miridae: Psallopinae); C. FTIR spectra of amber from Orp-le-Grand and Oise (France).