DFG Research Unit FOR 2685 | C2
Soft tissue preservation in amber – a comparative study on the taphonomy and limits of fossilization of resin embedded arthropods
Abstract
Amber is one of the most important sources of fossil insects and gives insight into Mesozoic and Cenozoic terrestrial ecosystems (Fig 1). The fossilized resin preserves trapped organisms with a unique cellular and ultra-structural fidelity, but the processes leading to this exceptional conservation are still not understood. The characteristic of Indian amber to be completely soluble in certain solvents opens up new possibilities on the examination of amber preservation. Integration of extant, and museum samples, as well as copal alongside amber collections around the world, will lead to the most extensive study on amber inclusion taphonomy so far.
Figure 1 | Ant (Formicidae) and mite (Acari) in Baltic amber (~ 50 Ma).
Many reports note the excellent conservation of musular, digestive, respiratory, nervous, and sensory tissues in amber [1-4]. Large differences in organic compound preservation between amber deposits [5-6] imply diverse taphonomic pathways of the fossil organisms. A known phenomenon is the preservation as an outer cast, with specimens being hollow inside [7].This type often occurs in Baltic amber, but for the Lebanese and Indian amber real body fossils expressing cuticle preservation are evidenced [8-9]. These differences in preservation may refer to crucial factors such as the depositional environment, the resin compounds, or the geologic age.
Several inclusions of Indian Cambay amber have been extracted with organic solvents (Fig. 2) [11]. Different types of internal soft tissues are preserved with lifelike fidelity, allowing detailed examinations not only with SEM but also with TEM, Raman spectroscopy, histology or even histochemical methods (Fig. 3). A non-destructive screening of promising specimens has been carried out at the DESY in Hamburg and will be continued throughout the project in combination with Micro-CT scans. Raman spectroscopy of an Anolis sp. limb in Dominican amber revealed large modifications in the organic parts of the bone and verified this method as a viable tool with regard to the project.
Figure 2 | Midge extracted from Indian amber (~ 53 Ma).
Figure 3 | SEM image of the tracheal system of an extracted beetle from Indian amber (~ 53 Ma).
- Examination of the different processes that affect the diverse preservation of resin embedded arthropods. Specimens will comprise extant material, museum samples, and amber fossils as well as copal inclusions.
- Identifying the limits of amber preservation with a focus on cellular components and chemical investigations of different tissues and organ systems.
Prinzipal Investigator(s)
Prof. Dr. Jes Rust
Institut für Geowissenschaften / Paläontologie, Universität Bonn
Nussallee 8, 53115 Bonn
Phone: +49 228 73-48 42
E-mail: rust [at] uni-bonn.de
Researcher(s)
PhD Jonas Barthel
Institut für Geowissenschaften / Paläontologie, Universität Bonn
Nussallee 8, 53115 Bonn
Phone: +49 228 73-93 38
E-mail: jbarthel [at] uni-bonn.de
Dr. David Peris
Institut für Geowissenschaften / Paläontologie, Universität Bonn
Nussallee 8, 53115 Bonn
Phone: +49 228 73-46 82
E-mail: daperce [at] gmail.com
(Klick to entlarge)
- Henwood AA. 1992. Soft-part preservation of beetles in Tertiary amber from the Dominican Republic. Palaeontology 35: 901–912.
- Penney D. 2005. Fossil blood droplets in Miocene Dominican amber yield clues to speed and direction of resin secretion. Palaeontology 48:925–927.
- Anderson SR. 2004. Insect meals from a leptodactylid frog (Amphibia: Leptodactyidae) in Dominican amber (Miocene, 23 Ma). Entomological News 115:55–57.
- Grimaldi DA, Bonwich E, Delannoy M, and Doberstein S. 1994. Electron microscopic studies of mummified tissues in amber fossils. American Museum Novitates 3097: 1–31.
- Stankiewicz BA, Poinar HN, Briggs DEG, Evershed RP, and Poinar GO. 1998. Chemical preservation of plants and insects in natural resins. Proceedings of the Royal Society B 265: 641–647.
- Koller B, Schmitt JM, and Tischendorf G. 2005. Cellular fine structures and histochemical reactions in the tissue of a cypress twig preserved in Baltic amber. Proceedings of the Royal Society B 272: 121–126.
- Grimaldi DA, Shedrinsky AM, Ross A, and Baer NS. 1994. Forgeries of “fossils” in amber: History, Identification and Case Studies. Curator: The Museum Journal 37:251–274.
- Rust J, Singh H, Rana RS, McCann T, Singh L, Anderson K, Sarkar N, Nascimbene PC, Stebner F, Thomas JC, and others 2010. Biogeographic and evolutionary implications of a diverse paleobiota in amber from the early Eocene of India. Proceedings of the National Academy of Sciences 107:18360–18365.
- Azar D. 1997. A new method for extracting plant and insect fossils from Lebanese amber. Palaeontology 4:1027–1029. .
- Stebner F, Szadziewski F, Rühr PT, Singh H, Hammel J, Kvifte GM, and Rust J. 2016. A fossil biting midge (Diptera: Ceratopogonidae) from early Eocene Indian amber wirh a complex pheromone evaporator. Scientific Reports 6:34352.
- Mazur N, Nagel M, Leppin U, Bierbaum G, and Rust J. 2014. The extraction of fossil arthropods from Lower Eocene Cambay amber. Acta Palaeontologica Polonica 59: 455–459.References
