Taphonomy of the insects from the Insect Bed (Bembridge Marls), late Eocene, Isle of Wight, England

Abstract

The environmental setting and taphonomy of the insect fauna of the Insect Bed, Bembridge Marls (late Eocene; 36 Ma) of the Isle of Wight is described. Cluster analysis of taxonomic data on the insect fauna of a diversity of modern tropical environments, together with that of the Bembridge Marls, shows that the insects of the latter are characteristic of a primary sub-tropical/tropical forest subject to significant seasonal rainfall. A similar approach indicates that the sample of taxa preserved in the Insect Bed is biased toward insects from leaf litter and lower herbage microhabitats. External ornamentation of the cuticle is preserved on a micron scale, and the individual microfibrils of the procuticle can be distinguished. The insects of the Bembridge Marls are remarkable in preserving cuticle and mineralized internal tissues in a largely uncompacted state. Chemical analysis (py-GC/MS) reveals that the cuticle is composed of an aliphatic polymer, possibly due to polymerization of cuticular waxes during diagenesis. No chitin was detected. The soft tissues, which include sarcolemma and muscle fibres, are preserved through replacement in calcite.

Ancient fig wasps indicate at least 34 Myr of stasis in their mutualism with fig trees

“…They are the oldest known representatives of the Agaonidae. Typically for this bed, they are preserved in three dimensions in extremely fine-grained limestone (McCobb et al 1998). Organic cuticle is well preserved, showing original structures at the micron scale.…”

Preliminary elemental analysis of fossil insects from the Middle Jurassic of Daohugou, Inner Mongolia and its taphonomic implications

“…In recent 10 years, some considerable progress has been made in studying the insect taphonomy [3][4][5][6][7][8][9][10][11][12][13] , and major studies refer to the preburial processes before the fossilization [3][4][5][6] . Analyses of the chemical composition of fossil insects focused mainly on those in amber [7,8] and some Cenozoic specimens [9][10][11][12][13] , but much less on Mesozoic ones [4] . So far, the taphonomy of some early arthropods in some famous lagerstatten has been studied in detail [14][15][16][17] , and these methods and results could also be applied to the study of Mesozoic fossil insects.…”

The first Cenozoic spinicaudatans from North America

“…Calcium carbonate precursors have been observed to form from the breakdown of organic matter in aqueous solution (Berner, 1968) and have been implicated in the development of concretions as well as exoskeleton and softtissue replacement in insects and shrimp (McCobb et al, 1998; Figure 4.1, scale bar = 25 μm, notice the thickened distal edge, which corresponds with the stronger depressions marking the distal edge of the growth bands in moldic specimens; (7) spectral data for the growth band illustrated in Figure 4.6, location of scan marked as + in 4.6, composition is dominantly calcium carbonate. (YPM 531200, upper;531201, lower), scale bar = 1 mm, margins of these specimens appear warped, probably from desiccation before burial; (6) laterally compressed specimen (YPM 531202), scale bar = 1 mm; (7) E.?…”