Gratuitous extant collembolan picture.
Fossilized amber famously can preserve insects trapped in it. Sometimes we’re lucky enough to get a glimpse of a bug’s life from these specimens. One such fossil, found in a mine in the Dominican Republic, preserves a tiny springtail piggybacking on a larger fishfly (or mayfly, if you like). Springtails (subclass Collembola – close relatives of insects and teddy bears*) are wingless, but so small that they can easily disperse by hitching a ride on a larger insect. This individual was caught in the act, and in fact represents the first known case of such hitchiking (the technical term is phoresy) on a fishfly (order Ephemeroptera). Here’s part of the figure from the paper that described this fossil, showing the miniscule springtail clinging to the fishfly’s back. There’s also a video in the supplemental section of the paper showing a 3D reconstruction of the bugs.
Figure 1B from Penney et al. 2012: thorax of a fishfly with springtail on the upper edge, just left of where the wing attaches.
The second unusual fossil o’the day is one that it never occurred to me could be fossilized: a bird’s nest. And not just any bird’s nest: an ancient flamingo’s! The 18-million-year-old nest consists of leafy twigs and contains five eggs. It is thought that it was abandoned and sank to the bottom of the saline lake in which it was built before becoming fossilized. This sort of habitat is much like the ones flamingos inhabit today. The authors examined the eggshells microscopically to identify them as flamingo eggs, but, interestingly, the nest characteristics and egg number and size resemble those of grebes, the flamingo order’s closest living relatives.
So, two strange fossils that shed a bit of light on prehistoric animals’ behaviour. This is the sort of thing that makes me say “Yay science!”
Gratuitous flamingo picture. There are two species here – can you ID them?
*Not intended to be a factual statement.
References
Gerald Grellet-Tinner, Xabier Murelaga, Juan C. Larrasoaña, Luis F. Silveira, Maitane Olivares, Luis A. Ortega, Patrick W. Trimby, Ana Pascual (2012). The First Occurrence in the Fossil Record of an Aquatic Avian Twig-Nest with Phoenicopteriformes Eggs: Evolutionary Implications PLoS ONE, 7 (10) : 10.1371/journal.pone.0046972
David Penney, Andrew McNeil, David I. Green, Robert S. Bradley, James E. Jepson, Philip J. Withers, Richard F. Preziosi (2012). Ancient Ephemeroptera–Collembola Symbiosis Fossilized in Amber Predicts Contemporary Phoretic Associations PLoS ONE, 7 (10) : 10.1371/journal.pone.0047651
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