A Flower Trapped in Amber

Thanks to a 30 year old collection of amber tucked away in the drawers of a museum, we now have the first fossil record of the asterid lineage. Discovered in the Dominican Republic back in 1986, this particular chunk of amber contains a tiny flower about a centimeter in length. The preservation is astounding, allowing researchers to accurately identify this as a member of the genus Strychnos.

The asterid lineage contains many orders that we would be familiar with including Gentianales, Lamiales and Solanales. It is highly derived yet poorly represented in the fossil record. Because of the challenges associated with accurately dating amber, scientists estimate that this flower is somewhere between 15 - 45 million years old. To put this in perspective, North and South America were not even connected at this point in time. What's more, the details preserved in these amber deposits are allowing researchers to piece together what the forest in this region would have looked like.

These fossils show that this forest "contained a distinct canopy layer composed of legumes such as algarroba (Hymenaea protera), cativo (Prioria spp.) and nazareno (Peltogyne spp.), with emergent trees like caoba (Swietenia; Meliaceae) extending through the canopy. The subcanopy and understory were represented by royal palms (Roystonea) and figs (Ficus; Moraceae). The shrub layer included other types of palms as well as acacias. Grasses like pega-lega (Pharus) and bambusoids (Alarista) colonized the forest floor. Orchids, bromeliads, ferns and vines covered the trees, and various lianas were also part of this tropical forest."

Pretty amazing for bits and pieces of solidified tree sap. This particular flower has been named Strychnos electri, a now extinct species. However, the morphological characteristics show that this particular genus as well as the asterid lineage were already well established at this time. Discoveries such as this are offering highly detailed windows into the past, which allows us to better understand flowering plant evolution and ecosystem change.

Photo Credit: George Poinar

Further Reading:
http://www.nature.com/articles/nplants20165