A 95-million-year-old amber deposit discovered in ethopia has added 30 arthropods from thirteen families of insects and spiders. The fossils represent some of the earliest African fossil records for a variety of arthropods, including wasps, barklice, moths, beetles, a primitive ant, a rare insect called a zorapteran, and a sheet-web weaving spider.

Parasitic fungi that lived on the resin-bearing trees were also found, as well as filaments of bacteria and the remains of flowering plants and ferns.  In addition, the amber deposit may provide fresh insights into the rise and diversification of flowering plants during the Cretaceous.

The find is documented in a new paper published this week in PNAS.

"Until now, we had discovered virtually no Cretaceous amber sites from the southern hemisphere's Gondwanan supercontinent," says author Paul Nascimbene of the Division of Invertebrate Zoology at the American Museum of Natural History. "Significant Cretaceous amber deposits had been found primarily in North America and Eurasia."

"The first angiosperms, or flowering plants, appeared and diversified in the Cretaceous," says first author Alexander Schmidt of the University of Göttingen in Germany. "Their rise to dominance drastically changed terrestrial ecosystems, and the Ethiopian amber deposit sheds light on this time of change."

While studying the amber despoit, researchers found that the resin that seeped from these Cretaceous Gondwanan trees is similar chemically to more recent ambers from flowering plants in Miocene deposits found in Mexico and the Dominican Republic. The amber's chemical designation is Class Ic, and it is the only Ic fossil resin discovered thus far from the Cretaceous. All other documented Cretaceous ambers are definitively from non-flowering plants, or gymnosperms.

"The tree that produced the sap is still unknown, but the amber's chemistry is surprisingly very much like that of a group of more recent New World angiosperms called Hymenaea," says Paul Nascimbene, one of the study's co-authors. "This amber could be from an early angiosperm or a previously-unknown conifer that is quite distinct from the other known Cretaceous amber-producing gymnosperms."


Citation: Schmidt et al., 'Cretaceous African life captured in amber', PNAS, April 2010; doi:10.1073/pnas.1000948107