Wednesday, 28 September 2011

A New Group Of Wasps Described From North American Amber

The holotype specimen of Pulmolexius rasnitsyni
Recent discoveries preserved within the prison of hardened tree resin known as amber have shed light upon many palaeontological mysteries. Ancient feathers found in Canada have given scientists great insight into the evolution of such structures. Yet revolutionary new fossils are rare. The creatures most commonly preserved in amber are arthropods. Their light weight and lack of relative strength means that they get stuck very easily and become caged within the resin.

A recent discovery bridges the gap between both categories. Pieces of amber containing insect fossils that are a completely new species have been discovered in New Jersey, USA, by the Denis brothers from the KwaZulu University of South Africa. The amber samples, upon field analysis, were revealed to contain, amongst other things, two wasps. These wasps were very unusual and did not fit in with any known species of the group Hymenoptera (wasps, bees and ants).

The Denis brothers alerted Russian palaeontologist Alexandr Rasnitsyn, the world authority on fossil hymenopterans. Rasnitsyn quickly concluded that the wasps were not only a completely new species, but were also a completely new family of wasps, unknown to science. The creatures were given the name of Pulmolexius rasnitsyni, in honor of Alexandr Rasnitsyn and the commemoration of his 75th birthday, and placed in the new wasp class Pulmolexiidae.

The two, 90 million year old, specimens were both males and would have lived in a large swampland forest that covered much of New Jersey during the Middle Cretaceous. They are most closely related to the family Plumariidae, now found only in South America and Africa. This dispersal raises a number of important questions, including the origins of the stinger in certain hymenopterans. While these fossils have yet to answer such questions, they do present scientists with an intriguing find.