Thursday 21 June 2012

A Hatchet Wasp preserved in Tertiary amber from Mexico.

Hatchet Wasps (Evaniidae) are solitary parasitic Wasps targeting the eggs of Cockroaches. Cockroaches lay their eggs in cases called oothecae which can contain upwards of 40 eggs, Hatchet Wasps lay their eggs inside these cases and the larvae emerge and consume the eggs (strictly speaking this is carnivorey, since the Wasp larvae are external to the eggs, but Hatchet Wasps are closely related to true parasitic Wasps, are presumed to have evolved from such, so they are generally referred to as part of the wider group 'Parasitic Wasps').

The group have a good fossil record, with many excellent specimens preserved in amber. The oldest known specimens are from the Late Jurassic, and the group appears to have undergone a significant evolutionary radiation in the Cretaceous. However the Tertiary fossil record is not so good, making the precise origin of modern genera unclear.

In a paper published in the journal Zootaxa on 18 June 2012, John Jennings of the Australian Centre for Evolutionary Biology and Biodiversity and the School of Earth and Environmental Sciences at the University of Adelaide, Lars Krogmann of the Entomology Department of the Stuttgart State Museum of Natural History and Steven Mew of the School of Earth and Environmental Sciences at The University of Adelaide describe Hatchet Wasp preserved in amber from a mine near Simojovel in  Chiapas State, Mexico.

The precise age of the specimen is unclear, since the sediments that produced it are marine and the ambers there thought to be reworked, but it is thought to be Late Oligocene or Early Miocene in age, or possibly a little older.

The specimen is placed in the extant genus Hyptia, and given the specific name deansi, in honor of Andy Deans of North Carolina State University, an expert on the Evaniidae. The only known specimen of Hyptia deansi is a 5.55 mm female wasp, though Jennings et al. note that there are a considerable number of undescribed insects in Mexican amber in collections around the world.

Hypatia deansi. (1) Left lateral view. (2) Right lateral view. Scale bars are 1 mm. Jennings et al. (2012).

See also Three new species of Braconid Wasps from the Late Cretaceous of Magadan Province in the Russian Far EastThree new species of Braconid Wasp from PeruAn Eocene False Scorpion from Baltic amber and Evidence of fungal parasites modifying the behavior of ants from the Eocene Messel Shale.

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