Wednesday 13 September 2017

Linguamyrmex vladi: A new species of Hell Ant from Burmese Amber.

Ants first appeared in the Cretaceous, with fossil Ants known from deposits between 100 and 78 million years ago, from six locations across Laurasia (Eurasia plus North America) and one from Botswana in Southern Africa. None of the known Cretaceous fossil Ants can be placed within any living group, rather they are thought to be stem group Ants, more closely related to living Ants than any other group, but not descended from the most recent common ancestor of all living Ants, which is thought to have lived around the end of the Cretaceous. One distinctive group of Ants found in several different Cretaceous deposits are the Hell Ants, Haidomyrmecini, which have distinctive enlarged jaws, and are thought to be the sister group to all other Ants. 

In a paper published in the journal Systematic Entomology on 4 September 2017, Philip Barden of the Department of Biological Sciences at the New Jersey Institute of Technology, and the  Department of Invertebrate Zoology at the American Museum of Natural History, and Hollister Herhold and David Grimaldi, also of rhe Department of Invertebrate Zoology at the American Museum of Natural History, describe a new species of Hell Ant from Middle Cretaceous Burmese Amber.

Middle Cretaceous ‘Burmese Amber’ has been extensively worked at several sites across northern Myanmar (though mostly in Kachin State) in the last 20 years. The amber is fairly clear, and often found in large chunks, providing an exceptional window into the Middle Cretaceous Insect fauna. This amber is thought to have started out as the resin of a Coniferous Tree, possibly a Cypress or an Araucaria, growing in a moist tropical forest. This amber has been dated to between 105 and 95 million years old, based upon pollen inclusions, and to about 98.8 million years by uranium/lead dating of ash inclusions in the amber. 

The new species is named Linguamyrmex vladi, where 'Linguamyrmex' means 'tounged Ant' in reference to a tongue-shaped process on the Ant's head against which the Insect's mandible appear to be opposed, and 'vladi' refers to Vlad the Impaler (Vlad Dracula), in reference to its enlarged teeth, and presumed feeding habit, impaling soft bodied invertebrates and draining their bodily fluids. The species is described from a single specimen from Burmese Amber, with three other specimens referred to the genus but nor the species.

Photomicrographs of Linguamyrmex vladi. (A) Lateral view of specimen. (B) View of head capsule and mesosoma. Scale bars, 0.5 mm. Barden et al. (2017).

X-ray imaging of the specimen showed the presence of what appeared to be metal in the tongue-shaped process. This is not altogether surprising as a variety of Insects (including some Ants) and some other animals (including some Mammals) are known to be able to sequester metals in parts of their bodies, typically in the mouthparts where they can provide a degree of extra strength. This supports the idea that the process was part of a feeding system, with prey animals braced between the two mandibles and the process while they were drained of fluids.

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