It was believed extinct, but a team of researchers from the Smithsonian Museum of Natural History (USA) and the University of Copenhagen (Denmark) has announced the discovery of up to 18 new pelican spiders living in Madagascar.
Their name is due to the fact that their strange heads and extended mouthparts resemble the head of a pelican, and they behave in an equally curious way.
First discovered in 1854 in a specimen preserved in a piece of amber dating back 50 million years to the Eocene epoch, naturalists thought the peculiar creature was a relic of a bygone age.
However, in 1881, live pelican spiders were found in Madagascar, and they became known for their peculiar morphology. They are relatively small creatures, between 2 and 8 millimeters in length, and have an elongated and quirky head with a “neck”, from which a set of extended jaws protrude.
They are also known as killer spiders for the way they hunt and also for what they hunt. Instead of spinning webs to catch their prey, they roam the forest at night, following silk chains woven by other spiders.
When they locate their potential victim, they pluck the threads from its fabric, mimicking the vibrations of an insect in distress. And when the owner of the web comes to investigate, the pelican spider attacks, impaling the hapless spiders as they unsuccessfully wriggle in their long jaws.
Their habitats are remote forests in Australia, South Africa, and Madagascar , and this, combined with their diminutive size, has led to relatively little being known about them until recently.
Species new to science
Arachnid and myriapod curator Hannah Wood and entomologist Nikolaj Scharff from the University of Copenhagen worked together to examine and analyze hundreds of specimens of Madagascar pelican spiders in the field and in museum collections, classifying them into species and describing them scientifically.
Focusing on the genera Eriauchenius and Madagascarchaea, the experts classified them into 26 individual species, of which 18 are completely new to science.
Although they all have the same “pelican” shape, the 26 species can be distinguished from each other by characteristics such as different jaw lengths or different patterns on their abdomens.
The most curious thing is that the species that still live today are remarkably similar to those that are preserved in amber, hence they can be considered “living fossils”. Because living spiders have been found after their ancestors were considered extinct, they can be considered a Lazarus taxon (apparently extinct but reappearing recently).
Madagascar is home to a large number of plant and animal species that exist only on the island , but until recently, only a few species of pelican spiders had been documented there. Wood’s detailed observations and measurements of hundreds of specimens led to the identification of 18 new species, but the expert believes there is almost certainly more to discover. As field workers continue to collect specimens across Madagascar, “I think there will be many more species that have yet to be described or documented,” he said.
All of the pelican spiders that Wood described live only on Madagascar, an island whose enormous biodiversity is currently threatened by widespread deforestation.
The document describing the 26 species has been published in the magazine ZooKeys.
Reference: Hannah M. Wood et al, A review of the Madagascan pelican spiders of the genera Eriauchenius O. Pickard-Cambridge, 1881 and Madagascarchaea gen. n. (Araneae, Archaeidae), ZooKeys (2018). DOI: 10.3897 / zookeys.727.20222
Image credit: Nikolaj Scharff
You can see more images of the spiders in this presentation:
