Mesothelae is one suborder of spiders (Order Araneae) that includes the families Liphistiidae, Arthrolycosidae, and Arthromygalidae. The latter two families are known only from fossil records.

Recent Mesothelae are characterized by the narrow sternum on the ventral side of the prosoma. Several plesiomorphic characters may be useful in recognizing these spiders: there are tergite plates on the dorsal side and the almost-median position of the spinnerets on the ventral side of the opisthosoma.

Mesothelae were once two considered to be two families, the Liphistiidae and the Heptathelidae. These can easily be distinguished by their sexual organs and the way they construct their burrows: Liphistiides always have fishing lines in front of the entrance, while Heptathelids have none. Therefore, the latter are more difficult to find. Female Liphistiids have an unpaired receptaculum, in Heptathelids it is paired. Male Liphistiids lack a conductor in their palpal organ, while such structure is present in Heptathelids. Today, however, the Heptathelidae are incorporated into the Liphistiidae. Before mating, the male creates a sound (inaudible to humans) to induce the female to appear at her trap door. Then mating may take place.

Distribution

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Liphistiidae spiders are distributed in Myanmar, Thailand, the Malayan peninsula and in Sumatra. Heptathelidae are found in Vietnam, the Eastern provinces of China, and Southern Japan.

In Popular Culture

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In the BBC documentary Walking with Monsters (2005), one Carboniferous era species of mesothelae was described as being as large as a human head and hunted reptiles the size of today's cats. It lived like the tarantulas in burrows, and would either lie in wait for its prey, or chase it through the jungle.

External links

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• http://insects.tamu.edu/research/collection/hallan/acari/Araneae1.htm

Mesothelae

Gliederspinnen | Mesothelae