Schizomida
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Calcitronidae † Petrunkevitch, 1945b |
Schizomida is an order of arachnids. Schizomids present the prosoma covered by a large protopeltidium and smaller, paired, mesopeltidia and metapeltidia. There are no eyes. The opisthosoma is a smooth oval of 12 recognizable somites. The first is reduced and forms the pedicel. The last three are much constricted, forming the pygidium. The last somite bears the flagellum, which in this order is short and consists of not more than four segments.
The name means "split or cleaved middle", referring to the way the cephalothorax is divided into two separate plates. Like the related orders Uropygi, Amblypygi, and Solpugida, the schizomids use only six legs for walking, having modified their first two legs to serve as sensory organs. They also have large well-developed pedipalps (pincers) just behind the sensory legs. A systematic review including a full catalogue may be found in Reddell & Cokendolpher(1995).
Schizomids tend to live in the top layer of soil.
[edit] Subtaxa
Families of schizomids include:
- Calcitronidae †
- Hubbardiidae
- Protoschizomidae
- Schizomidae
As of 2000, 219 species of schizomids have been described worldwide, most belonging to the Hubbardiidae family.
[edit] References
- Reddell, J.R. & Cokendolpher, J.C. (1995). Catalogue, bibliography, and generic revision of the order Schizomida (Arachnida). Tex. Mem. Mus., Speleol. Monogr. 4: 1-170
- Savory, T., 1977. Arachnida. second edition. Academic Press inc. New York. 339pp.
