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Schizomida (common name shorttailed whipscorpion) is an order of arachnids, generally less than in length. The order is not yet widely studied. As of 2005, more than 230 species of schizomids have been described worldwide, most belonging to the Hubbardiidae family. A systematic review including a full catalogue may be found in Reddell & Cokendolpher (1995). ==Anatomy== Schizomids are relatively small, soft-bodied arachnids, somewhat similar in appearance to whip scorpions. The prosoma (cephalothorax) is divided into three regions, each covered by plates, the large protopeltidium and the smaller, paired, mesopeltidia and metapeltidia. The name means "split or cleaved middle", referring to the way the prosoma is divided into two separate plates. The opisthosoma (abdomen) is a smooth oval of 12 recognizable segments. The first is reduced and forms the pedicel, while the last three are constricted, forming the pygidium. The last segment bears a short whip-like tail or flagellum, consisting of no more than four segments. The females generally have 3-4-segmented flagella, while in males it is single segmented.〔Coddington J.A. et al. "Arachnida", p. 306, in: J. Cracraft (ed.) ''Assembling the Tree of Life'', pp. 296-318〕 Like the related orders Thelyphonida, Amblypygi, and Solifugae, 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 pincer-like pedipalps just before the sensory legs. The hind legs are modified for jumping, as part of their escape response when threatened.〔Humphreys, W.F., et al. (1989) The biology of ''Schizomus vinei'' (Chelicerata: Schizomida) in the caves of Cape Range, Western Australia. J. ZOol. Lond. 217: 177-201.〕 Schizomids have no actual eyes, but a few species have vestigial eyespots capable of telling light from dark. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Schizomida」の詳細全文を読む スポンサード リンク
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