Reproductive system of female scorpion: a partial review

The female scorpion ovariuterus was examined in 10 scorpion species belonging to five families: Buthidae, Vaejovidae, Scorpionidae, Urodacidae, and Diplocentridae. Two main patterns of development are known in scorpions: (1) The apoikogenic type with an ovariuterus containing yolk-rich eggs housed in follicles. This type is found in many scorpion taxa (largely buthids). A peculiar case of apoikogenic ovariuterus is a "beaded" ovariuterus where most of the ova's embryogenesis takes place inside the ovariuterus rather than on pedicels situated on the external wall of the ovariuterus as in most buthids. This type is found in a few scorpion species. (2) The katoikogenic type with an ovariuterus where the embryo develops in a diverticulum composed of four parts: a stalk (pedicel), a thickened collar, a conical portion containing the ovum, and an appendix containing the oral feeding apparatus where the embryos' chelicerae grip a "teat"-like structure, described in four families: Hemiscorpiidae, Scorpionidae, Urodacidae, and Diplocentridae. There are three kinds of diverticulae: small rudimentary finger-like diverticulae, embryonic (ED) large projections, and postpartum diverticulae (PPD) empty diverticulae, which are remnants after parturition. The subject is reviewed and its bearing on reproduction in scorpions are discussed.