Members are monotarsate; that is, all pedal tarsi consist of a single segment. For this reason they are usually included in the suborder Monosphyronida by other authors. In addition, the femora of all legs are similar in structure, with the telofemur attached firmly to the basifemur. The movable cheliceral finger is not dentate, but has a subapical lobe. The plates of the serrula interior are fused into a membranous velum. A laminal seta is present on the fixed cheliceral finger. The subterminal tarsal setae are simple and acute. The carapace is widened posteriorly. The chelicerae are small, no more than one-third as long as the carapace. One or both chelal fingers have a venom apparatus. The abdominal tergites and sternites are divided or undivided. There may be two weak eyes, or none. This superfamily is distributed widely, but mainly tropical and subtropical. Members are found in litter and under the bark of living trees, and in the nests of birds and mammals. They are small; most are less than 1 mm in body length.
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CHEIRIDIIDAE
These pseudoscorpions are monotarsate, and all the femora are similar. In addition, the femurs are undivided; that is, there is no or little indication of a division into a basifemur and telofemur. The carapace is distinctly triangular when viewed from above. There are two very small eyes. The abdomen is broadly ovate. The tergites and sternites are divided. The body surfaces are generally heavily sclerotized and granulate. The setae on the appendages are strongly curved and usually have a distinct tooth at or near the middle. One or both fingers of the palpal chela have a well-developed venom apparatus. The number of trichobothria on the chela is always reduced, to one or two on the movable finger. These animals are widely distributed around the world. They are generally found in litter, in animal nests, and under bark; 1 species, Cheiridium museorum, is commonly found in human habitations in Europe. They are all very small, most being about 1 mm in length. For this reason the family has not been well studied, and only 5 or 6 genera have been defined, the best known being Cheiridium and Apocheiridium.
STERNOPHORIDAE
Members are unique among pseudoscorpions in having a pseudosternal plate between the widely separated coax of legs II and III. The carapace is only slightly narrowed anteriorly, and bears no eyes. The abdomen is long and ovate, and the tergites and sternites are undivided. The whole body is markedly flattened, and the short legs extend out to the sides. The body surfaces are generally smooth, except for the palpi, which are finely granulate. All setae are straight and simple. Both fingers of the palpal chela have well-developed venom apparatus. The trichobothria on the chela are reduced in number to seven on the fixed finger and two or three on the movable finger. The legs are monotarsate and more or less alike, each femur clearly divided into a basifemur and telofemur. These forms are strongly modified for subtropical existence and are usually found under the bark of living trees. Four genera have been described in this family: Sternophorus, from western Mexico, Australia, southeastern Asia, and Africa; Sternophorellus, from New Guinea; Garyops, from Central America and the West Indies; and Idiogaryops, from the southern United States. | |
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