Schizomida
Schizomida Temporal range:
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Female Hubbardia pentapeltis | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Clade: | Tetrapulmonata |
Order: | Schizomida Petrunkevitch, 1945 |
Families | |
† Calcitronidae Petrunkevitch, 1945b |
Schizomida, also known as sprickets[1] or short-tailed whip-scorpions,[2] is an order of arachnids, generally less than 5 millimetres (0.20 in) in length. The order is not yet widely studied. E. O. Wilson has identified schizomids as among the "groups of organisms that desperately need experts to work on them."[3]
Taxonomy
Schizomids are grouped into three families:
- Calcitronidae † (fossil; dubious)
- Hubbardiidae
- Protoschizomidae (2 genera, 15 species)
About 300 species of schizomids have been described worldwide,[4] most belonging to the Hubbardiidae family. A systematic review including a full catalogue may be found in Reddell & Cokendolpher (1995). The Schizomida is sister to the order Uropygi, the two clades together forming the Thelyphonida (in the broad sense of the name).[5] Based on molecular clock dates, both orders likely originated in the late Carboniferous somewhere in the tropics of Pangea, and the Schizomida underwent substantial diversification starting in the Cretaceous.[5] The oldest known fossils of the group are from the Mid-Cretaceous Burmese amber of Myanmar, which are assignable to the Hubbardiidae.[6][7]
Morphology
Schizomids are relatively small, soft-bodied arachnids, somewhat similar in appearance to
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Hubbardia_pentapeltis_male_flagellum.jpg/260px-Hubbardia_pentapeltis_male_flagellum.jpg)
The
Like the related orders Uropygi and Amblypygi, and the more distantly related 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.[10]
Schizomids have no actual eyes, but a few species have vestigial eyespots capable of telling light from dark. They breathe through a single pair of
Distribution and habitat
Schizomids are generally tropical and subtropical creatures, and they have a global distribution in these habitats, including in
While sprickets are not typically found in colder climates, several Californian Hubbardia species have been found living under snow-covered rocks, and Hubbardia briggsi in particular is often found in snowy habitats during the winter.[13]
Biology
While not much is known about the lifespans of schizomids, they have been found to live for several months in captivity.[16]
Mortality and defense
Not much is known about the natural predators of sprickets.[15] Amblypygids have been observed eating schizomids.[15] Additionally, despite their small size, schizomids have been observed being parasitized by tiny nematodes; the opisthosoma of one Stenochrus goodnightorum was nearly completely filled by a parasitic nematode.[15]
Diet and feeding
Sprickets are active predators, constantly using their antenniform legs to examine the forest soil for potential prey.
Schizomids can survive a long time without food; some Hubbardia pentapeltis have been shown to survive five months without food.[15]
References
- ^ "Researchers count 13 new species of fanged arachnids in the Pilbara". Western Australian Museum. WAM. 2020-10-28. Retrieved 2023-09-23.
- ISBN 1-929427-11-5. Archived from the original(PDF online publication) on 2006-09-27.
- ^ Tyson, Charlie (May 7, 2019). "A Legendary Scientist Sounds Off on the Trouble With STEM". The Chronicle of Higher Education. Retrieved March 27, 2021.
- PMID 35273227.
- ^ S2CID 49523249.
- S2CID 202899476.
- ISSN 0024-4082.
- ISBN 0-03-056747-5.
- ^ Coddington J.A. et al. "Arachnida", p. 306, in: J. Cracraft (ed.) Assembling the Tree of Life, pp. 296-318
- ^ 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.
- PMID 20093195. Archived from the original(PDF) on 2017-02-14. Retrieved 2017-02-13.
- PMID 29783957.
- ^ a b c d e f g h i Beccaloni 2009, p. 134
- S2CID 55064714. Retrieved March 26, 2021.
- ^ a b c d e f g h i j k l m n o Beccaloni 2009, p. 135
- ^ Beccaloni 2009, p. 137
Cited texts
- Beccaloni, Jan (2009). Arachnids. Berkeley, CA: University of California Press. ISBN 978-0-520-26140-2.
- 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.
Videos
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[1] von Stefan F. Wirth