Members of the order Solifugae, usually referred to as solifuges,
solifugids, solpugids or by an assortment of vernacular names (e.g., camel
spiders, false spiders, haarskeerders, jagspinnekoppe, jerrymanders, roman
spiders, sun spiders, walzenspinnen, wind scorpions), are a diverse and
fascinating, yet poorly known, order of specialized, mostly nocturnal, cursorial
hunting arachnids notable for their massively powerful two-segmented chelicerae,
voracious appetite, and tremendous speed (Punzo, 1998). They constitute
the sixth most diverse order of arachnids in number of families, genera, and
species (Harvey, 2002). Many solifuges are able to run at extremely fast
speeds (53 cm/sec) for short bursts, but like most arachnids, cannot sustain
such rapid locomotion for long periods. Solifuges vary from a few
millimeters to 10 centimeters in length and look superficially like stout,
hairy, fast-running spiders with an extra pair of legs (leg-like, sensory
pedipalps, held out in front of the body). They are, however, more closely
related to members of the order Pseudoscorpiones (Kraus, 1976; van der Hammen,
1977; Grasshoff, 1978; Weygoldt and Paulus, 1979; Shultz, 1990; Wheeler,
Cartwright, and Hayashi, 1993; Wheeler and Hayashi, 1998; Giribet and Ribera,
2000; Giribet, Edgecomb, Wheeler, and Babbitt, 2002; Coddington, Giribet,
Harvey, Prendini, and Walter, 2004)
than they are to spiders (order
Araneae). The orders Solifugae and Pseudoscorpiones are
placed together as the sole
members of the superorder
Haplocnemata (Shultz, 1990) within the class Arachnida. The order
Solifugae is indisputably a monophyletic group (a group whose members
share a common ancestor and which includes all descendants of that ancestor)
based upon both morphological and molecular analyses
(Wheeler, Cartwright, and Hayashi,
1993; Wheeler and Hayashi, 1998; Giribet and Ribera, 2000; Giribet, Edgecomb,
Wheeler, and Babbitt, 2002).
Besides their enormous chelicerae,
autapomorphic characters (derived features shared uniquely by members of the
group) include stalked, leaf-like chemosensory structures (malleoli or racquet
organs) on the coxae and trochanters of the fourth pair of legs (Brownell
and Farley, 1974), prosomal stigmata, peculiar cheliceral flagellae on
males (Lamoral, 1974), palpal coxal gland orifices, palpal suctorial organs
(Cushing, Brookhart, Kleebe, Zito, and Payne, 2005); opisthosomal ctenidia; and
a monocondylar walking leg joint between the femur and patella (Shultz, 1989).
Much of the systematics, morphology, behavior, and natural history of Solifugae
remains unknown (Coddington, Giribet, Harvey, and Prendini, 2004; Harvey, 2002,
Brownell, P.H., & Farley,
R.D. 1974. The organization of the malleolar sensory system in the solpugid
Chanbria sp. Tissue and Cell 6(3): 471485.
Coddington, J.A., Giribet,
G., Harvey, M.S., Prendini, L. & Walter, D.E. 2004. Arachnida. Pp. 296318.
In Assembling the Tree of Life (J. Cracraft and M.J. Donoghue, eds). Oxford
University Press: New York.
P.E., Brookhart, J.O.,
Kleebe, H.-J., Zito, G. & Payne, P. 2005. The suctorial organ of the Solifugae
(Arachnida, Solifugae). Arthropod Structure and Development 34: 397406.
Edgecombe, G.D., Wheeler, W.C. & Babbitt, C. 2002.
Phylogeny of the Arachnida and Opiliones: a combined approach using
morphological and molecular sequence data.
Giribet, G. &
Ribera, C. 2000. A
review of arthropod phylogeny: new data based on ribosomal DNA sequences and
direct character optimization.
Grasshoff, M. 1978. A model
of the evolution of the main chelicerate groups. Symposia of the Zoological
Society of London 42: 273284.
Harvey, M.S. 2002. The
neglected cousins: what do we know about the smaller arachnid orders? The
Journal of Arachnology 30: 357372.
2003. Catalogue of the Smaller Arachnid Orders of the World: Amblypygi,
Uropygi, Schizomida, Palpigradi, Ricinulei and Solifugae. CSIRO Publishing:
Kraus, O. 1976.
Zur phylogenetischen Stellung und Evolution der Chelicerata.
Lamoral, B.H. 1975. The
structure and possible function of the flagellum in four species of male
solifges of the family Solpugidae. In, Proceedings of the 6th International
Arachnological Congress: 136141. Vrije Universiteit of Amstersdam: Amsterdam.
Punzo, F. 1998. The
Biology of Camel-Spiders (Aachnida, Solifugae). Kluwer Academic Publishers:
Shultz, J.W. 1989.
Morphology of locomotor appendages in Arachnida: evolutionary trends and phylogenetic implications. The Journal of the Linnean Society of London.
Zoology 97: 156.
Shultz, J.W. 1990. Evolutionary morphology and phylogeny
of Arachnida. Cladistics 6: 138.
van der Hammen, L.
1977. A new classification of Chelicerata. Zoologische Mededelingen, Leiden
Weygoldt, P. &
Paulus, H.F. 1979. Untersuchungen zur Morphologie, Taxonomie und Phylogenie der
Chelicerata. Zeitschrift für zoologische Systematik und Evolutionsforschung
17: 85116, 177200.
Wheeler, W.C., Cartwright, P. and Hayashi, C.Y.
1993. Arthropod phylogeny: a combined approach. Cladistics 9: 139.
Wheeler, W.C. & Hayashi, C.Y.
1998. The phylogeny of extant chelicerate orders. Cladistics 14: 173192.