Taxonomy and Phylogeny

Twelve families of solifugids, comprising 141 genera and 1095 described species, are currently recognized. Five monotypic fossil genera have been described (Petrunkevitch 1913; Poinar and Santiago-Blay 1989; Lebrun 1996; Mursch and Steffan 1996; Selden, and Shear 1996; Selden and Dunlop 1998; Dunlop and Rössler 2003; Dunlop, Wunderlichand Poinar 2004). No suborders or superfamilies have been proposed within Solifugae and phylogenetic relationships are unknown. Early attempts to produce a suprageneric classification were presented in the mid-late 1800s (Koch 1842; Simon 1879; Kraepelin 1899), but the modern classification was instigated in the 1930s by C.F. Roewer (1932, 1933, 1934, 1941), who described many new genera and species in a series of monographs that remain the most comprehensive treatments on the order. Roewer’s classification is devoid of phylogenetic content (Harvey 2002, 2004) and has been repeatedly criticized (Birula 1938; Panouse 1961; Muma 1951; Lawrence 1955; Muma 1976; Simonetta and Delle Cave 1968; Lawrence 1976; Wharton 1981; Gromov 2000). Several of his genera and subfamilies have been rejected (Birula 1938; Turk 1960; Delle Cave and Simonetta 1971). Fundamental concepts of monophyly and diagnosibility are absent from the classification, which relies on a small set of variable characters for separating subfamilies and genera. Some families (e.g., Galeodidae, Rhagodidae, Solpugidae), containing an abundance of arbitrarily defined genera that provide an inconsistent reflection of cladistic diversity, are in particularly dire need of revision. Numerous genera are monotypic and narrowly delineated due to excessive ‘splitting’, while other genera are large and broadly inclusive and appear to consist of multiple lineages that have been ‘lumped’ together. As many as 50% of the current solifuge genera may be paraphyletic or polyphyletic, as could several families (e.g., Daesiidae, Gylippidae, Melanoblossidae), although some (e.g., Hexisopodidae, Rhagodidae) seem to be clearly defined by obvious autapomorphies. The only published phylogenetic work conducted on any group of solifuges was a study of relationships in a single species-group of Eremobates (Brookhart and Cushing 2004). Excepting Muma’s revision of the North American Eremobatidae (Muma 1951, 1962), no solifuge families have been revised since Roewer (1932, 1933, 1934, 1941), whose classification has been largely discredited. The only regional faunas in relatively ‘good condition’ occur in the New World, where Roewer had little impact, and later researchers (e.g., Muma 1951, 1962, 1963, 1967, 1970, 1971, 1974, 1976, 1982, 1986, 1987, 1989; Muma and Muma 1988; Brookhart and Muma 1987; Muma and Brookhart 1988; Maury 1970, 1976, 1977, 1979, 1980a, 1980b, 1981, 1982a, 1982b, 1983, 1984, 1985, 1986, 1987, 1992, 1998) formulated a more meaningful classification based on the synthesis of multiple characters (although even here, there are significant problems with the existing classification). Few large monographic syntheses of solifuge genera have appeared in the last 25 years. Recent workers have tended to publish short papers, and these have tended to merely add new species to existing groups without addressing phylogenetic relations within or between those groups. The rigor of traditional taxonomy has barely advanced in studies fo the Solifugae. Few specimens are examined, few illustrations presented, and modern techniques (phylogenetics, molecular systematics, SEM, digital imaging, GIS, computerized databasing) are seldom applied. Workable diagnostic keys to genera and species are available for few regions of the world (North and South America, southern Africa)(Muma 1951, 1970, 1976; Lawrence 1955; Maury 1984; Muma and Muma 1988; Armas 1996; Punzo 1998). The order Solifugae is in urgent need of a higher-level phylogenetic analysis and monographic, family-scale revision to begin to sort out the confusion. The described species diversity of Solifugae, just slightly lower than that of Scorpiones, is almost certainly a gross underestimate of the world fauna. The regions where solifuges are most diverse (e.g., southern Africa, southwestern U.S.A.) have been best documented by past solifuge specialists (e.g., R.F. Lawrence, M.H. Muma). However, these regions have not by any means been thoroughly surveyed: new species and distribution records continue to be discovered, e.g., in the southwestern U.S.A. (Brookhart and Cushing, 2002, 2004, 2005). Many solifuge species are cryptic, seasonal, habitat-specific, and difficult to collect without appropriate methods (Muma 1966, 1970, 1975a, 1975b, 1979. 1980a, 1980b; Griffin 1990; Punzo 1994, 1997), and most regions where solifuges occur have not been surveyed in appropriate seasons or using appropriate methods. Many species are known from one or a few specimens (often only the types), usually collected serendipitously at a single locality; hence little is known about their distributions. The world’s solifuge fauna will probably double when all appropriate habitats are thoroughly surveyed. Species delimitation in many families is largely based on secondary sexual characters of adult males (flagellum, cheliceral dentition)(e.g. Kraepelin, K. 1899; Roewer 1932, 1933, 1934, 1941; Muma 1951; Lawrence 1955; Wharton 1981), rendering females and immatures difficult or impossible to identify below genus. Extensive field collecting, new morphological character systems, and molecular approaches for associating different sexes and life stages are needed to advance solifuge systematics. This section of the website presents the current classification of the order Solifugae, along with a key to its contained families. You may access this information through the links on the left side of the page.

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