Diagnosis.  - Elongate, narrow fingers on the pedipalp chela terminate in a pronounced tooth.   Proximal pectinal teeth of females enlarged; rounder and smoother than other teeth. 

Comparisons. -  Most closely related to Vaejovis .

Subordinate taxa. - The genus Serradigitus currently includes sixteen species (one of which is divided into two subspecies):  

Distribution. - Western North America, in rocky habitats from California east to Texas and southward into the Baja California penisula and mainland Mexico.  The genus is represented in California by the following taxa:

Taxonomic History and notes. -

Type species:  Vejovis wupatkiensis Stahnke 1940.

Synonomy:

Uroctonoides Hoffmann, 1931:405; not Chamberlin 1920:36.

Paruroctonus Werner, 1934:283 (Jan.); Gertsch and Allred 1965:9 (subgenus of Vaejovis Koch,1836; in part); Gertsch and Soleglad 1966:3 (subgenus of Vaejovis; in part); Williams 1972:2 (in part), 1974:15 (in part), 1980:31 (in part); Hjelle 1972:26 (in part); Soleglad 1973:353, 355 (in part); Francke and Soleglad 1981:241, 243 (in part).

Hoffmanniellius Mello-Leitao,1934:80 (June).

In his unpublished Master's Thesis, Berke (1987) divided the California members of the genus into two groups, based on overall size and on the relative placement of trichobothria ib and it on the pedipalp chela.  The smaller species (S. gertschi, S. joshuaensis, S. torridus, and S. wupatkiensis), in which trichobothria ib and it are on the proximal half of the fixed chelal finger, constituted one group.  The larger species (S. harbisoni, S. subtilimanus, and S. deserticola), in which trichobothria ib and it or on the distal half of the fixed chelal finger, formed the other. 

Remarks. -  One of the more striking dichotomies in the nominate subgenus is that between the generally large species with many pectinal teeth and the generally small species with few pectinal teeth . Although there are exceptions in each group, the divergent tendencies in size and pectinal tooth counts, as well as in several coincident characters, are quite conspicuous. This dichotomy is also supported by the observations that the two groups are widely sympatric, whereas the species within each group are, with few exceptions, allopatric . However, one of the large species, Paruroctonus gracilior (Hoffmann,1931), is geographically removed and morphologically divergent from the other large species, and in various characters tends to link the large and small species. The link is completed by Paruroctonus becki (Gertsch and Allred,1965) among the large species and Paruroctonus stahnkei (Gertsch and Soleglad,1966)among the small species, each of which is intermediate to P. gracilior and most or all of the other species in their respective groups with respect to infragroup characters 1-3 (see infragroup diagnoses below) as well as in the number of retroinferior terminal setae on the telotarsi, the number of primary denticle rows on the pedipalp movable finger, and the development of denticles on the inferior carina of the cheliceral fixed digit . The various characteristics shared by P. gracilior and the remaining large species (i .e., infragroup characters 5-10) all appear plesiomorphic, relative to the outgroup subgenus Smeringurus, and thus do not necessarily support a closer relationship than one between P. gracilior and the small species, a relationship for which, likewise, no synapomorphies are known. Therefore, the classification that, in my opinion, best describes the available observations is one involving three infragroups; namely, gracilior, boreus (including P. becki), and stahnkei.