Diagnosis: Diagnosis.—An infragroup of nominate subgenus Paruroctonus differentiated by combination of: (1) cheliceral fixed digit with inferior carina extending proximally at least to level of bicusp (see Gertsch and Soleglad 1966: fig. 36); (2) cheliceral movable digit with superior distal tine essentially triangular or elongate and curved, inferior distal tine length/superior distal tine length ratio 3 .0 or less; (3) carapace length/cheliceral fixed digit length ratio 4.2-8.0; (4) basitarsus III with six or more superior seta, arranged in distal plus proximal rows (4+2 to 6+2) or in essentially single file; (5) pectinal teeth in males 13-23 (except 26-27 in one new species; rarely 24 in P. stahnkei or P. simulatus, n. sp.), females 8-17 (except 18 in one new species); (6) pedipalp movable finger length/palm length ratio in adult males 0.8-1.0 (except 1.0-1.1 in shulovi microgroup), adult females 1 .0-1.1 ; (7) carapace length/pectine length ratio in adult males 1 .0-1 .2, adult females 1.5-2 .2 (except 1.4-1.5 in P. stahnkei, and 1.4 in shulovi microgroup); (8) humerus with two inframedial macrosetae on proximal 3/5 of internal surface (except two to three in shulovi microgroup); (9) pedipalp primary denticles, excluding proximal row, total 17-47 on fixed finger, 22-57 on movable finger; (10) adult carapace length generally 3 .0-5.0 mm in males, 3.5-5.5 mm in females.
Distribution: Western and southern Great Basin southward into northern Baja California Sur, northwestern Sonora and Chihuahuan Desert.
Subordinate taxa.—The stahnkei infragroup comprises four primarily allopatric elements, differentiated as follows and in Table 5 .
STAHNKEI MICROGROUP. Diagnosis: combination of carapace length/ cheliceral fixed digit length ratio 4.2-5.0; telotarsi II-IV with one retroinferior terminal seta (similar to Fig . 16). Distribution: Northern Sonoran Desert. Included species : P. stahnkei (Gertsch and Soleglad, 1966) .
SHULOVI MICROGROUP . Diagnosis : combination of carapace length/ cheliceral fixed digit length ratio 7 .0-8 .0 ; basitarsus II with mrs seta . Distribution: Western and southern Great Basin. Included taxa: P. shulovi (Williams, 1970); P. shulovi nevadae, n. ssp.; P. simulatus, n. sp.
BORREGOENSIS MICROGROUP. Diagnosis: basitarsus II without mrs seta. Distribution: Southern Great Basin, southward into northwestern Sonora and northern Baja California Sur. Included species: This microgroup, named after P. borregoensis Williams, 1972, is discussed in detail by Haradon (1984b).
WILLIAMSI MICROGROUP. Diagnosis : combination of carapace length/cheliceral fixed digit length ratio 4 .8-5 .8 ; telotarsi II-IV with two retroinferior terminal setae. Distribution: Chihuahuan Desert. Included species: P. williamsi Sissom and Francke, 1981; P. pecos Sissom and Francke, 1981; P. coahuilanus, n. sp .
| Table 5. - Distribution and diagnostic characteristics of the four microgroups constituting the stahnkei infragroup of the nominate subgenus Paruroctonus. |
|Character ||stahnkei || williamsi || shulovi || borregoensis |
| Desert region || Sonoran || Chihuahuan || Great Basin || Mojave to Vizcaino |
Cheliceral fixed digit, inferior denticles
(A) absent (B) present
|A ||A ||B ||B |
|Pedipalp movable finger length/palm length, adult male ||1 .0 ||0.9-1.0 ||1.0-1.1 || 0.8-1.0 |
|Pedipalp primary denticles, |
rows on movable finger
less proximal row, fixed finger
|Pedipalp fingers, adult male: |
(A) unscalloped, (B) scalloped
| A || A || B || A,B |
|Pedipalp palm carinae, adult female |
(A) granular (B) smooth
|A ||B ||A ||B |
|Humeral internal inframedial macrosetae ||2 ||2 ||2-3 ||2 |
|Basitarsus II mid-retrosuperior seta (A) present, (B) absent ||A ||A ||A ||B |
|Telotarsi II-IV retroinferior terminal setae ||1 ||2 ||1-2 ||2 |
|Carapace length/pectine length ♀ || 1-4-1.5 || 1.6 || 1.4 || 1.5-2.2 |
| || || || || |
Comparisons: the gracilior infragroup (above) differs primarily in characters 1-4, but also significantly in 5-10 ; the boreus infragroup (above) differs primarily in character 5, but also significantly in 6-10. Specimens with pectinal tooth counts exceeding 23/24 in males or 17/17 in females (see Haradon, 1984b) have 34 or fewer primary denticles on pedipalp movable finger; all species in the boreus infragroup have 35 or more primary denticles on the movable finger. Distribution.—Western and southern Great Basin, southward into Sonoran Desert and Baja California Sur; also Chihuahuan Desert. Key Hsradon 1985 Cheliceral fixed digit inferior carina extends proximally at least to level of bicusp; carapace length/cheliceral fixed digit length ratio 4 .2 or more; Pectinal teeth 23/24 or fewer in males and 17/17 or fewer in females and 36 or fewer primary denticles (less proximal row) on pedipalp movable fingers, or either (1) more pectinal teeth, or (2) more primary denticles but dorsal metasomal setae I-IV 0,1,1,1 or more and mrs seta on basitarsus II ………..stahnkei infragroup