Vaejovis nigrescens Pocock 1898
HOLOTYPE: Vaejovis nigrescens Pocock Holotype: F (BMNH), “México”.
Original description: Vaejovis nigrescens Pocock, 1898: 396
distribution: NORTH AMERICA. México (Aguascalientes, Guanajuato, Jalisco, Querétaro, Estado de México, Michoacán, Zacatecas).
notes: Beutelspacher's (2000) record of this species from Hidalgo are based on misidentifications of V. nitidulus; his records from Morelos, Oaxaca, and Puebla are probably all erroneous. The listing of the species from Distrito Federal by Sissom (1991, 2000) was based on the suggestion that Hoffmann's specimens of V. nitidulus intermedius were misidentified as V. nigrescens. Alternately, E. González Santillán (pers. observation) suggests the specimens are V. mexicanus mexicanus or are mislabeled. The specimens are apparently lost.
Vaejovis nigrescens Pocock
Vaejovis nigrescens Pocock 1898: 396.
Type data.—Adult female holotype from Mexico (no date or collector); deposited in the British Museum (Natural History); examined. The holotype, formerly a pinned specimen, is in poor condition: metasomal segments II-V and the telson are detached from the body and held together with a pin ; the right pedipalp, its movable finger, and most of the legs are also detached; the pectines are shriveled and broken; and the specimen is strongly discolored.
Distribution.—The specimens we have examined are from the central Mexican states of Aguascalientes, Distrito Federal, and Guanajuato. Hoffmann (1931, 1937) and Diaz Najera (1964, 1975) record V. nigrescens additionally from Hidalgo, Queretaro, and adjacent parts of Jalisco, Michoacan, San Luis Potosi, and Zacatecas. As in the case of V. intermedius, these records need to be verified. We have also examined a series of specimens from Dinamita, Durango collected by Duges; this record is far outside the range of nigrescens (including the records of Hoffmann and Diaz Najera) and may possibly be the result of a labeling error.
Diagnosis.—Adults 42-68 mm in length . Base color orange brown to reddish brown with variable faint underlying dusky markings. Sternite VII with submedian keels obsolete; lateral keels weak to moderate, granular. Metasomal segments I-II wider than long, III as long s wide, V less than twice as long as wide; ventrolateral carinae of I-IV weak, smooth to finely granular; ventral submedian carinae obsolete. Pedipalp: tibia with 14 trichobothria (3 et, 1 est, 2 em, 2 esb, 5 eb, 1 v) on external face; fixed finger of chela with primary row of denticles broken into six subrows by five enlarged denticles; femur as long as
carapace ; dorsointernal Carina of chela with eak to moderate, rounded granules .
Pectinal tooth count 19-21 in males ; 17-21 in emales .
Vaejovis nigrescens is most similar to V. i termedius. For comparisons between
these two species, see the diagnosis of the latter species .
Redescription .-The following redescripton is based on adult males an d
females. Parenthetical statements refer to females . Measurements of the female
holotype and an adult male appear in Table 1 .
Coloration. Base color of carapace and tergites orange brown to reddish
brown, with faint underlying dusky markings . Venter yellow brown to orange
brown; third sternite in males with whitish patch along posteriomedial margin
(absent). Metasomal segments I-III orange brown to reddish brown, IV-V dark
reddish brown . Telson reddish brown, with dark brown aculeus . Chelicerae yellow
brown at base, mottled with brown distally; teeth brown. Pedipalps: Femur and
tibia yellow brown to orange brown withcarinae somewhat darkened ; chel a
manus reddish brown to dark orange brown ; fingers dark brown basally, reddis h
brown to dark orange brown distally . Legs yellow to orange brown, usuall y
lighter than body. Pectines whitish .
Prosoma. Carapace slightly longer than wide . Median ocular prominence only
slightly raised above carapacial surface . Three pairs of lateral eyes, diameter o f