Allocation of Populations of Whiptail Lizards to septemvittatus Cope, 1892 (Genus Cnemidophorus) in Chihuahua, México, and the scalaris Problem

We used 11 samples comprising 224 specimens collected between 1966 and 1999 in Chihuahua, México, and Texas to clarify aspects of color pattern and meristic variation in the notoriously difficult gonochoristic Cnemidophorus gularis-scalaris-septemvittatus complex which is characterized by enlarged mesoptychial scales and enlarged and platelike postantebrachial scales. We allocated populations represented in all SEPT-CMX samples except SEPT-CMX5 from northeastern Chihuahua to Cnemidophorus gularis septemvittatus Cope, 1892, type locality Marfa, Presidio County, Texas, represented by sample SEPT-TUS1. This allocation adds 28 newly discovered sites in Chihuahua to the single valid record previously known for the taxon in that state. Our study revealed that three taxonomically distinct forms, one in Trans-Pecos Texas east of Alamito Creek, Presidio County, and another in southern Coahuila, México (both beyond the scope of this study), were included in septemvittatus in a 1962 taxonomic revision. Clarification of the distribution and variation of C. g. septemvittatus in Chihuahua sets the stage for further systematic studies. Whiptail lizards in our SCAL-CMX samples from Chihuahua, for which only the name Cnemidophorus gularis scalaris Cope, 1892, is available, represent two forms distinguishable from each other and from C. g. septemvittatus on the basis of color patterns that remain distinct through ontogeny. Further sampling of Cnemidophorus populations in Chihuahua will be required to fully resolve the scalaris problem.

Fig. 1.

Outline map of Chihuahua showing the geographical areas inhabited by populations of Cnemidophorus gularis septemvittatus (five SEPT-CMX samples; SEPT-TUS1 is in Presidio County Texas) and populations assigned to Cnemidophorus gularis scalaris (three SCAL-CMX samples). Samples SEPT-CMX5 and SCAL-CMX3 are of different undescribed subspecies as discussed in the text

Fig. 2.

Dorsal color pattern variation (ontogenetic, sexual, and individual) in Cnemidophorus gularis septemvittatus as represented in samples SEPT-CMX1 (A–D, F–H) and SEPT-CMX4 (E): (A) JAL-E 3708, juvenile female, SVL 58 mm; (B) JAL-E 3607, female, SVL 94 mm; (C) JAL-E 3624, female, SVL 83 mm; (D) JAL-S 3699, male, SVL 85 mm; (E) UADZ 4586, female, SVL 104 mm; (F) JAL-E 3711, male, SVL 89 mm; (G) JAL-E 3609, male, SVL 95 mm; and (H) JAL-E 3749, male, SVL 111 mm (see Appendix 1 for actual sites of collection)

Fig. 5.

Projections of scores on canonical variate axes (solid symbols represent distributional centroids for each group of scores) for (A) individuals of Cnemidophorus gularis septemvittatus, Cnemidophorus gularis scalaris, and an undescribed subspecies (Cnemidophorus gularis subsp.) in samples from Chihuahua, México, and Texas; (B) individuals of C. g. septemvittatus from three sites in Chihuahua and one site in Texas; and (C) individuals of C. g. scalaris from three sites in Chihuahua

Fig. 4.

Dorsal color pattern extremes in extent of spotting and barring in sample SEPT-CMX2 (Cnemidophorus gularis septemvittatus): (A) JAL-E 4280, male, SVL 96 mm; (D) JAL-E 3765, male, SVL 103 mm. Dorsal and ventral pattern typical of adult males in sample SCAL-CMX3 (Cnemidophorus gularis subsp., note absence of purple-blue suffusion on ventral surfaces of forelimbs and chest): (B and E) JAL-E 3591, male, SVL 98mm. Dorsal and ventral pattern typical of adult males in sample SCAL-CMX2 (Cnemidophorus gularis scalaris, note presence of purple-blue suffusion on ventral surfaces of forelimbs and chest): (C, F) JAL-E 4043, male, SVL 97 mm (see Appendix 1 for actual sites of collection)

Fig. 3.

Dorsal color pattern variation in Cnemidophorus gularis septemvittatus as represented in sample SEPT-CMX2 (A–F) and SEPT-CMX4 (G, H): (A) JAL-E 3789, female, SVL 90 mm; (B) JAL-E 3804, male, SVL 91 mm; (C) JAL-E 3869, male, SVL 99 mm; (D) JAL-S 3842, male, SVL 83 mm; (E) JAL-E 3788, male, SVL 82 mm; (F) JAL-E 3868, male, SVL 83 mm; G–H (UADZ 5825, male, SVL 95 mm (see Appendix 1 for actual sites of collection)

Accepted: 29 Nov 2000