ZOOTAXA

ISSN 1175-5326 (print edition)

ISSN 1175-5334 (online edition)Copyright © 2014 Magnolia Press

Zootaxa 3790 (3): 439–450

www.mapress.com/zootaxa/Article

http://dx.doi.org/10.11646/zootaxa.3790.3.3

http://zoobank.org/urn:lsid:zoobank.org:pub:446D1195-E507-4D0A-92C1-289E20B4567A

A new species of bunchgrass lizard (Squamata: Phrynosomatidae) from the

southern sky islands of the Sierra Madre Occidental, Mexico

JARED A. GRUMMER1,2 & ROBERT W. BRYSON, JR.1

1Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Box 351800, Seattle, WA

98195-1800, USA2Corresponding author. E-mail: grummer@uw.edu

Abstract

A new species of bunchgrass lizard in the Sceloporus scalaris group is described from the southern portion of the Sierra

Madre Occidental in Mexico. The new species, Sceloporus aurantius sp. nov., was previously confused with S. browno-

rum but differs from this and all but one species within the S. scalaris group by a lack of blue belly patches in males. It

shares with S. chaneyi an absence of blue belly patches, but differs from this species in size, number of dorsal scales, num-

ber of scales around midbody, and presence of an un-patterned morph. The new species further differs from S. chaneyi,

and all other species in the S. scalaris species group, by unique phylogenetic position revealed through species delimita-

tion based on multi-locus nuclear DNA. Principal component analyses of 24 traditional morphological characters used to

describe previous S. scalaris group taxa indicate that these characters may be of limited use to delineate species in this

species group. However, male lateral and ventral coloration may still be an important character for diagnosing species.

Key words: Aguascalientes, Jalisco, Reptilia, Sceloporus scalaris group, Zacatecas

Resumen

Se describe una especie nueva de lagartija de pastizal dentro del grupo Scelopous scalaris en la región sur de la Sierra

Madre Occidental de México. La especie nueva, Sceloporus aurantius sp. nov., estaba considerada previamente como S.

brownorum y difiere de todas las especies del grupo S. scalaris excepto de la especie S. chaneyi, debido a que los

machos carecen de parches ventrales de color azul. Difiere de la especie S. chaneyi la cual también carece de parches, en

el tamaño, número de escamas dorsales, número de escamas alrededor del cuerpo, y presencia de un morfo sin patrón. La

especie nueva además difiere de S. chaneyi y de todas las especies del grupo S. scalaris, por tener una

posición filogenética única basada en múltiples locus de DNA nuclear. El análisis de componentes principales de 24 car-

acteres morfológicos tradicionales utilizados previamente para describir los taxa dentro del grupo S. scalaris, indica que

estos caracteres pueden tener un uso limitado para diagnosticar especies dentro del grupo. Sin embargo, la coloración ven-

tral y lateral en los machos, aún es considerada un caracter importante para diagnosticar especies.

Palabras claves: Aguascalientes, Jalisco, Reptilia, groupo de Sceloporus scalaris, Zacatecas

Introduction

The taxonomy of the Sceloporus scalaris species group has been in flux since its conception over 75 years ago

(Smith 1937). Although the species group as originally described contained seven species and subspecies, this

number has fluctuated from 11 species and subspecies (Watkins-Colwell et al. 2006) to only three monotypic

species (Thomas & Dixon 1976). This is due in part to the additions of new species and subspecies (S.

samcolemani Smith & Hall 1974; S. chaneyi Liner & Dixon 1992; and S. s. brownorum Smith, Watkins-Colwell,

Lemos-Espinal, & Chizar 1997). However, much of the instability is caused by variability in several key

morphological characters used to delineate taxa within the group. Previous descriptions have distinguished species

Accepted by S. Carranza: 6 Mar. 2014; published: 22 Apr. 2014 439

and subspecies primarily based on the number of canthal scales, extent of throat barring, or color of semeion

(lateral/ventral body) patches. Whereas Thomas & Dixon (1976) found these characters to be highly variable and

of limited use to delineate subspecies, Smith et al. (1996) considered them to be critically important in

distinguishing among the various species and subspecies within the group.

A number of studies of the S. scalaris group based on molecular data have emerged during the past decade

(Mink & Sites 1996; Benabib et al. 1997; Bryson et al. 2012; Grummer et al. 2014). These studies generally

support the recognition of previously described species and suggest that several undescribed species may be

present within the group (Bryson et al. 2012; Grummer et al. 2014). The S. scalaris group as currently recognized

consists of S. aeneus Wiegmann 1828, S. bicanthalis Smith 1937, S. brownorum, S. chaneyi, S. goldmani Smith

1937, S. samcolemani, S. scalaris Wiegmann 1828, S. slevini Smith 1937, S. subniger Poglayen & Smith 1958, S.

unicanthalis Smith 1937, and three undescribed species (Grummer et al. 2014).

FIGURE 1. Distribution of bunchgrass lizards in the Sceloporus scalaris group included in this study. Stars denote the known

localities of Sceloporus aurantius sp. nov. (yellow star is type locality). Colors of S. brownorum, S. scalaris, S. slevini, and S.

unicanthalis match the colors in principal components analyses results presented in Figure 3.

GRUMMER & BRYSON440 · Zootaxa 3790 (3) © 2014 Magnolia Press

Within the S. scalaris group, S. chaneyi is the only described species characterized by an absence of blue belly

patches in males (Liner & Dixon 1992). This small species is restricted to high-elevation pine-oak forests in the

northern Sierra Madre Oriental of eastern Mexico (Watkins-Colwell et al. 1996; Fig. 1). Recently we discovered a

population of S. brownorum in the oak forest of the Sierra del Laurel mountains in southwestern Mexico that

contained males with orange lateral streaks and no blue belly patches. Males of this population differed from S.

brownorum to the north that have only blue belly bars (Smith et al. 1997). Interestingly, specimens from the Sierra

del Laurel were part of the type series of S. brownorum (Smith et al. 1997). Grummer et al. (2014) tested species

limits within the S. scalaris group using multi-locus data and found compelling genetic evidence that this

population represents a distinct species (Fig. 2). Here we describe this new species, which represents the eleventh

species within the S. scalaris group.

FIGURE 2. Multi-locus species tree from Grummer et al. (2014) derived from coalescent-based analyses of 4,635 base pairs of

nuclear DNA. The phylogenetic distinctiveness of Sceloporus aurantius sp. nov. was supported by Bayes factor species

delimitation. Numbers at nodes represent Bayesian posterior probability support values.

Materials and methods

Molecular species delimitation. In a previous study (Grummer et al. 2014), we generated a multi-locus nuclear

DNA (nDNA) dataset to test species limits in the S. scalaris group. Because this dataset helps establish the

distinctiveness of the new species from the Sierra del Laurel in relation to other species in the group, we include a

summary of the methods and results here. We amplified nuclear regions of five protein-coding genes and one intron

for 34 individuals from the S. scalaris group, including two individuals of the new species. We then used this

molecular dataset to perform Bayes factor delimitation of species (BFD) in the coalescent-based species tree

inference program *BEAST (Heled & Drummond 2010). Briefly, using the new BFD method in Grummer et al.

(2014), we generated competing species delimitation models in which i) the individuals of the new species were

constrained to belong to the S. brownorum species, and ii) the individuals of the new species were placed in their

own lineage. The loge likelihood scores resulting from the fit of the molecular data to each model were compared

using Bayes factors with the criterion that a lineage is distinct if the Bayes factor value of the best model was > 10

over other models.

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Principal components analysis. We took morphological measurements of 51 bunchgrass lizards, including 19

S. brownorum, three S. scalaris, 10 S. unicanthalis, five S. slevini, and 14 individuals of the new species (Appendix

1). These species were selected for comparison because they were geographically proximate to the new species and

closely related (Grummer et al. 2014; Figs. 1–2). We also obtained data for S. chaneyi from Liner & Dixon (1992).

Morphometric measurements were taken with either a ruler or digital calipers, and measurements were recorded to

the nearest half-millimeter or hundredth of a millimeter, respectively. Snout-vent length was measured from the tip

of the snout to the posterior portion of the cloacal opening. Head length was measured from the tip of the snout to

the posterior edge of the interparietal. The length of the tibia was measured on the left leg from the top of the tibia

to where the tibia meets the tarsi. Dorsal scales were counted from the posterior margin of the interparietal to the

posterior level of the thighs. The number of scales around the middle of the body was counted halfway between the

axial and groin regions. Ventral scales were counted from the incomplete gular fold to the anterior margin of the

cloaca. Scale morphology and descriptions follow Smith (1939).

We ran principal components analysis (PCA) on the complete morphological dataset to examine group

membership and clustering. This dataset consisted of 49 individuals with complete morphological data (two

damaged specimens were not used; Appendix I) for the following 24 characters: snout-vent length (SVL); head

length; tibia length; entire hind limb length; the number of dorsals, midbody scales, ventrals, canthals, frontonasals,

internasals, supralabials, infralabials, preoculars, loreals, lorilabials, frontoparietals, parietals bordering

interparietal, scales bordering interparietal, scales between second pair of postmentals, scales between third pair of

postmentals, and postnasals; and presence or absence of interparietal with posterior notch, scale in front of frontal,

and scale behind frontal. PCA analyses were performed with the “prcomp” stats function in R on three groups:

combined female and male, female, and male; grouping by sex allowed us to account for sexual dimorphism. We

normalized and log10

-transformed our data; however, the PCA results did not change from the original data matrix.

We therefore only show results for the non-normalized, non-transformed dataset.

Results

Molecular species delimitation. Our final molecular dataset totaled 4,635 aligned base pairs (bp) and included six

nuclear loci that ranged from 521–1,254 bp with 433 parsimony-informative sites. Species delimitation using the

BFD approach provided decisive support for the species delimitation model with the individuals of the new species

comprising their own lineage (Bayes factor value > 29). The phylogeny showing the phylogenetic placement of the

new species in relation to other S. scalaris group members is shown in Figure 2. In addition to our quantitative

coalescent-based delimitation, concatenation (Fig. 5 in Grummer et al. 2014) and individual gene tree analyses

(supplemental file in Grummer et al. 2014) strongly placed the new species in clades distant from S. brownorum.

Principal components analyses. We conducted PCA analyses with and without binary characters, and their

inclusion did not affect our results so we used the full dataset of binary, discrete, and continuous characters in final

analyses. Principal component 1 loaded strongly with SVL and hind limb length, whereas principal component 2

loaded strongly with the number of dorsal scales, number of scales around midbody, and number of ventral scales

(Table 1). Because SVL and hind limb length were positively correlated, as were number of dorsal, midbody, and

ventral scales with each other, we performed separate analyses without SVL, dorsal and midbody scales (6

permuted analyses), but our PCA results were not sensitive to these correlations (i.e., our PCA results did not differ

with these different datasets). The first two and three principal components explained approximately 60% and 80%

of the variance in the dataset, respectively. Plotting PC1 vs. PC2 across sexes revealed a distinct grouping of the

new species from the type locality, whereas other individuals of the new species fell outside this tighter cluster

(Fig. 3). However, all individuals of the new species were nested within the morphospace that enveloped S.

brownorum, and also partially overlapped with S. slevini and S. unicanthalis. Analyses of females revealed a

grouping of the new species, whereas the analysis of males alone showed similar results to the analysis including

both sexes where the new species clustered by population (Fig. 3).

GRUMMER & BRYSON442 · Zootaxa 3790 (3) © 2014 Magnolia Press

FIGURE 3. Results of the principal components analyses when all individuals of Sceloporus scalaris group species were

analyzed together (a), females only (b), and males only (c).

Zootaxa 3790 (3) © 2014 Magnolia Press · 443A NEW SPECIES OF BUNCHGRASS LIZARD (GENUS SCELOPORUS)

Sceloporus aurantius sp. nov.

Sceloporus scalaris (part): (McCranie & Wilson 2001): 20.

Sceloporus scalaris (part): (Vázquez-Díaz & Quintero-Díaz 2005): 155.

Sceloporus scalaris brownorum (part): Smith et al. 1997: 290.

Sceloporus scalaris brownorum (part): Watkins-Colwell et al. 2006: 814.1.

Sceloporus scalaris brownorum (part): Bryson et al. 2012: 448.

Sceloporus scalaris brownorum (part): Grummer et al. 2014: 120.

Holotype. MZFC 28392 (field number RWB 1042; Fig. 4). Adult female. Mexico: Aguascalientes: Municipio

Calvillo, Los Alisos, Sierra del Laurel (N 21°43’32.2”, W102°42’01.4”; 2419 m). 20 July 2010. Robert W. Bryson, Jr.

Paratypes. Thirteen specimens. Mexico: Aguascalientes: Same locality as the holotype. 20 July 2010. Robert

W. Bryson, Jr., José Carlos Arenas-Monroy, and Michael Torocco. MZFC 25101–25106 (field numbers RWB

1019–1024). Four adult females, two adult males (Fig. 5). Ciénega [Sierra del Laurel] (N 21°45’0.0”, W

102°43’01.2”; 2370 m). 4 August 1979. Larry Wilson. USNM 346561–346564. Two adult females, two adult

males. Jalisco: 1 mi NE Villa Hidalgo [foothills of the Sierra del Laurel]. 24 October 1950. KUH 29636. Juvenile

male. Zacatecas: Ojo de Agua, 2.5 km NW Rancho Los Adobes (N 21°44’53.86”, W 103°29’42.9”; 2140 m). 27

April 2008. Iván T. Ahumada Carrillo. MZFC 24818. Adult male (Fig. 6). 3.4 km S La Estancia (N 21°41’44.2”, W

103°28’56.1”; 2228 m). 26 May 2008. Iván T. Ahumada Carrillo. MZFC 24831. Adult male.

TABLE 1. Morphological characters of bunchgrass lizards in the Sceloporus scalaris group used in the principal

components (PC) analyses along with their respective PC loadings.

Character PC1 PC2 PC3

Snout-vent length 0.8883 0.0728 -0.0544

Head length 0.1337 -0.0005 -0.0164

Tibia length 0.1707 -0.0588 0.0667

Hind limb length 0.3890 -0.1004 0.2463

Number of dorsals 0.0491 0.4934 -0.4628

Number of mid-body scales -0.0101 0.4498 -0.4574

Number of ventrals -0.0410 0.7161 0.6158

Number of canthals 0.0303 0.0274 0.0426

Number of frontonasals 0.0010 -0.0281 -0.0084

Number of internasals -0.0449 0.1194 0.2153

Number of supralabials 0.0046 0.0032 -0.0136

Number of infralabials -0.0202 0.0407 -0.0037

Number of preoculars 0.0006 -0.0296 0.0041

Number of loreals -0.0012 -0.0182 0.0000

Number of lorilabials -0.0346 -0.0069 0.1055

Number of frontoparietals 0.0232 0.0208 0.0409

Number of parietals -0.0113 -0.0138 -0.0081

Number of scales bordering interparietal -0.0402 -0.0001 0.1879

Number of scales in 2nd row of postmentals -0.0114 -0.0263 -0.1204

Number of scales in 3rd row of postmentals -0.0314 0.0385 -0.1289

Number of postnasals contacting nasal scale 0.0007 -0.0129 0.0217

Posterior notch on interparietal 0.0049 0.0152 0.0181

Scale anterior to frontal -0.0182 0.0267 0.0194

Scale posterior to frontal 0.0075 0.0039 0.0038

GRUMMER & BRYSON444 · Zootaxa 3790 (3) © 2014 Magnolia Press

FIGURE 4. Holotype specimen of Sceloporus aurantius sp. nov. (MZFC 28392) in dorsal (a), ventral (b), and in-life (c) views.

Zootaxa 3790 (3) © 2014 Magnolia Press · 445A NEW SPECIES OF BUNCHGRASS LIZARD (GENUS SCELOPORUS)

FIGURE 5. Dorsal pattern variation within the paratype series of Sceloporus aurantius sp. nov. from the Sierra del Laurel,

Aguascalientes: a) MZFC 25102 (female), b) MZFC 25103 (female), c) MZFC 25106 (male), and d) MZFC 25101 (male).

Diagnosis. Sceloporus aurantius sp. nov. belongs to the S. scalaris species group, sharing with other species in

that group the following characters: parallel lateral scale rows (except in S. goldmani), femoral pore series in

contact or separated by no more than two scales, females with smooth preanal scales, and males with lateral

abdominal color patches (Smith 1939; Smith et al. 1997; Watkins-Cowell et al. 2006). Sceloporus aurantius sp.

nov. differs from all S. scalaris group species except S. chaneyi by the lack of blue belly bars in adult males.

Sceloporus aurantius sp. nov. differs from S. chaneyi in adult size (mean snout-to-vent length 49.8 mm vs. 45.7

mm), number of dorsal scales (mean of 39.2 vs. 42.3), number of scales around midbody (mean of 37.9 vs. 40.4),

and presence of an un-patterned morph (absent in S. chaneyi). Although not a diagnostic character state, Sceloporus

aurantius sp. nov. further differs from S. chaneyi, and all other species in the S. scalaris species group, by unique

phylogenetic position revealed through species delimitation (Grummer et al. 2014; Fig. 2).

Description of holotype. Adult female (Fig. 4). SVL 55 mm, 117 mm with tail. Head length 11.05 mm. Tibia

length 10 mm. Entire hind limb length (including 4th toe) of 24 mm. Forelimb length 13 mm. Dorsal head scales

keeled and rugose. Five internasals of irregular shape. Canthals 2–2 (right–left). Loreals 1–1. Supralabials 5–5.

Infralabials 6–5. Postnasals 2–2, irregular. Preoculars 1–1 with a strong transverse keel on posterior margin. Five

frontonasals, keeled. Two prefrontals, rugose and keeled with medial contact posteriorly, divided by a frontonasal

anteriorly. One frontal transversely divided, rugose, with two keels on lateral margins. Interparietal coronate with

posterior notch. Frontoparietals 2–2. Parietals 2–2, rugose. Two complete lorilabial rows. Dorsal scales keeled,

acuminate, smooth (not serrate). Thirty-nine dorsal scales. Parallel lateral scale rows on body. Scales around

midbody 38. Ventral scales rounded with posterior notch.

Pale vertebral stripe two scales wide. Two pale dorsolateral stripes approximately ½ scale wide, interspersed

with dark flecks. Vertebral and dorsolateral stripes separated by three scale rows. Two pale lateral stripes ½ scale

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wide, separated from dorsolateral stripes by two scale rows. Chevrons in four rows between each pair of dorsal

stripes; 7 between left lateral and dorsolateral stripes, 12 between left dorsolateral and vertebral stripes, 12 between

vertebral and right dorsolateral line, 8 between right dorsolateral and lateral stripes. Chevrons are dark with scales’

posterior margins pale. Dorsolateral and ventral surfaces pale with minute dark flecks throughout. Gular region

lacking distinct markings.

Color in preservative. Dorsal and lateral portions of head brown with white between ocular and opercular

openings; white loreal scales. Underside of head is white with small black flecks. Two white dorsolateral lines (~1

scale wide) and a broad (~3 scales wide) light gray vertebral stripe fading into base of tail. Numerous black

chevrons with white posterior margins, between vertebral and dorsolateral stripes. Scales between chevrons are

brown. A single white line (~1 scale wide) extends from posterior portion of operculum to inguinal area where the

femur joins the body on the lateral portion of the belly, separated from dorsolateral line by black chevrons with

brown scales between. Front and hind limbs are brown with black, grey, and white scales scattered throughout.

Proximal dorsal portion of tail with black and grey scales on a grey/brown background. Distal portion of tail is

brown. Undersides of limbs, venter, and tail are white with sparsely distributed small black flecks. Chin and throat

without distinct black or grey streaks or bars.

Color in life. Head: brown/rust on dorsal portion, grey-brown on sides in front of and below eyes. Dorsum

with two cream-colored dorsolateral lines and dark grey vertebral stripe. Black chevrons in between vertebral and

dorsolateral lines, with posterior margins of dark scales containing white margins. Portions between chevrons are

rust/brick red. On each side of the belly, a white line (~1 scale wide) extends from head to femur as described

above. Lateral scales between white lateral line and ventral scales are light red/brown. Front limbs grey with a

black shoulder spot. Hind limbs grey with faint black bars lined with white on posterior edges. Proximal dorsal

portion of tail with black triangles; distal dorsal portion brown.

FIGURE 6. Male paratype Sceloporus aurantius sp. nov. (MZFC 24818) from southern Zacatecas.

Morphometric variation. Adults only. Includes 7 females and 6 males. Snout-vent length 48–55 mm (x̅

=50.85; SD=3.41). Head length (snout to posterior edge of interparietal) 9.6–11.35 mm (10.68 mm; 0.55). Tibia

Zootaxa 3790 (3) © 2014 Magnolia Press · 447A NEW SPECIES OF BUNCHGRASS LIZARD (GENUS SCELOPORUS)

length (left side) 9–10.5 mm (9.46 mm; 0.52). Entire hind limb length (including fourth toe) 22–26.5 mm (23.46

mm; 2.08).

Scalation variation. Includes 7 females and 7 males. Dorsal scales range 37–43 (x̅ =39.21; SD=1.72). Scales

around midbody 35–42 (37.93; 1.82). Ventral scales 35–46 (42.21; 2.81). Canthals 2–2 (LR; 14/14). Frontonasals

3–4 (3.36; 0.74). Supralabials 5–5 (LR; 12/14), 6–5 (1/14), 6–6 (1/14). Infralabials 5–6 (1/14), 6–6 (5/14), 7–6 (2/

14), 7–7 (6/14). Preoculars (missing data from one damaged specimen, USNM 346564) 1–1 (10/13), 1–2 (1/13),

2–2 (2/13). Loreals (missing data from USNM 346564) 1–1 (1/13), 1–2 (1/13), 2–1 (1/13), 2–2 (6/13), 2–3 (2/13),

3–2 (1/13), 3–1 (1/13). Frontoparietals 2–4 (2.64; 0.84).

Coloration variation. In life, lateral edge of body and venter with orange streak in males, becoming less

distinct at midbody towards back leg (Figs. 5–6). A male paratype (USNM 346561) was elsewhere described in life

as having an orange-colored side with cream spotting below the lateral line (McCranie & Wilson 2001). This

orange streak is not apparent in preservative. A pattern-less morph occurred in both males and females. One male

(MZFC 24831) had some dark mottling on chin.

Etymology. The specific epithet is formed by the Latin adjective aurantius, which means “orange colored”, in

reference to the orange dorsolateral streak of males. As common names we suggest Southern Occidental

Bunchgrass Lizard (English) and Lagartija de Pastizal Sur Occidental (Spanish).

Distribution. Known from the oak forests of the Sierra del Laurel in southwestern Aguascalientes and

southern Zacatecas (Fig. 1). However, we suspect that S. aurantius sp. nov. may be more widespread across the

southern sky islands of the Sierra Madre Occidental. Unfortunately, because females are difficult to distinguish

from other regional species of bunchgrass lizard, we could not confidentially ascertain whether the female

specimens from this region (LSUMZ 35078, 35108; and UTEP 6504–6506) are S. brownorum (as currently

designated in Smith et al. 1997) or S. aurantius sp. nov.

Natural history. Most of the type series (MZFC 25101–25106, 28392) were collected on 20 July 2010

throughout the day in patches of bunchgrass within oak forest (Fig. 7). Four females contained well-developed

eggs. The two specimens from southern Zacatecas were collected in oak forest.

FIGURE 7. Habitat at the type locality for Sceloporus aurantius sp. nov., Los Alisos, Sierra del Laurel, Aguascalientes.

GRUMMER & BRYSON448 · Zootaxa 3790 (3) © 2014 Magnolia Press

Discussion

Although S. aurantius sp. nov. is distinct based on traditional phylogenetic methods and Bayes factor delimitation

of species (Grummer et al. 2014), our PCA analyses of traditional morphological characters used to describe

previous S. scalaris group taxa (e.g., Smith 1937; Smith et al. 1997) revealed strong morphological overlap

between S. aurantius sp. nov. and other recognized species (Fig. 3). In fact, all species that were measured

overlapped in PCA analyses, a finding that supports previous claims that these characters are highly variable and

probably of limited utility in the S. scalaris species group (Thomas & Dixon 1976). The only morphological

character that we are aware of to distinguish S. aurantius sp. nov. from other S. scalaris group taxa is the lack of

blue belly patches and presence of an orange dorsolateral streak in male S. aurantius sp. nov. Male ventral

coloration is critical for sexual selection and species-specific mate recognition (e.g., Wiens 1999) and so this

morphological character is probably still important in diagnosing species.

Distinguishing between S. aurantius sp. nov. and regional species of bunchgrass lizards based only on male

ventral coloration makes discernment of female S. aurantius sp. nov. from geographically proximate species such

as S. brownorum difficult. However, the predominantly oak forest habitat at the type locality of S. aurantius sp.

nov. (Fig. 7) is different from the Madrean pine-oak habitat of S. brownorum (Vázquez-Díaz & Quintero-Díaz

2005) and may be an indicator of ecological differences. Additional fieldwork and geographic sampling is needed

to identify the full geographic range of S. aurantius sp. nov., perhaps in concert with DNA barcoding to help

distinguish females from adjacent S. scalaris group species.

Acknowledgements

We thank the following museums and their personnel for the loan of specimens used in this paper: California

Academy of Sciences (CAS), Field Museum of Natural History (FMNH), Kansas University (KUH), Museum of

Vertebrate Zoology (MVZ), Museo de Zoología “Alfonso L. Herrera”, Facultad de Ciencias, Universidad Nacional

Autónoma de México (MZFC), University of Michigan (UMMZ), Smithsonian (USNM), and University of Texas

at El Paso (UTEP). We also thank J.C. Arenas-Monroy and M. Torocco for assistance in the field, and to M. Hedin

for the use of his camera to photograph the holotype. Permits to collect in Mexico were issued by SEMARNAT to

RWB, the late F. Mendoza-Quijano, and the MZFC. We also thank I.W. Caviedes, C. Franklin, O. Flores-Villela, J.

Jones, A. Nieto-Montes, E. Pérez-Ramos, G. Quintero-Diaz, T. Reeder, B.R. Riddle and C. Spencer for additional

support. Color photo in Fig. 6 graciously provided by I.T. Ahumada-Carrillo. This paper is based in part upon work

supported by the National Science Foundation grants DEB- 1257785 and DEB- 1258205.

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APPENDIX I. Specimens examined. Asterisks denote two damaged specimens not used in principal components

analyses.

Sceloporus brownorum. Mexico: Aguascalientes: Sierra Fria (LSUMZ 35027, 35028, 35099; UMMZ 110879, 110893, 113650;

USNM 346560). Granja Huentepec (CAS 19470*). Durango: El Salto (CAS 91854; MVZ 76550). Zacatecas:

Chalchihuites (CAS 95910–95918).

Sceloporus aurantius sp. nov. Mexico: Aguascalientes: Municipio Calvillo, Los Alisos, Sierra del Laurel (MZFC

25101–25106, 28392). Ciénega [Sierra del Laurel] (USNM 346561–346563, 346564*). Jalisco: 1 mi NE Villa Hidalgo

[foothills of the Sierra del Laurel] (KUH 29636). Zacatecas: Ojo de Agua, 2.5 km NW Rancho Los Adobes (MZFC

24818). 3.4 km S La Estancia (MZFC 24831).

Sceloporus scalaris. Mexico: Guanajuato: Sierra Cualtraba (MZFC 25107–25108). Jalisco: 5 mi N of Cuautla (KUH 93480).

Sceloporus slevini. U.S.A.: Arizona: Las Cienegas grassland, NE Sonoita (UTA R 60720). Chiricahua Mountains (UTA R

60716–60718). Santa Rita Mountains (UTA R 60719).

Sceloporus unicanthalis. Mexico: Durango: ca. 21 km S & 12 km W Teneraca (UTEP 7408–7410). near Huazamota, between

Huazamota and Santa Teresa, Nayarit (USNM 46626). Jalisco: 3 mi WSW Mazamitla (KUH 37732–37733). 4 mi W

Mazamitla (KUH 29795). Magdalena (FMNH 32009). Nayarit: 37.1 mi E Ixtlan del Rio on Mexico Hwy 15 (MVZ 72185)

ca. 1 km S & 27 km E Huajicori (UTEP 7417)..

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