Mexico Herpetology

VENERABLE COLLARED LIZARD
Crotaphytus antiquus – Axtell & Webb 1995

IDENTIFICATION:
DISTRIBUTION:
Crotaphytus antiquus is known only from three small mountain ranges in the Mayran (AKA Parras) Basin in the vicinity of Torreon, Coahuila, Mexico. These are the Sierra Solis, Sierra Texas and Sierra San Lorenzo.

HABITAT:
Crotaphytus antiquus occurs on the lower slopes of several extremely dry desert ranges. The desert is described as Chihuahuan and has essentially the same flora as the region around El Paso, Texas. Creosote is a common plant where this species occurs.
NATURAL HISTORY:
This species is saxicolous and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus antiquus display their breeding coloration in May and early June. Smaller lizards are a large part of the diet of most Crotaphytus, and the Venerable Collared Lizard is probably no exception. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. Other species of lizard found in the habitat of C. antiquus are Sceloporus cyanostictus, Holbrookia maculata, Cophosaurus texanus, Aspidoscelis marmoratus variolosus, and Phrynosoma modestum. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
This species is closely related to Crotaphytus reticulatus.
TYPE:
Described as Crotaphytus antiquus by Axtell and Webb (1995). Holotype: UTEP 15900. Type locality: 2.1 km N, 1.6 km E Vizcaya (25 46′ 04″N, 103 11′ 48″W, el 1100 m) in the Sierra Texas, Coahuila, Mexico. An adult male collected on 22 June 1978 by Eric C. Axtell and Ralph W. Axtell.

PERSONAL NOTES:
In July, 2007 Troy Hibbits and I visited the Sierra San Lorenzo to search for this species; we found a juvenile male, a spectacular adult male and an adult female C. antiquus on the lower slopes of the range. The juvenile was basking on the top of a boulder on the edge of a small draw while the adult male was flushed from beneath some thick brush where it had been concealed until our approach. The adult female was basking on a large rock and unlike the other two lizards, was extremely wary. We also observed many Sceloporus cyanostictus and several Cophosaurus texanus.
CONSERVATION STATUS:
The existance of Crotaphytus antiquus was kept a secret for many years after it’s discovery; the authors of the original description felt that “conservation by silence” was the best route to take at first. This species does have a very small natural range and could potentially be susceptible to overcollection. Fortunately, due to the isolation and arid nature of this species’ habitat, overcollection appears to be the only immediate threat to it’s existance. This species is probably not being collected except by permitted researchers, and then only in very limited numbers.
REFERENCES:
Axtell, R. W. and Webb, R. G. 1995. Two New Crotaphytus from Southern Coahuila and the Adjacent States of East-Central Mexico. Bulletin of the Chicago Academy of Sciences, Vol. 16(2):1-15.

WESTERN COLLARED LIZARD
Crotaphytus collaris – Say in James 1823
Crotaphytus collaris baileyi – Stejneger 1890

IDENTIFICATION:
DISTRIBUTION:
In Sonora, Mexico the range of this species and Crotaphytus nebrius closely approach one-another but do not overlap.

HABITAT:
This lizard inhabits both Sonoran upland and high desert sites, generally where rocks are present. It is most common on alluvial fans and the lower slopes of ridges and Madrean sky island ranges.
NATURAL HISTORY:
This species is saxicolous and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus collaris baileyi display their breeding coloration in May and early June. Smaller lizards are a large part of the diet of Crotaphytus collaris. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
Some authors suggest that Crotaphytus collaris is a highly variable species with several pattern classes, but none of the various forms are sufficiently distinct enough to warrant recognition. I chose to retain use of the subspecific names until further notice.
TYPE:
PERSONAL NOTES:
I have seen this subspecies on many occasions, but have never looked for it in Mexico. Close to the Mexico border I have commonly seen this lizard basking on small rocks along roads leading in to the Santa Rita Mountains of Santa Cruz County, Arizona.
CONSERVATION STATUS:
Crotaphytus collaris is common, widespread and in no need of protection.
REFERENCES:

CHIHUAHUA COLLARED LIZARD
Crotaphytus collaris – Say 1823
Crotaphytus collaris fuscus – Ingram & Tanner 1971

IDENTIFICATION:
DISTRIBUTION:

HABITAT:

Rocky Grassland Habitat, Hidalgo Co., New Mexico

NATURAL HISTORY:
This species is saxicolus and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus collaris fuscus display their breeding coloration in May and early June. Smaller lizards are a large part of the diet of Crotaphytus collaris. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
Some authors suggest that Crotaphytus collaris is a highly variable species with several pattern classes, but none of the various forms are sufficiently distinct enough to warrant recognition. I chose to retain use of the subspecific names until further notice.
TYPE:
PERSONAL NOTES:
I have seen the fuscus subspecies on several occasions, all in either Cochise County, Arizona or Hidalgo County, New Mexico. I have never looked for it in Mexico. At the two localities in which I have viewed this subspecies, it occurred on rocks of ancient lava flows in Chihuahuan Grassland habitat. Other lizards common at these sites are Urosaurus ornatus (preyed upon by Crotaphytus), Sceloporus poinsetti, and Phrynosoma cornutum.
CONSERVATION STATUS:
Crotaphytus collaris is common, widespread and in no need of protection.
REFERENCES:

Adult Female, San Luis Potosi, Mexico

BLACK-SPOTTED COLLARED LIZARD
Crotaphytus collaris – Say in James 1823
Crotaphytus collaris melanomaculatus – Axtell & Webb 1995

IDENTIFICATION:
DISTRIBUTION:
Crotaphytus collaris melanomaculatus occurs from northeast Durango eastward through southern Coahuila, northern Zacatecas, southern Nuevo Leon, central and north-central San Luis Potosi and extreme southwest Tamaulipas. In Tamaulipas, this lizard is found in the Municipios of Tula, Palmillas, Bustamante and Miquihuana.

HABITAT:
This lizard inhabits both upland and low desert sites, generally where rocks are present. It is most common on alluvial fans and the lower slopes of ridges and mountain ranges.
NATURAL HISTORY:
This species is saxicolus and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus collaris melanomaculatus display their breeding coloration in May and early June. Smaller lizards are a large part of the diet of Crotaphytus collaris. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
Some authors suggest that Crotaphytus collaris is a highly variable species with several pattern classes, but none of the various forms are sufficiently distinct enough to warrant recognition. I chose to retain use of the subspecific names until further notice.
TYPE:
Described as Crotaphytus collaris melanomaculatus by Axtell and Webb (1995). Holotype: UTEP 15915. Type locality: 3.8 km S, 1.7 km E Graseros on the highway to Presa Francisco Zarca, el 1250 m, Durango, Mexico (25 14′ 10″N, 103 47′W). An adult male collected by Eric C. Axtell on 6 July 1982.
PERSONAL NOTES:
I have seen this species on two occasions; the first was along San Luis Potosi Hwy 80 in the vicinity of Presa de Guadalupe in May 2003 where I found the above-pictured individual. When I approached her she flattened against the ground and lay motionless while I took several pictures. I had to prod her before she would take flight, but when she did it was using bipedal movement (my first experience with such behavior).
I also found this subspecies in the desert hills near Tula, Tamaulipas in August 2004. A single male was observed basking on a limestone outcrop above a small wash. Other lizards found at this locality were Sceloporus spinosus spinosus, Cophosaurus texanus, Phrynosoma modestum, Aspidoscelis colossus, Aspidoscelis inornata inornata and a single Anelytropsis papillosus.
In September, 2007 W. Farr and I sought to fill in the known distribution of this lizard in Tamaulipas; we found it abundant in the Municipios of Tula, Bustamante and Miquihuana (it was previously known from only Tula and Palmillas). We found Sceloporus cautus, S. spinosus, S. parvus, Cophosaurus texanus, Aspidoscelis colossus and Aspidoscelis inornata inornata in association with this species. We found one adult male in the Municipio de Tula that exceeded the previous maximum size record for this species by a small margin.
CONSERVATION STATUS:
This form of the Western Collared Lizard is in no danger of large or small-scale population declines; it is not protected except by general Mexican Law.
REFERENCES:
Axtell, R. W. and Webb, R. G. 1995. Two New Crotaphytus from Southern Coahuila and the Adjacent States of East-Central Mexico. Bulletin of the Chicago Academy of Sciences, Vol. 16(2):1-15.

Adult male, 200′, Sonora, Mexico

Adult male, 200′, Sonora, Mexico

Adult male, 200′, Sonora, Mexico

Adult male, 200′, Sonora, Mexico

Venter of adult male, 200′, Sonora, Mexico

Female showing gravid coloration, 200′, Sonora, Mexico

Subadult male, 200′, Sonora, Mexico

Juvenile male, 200′, Sonora, Mexico

DICKERSON’S COLLARED LIZARD
Crotaphytus dickersonae – Schmidt 1922

IDENTIFICATION:
DISTRIBUTION:
This colorful species is found only in a narrow band of rocky hills along the coast of Sonora, Mexico from the town of El Desemboque south to Bahia Kino Nuevo; it is also found on Isla Tiburon in the Gulf of California. They are found from near sea level to the highest peaks of these hills, which are just a few hundred meters in elevation.

HABITAT:
This lizard inhabits Sonoran upland and rocky coastal desert sites. It is most common on the low-mid rocky slopes of ridges and hills.

Habitat, 200′, Sonora, Mexico

NATURAL HISTORY:
This species is saxicolous and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus dickersonae display their breeding coloration in April, and females are thought to lay their eggs in May and June. Smaller lizards are a large part of the diet of Crotaphytus dickersonae. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
In the Crotaphytus collaris species group, its closest relatives are C. collaris and C. nebrius.
TYPE:
Described as Crotaphytus dickersonae by K. P. Schmidt (1922). Holotype: USNM 64451. Type locality: Tiburon Island, Sonora, Mexico.
PERSONAL NOTES:
I found C. dickersonae in 2004 and 2005 at the same locality in coastal Sonora, Mexico. Males seemed to outnumber females by a large margin, but this may have been due to the activity patterns of the sexes. Males basked on open boulders and were ubiquitous due to their gawdy coloration, while the few females we found were often flushed from terrestrial locations beneath large bushes and cactus patches. Other species of reptiles I observed here are: Dipsosaurus dorsalis sonoriensis, Aspidoscelis tigris ssp., Salvadora hexalepis hexalepis, and Masticophis bilineatus.
CONSERVATION STATUS:
This species is abundant and needs no special protection.
REFERENCES:

SIERRA LOS CUCAPAS COLLARED LIZARD
Crotaphytus grismeri – McGuire 1994

IDENTIFICATION:
DISTRIBUTION:
This newly described species is only found at a few localities in the Sierra los Cucapas and Sierra el Mayor of northeast Baja California Norte, Mexico. Elevational distribution from 50-250 meters.

HABITAT:
C. grismeri is most often observed on or around rocky slopes, canyons, ridges, and among rocky rubble at the base of hills. Its habitat is especially hot and dry.
NATURAL HISTORY:
This species is saxicolous and is most often observed perched on rocks and rock outcrops between the months of March and September. Male and female Crotaphytus grismeri display their breeding coloration in April and May and lay eggs from May to September. Smaller lizards are a large part of the diet of most Crotaphytus, and the this species is no exception. C. grismeri will bask during the heat of the day in temperatures that are too extreme for some other lizards. Sympatric species of lizard found in the habitat of C. grismeri are Dipsosaurus dorsalis, Uta stansburiana, and Aspidoscelis tigris. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
This species is in the C. bicinctores species group and is cloesly related to C. bicinctores, C. vestigium and C. insularis.
TYPE:
Described as Crotaphytus grismeri by J. McGuire (1994). Holotype: CES 067-629. Type locality: East face of the Sierra de los Cucapas, approximately 50 km south of Mexicali, Baja California, Mexico.
PERSONAL NOTES:
I looked for this species once, with no success, south of Mexicali on the east slope of the Sierra el Mayor. We saw only Uta stansburiana and Dipsosaurus dorsalis.
CONSERVATION STATUS:
While this species has the smallest natural range of any member of the Genus, it is not in danger of local population decline because of the arid nature of its habitat, and the apparent lack of collecting interest.
REFERENCES:

Adult, 400′, Isla Angel de la Guarda, Baja California, Mexico

ISLA ANGEL DE LA GUARDA COLLARED LIZARD
Crotaphytus insularis – Van Denburgh & Slevin 1921

IDENTIFICATION:
DISTRIBUTION:
This species is found only on Isla Angel de la Guarda, a large island off the coast of Baja California Norte in the Gulf of California, Mexico.

HABITAT:

Rocky arroyo habitat, Isla Angel de la Guarda, Baja California, Mexico

NATURAL HISTORY:
This species is saxicolous and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus insularis display their breeding coloration in April and early May, and lay eggs from June through September. Smaller lizards are a large part of the diet of Crotaphytus insularis, but insects and even some plant material are also consumed. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
In the C. bicinctores species group, it is related to C. bicinctores, C. grismeri and C. vestigium.
TYPE:
Described as Crotaphytus insularis by J. Van Denburgh and J. L. Slevin (1921). Holotype: CAS 49151. Type locality: East coast of Angel de la Guarda Island 7 mi N of Pond Island, Gulf of California (Baja California), Mexico.
PERSONAL NOTES:
I found this species in June, 2002 in an arroyo on the west side of Isla Angel de la Guarda. It was basking on large volcanic rocks during the mid-day heat. Other species observed in the arroyo were Sauromalus hispidus, Callisaurus draconoides splendidus, Aspidoscelis tigris disparilis, Uta stansburiana and Crotalus angelensis.
CONSERVATION STATUS:
This species is in no need of special protection.
REFERENCES:

SONORA COLLARED LIZARD
Crotaphytus nebrius – Axtell & Montanucchi 1977

IDENTIFICATION:
DISTRIBUTION:

HABITAT:

Habitat, 100′, Sonora, Mexico

NATURAL HISTORY:
TAXONOMY:
TYPE:
PERSONAL NOTES:
I have seen C. nebrius in the vicinity of Ajo, Arizona in Organ Pipe Cactus National Monument. In July, 2003 Chris Gruenwald and I found an adult male in the vicinity of the Rio Yaqui just N of Sahuaripa, Sonora. It was basking on a large rock in an open area above the bridge.
CONSERVATION STATUS:
This species is widespread and common where it occurs, and does not need special protection.
REFERENCES:

RETICULATE COLLARED LIZARD
Crotaphytus reticulatus – Baird 1858

IDENTIFICATION:
DISTRIBUTION:

HABITAT:
NATURAL HISTORY:
Unlike other species of Crotaphytus, this lizard spends the majority of its time on bare earth; however, it will bask on small limestone rocks and associated formations when available. It is largely insectivorous but also consumes smaller lizards with vigor. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
This species is closely related to C. antiquus of southern Coahuila.
TYPE:
PERSONAL NOTES:
I finally found this species in September, 2007 while traveling with W. Farr in Tamaulipas, Mexico. I spotted a single female basking on a roadside rock along a dirt track south of Reynosa. Sceloporus variabilis was also common on these rocks. This female represents the farthest south this species has ever been recorded.
CONSERVATION STATUS:
This species is in no need of protection. Some habitat modification in Tamaulipas has destroyed reticulatus habitat, but this appears to threaten only a small portion of the population.
REFERENCES:
Axtell, R. W. and Webb, R. G. 1995. Two New Crotaphytus from Southern Coahuila and the Adjacent States of East-Central Mexico. Bulletin of the Chicago Academy of Sciences, Vol. 16(2):1-15.

BAJA CALIFORNIA COLLARED LIZARD
Crotaphytus vestigium – Smith & Tanner 1972

IDENTIFICATION:
DISTRIBUTION:
This species is found from the US border south to at least San Jose Comondu, Baja California Sur. Largely this distribution lies to the east of the Sierra de Juarez and Sierra San Pedro Martir but it also occurs in a narrow band of the pacific San Pedro Martir foothills from Mesa San Carlos to Arroyo San Antonio (Rancho San Jose). An apparently isolated pacific population occurs on Tecate Peak, on the US/Mexico border. Along the Gulf of California coast, C. vestigium occurs as far south as Bahia Concepcion; seemingly suitable habitat extends south of this point but strangely, no Crotaphytus have ever been found there.

HABITAT:
C. vestigium occurs in a variety of habitats with a common denominator: rock. It is occasionally found foraging on the open earth in the vicinity of rock structure, but retreats to it when threatened.

Rocky oceanside habitat, Baja California Sur, Mexico

NATURAL HISTORY:
This species is saxicolous and is most often observed perched on rocks and rock outcrops. Male and female Crotaphytus vestigium display their breeding coloration in April and early May. Smaller lizards are a large part of the diet of Crotaphytus vestigium, but it is also insectivorous. This species will bask during the heat of the day in temperatures that are too extreme for other lizards. When frightened, collared lizards have the ability to run on their hind legs (bipedal motion) for short distances.
TAXONOMY:
In the C. bicinctores species group, it is related to C. bicinctores, C. insularis, and C. grismeri.
TYPE:
Described as Crotaphytus insularis vestigium by H. M. Smith and W. W. Tanner (1972). Holotype: BYU 23338. Type locality: Guadalupe Canyon, Juarez Mountains, Baja California, Mexico.
PERSONAL NOTES:
In Baja California Sur, I found this lizard basking on rocks along Hwy 1 just west of San Ignacio (June, 2002).
CONSERVATION STATUS:
This species is abundant, widespread and in no need of protection.
REFERENCES: