We compiled a checklist of the amphibians and reptiles of the state of Coahuila, Mexico. The list comprises 133 species (24 amphibians, 109 reptiles), representing 27 families (9 amphibians, 18 reptiles) and 65 genera (16 amphibians, 49 reptiles). Coahuila has a high richness of lizards in the genus Sceloporus. Coahuila has relatively few state endemics, but has several regional endemics. Overlap in the herpetofauna of Coahuila and bordering states is fairly extensive. Of the 132 species of native amphibians and reptiles, eight are listed as Vulnerable, six as Near Threatened, and six as Endangered in the IUCN Red List. In the SEMARNAT listing, 19 species are Subject to Special Protection, 26 are Threatened, and three are in Danger of Extinction. Coahuila is home to several species of conservation concern, especially lizards and turtles. Coahuila is an important state for the conservation of the native regional fauna.

Biogeography, Checklist, Conservation Status, Herpetofauna, IUCN Red List

Coahuila is the third largest state of Mexico, encompassing 151,571 km2, between latitudes 24°32'S and 29°53'N and between longitudes 99°51'E and 103°58'W. It is bordered by the Rio Grande of Texas to the north, by the states of Durango, Zacatecas, and San Luis Potosí to the south, Chihuahua to the west, and Nuevo León to the east (Fig. 1). It represents 7.74% of the total area of Mexico.

Figure 1. 

Topographical map of the state of Coahuila (INEGI 2001).

Extensive sierras in the northern part of the state appear to form a single mountain mass, although they are actually composed of three ranges: Sierra El Carmen, the western third; Sierra El Burro, the eastern third; and Sierra de Santa Rosa, the southern third. The greatest altitude (2,120 m) is reached in the Sierra de Santa Rosa (28°18'N, 102°4'W). These sierras constitute about 40–50% of the northern part of the state; the rest of the northern part consists of plains whose average elevation is 1,000 m. In the extreme western part of the state, isolated, relatively small sierras, oriented north to south, arise abruptly from the arid/semiarid plains. The principal ones are Sierra Las Cruces, Sierra Mojada, Sierra El Pino and Sierra de Tlahualilo. The highest of these is Sierra Mojada (27°16'N, 103°42W), with a maximum altitude of 2,450 m. Around these mountains the plains, at an average altitude of 1,250 m, are dominated by areas of sand dunes. One set lies between Estación Sabaneta and an area east of Jaco (Chihuahua), a part of the Bolsón de Mapimí. Another is on the plains of Aguanaval east of the Sierra de Tlahualilo (Dunas Magnéticas), part of the Zona del Silencio. Still another is on the plains of the municipalities of Matamoros and Viesca, located in the extreme southwestern part of the area known as the Laguna de Mayrán. The extreme south central and southeastern parts of the state are characterized by a series of east-west crustal folds forming several sierras, notably the Sierra de Arteaga, Sierra La Concordia, and Sierra de Parras, contiguous to the east with the Sierra Madre Oriental. Cerro La Nopalera (25°8'N, 103°14'W), at 3,120 m, is the highest elevation in the area. Toward the southwest these ranges are continuous with those that form the southern limit of the Laguna de Mayrán. The eastern part of the state is mostly flat, broken by several isolated, low ranges extending N-S, notably the Sierra Pájaros Azules (27°0'N, 100°53'W), reaching an altitude of 1,930 m, and Sierra La Gloria. In the central part of the state is a small, low (~750 m) valley of 120 km² surrounded by mountain ranges with altitudes of up to 2,500 m. For tens of thousands of years this valley was of strictly internal drainage, fed by waters from several arroyos, creating a wide variety of aquatic habitats, including streams, wells, lakes and marshes. Its isolation and antiquity led to a high degree of endemism there (McCoy 1984). At present this valley is known as the Cuatro Ciénegas Basin.

Much of Coahuila lies within the Chihuahuan Desert. The highlands in the extreme southeastern corner, including the Sierra de Arteaga, are an exception, and constitute the extreme northern end of the Sierra Madre Oriental. The vegetative cover of the state is made up of six types of vegetation (Chihuahuan Desert Scrub; Tamaulipan Thornscrub; Montane Forest; Sacatal Grassland; and Aquatic, Subaquatic and Riparian Vegetation) and 12 plant communities, that basically correspond to three floral provinces: The Mexican Plateau, the Coastal Plain of the Northeast and the Sierra Madre Oriental (Rzedowski 1978; Lemos-Espinal and Smith 2015b).

Lemos-Espinal and Smith (2015b) reviewed herpetological studies previously done in the state of Coahuila, with the majority of herpetological collections in Coahuila focused in the central part of the state (Bolsón de Cuatro Ciénegas), the southwestern part of the state (Laguna de Mayrán), and the extreme southeastern part of the state (Sierra de Arteaga). Other important regions of the state remain poorly studied, such as the extreme northwestern part of the state, due to lack of road access to these regions. However, in recent years, new highways has been constructed allowing access to previously unstudied areas, for example the highway from Múzquiz to Ojinaga, that traverses the northwestern part of Coahuila and connects this area with extreme northeastern Chihuahua. It is anticipated that this highway will increase herpetological studies of this region which is home of two important protected areas in Mexico: Área de Protección de Flora y Fauna Cañón de Santa Elena (Chihuahua) and Área de Protección de Flora y Fauna Maderas del Carmen (Coahuila).

Here, we report the list of amphibians and reptiles that have been recorded so far for the state of Coahuila. While checklists for Coahuila are available (e.g., Lemos-Espinal and Smith 2007, 2015b), we expand on these earlier efforts by also collecting and summarizing the conservation statuses of each documented species. We also compare the observed list to those available for the five adjoining states in the United States and Mexico for which recent checklists are available (Texas, Chihuahua, Durango, San Luis Potosí, and Nuevo León). Our goal is to place this checklist into a regional and conservation context not available in the previously published checklists.

We compiled the list of amphibians and reptiles of the state of Coahuila from the following sources: (1) our own field work; (2) specimens from the Laboratorio de Ecología - UBIPRO (LEUBIPRO) collections; (3) databases from the Comisión Nacional para el Conocimiento y Uso de la Biodiversidad (National Commission for the Understanding and Use of Biodiversity; CONABIO), including the 22 collections listed in Appendix I; and (4) a thorough examination of the available literature on amphibians and reptiles in the state. Species were included in the checklist only if we were able to confirm the record, either by direct observation or through documented museum records or vouchers in the state. In addition, we recorded the conservation status of each species based on three sources: 1) the IUCN Red List, 2) Environmental Viability Scores from Wilson et al. (2013a,b), and 3) listing in SEMARNAT (2010).

Scientific names used in this publication are based on the taxonomic list published in Lemos-Espinal (2015). The arrangement of the amphibian names follows Frost (2015) and arrangement of the reptile names follows Uetz and Hošek (2015). State lists used to compare the species composition between Coahuila and the adjoining states were: Lemos-Espinal and Smith (2015a: Chihuahua); Valdez-Lares et al. (2013: Durango); Lemos-Espinal and Dixon (2013: San Luis Potosí); Lemos-Espinal and Cruz (2015: Nuevo León); Dixon (2015: Texas). We modified the list provided by Valdez-Lares et al. (2013) to be able to compare it with the list of the rest of the states. These modifications were the following: we regarded the population of Barisia imbricata (Wiegmann) as Barisia ciliaris (Smith); 2) we regarded Sceloporus edbelli Smith et al. as part of Sceloporus consobrinus Baird & Girard; 3) we regarded Sceloporus lineolateralis Smith as part of Sceloporus jarrovii Cope; and 4) we regarded Aspidoscelis scalaris (Baird & Girard) as part of Aspidoscelis gularis (Baird & Girard). For these states we also determine the number of overlapping species.

We documented a total of 132 native species: 24 amphibians (four salamanders, 20 anurans) and 108 reptiles (11 turtles, 49 lizards, 48 snakes) (Tables 1, 2). These represent 26 families: 9 of amphibians (two of salamanders and seven of frogs), and 17 of reptiles (four of turtles, seven of lizards and six of snakes), and 64 genera: 16 of amphibians (three of salamanders and 13 of frogs), and 48 of reptiles (six of turtles, 16 of lizards and 26 of snakes) (Tables 1, 2). Additionally, one introduced species, the Mediterranean House Gecko (Hemidactylus turcicus), was recorded.

The difficult access to large and important parts of the state assure us that the number of native amphibian and reptile species that inhabits Coahuila is larger than the one we are reporting here. Species such as the Texas Salamander (Eurycea neotenes Bishop & Wright) and the Plains Spadefoot (Spea bombifrons [Cope]) likely inhabit extreme northern Coahuila. Dixon (2000) indicated the occurrence of these species at several localities in Texas adjacent to the extreme northern border of the state. The Ornate Box Turtle Terrapene ornata (Agassiz) very likely inhabits the Chihuahuan Desert of Coahuila, although as yet there are no records of this species in the state. According to Lemos-Espinal and Smith (2007, 2015b) species such as the Common Lesser Earless Lizard (Holbrookia maculata Girard), the Hernández Short-horned Lizard (Phrynosoma hernandesi Girard), and the Chihuahuan Spotted Whiptail (Aspidoscelis exsanguis [Lowe]), possibly inhabit extreme northwestern Coahuila. The Pigmy Alligator Lizard (Gerrhonotus parvus [Knight & Scudday]) may occur in the pine forests of the Sierra de Arteaga, and the Eastern Spiny Lizard (Sceloporus spinosus Weigmann) may occur in the semiarid region of the extreme southeastern part of the state. The Green Anole (Anolis carolinensis [Voigt]), the Laredo Striped Whiptail (Aspidoscelis laredoensis [McKinney et al.]), and the Six-lined Racerunner (Aspidoscelis sexlineata [Linnaeus]) probably occur in extreme northeastern Coahuila adjacent to Texas. The Torquate Lizard (Sceloporus torquatus Wiegmann) and the Bolson Night Lizard (Xantusia bolsonae Webb) likely occur in extreme southwestern Coahuila. Lemos-Espinal and Smith (2007, 2015b) also suggested that several species of snakes not recorded for Coahuila may inhabit the state, including Taylor´s Cantil (Agkistrodon taylori Burger & Robertson), the Tamaulipan Hook-nosed Snake (Ficimia streckeri Taylor), and the Red Black-headed Snake (Tantilla rubra Cope) in the southeastern portion of the state; the Tampico Threadsnake (Rena myopica [Garman]) and the Nuevo León Graceful Brownsnake (Rhadinaea montana Smith) in the extreme eastern portion; Dekay´s Brownsnake (Storeria dekayi [Holbrook]) and the Trans-Pecos Black-headed Snake (Tantilla cucullata Minton) in the extreme northeastern part; and the Big Bend Patch-nosed Snake (Salvadora deserticola Schmidt) and Texas Lyresnake (Trimorphodon vilkinsonii Cope) in the extreme northwestern part. Rossman et al. (1996) indicated the presence of the Mexican Gartersnake (Thamnophis eques (Reuss)), the Mexican Black-bellied Gartersnake (Thamnophis melanogaster [Peters]), and the Madrean Narrow-headed Gartersnake (Thamnophis unilabialis Tanner) in extreme southwestern Coahuila; however, no records for these species exist for Coahuila and we did not include them in the species list for this state.

Thirty five of the 132 species of amphibians and reptiles that inhabit Coahuila are endemic to Mexico, 20 of them are limited to areas of the Chihuahua Desert, including six endemic to Coahuila: Terrapene coahuila (Fig. 2), Trachemys taylori (Fig. 3), Gerrhonotus lugoi (Fig. 4), Crotaphytus antiquus (Fig. 5), Uma exsul (Fig. 6), and Scincella kikaapoa. Three of these six are limited to the Cuatro Ciénegas Bolson (T. coahuila, G. lugoi, and S. kikaapoa), with one more, T. taylori limited to the Cuatro Ciénegas Bolson and a small area around it. The other two Coahuila endemics, Crotaphytus antiquus and Uma exsul, are endemic to southwestern Coahuila. Four more species are limited to scattered regions of northern Mexico: Sceloporus couchi to the northern Sierras of Coahuila and central western Nuevo León; Sceloporus goldmani to a small area in southeastern Coahuila, adjacent Nuevo León, and northeastern San Luis Potosí; Sceloporus maculosus to the drainage of the Río Nazas in Durango and Coahuila; and Xantusia extorris to a small area in western Durango and southwestern Coahuila. Four more species are limited to the Mexican Plateau (Sceloporus cautus, S. samcolemani, and Lampropeltis mexicana) and central Mexico (Sceloporus spinosus). Another three species are limited to the small area of the Bolsón de Mapimí of southeastern Chihuahua, western Coahuila, and northeastern Durango (Kinosternon durangoense, Gopherus flavomarginatus, and Uma paraphygas). Two more species (Sceloporus cyanostictus and S. ornatus) are limited to Coahuila and extreme western Nuevo León. The last of these 35 endemic species (Holbrookia approximans) is limited to the Chihuahuan Desert of Mexico; however, it is highly likely that it occurs in adjacent parts of the United States. The remaining 15 endemic species are limited in eastern Mexico to the mountains and foothills of the Sierra Madre Oriental (Chiropterotriton priscus, Pseudoeurycea galeanae, P. scandens, Eleutherodactylus longipes, Ecnomiohyla miotympanum, Barisia ciliaris, Phrynosoma orbiculare, Sceloporus minor, S. oberon, S. parvus, Plestiodon dicei, Scincella silvicola, Pituophis deppei, Storeria hidalgoensis, and Thamnophis exsul). These species enter Coahuila only in the southeastern corner of the state.

Figure 2. 

Terrapene coahuila. Cuatro Ciénegas, Coahuila. Species endemic to Coahuila. Photo courtesy of Michael Price.

Figure 3. 

Trachemys taylori. Cuatro Ciénegas, Coahuila. Species endemic to Coahuila. Photo courtesy of Peter Heimes.

Figure 4. 

Gerrhonotus lugoi. Cuatro Ciénegas, Coahuila. Species endemic to Coahuila. Photo courtesy of Peter Heimes.

Figure 5. 

Crotaphytus antiquus (top: male; bottom: female). Sierra de San Lorenzo, Coahuila. Species endemic to Coahuila. Photos courtesy of Jimmy McGuire (male) and Tim Burkhardt (female).

Figure 6. 

Uma exsul (male). Dunas de Bilbao, Viesca, Coahuila. Species endemic to Coahuila. Photo by Julio Lemos-Espinal.

The remaining 97 of the 132 native species of amphibians and reptiles in Coahuila are not endemic, and all of them are shared with the United States; most of these shared species (95% = 93/98) occur in the Chihuahuan Desert and extend their ranges southward from the Great Plains of the United States to the southern tip of the Chihuahua Desert in the Mexican states of San Luis Potosí or Querétaro. Only four of these shared species are characteristic of the American tropics and subtropics (Rhinella marina, Smilisca baudinii, Drymarchon melanurus, and Leptodeira septentrionalis). Rhinella marina has been recorded in the lowlands of central Coahuila, in the semiarid Cuatro Ciénegas Bolson, whereas the other three occur in the lowlands of northeastern Coahuila and the western foothills of the Sierra Madre Oriental. All four of the species with tropical affinities enter the United States only in the southern part of Texas.

When comparing Coahuila to its surrounding states (Chihuahua, Durango, San Luis Potosí, Nuevo León, and Texas) we found that the total number of native species for these six states together is 451: 122 amphibians (38 salamanders and 85 anurans), and 323 reptiles (two crocodilians, 43 turtles, 120 lizards, and 164 snakes) (see Tables 3, 4). These represent 45 families: 15 of amphibians (six of salamanders and nine of frogs), and 30 of reptiles (one of crocodiles, eight of turtles, 14 of lizards, and seven of snakes), and 143 genera: 34 of amphibians (11 of salamanders and 23 of frogs), and 109 of reptiles (two of crocodilians, 19 of turtles, 29 of lizards, and 59 of snakes). Additionally, we found that there are 11 introduced species that maintain reproductive populations in one or more of these six states. One of these 11 introduced species, the Greenhouse Frog (Eleutherodactylus planirostris [Cope]), occurs naturally in Cuba and the West Indies and has been introduced to Texas; another one, the Brown Anole (Anolis sagrei Duméril & Bibron), occurs in Cuba, The Bahamas, the Yucatán Peninsula, and the northern part of Central America and has also been introduced to Texas. Another introduced species, the Florida Red-bellied Cooter (Pseudemys nelsoni Carr) is native to Florida and has been introduced to Texas. Another six non-native species, five of them belonging to the Family Gekkonidae, are native of Asia, Africa, and /or the Indo-Australian Archipielago: the Rough-tailed Gecko (Mediodactylus scabrum [Heyden]) introduced to Texas, the Stump-toed Gecko (Gehyra mutilata [Wiegmann]) introduced to San Luis Potosí, the Common House Gecko (Hemidactylus frenatus Schlegel) introduced to San Luis Potosí and Texas, the Indo-Pacific House Gecko (Hemidactylus garnoti Duméril & Bibron) introduced to Texas, the Mediterranean House Gecko (Hemidactylus turcicus) introduced to all six states, and the last species, belonging to the Family Typhlopidae, the Brahminy Blindsnake (Indotyphlops braminus [Daudin]) introduced to Durango, Nuevo León, and Texas. Two other species occur naturally in one or more of these six states but have been introduced to at least to one of these states where it does not occur naturally: the American Bullfrog (Lithobates catesbeianus [Shaw]) which ranges in southeastern Canada, central and eastern United States and eastern Mexico and has been introduced to Chihuahua, Durango, and San Luis Potosí, and the Mexican Spiny-tailed Iguana (Ctenosaura pectinata [Wiegmann]) which ranges in western Mexico and has been introduced to Texas.

Coahuila shares the most species with Nuevo León and Texas, and shares fewer species with Chihuahua, Durango, and San Luis Potosí (Table 5). The other states share several species with each other. The two states that share the highest number of species are Chihuahua and Durango with 108 species shared, followed by Coahuila and Nuevo León with 102 shared species. The lowest numbers of shared species are found between Chihuahua and San Luis Potosí (61), Durango and Texas (61), Chihuahua and Nuevo León (65), and Durango and Nuevo León (65).

Thirty seven species are present in all the six states that we compared: Anaxyrus cognatus, A. debilis, A. punctatus, Rhinella marina, Craugastor augusti, Smilisca baudinii, Gastrophryne olivacea, Lithobates berlandieri, Scaphiopus couchi, Spea multiplicata, Crotaphytus collaris, Cophosaurus texanus, Phrynosoma cornutum, P. modestum, Sceloporus consobrinus, S. poinsettii, Plestiodon obsoletus, Aspidoscelis gularis, A. inornata, Arizona elegans, Drymarchon melanurus, Gyalopion canum, Lampropeltis getula, Masticophis flagellum, Pantherophis emoryi, Pituophis catenifer, Rhinocheilus lecontei, Salvadora grahamiae, Diadophis punctatus, Heterodon kennerlyi, Hypsiglena jani, Thamnophis cyrtopsis, T. marcianus, Crotalus atrox, C. lepidus, C. molossus, and C. scutulatus.

Twenty-three species are present in all but one of the six states that we compared. There are 10 species that are absent only in San Luis Potosí: Ambystoma mavortium, Coleonyx brevis, Sceloporus merriami, Uta stansburiana, Aspidoscelis marmorata, Bogertophis subocularis, Masticophis taeniatus, Sonora semiannulata, Tantilla nigriceps, and Nerodia erythrogaster. The main distribution of most of these species involves the North American deserts and have their southernmost distributions slightly north of San Luis Potosí. Another six of these 23 species are absent in Texas, four of them are species endemic to Mexico: Barisia ciliaris, Holbrookia approximans, Phrynosoma orbiculare, and Pituophis deppei, and two more are species that are distributed far to the south or west of Texas: Tantilla wilcoxi, and Crotalus pricei. Three more species are absent in Chihuahua: Gerrhonotus infernalis, Sceloporus grammicus, and Tantilla atriceps. Another three are absent from Durango: Apalone spinifera, Plestiodon tetragrammus, and Lampropeltis triangulum, and one more is absent in Nuevo León: Kinosternon hirtipes (Wagler). Texas is the only state with a marine coast in the Gulf of Mexico and thus is the only state with sea turtles: Loggerhead Sea Turtle (Caretta caretta [Linnaeus]), Green Sea Turtle (Chelonia mydas [Linnaeus]), Hawksbill Sea Turtle (Eretomochelys imbricata [Linnaeus]), Kemp’s Ridley Sea Turtle (Lepidochelys kempii [Garman]), and Leatherback Sea Turtle (Dermochelys coriacea [Vandelli]).

On the other hand, the region hosts 35 endemic species, 20 of them endemic to Texas: Salado Salamander (Eurycea chisholmensis Chippindale et al.), Cascade Caverns Salamander (E. latitans Smith & Potter), San Marcos Salamander (E. nana Bishop), Georgetown Salamander (E. naufragia Chippindale et al.), Texas Salamander (E. neotenes Bishop & Wright), Fern Bank Salamander (E. pterophila Burger et al.), Texas Blind Salamander (E. rathbuni [Stejneger]), Blanco Blind Salamander (E. robusta [Potter & Sweet]), Barton Springs Salamander (E. sosorum Chippindale et al.), Jollyville Plateau Salamander (E. tonkawae Chippindale et al.), Comal Blind Salamander (E. tridentifera Mitchell & Reddell), Valdina Farms Salamander (E. troglodytes Baker), Austin Blind Salamander (E. waterlooensis Hillis et al.), and Western Slimy Salamander (Plethodon albagula Grobman), Houston Toad (Anaxyrus houstonensis [Sanders]), Cagle’s Map Turtle (Graptemys caglei Haynes & McKown), Texas Map Turtle (G. versa Stejneger), Texas Cooter (Pseudemys texana Bauer), Trans-Pecos Black-headed Snake (Tantilla cucullata Minton), and Harter’s Watersnake (Nerodia harteri [Trapido]); six more to Coahuila: Coahuilan Box Turtle (Terrapene coahuila), Cuatrociénegas Slider (Trachemys taylori), Lugo’s Alligator Lizard (Gerrhonotus lugoi), Venerable Collared Lizard (Crotaphytus antiquus), Fringe-toed Sand Lizard (Uma exsul), and Cuatrociénegas Little Skink (Scincella kikaapoa); three more to Chihuahua: Lemos-Espinal’s Leopard Frog (Lithobates lemosespinali [Smith & Chiszar]), Chihuahuan Alligator Lizard (Barisia levicollis Stejneger), and Chihuahuan Skink (Plestiodon multilineatus [Tanner]); another three to Durango: Bolson Night Lizard (Xantusia bolsonae Webb), Fox’s Mountain Meadow Snake (Adelophis foxi Rossman & Blaney), and Durango Spotted Garthersnake (Thamnophis nigronuchalis Thompson); two to Nuevo León: Pigmy Alligator Lizard (Gerrhonotus parvus [Knight & Scudday]) and Nuevo León Graceful Brown Snake (Rhadinaea montana Smith); and only one to San Luis Potosí: Newman’s Knob-scaled Lizard (Xenosaurus newmanorum Taylor).

Like many other states in Mexico, Coahuila has a rich herpetofauna, but especially a rich reptile fauna. In particular, Coahuila has a high diversity of lizards in the genus Sceloporus (19 species). The richness of reptiles is consistent with the importance of desert habitats in Coahuila. Despite its richness in reptiles and amphibians, Coahuila has a relatively small number of endemics to the state. However, several regional endemics are present in Coahuila, and thus the state serves as a reservoir for regional endemism. In addition, Coahuila is home to several species of conservation concern, especially lizards and turtles. Coahuila thus may be an important state for the conservation of the native regional fauna. Given the relatively unstudied nature of some regions of Coahuila, including the northwestern part of the state that houses two protected areas, the importance of Coahuila may be greater than we currently understand. Indeed, parts of Coahuila have been identified as “species richness hotspots” for lizards (Barrows et al. 2013). In addition, as with the relatively few endemic species, the relative number of species listed as being of conservation concern (i.e., endangered, near threatened, or vulnerable) is also low (22 total in these categories out of 132 native species; 16.7%). We therefore encourage more surveys and more studies on the conservation statuses of the state’s herpetofauna, especially the regions that are now becoming more accessible. This is especially important because as these regions become more accessible to herpetologists, they are also likely to become more susceptible to anthropogenic impacts which could affect the flora and fauna.

Coahuila shares several species with the neighboring states, with the greatest overlap with Nuevo León and Texas. In an analysis of the herpetofauna of the border states of the United States and Mexico, Coahuila frequently clustered with Nuevo León, but was less related to Texas (Smith and Lemos-Espinal 2015). Such overlap is not unexpected, especially given the shared habitats among these states. In particular, the sharing of habitats is likely to be important in explaining the overlap in species composition among states. Indeed, in a comparison of herpetofaunas among the United States-Mexico border states, Smith and Lemos-Espinal (2015) found that the sharing of herpetofaunas paralleled sharing of habitat types. For example, Coahuila shares much of its habitat types with Nuevo León and Tamaulipas, and to a lesser extent with Texas (Smith and Lemos-Espinal 2015). The patterns of shared species are also likely attributed in part to the geological history of the region (Riddle and Hafner 2006).