According to Morán-Zendero et al. (2018) and Morrone (2019) (see also Luja et al. (2014)), Nayarit contains five physiographic provinces: Sierra Madre Occidental; Trans-Mexican Volcanic Belt; Pacific Lowlands; Sierra Madre del Sur; and the Nayarit Islands (see Figs 2, 3). This differs from Woolrich-Piña et al. (2016) who used a different categorisation of physiographic regions and recognised only three (Coastal Plain, Sierra Madre Occidental, Transvolcanic Belt) on the mainland and also included the Nayarit Islands. Here, we provide some basic information of the five physiographic provinces that we use in this updated list of the herpetofauna of Nayarit, based on information in INEGI (2018a) and Blanco y Correa et al. (2021).

Figure 3. 

Topographical map of the State of Nayarit, Mexico (INEGI 2009).

The Sierra Madre Occidental Province covers 57.2% of Nayarit, including the entire eastern part of the State. In Nayarit, this Province being made up of three sub-provinces: Mesetas and Cañadas del Sur (50.01%); Pie de la Sierra (6.99%); and Sierras y Valles Zacatecanos (0.25%). The Trans-Mexican Volcanic Belt covers 20.03% of Nayarit, including the central portion of Nayarit from the coast to the south-eastern border of the State. In Nayarit, two sub-provinces of the Trans-Mexican Volcanic Belt are found: Sierras Neovolcánicas Nayaritas (18.34%); and Sierras de Jalisco (1.69%). The Pacific Lowlands Province encompasses 15.11% of Nayarit’s territory in the north-western part of the State. In Nayarit, this Province is made up of the Delta del Río Grande de Santiago sub-province, which is an extensive plain covering the coastal area of ​northern Nayarit. The Sierra Madre del Sur is found in 7.61% of Nayarit in the extreme southern Nayarit. In Nayarit, it consists of the Sierras de la Costa de Jalisco and Colima sub-province. The Mexican Pacific Island System is represented in Nayarit by the Nayarit Islands sub-province, made up of the archipelagoes of Islas Marías (San Juanito, María Madre, María Magdalena and María Cleófas), Islas Marietas (Redonda, Larga, Corbeteña, Ampolla, Morro and Cuates) and Isla Isabel. These islands encompass 0.93% of the State territory and are located 115 km to the west of the San Blas coast and 10 km to the west-southwest of Punta Mita (Figs 2, 3).

Most of the State is covered by warm weather types (INEGI 2018). The main types of this climate in the State are Warm Subhumid, present in 60.61% of Nayarit, along the coast and in the lower areas of the valleys of the Huaynamota and San Pedro Rivers, with important ramifications that extend to the east over the Sierra Madre Occidental and towards the south of the State. The Semi-warm Subhumid, present in 30.97% of the State, spreading in a strip that goes from the extreme northeast to the south of the State, including areas near Tepic and alternating with the Warm Subhumid in parts of medium altitude of the Sierra Madre Occidental. Another type of climate present in Nayarit is the Temperate Subhumid, covering only 6.16% of the State, restricted to small, very localised areas, scattered in the upper parts of the mountains. Semi-arid climate is present in only 1.7% of the State’s surface, in the extreme south of Nayarit (Fig. 4). Warm Humid, present in 0.56% of the State’s territory is found in the central part of the State, as well as in a small region in the north.

Figure 4. 

Climate map of the State of Nayarit, Mexico (modified from García – Comisión Nacional para el Conocimiento y Uso de la Biodiversidad 1998).

In the years since the writing and publication of Woolrich-Piña et al. (2016), there have been several taxonomic changes or additions with regard to the herpetofauna of Nayarit. In this section, we provide some information on these recent changes and additions.

Devitt et al. (2023) described a new species of Eleutherodactylus from the mountainous region of Sinaloa and Nayarit, this species representing populations of this region previously regarded as Eleutherodactylus nitidus. Campbell et al. (2018) described a new hylid frog from the southern Sierra Madre Occidental from Durango and southern Sinaloa, along the southern edge of the Mexican Plateau from Michoacán to Morelos. This new frog species replaces Sarcohyla bistincta in these States, including Nayarit. Pérez-Ramos and Luja-Molina (2022) studied populations of R. forreri from the Pacific Lowlands and distinguished two new species, one of them, Rana cora, inhabiting the States of Chihuahua, Sonora, Sinaloa, Nayarit and Colima. Flores-Villela et al. (2022) described a new species of Sceloporus from the mountainous region of Jalisco and Nayarit, this species representing populations of this region previously regarded as Sceloporus torquatus. Ramírez-Reyes et al. (2021a) presented genomic, phyllogenomic and morphological evidence showing that Phyllodactylus populations from María Cleofas Island, Nayarit, represent a new species related to P. saxatilis. Ramírez-Reyes et al. (2021b) showed that the arrangement of the subspecies P. tuberculosus saxatilis is polyphyletic. To avoid this polyphyletic arrangement and the use of infraspecific categories, they elevated this subspecies to the rank of species, whose distribution includes Nayarit. MacCranie et al. (2020) conducted a revision of the genus Marisora from Mexico and Central America and found support for the description of four new species, amongst them M. aquilonaris which includes populations previously regarded as M. brachypoda in Nayarit, south to Guerrero, Morelos and Puebla in the east. Hansen and Salmon (2017) presented a taxonomic update and a distribution analysis of the Lampropeltis mexicana group, providing morphological evidence that indicates the presence of L. greeri in Nayarit. Jadin et al. (2020) revised the taxonomy of Oxybelis aeneus recognising five additional taxa, including O. microphthalmus which is found in Nayarit. Grünwald et al. (2021) presented a molecular phylogeny of the Mexican snail-eating snakes, finding evidence that Tropidodipsas annulifera is more closely related to the genus Geophis than to other snail-eating snake genera, for which they proposed the new combination Geophis annuliferus Boulenger, 1894. Reyes-Velasco et al. (2020) demonstrated in the phylogenetic relationships within the genus Micrurus, that individuals distributed on the western coast of Mexico, from Nayarit to Guerrero, including M. proximans, represent M. browni. Loc-Barragán et al. (2020) showed that populations of K. chimalhuaca in Nayarit represent a new species (K. cora).

Twenty-four of the 37 species of amphibians found in Nayarit are endemic to Mexico (Table 1). This compares to 21 country endemics reported by Woolrich-Piña et al. (2016). Eleven of these 24 endemics are distributed mainly in the Pacific Lowlands. Five more are typical of western-central Mexico, mainly in the States of Sinaloa, Nayarit, Jalisco, Colima and Michoacán. Another five are distributed in several ecoregions, including the Pacific Lowlands, Trans-Mexican Volcanic Belt, Mesa Central and Sierra Madre del Sur. One species (Dryophytes eximius [Baird, 1854]) is widely distributed in both Sierra Madre Occidental and Sierra Madre del Sur and the Trans-Mexican Volcanic Belt. Another one (Isthmura bellii [Grey, 1850]) is found in central Mexico with isolated populations in Tamaulipas and Nayarit. Finally, the last one (Ambystoma rosaceum Taylor, 1941) ranges mainly in the Sierra Madre Occidental. Six more of the 37 amphibian species found in Nayarit are distributed in the United States and Mexico. Four more are species distributed in Mexico and Central America or even South America. The last three amphibian species found in Nayarit are distributed from extreme south-eastern United States to Central America or South America (Table 1).

The only crocodile that inhabits Nayarit, Crocodylus acutus (Cuvier, 1807), is widely distributed with populations in southern Florida, USA, the Caribbean, the Gulf of Mexico, the Mexican Pacific, Central and South America.

Thirty-one of the 44 species of lizards that inhabit Nayarit are endemic to Mexico, one of them (Phyllodactylus cleofasensis) to Nayarit (Table 1). This is an increase of seven country endemic lizards from the 24 reported in Woolrich-Piña et al. (2016). Sixteen of the other 30 are distributed mainly in the Pacific Lowlands, but can also inhabit in the Sierra Madre Occidental, Sierra Madre del Sur, Mesa Central, Trans-Mexican Volcanic Belt and Balsas Depression. Five more are typical of western-central Mexico. Another six are widely distributed in the Sierra Madre Occidental, Mesa del Centro, Trans-Mexican Volcanic Belt and some of them even in the Sierra Madre del Sur, Balsas Depression and Sierra Madre Oriental. One more, Sceloporus spinosus Weigmann, 1828, occurs in the Mesa del Centro, Trans-Mexican Volcanic Belt, Sierra Madre Oriental and Sierra Madre del Sur. Another one, Plestiodon parviauriculatus (Taylor, 1933), is found in the western slopes of the Sierra Madre Occidental. The last of the Mexican endemic lizards (Plestiodon aff. brevirostris [Günther, 1860]) is mainly found in the Trans-Mexican Volcanic Belt. Eight more of the 44 species of lizards found in Nayarit are distributed in the United States and Mexico. Four more are species of lizards distributed in Mexico and Central America or even South America. The last species of lizard (Gerrhonotus liocephalus Weigmann, 1828), found in Nayarit, is distributed from extreme south-eastern United States to Central America.

One of the 69 species of snakes that occur in Nayarit is endemic to Nayarit (Thamnophis rossmani) and 39 are endemic to Mexico (Table 1). This matches the number of country endemics reported by Woolrich-Piña et al. (2016). Of the 29 species of snakes not endemic to Mexico that inhabit Nayarit, 15 are found in the United States and Mexico. Nine are distributed from Mexico to Central or South America. Four are found from central or southern United States to Central or South America. The last one is a sea snake distributed across the Pacific and Indo-Pacific Oceans.

Five of the 11 species of turtles found in Nayarit are endemic to Mexico (Table 1). This is an increase of one species over the four reported in Woolrich-Piña et al. (2016). One, Kinosternon hirtipes (Wagler, 1830) is found in the United States and Mexico. Another one (Rhinoclemmys pulcherrima (Gray, 1855) is found in Mexico and Central America. The other four have a circumtropical or circumglobal distribution (Table 1).

The ecoregion containing the most species of amphibians and reptiles in Nayarit is the Trans-Mexican Volcanic Belt with 96 species inhabiting it, followed by the Sierra Madre Occidental with 95 species and the Sierra Madre del Sur with 77 species. The Pacific Lowlands with 62 species and the Nayarit Islands with 31 species are the least species-rich ecoregions by species of amphibians and reptiles in Nayarit. The mountain habitats in Trans-Mexican Volcanic Belt, Sierra Madre Occidental and Sierra Madre del Sur, host more species than the lowlands habitats in Pacific Lowlands and Nayarit Islands, such that Nayarit is dominated by species with temperate affinities of the first three ecoregions (Table 4). In general, the pattern of species richness amongst the ecoregions we found is similar to that in Woolrich-Piña et al. (2016); however, in the scheme we used, the Coastal Plain of Woolrich-Piña et al. (2016) is divided into the Pacific Lowlands and the Sierra Madre del Sur.

In general, the amphibians of the five ecoregions of Nayarit have none or a low percentage of species protected by the IUCN and SEMARNAT, except for the Trans-Mexican Volcanic Belt that has one species (Eleutherodactylus teretistes [VU]) in the IUCN protection categories and the Sierra Madre Occidental, which has one species (Isthmura bellii [A]) in the SEMARNAT protection categories and, although the percentages of amphibian species considered at high risk by the EVS are very different to those of IUCN and SEMARNAT, these are still relatively low, the highest of them in the Nayarit Islands with one (Eleutherodactylus pallidus [H-17]) of four species with a high risk EVS (Table 5).

On the other hand, the reptiles of the five ecoregions of Nayarit have greater protection than amphibians; however, these remain relatively low, not only for the IUCN and SEMARNAT, but also for the EVS assessments. These three lists have similar percentages for the Nayarit Islands: IUCN = 21.7%; SEMARNAT = 22.2%; and EVS = 23.8%. For the remaining four ecoregions, the EVS percentages are higher than those of the IUCN and SEMARNAT, in some cases more than double or triple (for example: Sierra Madre Occidental and Trans-Mexican Volcanic Belt) (Table 5).

A total of eight (= 5.8% [8/138]) species of amphibians and reptiles in Nayarit are IUCN-listed (i.e. Vulnerable, Endangered or Critically Endangered), 18 (= 11.1% [18/162]) are placed in a protected category (excluding NL and Pr, this last category being equivalent to the LC category of IUCN) by SEMARNAT and 49 (= 33.3% [49/147]) are categorised as high risk by the EVS (Table 2). Woolrich-Piña et al. (2016) found 6.7% were in threatened categories of the IUCN Red List, 11.4% in a protected category by SEMARNAT and 33.8% with high EVS (did not include marine species). For amphibians, 3.1% (1/32) are IUCN-listed, 2.7% (1/37) are protected by SEMARNAT and 23.5% (= 8/34) are at high risk according to the EVS (Table 2; Fig. 6). For reptiles, 6.6% (7/106) are listed by the IUCN, 13.6% (17/125) are protected by SEMARNAT and 36.3% (41/113) are at high risk according to the EVS (Table 2; Fig. 6). This summary suggests that the herpetofauna of Nayarit has relatively few species of conservation concern at a global and national scale (IUCN and SEMARNAT lists), but there might be greater conservation concerns using the EVS which is based on information specific to Mexico and Central America and so might be more likely to reflect the conservation status and needs of the Nayarit herpetofauna. The SEMARNAT list is also based on information specific to Mexico and, although this institution released a new update in 2019, it does not appear that conservation statuses have been re-evaluated since 2010 because all Nayarit statuses for amphibians and reptiles have remained the same. Therefore, although it is a local evaluation, it might not reflect the current conservation status of the species and so does not take into account the numerous recent taxonomic changes and the description of new species or more recent changes in conservation status or threats. There are several taxa that, based on their IUCN listing, SEMARNAT category or their EVS, are of conservation concern. Families with species of particular conservation concern include Eleutherodactylidae, Ranidae, Ambystomatidae, Crocodylidae, Eublepharidae, Helodermatidae, Iguanidae, Phyllodactylidae, Colubridae, Dipsadidae, Elapidae, Natricidae, Viperidae, Cheloniidae and Dermochelyidae (Table 2). The status of a species in Nayarit may differ (i.e. be worse or better) from the IUCN, SEMARNAT and EVS assessments. Thus, assessments at the State level are needed to fully understand the conservation or management needs for the Nayarit herpetofauna.

Figure 6. 

Proportion of A. Amphibians and B. Reptiles listed in protected categories on the IUCN Red List, SEMARNAT and high EVS for Nayarit. Green is the proportion in Data Deficient and Least Concern (IUCN); Not Listed and Subject to Special Protection (we regarded the category of Subject to Special Protection in SEMARNAT equivalent to Least Concern in IUCN) (SEMARNAT); or low or medium EVS. Red is percentage in protected categories or high EVS. N is the number of species assessed.

Overall, Nayarit shares the most herpetofaunal species with Jalisco, with 88.9% overlap (Table 6). Nayarit shares the most amphibian species with Jalisco (89.2%). Seven families, including Craugastoridae, Eleutherodactylidae, Hylidae, Leptodactylidae, Phyllomedusidae, Ambystomatidae and Plethodontidae, show complete overlap between Nayarit and Jalisco. Only four species of amphibians that inhabit Nayarit do not occur in Jalisco, two of them (Anaxyrus kelloggi and Gastrophryne mazatlanensis) reach their southernmost distribution in Nayarit, another (Scaphiopus couchii) reaches the southernmost distribution on the Mexican Pacific Coast extending its range eastwards to Hidalgo and Veracruz, the fourth (Rana cora) is a recently-described species that almost certainly occurs in Jalisco, but has not been reported there yet. The similarity between the amphibian composition of Nayarit and Sinaloa is also high (86.5%), showing complete overlap in almost the same families completely shared between Nayarit and Jalisco, with some slight differences. Sinaloa shows complete overlap with Nayarit in Bufonidae, Craugastoridae, Hylidae, Leptodactylidae, Microhylidae, Phyllomedusidae and Ambystomatidae. Only five species of amphibians that inhabit Nayarit do not occur in Sinaloa: Eleutherodactylus modestus is at its northernmost distribution in Nayarit; Rana megapoda, R. psilonota and Isthmura bellii are at their north-westernmost distribution in Nayarit; and Spea multiplicata extends to western Mexico in the Sierra Madre Occidental and Trans-Mexican Volcanic Belt of Nayarit and Pacific Lowlands of Jalisco. The neighbouring States that share the lowest percentage of amphibian species with Nayarit are Durango (48.6%) and Zacatecas (37.8%). The high similarity in amphibian composition between Nayarit and Jalisco and Sinaloa, but not with Durango and Zacatecas, is due to the dominance of amphibian species related to the region of the Pacific Lowlands, which are shared between these three States with wide Pacific coasts and the absence of these coasts in Durango and Zacatecas. Durango is mostly a mountainous State dominated by the Sierra Madre Occidental and the Chihuahuan Desert (Lemos-Espinal et al. 2019), whereas Zacatecas is also a mountainous State dominated by the Sierra Madre Occidental, Sierra Madre Oriental and the Chihuahuan Desert.

The number of reptile species shared between Nayarit and Jalisco is large, with 88.8% overlap. Sixteen of the 24 families of reptiles present in Nayarit show a complete overlap with Jalisco and 111 of the species that inhabit Nayarit are shared with Jalisco. Ten of the 14 species of reptiles that inhabit Nayarit, but have not been recorded in Jalisco, show their southernmost distribution in Nayarit (Holbrookia elegans, Urosaurus ornatus, Plestiodon parviauriculatus, Gyalopion quadrangulare, Rhinocheilus lecontei, Tantilla yaquia, Leptodeira polysticta, Thamnophis nigronuchalis, Crotalus willardi and Kinosternon cora), two more are endemic to Nayarit (Phyllodactylus cleofasensis and Thamnophis rossmani) and the other two have a discrete distribution that includes Nayarit, but not Jalisco (Plestiodon aff. brevirostris and Salvadora grahamiae). Nayarit shares a smaller, but still high percentage of reptile species with Sinaloa, with 68.8% overlap. Nine of the 24 families of reptiles present in Nayarit show a complete overlap with Sinaloa and 86 of the species that inhabit Nayarit are shared with Sinaloa. Twenty-three of the 39 species of reptiles that inhabit Nayarit, but have not been recorded in Sinaloa, show their northernmost distribution in Nayarit or Jalisco (Barisia imbricata, Basiliscus vittatus, Coleonyx elegans, Sceloporus asper, S. dugesii, S. heterolepis, S. horridus, S. huichol, S. melanorhinus, S. scalaris, S. unicanthalis, Plestiodon aff. brevirostris, Aspidoscelis lineattissimus, Holcosus sinister, Salvadora mexicana, Tantilla ceboruca, Hypsiglena affinis, Manolepis putnami, Rhadinaea taeniata, Sibon nebulatus, Micrurus proximans, Loxocemus bicolor and Kinosternon vogti). Six more species show a discrete distribution that does not include Sinaloa (Rena humilis, Thamnophis eques, T. errans, T. melanogaster, T. pulchrilatus and Salvadora grahamiae). Another eight species are found in the Sierra Madre Occidental and/or Trans-Mexican Volcanic Belt (Phrynosoma orbiculare, Sceloporus grammicus, Plestiodon lynxe, Thamnophis nigronuchalis, Crotalus armstrongi, C. campbelli, C. pricei and C. willardi). The last two species not shared with Sinaloa are endemic to Nayarit (Phyllodactylus cleofasensis and Thamnophis rossmani). Nayarit shares 61 species of reptiles with Durango, representing a 48.8% overlap. This relatively low overlap compared to Jalisco and Sinaloa can be explained by the fact that Durango is dominated by species from the Sierra Madre Occidental and the Chihuahuan Desert, while the other three States (Nayarit, Jalisco and Sinaloa) are dominated by species from the Pacific Coast. Nayarit has a coastline of 307 km, Jalisco 351 km and Sinaloa 622 km. The lowest number of shared species between Nayarit and a neighbouring State is represented by Zacatecas with only 57 species shared with Nayarit, representing 45.6% overlap. Just as Durango, Zacatecas is dominated by species from the Sierra Madre Occidental and the Chihuahuan Desert, which may explain this low overlap with Nayarit.

The relationship between the neighbouring States of Nayarit shows that Nayarit is a transition State between species with Nearctic and Neotropical affinities; most of the species present in Nayarit, but absent in Sinaloa, show their northernmost distribution in Nayarit, contrary to most of the species present in Nayarit, but absent in Jalisco show their southernmost distribution in Nayarit. In addition, Nayarit is also a State that contains species from the Pacific Coast as well as the mountains of the Sierra Madre Occidental, Trans-Mexican Volcanic Belt and Sierra Madre del Sur.