An updated list of the Mexican herpetofauna: with a summary of historical and contemporary studies.

The growth in our knowledge of the diversity of the herpetofauna of Mexico has occurred over the period of approximately 445 years from the work of Francisco Hernández to that of a broad multinational array of present-day herpetologists. The work of this huge group of people has established Mexico as one of the most significant centers of herpetofaunal biodiversity in the world. This status is the result of a complex orography, in addition to diverse habitats and environments and the biogeographic history of Mexico. The current herpetofauna consists of 1,421 native and introduced species, allocated to 220 genera, and 61 families. This figure is comprised of 1,405 native species and 16 non-native species (as of April 2023). The non-native species include two anurans, 13 squamates, and one turtle. The level of endemism is very high, presently lying at 63%, with this level expected to increase with time. Species richness varies among the 32 federal entities in the country, from a low of 50 in Tlaxcala to a high of 492 in Oaxaca. Amphibian species richness by state-level can be envisioned as comprising three levels of low, medium, and high, with the lowest levels occurring in the Peninsula of Baja California, a group of seven states in north-central and central Mexico, and a group of three states in the Yucatan Peninsula, with the highest levels occupying the southern states of Guerrero, Puebla, Veracruz, Oaxaca, and Chiapas, and the medium level in the remaining states of the country. Reptile species richness also can be allocated to three categories, with the lowest level occupying Baja California Sur, a group of central states, and the states of the Yucatan Peninsula, and the highest level found in a cluster of the states of Veracruz, Guerrero, Oaxaca, and Chiapas. Knowledge of the Mexican herpetofauna will continue to grow with additional studies on systematics, conservation, and the construction of checklists at various levels.

A Reexamination of the Herpetofauna of Oaxaca, Mexico: Composition Update, Physiographic Distribution, and Conservation Commentary.

A substantial number of changes to the composition of the herpetofauna of the Mexican state of Oaxaca, including taxonomic additions and deletions, have occurred in the five years since our original assessment of this region. These changes now establish a herpetofauna of 480 species for the state. A number of taxonomic and nomenclatural changes involving the Oaxacan herpetofauna also are discussed. Updated patterns of physiographic distribution, endemism, and conservation status of the members of the state herpetofauna are examined.

A review of the introduced herpetofauna of Mexico and Central America, with comments on the effects of invasive species and biosecurity methodology.

Among the principal causes producing detrimental effects on global biodiversity are introductions of alien species. Very few attempts to control introduced amphibians and reptiles in Middle America (Mexico and Central America) can be identified, so listings are provided for 24 exotic species, 16 translocated species, and 11 species that were removed from the introduced species listing because of lack of substantiating evidence that they are from established populations. Biosecurity methods are also identified that can be applied for preventing, controlling, and managing introduced and especially invasive species.

ResumenEntre las principales causas que producen efectos perjudiciales sobre la biodiversidad mundial se encuentran la introducción de especies exóticas. Se pueden identificar muy pocos intentos de controlar anfibios y reptiles introducidos en América Central (México y América Central), por lo que proporcionamos listas de 24 especies exóticas, 16 especies translocadas y 11 especies que eliminamos de la lista de especies introducidas debido a la falta de evidencia que corrobore que provienen de poblaciones establecidas. También identificamos métodos de bioseguridad que se pueden aplicar para prevenir, controlar y gestionar especies introducidas y especialmente invasoras.

An updated checklist of the herpetofauna of Querétaro, Mexico: species richness, diversity, and conservation status.

Mexico contains a large number of amphibian and reptile species, and the states in the southeastern part of the country are the richest and most diverse. Although the study of species richness within Mexico's individual states has been increasing over the last two decades, herpetofaunal species lists for several states in the central region are incomplete. Herein, we provide a list of the herpetofauna of the state of Querétaro, a state that remains relatively unexplored. We also indicate the conservation status of the component species in the state, based on the national and international categorizations, as well as their Environmental Vulnerability Scores (EVS). Based on a review of literature and specimens in scientific collections, our results show that the herpetofauna of Querétaro currently is composed of 138 species, of which 34 are amphibians (27 anurans and seven caudates) and 104 are reptiles (three turtles, 34 lizards, and 67 snakes). The number of Mexican endemic species occurring in the state consists of 19 amphibians and 50 reptiles, representing 55.9% and 48.1%, respectively, of the total numbers in these groups. A total of 61 species (13 species of amphibians and 48 of reptiles) are listed in NOM-059-SEMARNAT-2010, within the categories of Special Protection (Pr) and Threatened (A). According to the International Union for Conservation of Nature (IUCN 2019), 34 species of amphibians (100% of species) and 87 species of reptiles (83.65% of a total of 104) have been placed within a risk category, i.e., except for the DD and NE categories. The EVS results show that nine species of amphibians have high environmental vulnerability, 11 species medium vulnerability, and 14 low vulnerability, whereas among the reptiles, 22 species have high vulnerability, 43 medium vulnerability, and 37 species low vulnerability. The herpetofauna of Querétaro illustrates a high level of species richness, which is typical of central Mexico, as well as diverse groupings associated with the arid, temperate, and tropical environments found in the state. These types of studies are necessary for increasing our knowledge of the herpetofauna in the various states of Mexico, as well as for evaluating the conservation status and implementing management plans for species in both herpetofaunal groups.

Cryptic Diversity, but to What Extent? Discordance Between Single-Locus Species Delimitation Methods Within Mainland Anoles (Squamata: Dactyloidae) of Northern Central America.

Single-locus molecular barcoding is a useful method for identifying overlooked and undescribed biodiversity, providing the groundwork for further systematic study and taxonomic investigation. A variety of methods for delimiting species from barcoding libraries have been developed and applied, allowing for rapid estimates of species diversity in a broad range of taxa. However, tree-based and distance-based analyses can infer different group assignments, potentially over- or underestimating the number of putative species groups. Here, we explore diversity of mainland species of anole lizards from the Chortís Block biogeographical province of northern Central America using a DNA barcoding approach, generating and analyzing cytochrome oxidase subunit I (COI) sequences for over 400 samples assignable to 33 of 38 (86.8%) native and one introduced mainland species. We subsequently tested the effects different models of nucleotide substitution, different species-delimitation algorithms, and reducing our dataset had on species delimitation estimates. We performed of two distance-based (ABGD, RESL) and three tree-based (bPTP, mPTP, GMYC) analyses on both the full dataset and a dataset consisting only of unique halotypes. From 34 nominal taxa, analyses of the full dataset recovered between 34 and 64 operational taxonomic units (OTUs), while analyses of the reduced dataset inferred between 36 and 59. Reassigning individuals to either mPTP-inferred or ABGD clustered (7.2% threshold) groups improved the detection of a barcoding gap across three different models of nucleotide substitution, removing overlap between intra- and interspecific distances. Our results highlight the underestimated diversity of mainland Chortís Block anoles, but the lack of congruence between analyses demonstrates the importance of considering multiple analytical methods when dealing with single-locus datasets. We recommend future studies consider the effects of different models of nucleotide substitution on proposed barcoding gaps, as well as the effect reducing a dataset to unique haplotypes may have on proposed diversity estimates.

A new species of forest snake of the genus Rhadinaea from Tropical Montane Rainforest in the Sierra Madre del Sur of Oaxaca, Mexico (Squamata, Dipsadidae).

Content of the dipsadid genus Rhadinaea has changed considerably since Myers' 1974 revision. Three species groups are recognized currently in the genus. Our fieldwork in Oaxaca in June 2018 produced a single specimen of Rhadinaea considered to represent a new taxon. This new species is described from converted Premontane Wet Forest in the municipality of Santa Catarina Juquila in the Sierra Madre del Sur of southern Oaxaca, Mexico. It is most closely related to Rhadinaealaureata, from which it can be distinguished easily by color pattern and scutellation, and represents a species group distinct from the other three occupying the genus.

ResúmenLa conformación del género Rhadinaea ha cambiado considerablemente desde la revisión de Myers en 1974. Tres grupos de especies son reconocidos actualmente en el género. Nuestro trabajo de campo en Oaxaca en junio de 2018 produjo un espécimen de Rhadinaea que consideramos que representa un nuevo taxón. Describimos esta nueva especie de bosque húmedo premontano en el Municipio de Santa Catarina Juquila en la Sierra Madre del Sur en el sur de Oaxaca, México. Esta especie está más estrechamente relacionada con Rhadinaealaureata, de la cual se puede distinguir fácilmente por medio del patrón de color y escutelación, y representa un grupo distinto a los tres que forman parte del género.

The taxonomic status of Tantilla marcovani Lema 2004 (Squamata: Colubridae).

The colubrid snake genus Tantilla currently comprises 62 valid species distributed from the southern United States of America to southern Bolivia in the west, and Uruguay and northern Argentina in the east (Wilson & Mata-Silva 2014, 2015). Of these 62 species, 13 are found in South America (Wilson & Mata-Silva 2014, 2015). The most recently described of these Southamerican species is Tantilla marcovani Lema, 2004. While we were working on a checklist and key to the members of the Tantilla clade (sensu Holm 2008, including the genera Geagras Cope 1876, Scolecophis Fitzinger 1843, Tantilla Baird & Girard 1853, and Tantillita Smith 1941; Wilson & Mata-Silva 2015), it became apparent that the diagnosis of T. marcovani entirely falls to distinguish this nominal taxon from the widespread and extensively variable T. melanocephala Linnaeus 1758. Tantilla melanocephala, as presently envisioned, is the most broadly distributed member of its genus (Wilson & Mena 1980; Savage 2002; Greenbaum et al. 2004), occurring from Panama southward into the major portion of the South American continent, apart from Chile and southern Argentina.

A relict lineage and new species of green palm-pitviper (Squamata, Viperidae, Bothriechis) from the Chortís Highlands of Mesoamerica.

A new species of palm-pitviper of the genus Bothriechis is described from Refugio de Vida Silvestre Texíguat in northern Honduras. The new species differs from congeners by having 19 dorsal scale rows at midbody, a bright green dorsal coloration in adults, the prelacunal scale fused to the second supralabial, and in representing a northern lineage that is sister to Bothriechis lateralis, which is distributed in Costa Rica and western Panama and is isolated from the new taxon by the Nicaraguan Depression. This represents the 15th endemic species occurring in Refugio de Vida Silvestre Texíguat, one of the richest herpetofaunal sites in Honduras, itself being the country with the highest degree of herpetofaunal endemism in Central America. We name this new species in honor of a Honduran conservationist slain in fighting against illegal logging, highlighting the sacrifices of rural activists in battling these issues and the critical importance of conservation in these areas.

ResumenUna nueva especie de tamagás verde del género Bothriechis se describe del Refugio de Vida Silvestre Texíguat en el norte de Honduras. La nueva especie difiere de sus congéneres por tener filas de 19 escamas dorsales en la mitad del cuerpo, una brillante coloración verde en la porción dorsal del cuerpo en adultos, la escama prelacunal fusionada con la segunda supralabial, y en representación del linaje del norte que es clado hermano de Bothriechis lateralis, la cual se distribuye en Costa Rica y el Occidente de Panamá y está aislada del nuevo taxón por la Depresión de Nicaragua. Representa la decimoquinta especie endémica encontrada en el Refugio de Vida Silvestre Texíguat, uno de los lugares más ricos de herpetofauna en Honduras, el país con el más alto grado de endemismo de la herpetofauna en Centroamérica. Nombramos esta nueva especie en honor a un conservacionista Hondureño asesinado en contienda contra la tala ilegal, destacando los sacrificios de los activistas rurales luchando frente a estos problemas y la importancia crítica de la conservación en estas áreas.

Biogeography and conservation of the herpetofauna of the Upland Pine-Oak Forests of Honduras / Biodiversidad y conservación de la herpetofauna de los Bosques de Pino-Roble de la Altiplanicie de Honduras

The upland pine-oak forest herpetofauna constitutes the smallest segment distributed in the major habitat types in Honduras, due to its occurrence at moderate elevations in relatively inhospitable environments, compared to more mesic habitats in the country. This segment, however, is subject to considerable environmental threat as a consequence of annual burning and logging. Of the 356 herpetofaunal species known from Honduras, 105 are known from these habitats. These forests occur throughout much of the mountainous interior of Honduras. They are subject to the Intermediate Dry climate. Four salamanders, 27 anurans, four turtles, 29 lizards, and 41 snakes comprise the herpetofauna. These species are partitioned into restricted, widespread, and peripheral distributional categories. They can be allocated to eleven broad distributional categories, with most belonging to the category containing species whose ranges extend from somewhere in Mexico north of the Isthmus of Tehuantepec to somewhere in South America. The large majority are terrestrial forest inhabitants, arboreal forest inhabitants, terrestrial pondside species, or terrestrial forest pondside species. Most species are judged common, with the next largest group considered to be of infrequent occurrence, and the smallest group of rare occurrence. Upland pine-oak forest species are distributed among four ecophysiographic areas, with the greatest number of species being found in the Southeastern Uplands. Construction of a CBR diagram illustrates that the herpetofaunas of the Northwestern and Northeastern Uplands, the Northeastern Uplands and Southeastern Uplands, and the Southeastern Uplands and Southwestern Uplands are about equally related to one another. The greatest significance of the upland pine-oak forest herpetofauna lies in the relatively high percentage of members presently possessing stable populations, indicating their apparent greater ability to resist anthropogenic habitat...

La herpetofauna de los bosques de pino-roble del altiplano constituye el segmento más pequeño distribuido en los habitats principales de Honduras, debido a su ocurrencia a elevaciones moderadas en ambientes relativamente inhóspitos, especialmente comparados a los ambientes más húmedos de país. Este segmento, sin embargo, está sujeto a una amenaza ambiental considerable, debido a las quemas anuales y a la tala de árboles. De las 356 especies de herpetofauna conocidas en Honduras, 105 son de estos habitats. Esta clase de bosques es prevalente en gran parte del interior montañoso de Honduras. Están sujetos al clima Seco Intermedio. La herpetofauna consiste de 4 salamandras, 27 anuros, cuatro tortugas, 29 lagartijas, y 41 serpientes. Estas especies se clasifican en categorías de distribución restrictas, extensas, y periféricas. Es posible colocar estas especies en once categorías de distribución, con la mayoría encontrándose en la categoría que contiene las especies cuyos rangos se extienden desde alguna parte de México al norte del Istmo de Tehuantepec hasta alguna parte de Suramérica. La gran mayoría son habitantes terrestres del bosque, habitantes arbóreos del bosque, especies terrestres de la orilla de estanques de agua, o especies terrestres del bosque encontradas a la orilla de estanques de agua. La mayoría de las especies se consideran comunes, con el próximo grupo más grande considerado como de ocurrencia poco frecuente, y el grupo más pequeño de rara ocurrencia. Las especies de bosques de pino y roble del altiplano están distribuidas en cuatro áreas ecofisiográficas, con el mayor número de especies encontradas en los altiplanos del sureste. La creación de un diagrama de Coeficientes de Semejanza Biogeográfica (CBR por sus siglas en inglés) ilustra que la herpetofauna de los altiplanos del noroeste y del nordeste, la de los altiplanos del nordeste y del sureste, y la de los altiplanos del sureste y del suroeste, están relacionadas...

First report of sporangia of a myxomycete (Physarum pusillum) on the body of a living animal, the lizard Corytophanes cristatus.

Myxomycetes are protists whose life cycle depends on aerially dispersed spores that germinate into motile myxamoebae, which then pair and fuse to form a larger, motile plasmodium. The plasmodium seeks out a suitable fruiting site (usually atop vegetative material or detritus) and transforms into fruiting bodies that release the spores. In this paper we report the first known instance of a myxomycete, in this case Physarum pusillum, sporulating on the body of a living animal, the cryptic lizard Corytophanes cristatus, which was collected in eastern Honduras in 2003.

The conservation status of the herpetofauna of Honduras.

The conservation status of the members of the Honduran herpetofauna is discussed. Based on current and projected future human population growth, it is posited that the entire herpetofauna is endangered. The known herpetofauna of Honduras currently consists of 334 species, including 117 amphibians and 217 reptiles (including six marine reptiles, which are not discussed in this paper). The greatest number of species occur at low and moderate elevations in lowland and/or mesic forest formations, in the Northern and Southern Cordilleras of the Serranía, and the ecophysiographic areas of the Caribbean coastal plain and foothills. Slightly more than one-third of the herpetofauna consists of endemic species or those otherwise restricted to Nuclear Middle America. Honduras is an area severely affected by amphibian population decline, with close to one-half of the amphibian fauna threatened, endangered, or extinct. The principal threats to the survival of members of the herpetofauna are uncontrolled human population growth and its corollaries, habitat alteration and destruction, pollution, pest and predator control, overhunting, and overexploitation. No Honduran amphibians or reptiles are entirely free of human impact. A gauge is used to estimate environmental vulnerability of amphibian species, using measures of extent of geographic range, extent of ecological distribution, and degree of specialization of reproductive mode. A similar gauge is developed for reptiles, using the first two measures for amphibian vulnerability, and a third scale for the degree of human persecution. Based on these gauges, amphibians and reptiles show an actual range of Environmental Vulnerability Scores (EVS) almost as broad as the theoretical range. Based on the actual EVS, both amphibian and reptilian species are divided into three categories of low, medium, and high vulnerability. There are 24 low vulnerability amphibians and 47 reptiles, 43 medium vulnerability amphibians and 111 reptiles, and 50 high vulnerability amphibians and 53 reptiles. Theoretical EVS values are assessed against available information on current population status of endemic and Nuclear Middle American taxa. Almost half (48.8%) of the endemic species of Honduran amphibians are already extinct or have populations that are in decline. Populations of 40.0% of the Nuclear Middle American amphibian species are extirpated or in decline. A little less than a third (27.0%) of the endemic reptiles are thought to have declining populations. Almost six of every ten (54.5%) of the Nuclear Middle American reptilian species are thought to have declining populations. EVS values provide a useful indicator of potential for endangerment, illustrating that the species whose populations are currently in decline or are extinct or extirpated have relatively high EVS. All high EVS species need to be monitored closely for changes in population status. A set of recommendations are offered, assuming that biotic reserves in Honduras can be safeguarded, that it is hoped will lead to a system of robust, healthy, and economically self-sustaining protected areas for the country's herpetofauna. These recommendations will have to be enacted swiftly, however, due to unremitting pressure from human population growth and the resulting deforestation.

The herpetofauna of the cloud forests of Honduras.

The cloud forest amphibians and reptiles constitute the most important herpetofaunal segment in Honduras, due to the prevalence of endemic and Nuclear Middle American-restricted species. This segment, however, is subject to severe environmental threats due to the actions of humans. Of the 334 species of amphibians and reptiles currently known from Honduras, 122 are known to be distributed in cloud forest habitats. Cloud forest habitats are found throughout the mountainous interior of Honduras. They are subject to a Highland Wet climate, which features annual precipitation of >1500 mm and a mean annual temperature of <18 degrees C. Cloud forest vegetation falls into two Holdridge formations, the Lower Montane Wet Forest and Lower Montane Moist Forest. The Lower Montane Wet Forest formation generally occurs at elevations in excess of 1500 m, although it may occur as low as 1300+ m at some localities. The Lower Montane Moist Forest formation generally occurs at 1700+ m elevation. Of the 122 cloud forest species, 18 are salamanders, 38 are anurans, 27 are lizards, and 39 are snakes. Ninety-eight of these 122 species are distributed in the Lower Montane Wet Forest formation and 45 in the Lower Montane Moist Forest formation. Twenty species are distributed in both formations. The cloud forest species are distributed among restricted, widespread, and peripheral distributional categories. The restricted species range as a group in elevation from 1340 to 2700 m, the species that are widespread in at least one of the two cloud forest formations range as a group from sea level to 2744 m, and the peripheral species range as a group from sea level to 1980 m. The 122 cloud forest species exemplify ten broad distributional patterns ranging from species whose northern and southern range termini are in the United States (or Canada) and South America, respectively, to those species that are endemic to Honduras. The largest segment of the herpetofauna falls into the endemic category, with the next largest segment being restricted in distribution to Nuclear Middle America, but not endemic to Honduras. Cloud forest species are distributed among eight ecophysiographic areas, with the largest number being found in the Northwestern Highlands, followed by the North-Central Highlands and the Southwestern Highlands. The greatest significance of the Honduran herpetofauna lies in its 125 species that are either Honduran endemics or otherwise Nuclear Middle American-restricted species, of which 83 are distributed in the country's cloud forests. This segment of the herpetofauna is seriously endangered as a consequence of exponentially increasing habitat destruction resulting from deforestation, even given the existence of several biotic reserves established in cloud forest. Other, less clearly evident environmental factors also appear to be implicated. As a consequence, slightly over half of these 83 species (50.6%) have populations that are in decline or that have disappeared from Honduran cloud forests. These species possess biological, conservational, and economic significance, all of which appear in danger of being lost.