Descripción de los hábitos alimentarios de Aspidoscelis gularis (Sauria: Teiidae), durante la temporada de lluvias en el sureste de Querétaro, México

We assessed the food habits of adult males and females of Aspidoscelis gularis during the rainy season from a location in the municipality of San Joaquin, in the southeastern region of the state of Querétaro, Mexico. The items most consumed by both sexes were termites, and less frequently adult beetles, and cockroaches. These data reveal that in the rainy season these prey are most abundant, and the resource most consumed by both sexes, revealing a high degree of alimentary overlap between males and females

Herpetofauna de la cuenca baja del Río Temascatio, Irapuato, Guanajuato, México

México es considerado uno de los países con una de las diversidades de anfibios y reptiles más notables del mundo, con alrededor de 1,290 especies y con un alto grado de endemismo. Esto hace que la herpetofauna mexicana sea digna de analizarse bajo hipótesis taxonómicas, ecológicas y biogeográficas. En un contexto de diversidad de especies, el presente trabajo se enfoca en medir la composición y diversidad de anfibios y reptiles distribuidos en tres tipos de vegetación (bosque tropical caducifolio = BTC, matorral xerófilo = MX y bosque de encino = BE) presentes en la cuenca baja del Río Temascatio en el municipio de Irapuato, Guanajuato, México. La herpetofauna en la cuenca está compuesta por 14 familias, 23 géneros y 31 especies. Según el índice de Shannon-Wiener, el BE presentó el valor más alto de diversidad de especies (6.25), seguido por el BTC (5.29) y el MX (4.16). Las curvas de rango abundancia indicaron que, tanto en la estación de lluvias como en secas, la herpetofauna de la cuenca está integrada en su mayoría por especies raras y pocas especies abundantes. Según la Norma Oficial Mexicana NOM-059, tres especies de anuros y nueve de reptiles se encuentran bajo alguna categoría de riesgo. Solo una especie de anuro se encuentra catalogada como vulnerable de acuerdo con la lista roja de la IUCN. El EVS, índice que evalúa el estatus de vulnerabilidad ambiental de anfibios y reptiles mexicanos, considera a cuatro especies de anuros bajo riesgo alto, dos en riesgo medio, y cinco en riesgo bajo. Respecto a los reptiles, este índice ubica a seis especies en riesgo alto, seis en peligro medio, y ocho en riesgo bajo. Este trabajo representa el primer listado de la fauna de anfibios y reptiles de la cuenca baja del Río Temascatio, el cual puede ser considerado como base de información para desarrollar futuros estudios que involucren aspectos ecológicos y biogeográficos, encaminados a proponer estrategias de conservación de una fauna poco explorada en la porción noreste del Bajío mexicano.Mexico is considered one of the countries with one of the most notable diversities of amphibians and reptiles in the world, with around 1,290 species and a high degree of endemism. This makes Mexican herpetofauna worthy of analyse under taxonomic, ecological and biogeographic hypotheses. In a context of species diversity, the present work focuses on measuring the composition and diversity of amphibians and reptiles distributed in three types of vegetation (tropical deciduous forest = TDF, xerophytic scrub = XS and oak forest = OF) present in the Río Temascatio lower basin, municipality of Irapuato, Guanajuato, Mexico. The herpetofauna in the study area is composed of 14 families, 23 genera, and 31 species. According to the Shannon-Wiener index, the OF presented the highest value of species diversity (6.25), followed by the TDF (5.29) and the XS (4.16). The abundance range curves indicated that, both in the rainy and dry seasons, the herpetofauna of the basin is composed mostly of rare species and few abundant species. According to the Mexican regulation NOM-059, three species of anurans and nine species of reptiles are under some category of risk. Only one species of anuran is listed as vulnerable according to the IUCN Red List. The EVS, an index that evaluates the environmental vulnerability status of Mexican amphibians and reptiles, considers four species of anurans at high risk, two at medium risk, and five at low risk. For reptiles, this index places six species at high risk, six at medium risk, and eight at low risk. This work represents the first list of the amphibian and reptile fauna of the Río Temascatio lower basin, which can be considered as an information base for developing future studies involving ecological and biogeographical aspects, aimed at proposing conservation strategies for a little-explored fauna in the northeastern portion of the Mexican Bajío

HORIZONTAL POSITIONAL ACCURACY OF GOOGLE EARTH’S IMAGERY OVER RURAL AREAS: A STUDY CASE IN TAMAULIPAS, MEXICO

Due to the popularity of Google Earth (GE), users commonly assume that it is acredible and accurate source of information. Consequently, GE’s imagery isfrequently used in scientific and others projects. However, Google states that dataavailable in their geographic products are only approximations and, therefore, theiraccuracy is not officially documented. In this paper, the horizontal positionalaccuracy of GE’s imagery is assessed by means of comparing coordinates extractedfrom a rural cadastral database against coordinates extracted from well-defined andinferred check points in GE’s imagery. The results suggest that if a large number ofwell-defined points are extracted from areas of high resolution imagery, GE’simagery over rural areas meets the horizontal accuracy requirements of the ASPRSfor the production of “Class 1” 1:20,000 maps. Nonetheless, the results also showthat georegistration and large horizontal errors occur in GE’s imagery.Consequently, despite its overall horizontal positional accuracy, coordinatesextracted from GE’s imagery should be used with caution

Sceloporus smithi Hartweg and Oliver, 1937 (Squamata: Phrynosomatidae): distributional range extension and a new elevation record from Oaxaca, México

A male Sceloporus smithi was collected at Hierve El Agua, in the Municipality of San Lorenzo Albarradas, Oaxaca, México. This record extends the known distribution of the species by approximately 25 km N from the closest acknowledged locality and also represents a new upward elevational record. Even though the elevation at this site is almost 700 m higher than for previously documented localities, the subhumid forest and igneous rock association is similar to other inhabited localities at lower elevations

Why is the egg retention in oviparous species a step to viviparity?: an example with lizards

Se presenta una revisión sobre las hipótesis ecológicas y fisiológicas en la transición de la oviparidad a la viviparidad usando como grupo modelo a las lagartijas (Squamata). Además, se incluyen ejemplos de especies de lagartijas que prueban la retención de los huevos en el oviducto durante el desarrollo embrionario prolongado en altas latitudes y ambientes templados de montaña. Las hipótesis ecológica y fisiológica indican que el clima frío favorece la retención del huevo por tiempos prolongados y la disminución de glándulas calcáreas, favoreciendo el paso evolutivo a la viviparidad en este grupo de vertebrados. Actualmente, hace falta estudios con especies ovíparas que habitan ambientes templados de altas latitudes (climas fríos) y de ambientes templados de montañas que presentan retención de huevos en estadios avanzados.A review on the ecological and physiological hypotheses in the transition from oviparity to viviparity is presented using lizards (Squamata) as a model group. In addition, examples of lizard species are included that test the retention of eggs in the oviduct during prolonged embryonic development in high latitudes and temperate mountain environments. The ecological and physiological hypotheses indicate that the cold climate favors the retention of the egg for long periods of time and the decrease in calcareous glands, favoring the evolutionary passage to viviparity in this group of vertebrates. To date, studies are needed with oviparous species that inhabit temperate environments at high latitudes (cold climates) and temperate mountain environments that present egg retention in advanced stages

Reproductive strategy of male and female eastern spiny lizards Sceloporus spinosus (Squamata: Phrynosomatidae) from a region of the Chihuahuan Desert, México

We examined the reproductive strategy of male (n = 84) and female (n = 62) S. spinosus from a single population in San Luis Potosí, México. The male reproductive cycle peaked in March and April and declined from May to September, and was not correlated with fat body mass, but was positively correlated with liver mass. The female reproductive cycle peaked in April and May and declined from June through November, and was not correlated with fat body mass, but was correlated with liver mass. Mean clutch size based on oviductal eggs was 17.5 ± 1.9 (n = 12), and was not correlated with female snout-vent length. Our results for S. spinosus are generally similar to those of other populations of the S. spinosus species group. However, there are differences in some traits (e.g., timing of the initiation of the female reproductive cycle; clutch size), suggesting that the S. spinosus group could serve as another model group within Sceloporus to explore ecological and evolutionary causes of among population life history variation

The herpetofauna of Veracruz, Mexico: composition, distribution, and conservation status

The herpetofauna of the state of Veracruz, Mexico, currently consists of 359 species, including 76 anurans, 45 caudates, one caecilian, one crocodylian, 217 squamates, and 19 turtles. The distribution of the herpetofaunal species are catalogued here among the four recognized physiographic regions in the state. The total number of species ranges from 179 in the Sierra de Los Tuxtlas to 236 in the Sierra Madre Oriental. The number of species shared among the four physiographic regions ranges from 100 between the Gulf Coastal Lowlands and the Transmexican Volcanic Belt, to 190 between the Sierra Madre Oriental and the Transmexican Volcanic Belt. A similarity dendrogram based on the Unweighted Pair Group Method with Arithmetic Averages (UPGMA) depicts two distinct clusters, one between the Sierra Madre Oriental and the Transmexican Volcanic Belt, and the other between the Gulf Coastal Lowlands and the Sierra de Los Tuxtlas. The former cluster refects two adjacent regions in highland environments that share a substantial number of herpetofaunal species, and the latter cluster shares a sizeable number of wide-ranging, generalist, lowland species found on the Atlantic and Pacifc versants of Mexico and Central America. The level of herpetofaunal endemism is relatively high, with 182 of 359 species either endemic to Mexico or to Veracruz. The distributional categorization of the total herpetofauna is as follows: 169 non-endemic species; 138 country endemic species; 44 state endemic species; and eight non-native species. The 169 non-endemic species are allocated to the following distributional categories: MXCA (89), MXSA (30), MXUS (29), USCA (11), USSA (four), and OCEA (fve). The principal environmental threats to the herpetofauna of Veracruz include deforestation, livestock, roads, water pollution, myths and other cultural factors, diseases, invasive species, and illegal commerce. The conservation status of each native species was evaluated using the SEMARNAT, IUCN, and EVS systems, of which the EVS system proved to be the most useful. The Relative Herpetofaunal Priority method was employed to determine the rank order signifcance of the four regions, and this identifed the Sierra Madre Oriental as the region of greatest importance. Only six protected areas exist in Veracruz, most of which are located in the Gulf Coastal Lowlands, the region of least conservation signifcance. The area of greatest signifcance, the Sierra Madre Oriental, does not contain any protected areas. A total of 265 species have been recorded within the six protected areas, of which 138 are non-endemics, 89 are country endemics, 31 are state endemics, and seven are non-natives. Finally, we provide a set of conclusions and recommendations to enhance the prospects for the future protection of the herpetofauna of Veracruz

Amphibian life history in a temperate environment of the Mexican Plateau: dimorphism, phenology and trophic ecology of a hylid frog, Hyla eximia (=Dryophytes eximius)

The study of demographic and life history aspects of an organism provides valuable information for its conservation. Here, we analyze the phenology of the Mountain Treefrog Hyla eximia (= Dryophytes eximius) in a temperate environment of the Mexican Plateau. Females were larger in snout-vent length and body mass than males. The peak period of activity occurred in the rainy season (May–September), with amplexus and egg deposition occurring between June and July, and larval development from July to August. A logistic model best explained observed male growth patterns, while the Von Bertalanffy model better described female growth. Notably, males grew faster than females, although females reached a larger overall body size. The diet of this species is made up of 10 prey categories. The index of diet importance indicated that males feed mainly on Coleoptera and Diptera, while females feed on Coleoptera, Diptera, Hemiptera, and Aranea. Both females and males showed a significant abundance of plant material in their stomachs, suggesting that H. eximia might exhibit highly specialized feeding behavior. Reproduction was seasonal, and both female and male reproductive cycles are synchronized with the rainy season. These natural history characteristics provide information to better understand their responses to environmental conditions

The herpetofauna of Hidalgo, Mexico: Composition, distribution, and conservation status

The herpetofauna of Hidalgo, Mexico, is comprised of 203 species, including 42 anurans, 17 caudates, one crocodylian, 137 squamates, and six turtles. Here, the distribution of the herpetofaunal species are catalogued among the four recognized physiographic regions. The total number of species varies from 77 in the Mexican Plateau to 166 in the Sierra Madre Oriental. The individual species occupy from one to four regions (mean = 2.1). About 69% of the Hidalgo herpetofauna is found in only one or two of the four regions, which is of considerable conservation significance. The greatest number of single-region species occupies the Sierra Madre Oriental (25), followed by the Gulf Coastal Lowlands (15), the Trans-Mexican Volcanic Belt (6), and the Mexican Plateau (2). The Coefficient of Biogeographic Resemblance (CBR) indicates that the Sierra Madre Oriental and the Gulf Coastal lowlands share the most species (72), because of their adjacent geographic position and they contain a significant number of generalist species that occur in the Gulf lowlands of Mexico, southern USA, Central America, and/or South America. The two largest geographic regions in Hidalgo by area, Sierra Madre Oriental and Mexican Plateau, reflect opposite patterns in species richness (166 and 77 species, respectively) due to overall differences in the ecological characteristics between them. A similarity dendrogram based on the Unweighted Pair Group Method with Arithmetic Averages (UPGMA) depicts two distinct clusters, one between the Sierra Madre Oriental and Gulf Coastal Lowlands and the other between the Mexican Plateau and Trans-Mexican Volcanic Belt. The former cluster reflects the two regions sharing a substantial number of herpetofaunal species that occur on the Gulf lowlands of North America and Central America, as well as a few that enter South America. The second cluster is due to the two montane regions being adjacent to one another and their ecological similarities. With respect to the distributional categories, the largest number of species is that of the country endemics (104 of 203), followed by non-endemics (92), state endemics (four), and non-natives (three). The principal environmental threats to the Hidalgo herpetofauna are deforestation, livestock, roads, pollution of water sources, cultural factors, and diseases. The conservation status of each native species was assessed by means of the SEMARNAT (NOM-059), IUCN, and EVS systems, of which the EVS system was the most useful. The Relative Herpetofaunal Priority (RHP) method was also used to designate the rank order significance of the physiographic regions and the highest values were found for the Sierra Madre Oriental. Most of the five protected areas in Hidalgo are located in the Trans-Mexican Volcanic Belt, which is only the second most important region from a conservation perspective. In addition, only 78 of the 200 native species found in Hidalgo are recorded in total from the five protected areas. Finally, a set of conclusions and recommendations are offered for the future protection of the Hidalgo herpetofauna

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