Fausto R. Méndez-de-la-Cruz

• Dr.
• Investigador Titular C at National Autonomous University of Mexico

Reproductive characteristics are determining factors in the evolutionary processes of reptiles; however, they remain poorly documented in many species. In this study, we evaluated aspects of reproductive biology and determined the influence of body size and weight on the reproductive effort of the lizard Abronia gadovii, an anguid species that is v...

Phyllodactylus consists of nocturnal, oviparous geckos that inhabit rocky areas in tropical and subtropical regions of the Americas. Despite their abundance, knowledge about their natural history is scarce. Here, we documented some reproductive aspects of P. delcampoi, a microendemic gecko from the tropical dry forests of Guerrero, Mexico. We found...

Reptiles, as ectothermic organisms, rely on environmental temperatures for optimal physiological performance. The thermal requirements for optimal locomotion in reptiles can severely affect their reproduction. However, some species are successful in environments with temperatures exceeding 40 °C. Holbrookuia propinqua is a species that reproduces a...

The processes that restrict gene flow between populations are fundamental to speciation. Here, we develop a simple framework for studying whether divergence in morphology, climatic niche, time and space contribute to reduced gene flow among populations and species. We apply this framework to a model system involving a clade of spiny lizards (Scelop...

Global warming is threatening ectotherms, with strong repercussions on their population dynamics. Body temperature in ectotherm reptiles is crucial to perform all their biological functions, which are maximized within a narrow interval. When faced with new or adverse thermal conditions, reptiles will respond with distributional changes, behavioural...

KEY POLICY INSIGHTS ● Socio-economic issues must be addressed simultaneously to agree in theoretical issues for the management of extant and new protected areas. ● An increase in the area covered by protected areas does not guarantee biodiversity conservation. ● The global development model, based on economic growth, is the major impediment to biod...

Long noncoding RNAs (lncRNAs) are essential regulatory elements of sex chromosomes that act to equalize gene expression levels between males and females. XIST , RSX , and roX2 regulate X chromosomes in placental mammals, marsupials, and Drosophila , respectively. Because the green anole ( Anolis carolinensis ) shows complete dosage compensation of...

La capacidad de las tortugas de desierto para construir madrigueras las reconoce como ingenieras del paisaje. Estas estructuras son espacios adecuados para tolerar cambios en la temperatura ambiental como el experimentado en zonas áridas. No obstante, la sobrevivencia de las tortugas del desierto en estas zonas de Norteamérica se observa cada vez m...

Aim: Squamate fitness is affected by body temperature, which in turn is influenced by environmental temperatures and, in many species, by exposure to solar radiation. The biophysical drivers of body temperature have been widely studied, but we lack an integrative synthesis of actual body temperatures experienced in the field, and their relationship...

The vulnerability of biodiversity to climate change and habitat alterations is a growing global concern. In the case of reptiles, it has been widely documented that relatively small changes in temperature can have drastic effects on biological processes with significant ecological consequences. This study used biophysical models to investigate how...

Recent climate change should result in expansion of species to northern or high elevation range margins, and contraction at southern and low elevation margins in the northern hemisphere, because of local extirpations or range shifts or both. We combined museum occurrence records from both the continental U.S. and Mexico with a new eco-physiological...

Sea turtles are vulnerable to climate change since their reproductive output is influenced by incubating temperatures, with warmer temperatures causing lower hatching success and increased feminization of embryos. Their ability to cope with projected increases in ambient temperatures will depend on their capacity to adapt to shifts in climatic regi...

The maternal transmission of microbiota during embryonic development of vertebrates is still poorly understood. Here, we used high-throughput sequencing of the 16S rRNA bacterial genes to determine the bacterial communities in the gastrointestinal tract and amniotic environment, i.e., the amniotic fluid, amniotic membrane and extraembryonic yolk, o...

RESuMEn: La 6ta extinción masiva ha sido declarada, siendo los anfibios el grupo más vulnerable de los vertebrados durante el an-tropoceno. La piel desnuda de estos verte-brados y sus hábitos los hace ser altamente susceptibles a agentes ambientales físicos y biológicos, provocando su disminución po-blacional e inclusive su extinción. Durante los 7...

The impact of daily and seasonal variation in environmental temperature on lizards is important, since their physiological processes are body temperature dependent. Lizards that occupy mountainous areas must have been favoured to colonize such habitats through selection on thermal biology traits to thermoregulate effectively. Moreover, mountain liz...

Hawksbill turtles are considered Critically Endangered. An understanding of how nest microenvironment (moisture and temperature) and maternal characteristics can influence embryonic development, hatching success, phenotype, and hatchling performance is needed to ensure effective conservation management. We undertook controlled egg incubations at di...

A Survey for the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis in the Mexico

The relative allocation of energy organisms devote to reproductive processes (aka reproductive effort) constitutes a central topic in life history theory. We document some aspects of the reproductive ecology and investment of 2 viviparous skinks of the genus Plestiodon from Mexico: an undescribed species previously assigned to P. brevirostris (Ples...

Temperature is a key abiotic factor that influences performance of several physiological traits in ectotherms. Organisms regulate their body temperature within a range of temperatures to enhance physiological function. The capacity of ectotherms, such as lizards, to maintain their body temperature within their preferred range influences physiologic...

The role of physiology on habitat specialization in terrestrial ectotherms constitutes a rarely addressed topic, despite the fact that habitat specialization often involves the coadaptation of multiple physiological traits, which in turn may confer a higher vulnerability to climate change. Here we documented aspects of the thermal and hydric physio...

La temperatura es la principal variable ambiental de la que dependen las lagartijas para mantener sus procesos metabólicos, esta influencia el desempeño locomotor. Debido a esto, si la temperatura ambiental aumenta como consecuencia del cambio climático, los lacertilios podrían verse afectados fisiológica y ecológicamente. Evaluamos la eficiencia t...

The biodiversity within tropical dry forests (TDFs) is astounding and yet poorly catalogued due to inadequate sampling and the presence of cryptic species. In the Mexican TDF, endemic species are common, and the landscape has been continually altered by geological and anthropogenic changes. To understand how landscape and environmental variables ha...

Cope's Largescale Spiny Lizards (Sceloporus utiformis) are endemic to the Pacific slope of Mexico. They are oviparous and are known to inhabit tropical and temperate forests from sea level to 1800 m a.s.l. Here, we expand this range based on the finding, in May 2022, of two individuals of S. utiformis in the southeastern portion of the Sierra de Ma...

The knob-scaled lizards (family Xenosauridae) comprise a clade of crevice-dwelling North American lizards with a trend towards low body temperature and high rates of water loss, and are often regarded as thermoconformers. However, there are few studies on their thermal ecology, most of them limited to documenting the body temperatures and their rel...

Viviparity, an innovation enhancing maternal control over developing embryos, has evolved >150 times in vertebrates, and has been proposed as an adaptation to inhabit cold habitats. Yet, the behavioral, physiological, morphological, and life history features associated with live-bearing remain unclear. Here, we capitalize on repeated origins of viv...

Climate change is one of the most pressing challenges for ectotherms due to their dependence on environmental temperature. Extirpation of populations of lizards have already been reported, including endemic species occurring in the mountains of Central México. Here, we characterize the thermal ecology of a montane, viviparous lizard species, Barisi...

Tortoises of the genus Gopherus evolved in North America and have survived major environmental challenges in the past 40 million years. However, this genus now faces multiple anthropogenic threats, such as the introduction of invasive plant species. Buffelgrass (Cenchrus ciliaris) is considered one of the greatest threats to arid and tropical ecosy...

Desert squamates need to regulate their body temperature within a specific range in response to extreme temperatures. Variation of thermal resources through altitudinal and latitudinal gradients influences the thermal physiological traits and thermoregulation of organisms. In some species, the physiological requirements between populations can vary...

Resumen El cambio climático es uno de los factores que ha provocado que la biota se enfrente a la sexta extinción masiva del planeta. Algunos de los organismos más sensibles son los ectotermos, por depender del calor ambiental, siendo los endémicos o microendémicos quienes pueden tener mayor riesgo debido a la limitada distribución que presentan. M...

Amphibians are one of the most diverse and successful groups on the planet, but they did not manage to become completely independent of water bodies and are subject to a constant loss of water through evaporation, which depends on factors determined by the habitat occupy. Gastrotheca marsupiata and Pleurodema cinereum are anuran amphibians that sha...

Liolaemus chaltin is distributed in northestern Argentina and southern Bolivia between 3400 - 3750 m elev. in the Puna ecoregion

Amphibians are one of the most diverse and successful groups on the planet, but they did not manage to become completely independent of water bodies and are subject to a constant loss of water through evaporation, which depends on factors determined by the habitat occupy. Gastrotheca marsupiata and Pleurodema cinereum are anuran amphibians that sha...

Barry Sinervo passed away on 15 March 2021 in Santa Cruz after battling cancer for six years. Barry was working until the very last day when he finished his last manuscript with his closest friend and collaborator Donald Miles. The herpetological community has lost an influential biologist who contributed with major works on evolutionary biology ,...

The thermal quality of the habitat is key for the regulation of body temperature in terrestrial ectotherms and, therefore, permits them to carry out their fundamental biological activities. In thermally heterogeneous environments, ectotherms might follow different behavioral or physiological strategies to maintain their body temperature within biol...

• Tropical ectotherm species tend to have narrower physiological limits than species from temperate areas. As a consequence, tropical species are considered highly vulnerable to climate change since minor temperature increases can push them beyond their physiological thermal tolerance. Differences in physiological tolerances can also be seen at fin...

Barry Sinervo fue un investigador que impactó al mundo de la biología por su capacidad de entender los problemas de manera integral y por su elocuencia en las conferencias y cursos. Era capaz de integrar la información generada por sus investigaciones con la teoría de diversas disciplinas, impactando y sembrando una semilla de conocimiento en cada...

Lizard species have diverse behavioral and physiological responses to thermo-environmental conditions, which allow them to inhabit a broad range of latitudes and elevations. Because the availability of suitable thermal resources is limited and more variable at high-elevation environments than at lower elevations, we expect high-elevation lizards to...

Thermoregulation is a critical process for ectotherms as non-avian reptiles, since their vital physiological processes depend on it. These organisms have a temperature range where their physiological processes are more efficient, this range is usually a requirement set phylogenetically even though they vary in the use of habitats. This research com...

In recent years, there has been an increase in the descriptions of members of the lizard genus Lepidophyma. Herein, we describe a new species of Lepidophyma from the Huasteca Potosina region of Mexico, previously confused with L. gaigeae, from which it differs in lacking parietal spot, among other characteristics. We inferred its phylogenetic posit...

The variation in temperament among animals has consequences for evolution and ecology. One of the primary effects of consistent behavioral differences is on reproduction. In chelonians some authors have focused on the study of temperament using different methods. In our research our first aim was i) establish a methodology to determine the degree o...

Global climate change and the associated erosion of habitat suitability are pervasive threats to biodiversity. It is critical to identify specific stressors to assess a species vulnerability to extinction, especially in species with distinctive natural histories. Here, we present a combination of field, laboratory, and modeling approaches to evalua...

Viviparity is an evolutionary innovation that enhances maternal protection of developing embryos relative to egg-laying ancestors. The behavioral, physiological, morphological, and life history pathways underpinning this innovation, however, remain unclear. We capitalized on the repeated origin of viviparity in phrynosomatid lizards to tease apart...

Background: Vertebrates exhibit diverse sex determination systems and reptiles stand out by having highly variable sex determinations that include temperature-dependent and genotypic sex determination (TSD and GSD, respectively). Theory predicts that populations living in either highly variable or cold climatic conditions should evolve genotypic s...

As climate change marches on, rapidly rising temperatures shatter records every year, presenting ever-growing physiological challenges to organisms worldwide. Ectotherms rely on behavioral and physiological plasticity to contend with environmental fluctuations. Nonetheless, our understanding of thermal plasticity has been largely limited to laborat...

The water skinks Eulamprus tympanum and E. heatwolei show thermally-induced sex determination where elevated temperatures give rise to male offspring. Paradoxically, Eulamprus species reproduce in temperatures of 12-15 °C making them outliers when compared to reptiles that use temperature as a cue for sex determination. Moreover, these two species...

Black (Ctenosaura similis) and green iguanas (Iguana iguana) occur in a great variety of habitats and could be a source of zoonotic diseases. Herein, we characterized the bacterial flora in oral and cloacal cavities of these species from Banco Chinchorro atoll, Mexico, where they are in close contact with humans. We obtained samples from 19 green a...

The viability of sea turtle populations during their early stages depends mostly on hatching success and a balanced sex ratio of the hatchlings. In sea turtles, sex is determined by the temperature at which the eggs are incubated. Consequently, climate change can play a critical role in population fitness, because increased temperatures can skew th...

El cambio climático (CC) podría ocasionar la extinción del 20% de las especies de lagartijas a nivel mundial para el año 2080. Sin embargo, el riesgo de extinción varía entre especies y depende de los requerimientos fisiológicos de los individuos y de la distribución geográfica de las poblaciones. En el presente trabajo evaluamos aspectos de la eco...

La herpetofauna tiene el estatus de amenaza más alta de todos los vertebrados terrestres, siendo afectada principalmente por la pérdida o degradación de hábitats. Sus pequeños rangos de distribución y sus microhábitats específicos, los vuelve vulnerables a alteraciones del hábitat. Históricamente, los desiertos han sido poco apreciados y se ha afec...

Global climate change is a major known threat against biodiversity, however, it is still unclear how it will affect different taxonomic groups as the answer is dependent on species-specific natural history and habitat complexity. Desert reptiles are of particular concern because they must thermoregulate within optimal limits despite high environmen...

Almost all lizard families in the pleurodont clade share the same XY system. This system was meticulously studied in Anolis carolinensis, where it shows a highly degenerated Y chromosome and a male-specific X chromosome dosage compensation mechanism. Corytophanids (casque-headed lizards) have been proposed as the only family in the pleurodont clade...

Hertz et al. (1993) designed what is now the most widely used protocol to analyse the thermal strategies and efficiency of small squamates. Preferred temperature range (Tp) is one of the most important variables required for determining the thermal efficiency index, and is calculated by monitoring the body temperature of the individuals in an enclo...

A new species of Nematoda, Raillietnema brachyspiculatum is described from a lizard, Lepidiphyma tuxtlae from Mexico

Water relations of terrestrial ectotherms are influenced by a number of environmental factors and physiological constraints. Whereas macroenvironment undoubtedly plays a role in determining such relations, microenvironmental conditions are likely to be of even greater importance for habitat specialist species. The aim of this study was to examine t...

Ambient temperature is a primary factor affecting the physiology and activity of reptiles. Thermoregulation involves a series of mechanisms to maintain an organism’s body temperature within a narrow range. The study of thermal ecology of lizards is relevant for understanding their distribution, life history, ecology and thermal requirements. Moreov...

Nuclear and mitochondrial genomes coexist within cells but are subject to different tempos and modes of evolution. Evolutionary forces such as drift, mutation, selection, and migration are expected to play fundamental roles in the origin and maintenance of diverged populations; however, divergence may lag between genomes subject to different modes...

The cold-climate hypothesis maintains that viviparity arose as a means to prevent increased egg mortality in nests owing to low temperatures, and this hypothesis represents the primary and most strongly supported explanation for the evolution of viviparity in reptiles. In this regard, certain authors have stated that viviparous species will exhibit...

Supplementary analysis performed.

Table S6. Loadings of Principal Component Analysis of bioclimatic variables from Supplementary Analysis.

Table S7. Evolutionary models for niche dimensions from Supplementary Analysis.

Table S1. Vouchers and GenBank accession numbers for the sequences used in phylogenetic reconstruction.

Table S2. Occurrences data.

Fig. S2. Phylogenetic tree of Sceloporus torquatus group from Bayesian analysis of combined nuclear and mitochondrial DNA sequences. Nodes with posterior probability values = 0.5 and bootstrap values = 50% are shown.

Fig. S4. Phylogenetic Principal Component Analysis (pPCA) with two global principal components (PC1/PC2) for the weighted means of PNOs of each bioclimatic variable. The arrows are the loadings that indicate the direction and strength of each environmental variable to the overall distribution. The percentages of variance explained by the first two...

Fig. S5. Principal Component Analysis (PCA) of the variables used to represent the ecological niche space of S. torquatus species from Supplementary Analysis. PCA Lebels: 1. Sceloporus aureolus, 2. S. binocularis, 3. S. bulleri, 4. S. cyanogenys, 5. S. cyanostictus, 6. S. dugesii, 7 S. insignis, 8. S. jarrovii, 9. S. lineolateralis, 10. S. macdouga...

Fig. S6. Variation in PC scores of bioclimatic variables along the phylogeny of the S. torquatus group from Supplementary Analysis.

Table S4. Model parameter estimated for bayou analyses.

Fig. S3. Phylogenetic trees showing the position of adaptive shifts under reversible-jump Bayesian method implemented in the bayou. The diameter of the circles at branches is proportional to the posterior probability of shift.

Table S3. Model parameters estimated for Brownian Motion (BM), Ornstein-Uhlenbeck (OU), Early Burst (EB) and, Pagel’s delta (Δ) for each bioclimatic variable.

Table S5. Pairwise comparisons of niche overlap indices in terms of Schoener’s D and Warren’s I. The upper triangle contains values of D and lower triangle contains values of I.

Fig. S1. Ecological niche models of the species of Sceloporus torquatus group. Models are based on MAXENT using a minimum training presence threshold and a clog log output.

Introgression is now commonly reported in studies across the Tree of Life, aided by recent advancements in data collection and analysis. Nevertheless, researchers working with non‐model species lacking reference genomes may be stymied by a mismatch between available resources and methodological demands. In this study, we demonstrate a fast and simp...

El propósito de este libro es documentar las especies de anfibios y reptiles del Parque Nacional La Malinche, así como aportar detalles de su historia natural y algunas características que ayuden a la identificación de las especies residentes. Esta área natural protegida fue decretada como parque nacional en 1938. Sin embargo, al igual que otros pa...

Liolaemus chaltin preferred and critical thermal temperatures

The US and Mexico share a common history in many areas, including language and culture. They face ecological changes due to the increased frequency and severity of droughts and rising energy demands; trends that entail economic costs for both nations and major implications for human well being. We describe an ongoing effort by the Environment Worki...

Determining the susceptibility of species to changing thermal niches is a major goal for biologists. In this paper we develop an eco‐physiological model of extinction risk under climate change premised on behavioral thermoregulation. Our method downscales operative environmental temperatures, which restrict hours of activity of lizards, hr, for pre...

Integrative behavioral studies show that the interplay between individual physiology and social behavior influences the ecology of the species, ultimately affecting individual fitness. Particularly in lizards, color polymorphism is associated with differential behaviors and reproductive strategies, which are evident in mature males during the matin...

The cold-climate hypothesis is the main and most supported explanation of the evolution of viviparity among reptiles. This hypothesis sustains that viviparity arose as a means to save eggs from an increased mortality in nests linked with low temperatures. In this sense, some authors have stated that viviparity could constitute an evolutionary const...

The cold-climate hypothesis is the main and most supported explanation of the evolution of viviparity among reptiles. This hypothesis sustains that viviparity arose as a means to save eggs from an increased mortality in nests linked with low temperatures. In this sense, some authors have stated that viviparity could constitute an evolutionary const...

The American crocodile (Crocodylus acutus) in coastal areas of Quintana Roo state (Mexico), is threatened by factors associated to the rapid development of this touristic region. As reproductive ecology the critical information to determine species conservation strategy, several studies on C. acutus reproduction have been carried out in Quintana Ro...

Aim: Biological and ecological aspects of a large part of the Mexican anuran species are largely unknown. Information about their habits is helpful to establish the role they play in their environment. Hyla arenicolor, Spea multiplicata and Hyla eximia are widely distributed species and apparently coexist in much of the Mexican Altiplane. However,...

Los cambios climáticos que han sucedido en los últimos años han afectado sensiblemente a las comunidades de lagartijas en todo el mundo. Un estudio reciente muestra que Argentina es uno de los países más afectados, en particular aquellas especies que seleccionan temperaturas menores de 32 oC. El presente estudio se realizó para determinar la ecolog...