Abraham Lozano

Instituto Politécnico Nacional | IPN · Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional, Unidad Durango

Sexual dimorphism is a widespread feature in the Animal Kingdom. In lizards of the Sceloporus grammicus complex, studies of sexual dimorphism that analyze the allometric trajectories of body traits remain unexplored. Here we investigate sexual dimorphism in key phenotypic traits, including body size (snout-vent length, SVL) as well as head length (...

Museum voucher numbers of the Sceloporus grammicus complex

The goal of this study is to describe patterns of reproductive activity and associated characteristics in a lizard community from an arid environment in the southern Chihuahuan Desert region of Mexico. Results of this study showed variation in snout-vent length (SVL) in adults female and male among 18 species. A similar pattern occurred in body mas...

Widely distributed lizard species that occur in contrasting habitats generally show distinctive morphological and thermal traits that are the results of local adaptations via sexual and natural selection. Here, we assessed the effect of sex and seasonality on morphology, thermal ecology, and perch height of Sceloporus grammicus of four populations...

We attempted to identify the factors influencing size and shape dimorphism between sexes, as well as among populations and species in the Sceloporus scalaris group (Sceloporus aeneus, S. scalaris, S. bicanthalis and S. subniger). Our analysis focused on five morphological characteristics: snout–vent length, head length, head width, forearm length a...

Morphological adaptations of individuals are directly (or indirectly) determined by the environment. Depending on sex, these adaptations may vary in different ways, given that different selective forces may be operating on organisms. Here, we evaluate intraspecific morphological variation (size and shape) in two populations of Sceloporus grammicus...

Sexual dimorphism in lizards is determined by ecological and environmental factors. Broadly distributed species may show variation in patterns of sexual dimorphism toward either sex, as well as exhibiting variation in morphological dimensions. In the present study, sexual dimorphism in size and shape attributes was evaluated in three populations of...

Variation in life history traits can arise from both genetic and environmental factors. We investigated reproductive activity and variation in some life history traits among four lizard species [Sceloporus bicanthalis, S. subniger (viviparous), S. aeneus and S. scalaris (oviparous)] from different populations of the S. scalaris group. We consider t...

It is well known that geographic variation in morphological traits occurs among populations of lizard species. In this study, we analysed body size and sexual size dimorphism among four populations of the lizard Sceloporus variabilis from contrasting elevations. Males from all populations were larger than females in snout-vent length, head length,...

Artificial ponds are important foraging and drinking resources for bats at La Michilía, a temperate forest with a marked seasonal drought. Using acoustic data we tested the hypothesis that water availability restricts bat activity in the dry season to ponds, whereas in the rainy season resources are widely available and therefore used throughout th...

We studied female reproductive characteristics (clutch size, clutch frequency, egg volume, egg mass, and snout–vent length [SVL] at sexual maturity) in five populations of the Mexican endemic oviparous lizard, Sceloporus aeneus, from the Transmexican Volcanic Belt. Adult females showed a range in SVL of 40–60 mm. Mean clutch size was determined by...

Very little information is documented about variation in sexual size dimorphism between years within populations of a single species, and studies covering related topics are very scarce. We present information on sexual size dimorphism and reproductive traits obtained during the years 1980–1983, in a population of the lizard Sceloporus aeneus from...

We analyzed the metacommunity structure of volant and nonvolant small-mammal assemblages along the San Pedro-Mezquital River to provide insights on its role as a biological corridor connecting the eastern and western versants of the Sierra Madre Occidental. Because the river bed descends from 1,800 m to sea level, and from arid to tropical environm...

Most bats depend strongly on surface water to survive and reproduce, and thus it is a limiting resource in markedly seasonal environments, such as semiarid and temperate Mexico. Cattle ranching, an important activity in these areas has resulted in construction of rainwater reservoirs that may represent the only available surface water during the dr...

The annual histological changes of the seminiferous tubules and anterior testicular ducts were described for the viviparous lizard, Sceloporus grammicus, in two populations inhabiting contrasting environments; relating the reproductive activity of males with temperature, rainfall and photoperiod for each population. Adult males were collected month...

The San Pedro-Mezquital River Basin is located in the southern Sierra Madre Occidental, at the Nearctic-Neotropical transition. The river traverses the Sierra through a canyon that reaches over 1000 m in depth. Based on examination of museum specimens, literature records, and our own collections, we documented the occurrence of 120 species (24.6% o...

The annual histological changes in ovarian morphology (oogenesis, follicular atresia, and corpus luteum) are described for the Mexican lizard Sceloporus grammicus, in two populations that inhabit contrasting environments (vegetation categories, climate, precipitation, and temperature) from Hidalgo State, Mexico. Two germinal beds were situated on t...

Mexico has higher mammalian diversity than expected for its size and geographic position. High environmental hetero geneity throughout Mexico is hypothesized to promote high turnover rates (β-diversity), thus contributing more to observed species richness and composition than within-habitat (α) diversity. This is true if species are strongly associ...

Aim We tested the hypothesis that distributions of Mexican bats are defined by shared responses to environmental gradients for the entire Mexican bat metacommunity and for each of four metaensembles (frugivores, nectarivores, gleaning insectivores, and aerial insectivores). Further, we identified the main environmental factors to which bats respond...

Abstract. 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 reproduct...

The spiny lizard Sceloporus grammicus (Squamata: Phrynosomatidae) is a small reptile from central México and the southern United States, occurring in a wide geographic area characterized by extensive variation in topographic and climatic regimes. Genetic variation among lineages from central México is substantial, though the extent to which this va...

An update on the state of knowledge on the neotropical otter (Lontra longicaudis) for the state of Durango, Mexico is presented based on the revision of literature reports and the addition of 2 new records. Upon revision, only 3 of the previous reports are supported by physical evidence or observations; and 2 more are newly documented records based...