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The body size and reproductive characteristics in populations of the same species is influenced by environmental and ecological factors. In this study, we analysed the relationship of environmental factors, morphological characters (body size and mass) and reproductive traits (clutch size) of females from 13 populations of Sceloporus variabilis. Results showed variation in snout‒vent length (SVL), body mass and clutch size among populations. An ANCOVA between SVL and clutch size showed an increase of the latter in females from Alvarado and Valle Nacional; ANCOVA between body mass and SVL revealed an increase in body mass in most populations. A canonical correlation analysis showed a positive relationship between SVL, body mass, and clutch size with elevation and precipitation, but not with temperature. Future studies should assess the effect of seasonality and food resource availability on reproductive investment among populations of S. variabilis to determine whether these characteristics are a function of differences in key ecological factors (e.g. availability of resources and seasonality) associated with each population, and determine the causes of geographic variation in morphological and life history characteristics among populations. [ABSTRACT FROM AUTHOR]

In this study, sexual dimorphism, reproductive cycles, litter size and offspring size of a population of the little‐known species Sceloporus palaciosi in central Mexico were analysed. Significant male‐biased sexual size dimorphism was recorded in snout–vent length (SVL), head length, head width, forearm length and tibia length. Both sexes showed asynchronous reproductive cycles, and males reached sexual maturity at a smaller SVL (33 mm) than females (37 mm). Testes volumes were small from January to February, testicular recrudescence began from March to June, and decreased in July, but increased again in August and September, followed by a second decrease from October to December. In females, vitellogenesis began from May until ovulation in December. Embryonic development extended from November to March, and a small number of females carried embryos through July. Mean litter size was 4.0 and was positively correlated with female SVL. The length of the reproductive period in S. palaciosi recorded in this study is longer than that recorded for other populations in other parts of this species range. Further studies are needed to clarify reproductive cycles in the other isolated populations of S. palaciosi, and then extended to other species and chromosome races in the Sceloporus grammicus complex. [ABSTRACT FROM AUTHOR]

We present a comparative analysis of the morphological and reproductive characteristics of adult female Anolis nebulosus, an arboreal lizard found on both mainland and insular habitats near the Pacific Coast of Mexico. Females from San Pancho Island were larger in all measured morphological variables than females from Biological Field Station Chamela ( BFSCH) on the mainland, and those also reproduced at smaller body size (snout-vent length, SVL: range = 35-44 [ABSTRACT FROM AUTHOR]

Male-biased sexual dimorphism is extensive in New World spiny lizards ( Sceloporus: Phrynosomatidae) and is particularly prominent in the polymorphic minor lizard Sceloporus minor. However, the possible relationship between patterns of sexual dimorphism and gonadal development is little known for most species. In this study, we explored aspects of sexual dimorphism in noncolor morphological traits in S. minor and characterized the gonadal cycle in males and females from each of two sites ( El Enzuelado and La Manzana) in Hidalgo, México, differing in key ecological aspects linked to life-history trait expression in other lizards. Males were generally larger than females in each population and expressed larger forms of several other morphological traits, although not all comparisons attained statistical significance. Both sexes attained reproductive maturity at a larger size in El Enzuelado relative to La Manzana, and females from El Enzuelado had larger litters. Gonadal cycles differed substantially between the two populations and suggest that reproductive activity of males and females was synchronous at El Enzuelado and asynchronous at La Manzana, an unusual pattern. Geographic variation in sex-specific responses to environmental variables may be at least partly responsible for the exceptional species diversity of spiny lizards in México. [ABSTRACT FROM AUTHOR]