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Variation in leaf morphology is correlated with environmental variables, such as precipitation, temperature and soil composition. Several studies have pointed out that individual plasticity can largely explain the foliar phenotypic differences observed in populations due to climatic change and have suggested that the environment plays an important role in the evolution of plant species by selecting for phenotypic variation. Thus, the study of foliar morphology in plant populations can help us identify the environmental factors that have potentially influenced the process of species diversification. In this study, we analyzed morphological variation in the leaf traits of the Ternstroemia lineata species complex (Penthaphylacaceae) and its relation to climatic variables across the species distribution area to identify the patterns of morphological differentiation within this species complex. Based on the collected leaves of 270 individuals from 32 populations, we analyzed nine foliar traits using spatial interpolation models and multivariate statistics. A principal component analysis identified three main morphological traits (leaf length and two leaf shape variables) that were used to generate interpolated surface maps to detect discrete areas delimited by zones of rapid change in the values of the morphological traits. We identified a mosaic coarse-grain pattern of geographical distribution in the variation of foliar traits. According to the interpolation maps, we could define nine morphological groups and their geographic distributions. Longer leaves, spatulate leaves and the largest foliar area were located in sites with lower precipitation and higher seasonality of precipitation following a northwest-southeast direction and following significant latitudinal and longitudinal gradients. According to the phenogram of the relationships of the nine morphological groups based on morphological similarity, the putative species and subspecies of the T. lineata species complex did not show a clear pattern of differentiation. In this study, we found a complex pattern of differentiation with some isolated populations and some other contiguous populations differentiated by different traits. Further genetic and systematic studies are needed to clarify the evolutionary relationships in this species complex., Competing Interests: The authors declare there are no competing interests., (©2020 Alcántara-Ayala et al.)

Morphological variation is strongly related to variation in the ecological characteristics and evolutionary history of each taxon. To explore how geographical variation in morphology is related to different climatic gradients and phylogenetic structure, we analyzed the variation of morphological traits (body size, bill, and wing) of 64 species of tyrant flycatchers (Tyrannidae) distributed in Mexico. We measured these morphological traits in specimens from biological collections and related them to the climatic and topographic data of each collection locality. We performed the analyses separately at two levels: (1) the regional level and (2) the assemblage level, which was split into (assemblage I) lowland forests and (assemblage II) highland forests and other vegetation types. We also calculated the phylogenetic structure of flycatchers of each locality in order to explore the influence of climatic variables and the phylogenetic structure on the morphological variation of tyrant flycatchers, by means of linear mixed-effects models. We mapped the spatial variation of the relationship between morphological traits and environmental gradients, taking into account the phylogenetic structure. Important climatic variables explaining the morphological variation were those of temperature ranges (seasonality) and the results suggest that the phylogenetic clustering increases towards the highlands of Sierra Madre Oriental and Sierra Madre del Sur, and the lowlands of Balsas Depression. For the regional level, the spatial distribution of body size showed a pattern coincident with Bergmann's rule, with increasing in size from south to north. In the tropical lowland forests assemblage, body size tend to increase in seasonally dry forests (western Mexico) and decrease in the humid ones (eastern Mexico). In the assemblage of highland forests and other types of vegetation, morphological trait values increased northeast to southwest. Phylogenetic structure helped to explain the variation of morphology at the assemblage level but not at the regional level. The patterns of trait variation in the lowland and highland assemblages suggest that parts of morphological variation are explained both by the climatic gradients and by the lineage relatedness of communities. Overall, our results suggest that morphological variation is best explained by a varied set of variables, and that regression models representing this variation, as well as integrating phylogenetic patterns at different community levels, provide a new understanding of the mechanisms underlying the links among biodiversity, its geographical setting, and environmental change., Competing Interests: The authors declare there are no competing interests., (©2019 Cortés-Ramírez et al.)

The distribution and abundance of species of Trochillidae family is usually influenced by the flowering and phenology of plants used as a feeding source, mainly in primary forest, so that changes in vegetation cover could impact their populations. We analyzed and characterized the geographical distribution and habitat for 22 species of resident hummingbirds in the state of Guerrero using the vegetation and the land use map of INEGI Series IV (2007-2010). Distribution models were generated with the Genetic Algorithm for Rule Set Production (GARP), using historical records of scientific collections and fieldwork (2001-2009), in combination with climatic and topographic variables. Of the 22 modeled species, six are endemic to Mexico, the same number of species found in a risk category. The highest concentration with regards to richness (14-20 species), endemism (5-6 species) and number of threatened species of hummingbirds (5-6 species) occurred in the biotic province of Sierra Madre del Sur. However, the potential distribution of most of the hummingbirds occurred in disturbed sites or agroecosystems, as a result of changes in land-use. For Campylopterus hemileucurus, Lamprolaima rhami and Heliomaster longisrostris, their potential distribution was highest in areas of primary vegetation. Areas of high hummingbirds presence do not coincide with the Important Bird Areas proposed for bird conservation in Guerrero, considering that, despite its diversity and its extreme popularity, from the conservation perspective hummingbirds have received relatively little attention.

Here we provide evidence to support an extension of the recognized distributional range of the Mountain Elaenia (Elaenia frantzii) to include southern Mexico. We collected two specimens in breeding condition in northwestern Sierra Norte de Chiapas, Mexico. Morphologic and genetic evidence support their identity as Elaenia frantzii. We compared environmental parameters of records across the entire geographic range of the species to those at the northern Chiapas survey site and found no climatic differences among localities.

Background: Leptospirosis is widespread in Mexico, yet the potential distribution and risk of the disease remain unknown., Methodology/principal Findings: We analysed morbidity and mortality according to age and gender based on three sources of data reported by the Ministry of Health and the National Institute of Geography and Statics of Mexico, for the decade 2000-2010. A total of 1,547 cases were reported in 27 states, the majority of which were registered during the rainy season, and the most affected age group was 25-44 years old. Although leptospirosis has been reported as an occupational disease of males, analysis of morbidity in Mexico showed no male preference. A total number of 198 deaths were registered in 21 states, mainly in urban settings. Mortality was higher in males (61.1%) as compared to females (38.9%), and the case fatality ratio was also increased in males. The overall case fatality ratio in Mexico was elevated (12.8%), as compared to other countries. We additionally determined the potential disease distribution by examining the spatial epidemiology combined with spatial modeling using ecological niche modeling techniques. We identified regions where leptospirosis could be present and created a potential distribution map using bioclimatic variables derived from temperature and precipitation. Our data show that the distribution of the cases was more related to temperature (75%) than to precipitation variables. Ecological niche modeling showed predictive areas that were widely distributed in central and southern Mexico, excluding areas characterized by extreme climates., Conclusions/significance: In conclusion, an epidemiological surveillance of leptospirosis is recommended in Mexico, since 55.7% of the country has environmental conditions fulfilling the criteria that favor the presence of the disease.

Leptospira interrogans has been identified to cause leptospirosis, a widespread zoonotic disease that has been identified in domestic and wild animals. This work analyzed kidneys from two species of wild rodents from the state of Campeche, Mexico. Analyses were made by PCR using specific primers for detection of Leptospira interrogans DNA. The rodent species that tested positive were Heteromys gaumeri and Ototylomys phyllotis, both of which are new hosts for the bacteria in Southeastern Mexico. These records provide new insights into the disease's transmission that should be studied carefully in order to identify other potential host species, including humans, which are at risk of becoming infected if they are in contact with infected wildlife.