Underlying and proximate drivers of biodiversity changes in Mesoamerican biosphere reserves.

Protected areas are of paramount relevance to conserving wildlife and ecosystem contributions to people. Yet, their conservation success is increasingly threatened by human activities including habitat loss, climate change, pollution, and species overexploitation. Thus, understanding the underlying and proximate drivers of anthropogenic threats is urgently needed to improve protected areas' effectiveness, especially in the biodiversity-rich tropics.

The phylogenetic reconstruction of the Neotropical cycad genus Ceratozamia (Zamiaceae) reveals disparate patterns of niche evolution.

The cycad genus Ceratozamia comprises 40 species from Mexico, Guatemala, Belize, and Honduras, where cycads occur throughout climatically varied montane habitats. Ceratozamia has the potential to reveal the history and processes of species diversification across diverse Neotropical habitats in this region. However, the species relationships within Ceratozamia and the ecological trends during its evolution remain unclear.

Genomic Insights into Cultivated Mexican Reveal High Levels of Heterozygosity Stemming from Hybridization.

Although vanilla is one of the most valuable spices, there is a lack of understanding of the genomic variability of the main vanilla producing species, within its cultivated origin, Mexico. High genomic heterozygosity levels within the globally cultivated 'Daphna' genome have raised questions on the possibility of a hybrid origin and analogous genomic signatures of vanilla cultivated within its origin. This study investigated these questions by assessing whether the genomic structure of Mexican reflected domestication events.

Uncovering haplotype diversity in cultivated Mexican vanilla species.

Premise: Although vanilla is one of the best-known spices, there is only a limited understanding of its biology and genetics within Mexico, where its cultivation originated and where phenotypic variability is high. This study aims to augment our understanding of vanilla's genetic resources by assessing species delimitation and genetic, geographic, and climatic variability within Mexican cultivated vanilla.

Methods: Using nuclear and plastid DNA sequence data from 58 Mexican samples collected from three regions and 133 ex situ accessions, we assessed species monophyly using phylogenetic analyses and genetic distances.

Speciation along a latitudinal gradient: The origin of the Neotropical cycad sister pair - (Zamiaceae).

Latitude is correlated with environmental components that determine the distribution of biodiversity. In combination with geographic factors, latitude-associated environmental variables are expected to influence speciation, but empirical evidence on how those factors interplay is scarce. We evaluated the genetic and environmental variation among populations in the pair of sister species , two cycads distributed along a latitudinal environmental gradient in northwestern Mexico, to reveal their demographic histories and the environmental factors involved in their divergence.

Niche conservatism promotes speciation in cycads: the case of Dioon merolae (Zamiaceae) in Mexico.

Niche conservatism is the tendency of lineages to retain the same niche as their ancestors. It constrains biological groups and prevents ecological divergence. However, theory predicts that niche conservatism can hinder gene flow, strengthen drift and increase local adaptation: does it mean that it also can facilitate speciation? Why does this happen? We aim to answer these questions.

Ups and downs: Genetic differentiation among populations of the Podocarpus (Podocarpaceae) species in Mesoamerica.

The biogeographical history of Mesoamerican cloud forests is complex, encompassing a diverse and heterogeneous mixture of species with temperate and tropical origins. The dynamic geological landscape and climate change from the Miocene to the Pleistocene affected the distributions and composition of cloud forests in the region, and contributed to divergence events at different time scales. We assessed genetic variation of 29 populations of P.

Spatio-temporal evolution of climbing habit in the Dahlia-Hidalgoa group (Coreopsidae, Asteraceae).

In this paper we focus on Hidalgoa, a small genus distributed in cloud forest from Mexico to Colombia with the uncommon climbing habit of enlarging its petioles. This genus belongs to tribe Coreopsideae (Asteraceae), a group mostly from the Neotropics with a few taxa in Oceania and Polynesia. The phylogenetic position of Hidalgoa has not yet been determined though it will most probably be closely related to Dahlia.

Ceratophila, a new genus of erotylid beetles (Erotylidae: Pharaxonothinae) inhabiting male cones of the cycad Ceratozamia (Cycadales: Zamiaceae).

Ceratophila new genus (Erotylidae: Pharaxonothinae) inhabiting male cones of the Mesoamerican cycad genus Ceratozamia Brongniart (Zamiaceae) is described for seven new species and compared to other genera of the Pharaxonothinae. Ceratophila differs from other genera of the Pharaxonothinae in many characters, most notable of which are: lateral pronotal carina thicker anteriorly in lateral view; head with supraocular and transverse occipital lines; elytra lacking a basal bead; and stridulatory files at base of head narrowly separated. Ceratophila has the male genitalia laterally compressed with a short median lobe and flagellum, similar to other Erotylidae.

The phylogeography of the cycad genus Dioon (Zamiaceae) clarifies its Cenozoic expansion and diversification in the Mexican transition zone.

Background And Aims: Biogeographic transition zones are promising areas to study processes of biogeographic evolution and its influence on biological groups. The Mexican transition zone originated due to the overlap of Nearctic and Neotropical biota, which promoted great biological diversification. However, since most previous studies in this area were focused on revealing the phylogeography of Nearctic plants, how historical biogeographic configuration influenced the expansion and diversification of the Neotropical flora remains almost unknown.

Aridification as a driver of biodiversity: a case study for the cycad genus Dioon (Zamiaceae).

Background And Aims: Aridification is considered a selective pressure that might have influenced plant diversification. It is suggested that plants adapted to aridity diversified during the Miocene, an epoch of global aridification (≈15 million years ago). However, evidence supporting diversification being a direct response to aridity is scarce, and multidisciplinary evidence, besides just phylogenetic estimations, is necessary to support the idea that aridification has driven diversification.

Phylogenetic analyses and morphological characteristics support the description of a second species of (Annonaceae).

Based on phylogenetic and morphological evidence, Escobar-Castellanos & Ortiz-Rodr., . (Annonaceae), a new species from the karst forest of southern Mexico, is described and illustrated.

A new and known cytotoxic aryltetralin-type lignans from stems of Bursera graveolens.

A new 4alpha-aryltetralin-type lignan called burseranin (1) and a known analogous lignan picropolygamain (2) were isolated along with known triterpenes, lupeol and epi-lupeol from the methanol extract of stems of Bursera graveolens, which showed a remarkable inhibitory activity against human HT1080 fibrosarcoma cells. The whole structure of 1 was established based on combined spectral studies and the absolute structure for 2 was first confirmed by CD spectral evidence. In addition, cytotoxic activities of the stem (methanol) extract and its components are evaluated in this paper.