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.

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.

Systematic relevance of pollen morphology in tribe Hylocereeae (Cactaceae).

Hylocereeae is one of the nine tribes in the subfamily Cactoideae (Cactaceae), for which the limits and recognition of genera have been controversial. Essentially, this group comprises epiphytic and hemiepiphytic genera with stems modified as climbing structures. The aim of this paper is to examine pollen attributes in representative species of genera of Hylocereeae, focusing on whose current circumscription comprises and three species, to find whether significant potentially apomorphic and/or autapomorphic systematic characters can be discovered.

Unlocking a high bacterial diversity in the coralloid root microbiome from the cycad genus Dioon.

Cycads are among the few plants that have developed specialized roots to host nitrogen-fixing bacteria. We describe the bacterial diversity of the coralloid roots from seven Dioon species and their surrounding rhizosphere and soil. Using 16S rRNA gene amplicon sequencing, we found that all coralloid roots are inhabited by a broad diversity of bacterial groups, including cyanobacteria and Rhizobiales among the most abundant groups.

Ethnobotany of Mexican and northern Central American cycads (Zamiaceae).

Background: This study documents cycad-human relationships in Mexico, Belize, Guatemala, El Salvador, and Honduras over the last 6000 years. The impetus was acute need for a better understanding of previously undocumented uses of cycads in this region, and the need to improve cycad conservation strategies using ethnobotanical data. We hypothesized that cycads are significant dietary items with no long-term neurological effects, are important to religious practice, and contribute to cultural identity and sense of place, but that traditional knowledge and uses are rapidly eroding.

Estimation of genetic variation in closely related cycad species in Ceratozamia (Zamiaceae: Cycadales) using RAPDs markers.

The Ceratozamia norstogii complex from Southern Mexico is made up of four closely related taxa and occurs in similar habitats (Quercus forest). All have linear-lanceolate leaflets with great similarity between them, especially in juvenile stages, but differentiate with age. There has been debate regarding delimitation of species due to character loss in herbarium specimens.

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.

A character-based approach in the Mexican cycads supports diverse multigene combinations for DNA barcoding.

A DNA barcoding study was conducted to determine the optimal combination of loci needed for successful species-level molecular identification in three extant cycad genera-Ceratozamia, Dioon, and Zamia-that occur in Mexico. Based on conclusions of a previous multigene study in representative species of all genera in the Cycadales, we tested the DNA barcoding performance of seven chloroplast coding (matK, rpoB, rpoC1, and rbcL) and non-coding (atpF/H, psbK/I, and trnH-psbA) regions, plus sequences of the nuclear internal transcribed spacer. We analysed data under the assumptions of the "character attributes organization system" (CAOS), a character-based approach in which species are identified through the presence of 'DNA diagnostics'.

Allozyme variation in the three extant populations of the narrowly endemic cycad Dioon angustifolium Miq. (Zamiaceae) from North-eastern Mexico.

Background And Aims: Dioon angustifolium was considered within D. edule. Recent morphometric and allozyme studies on D.

Diversity and genetic structure of the Mexican endemic epiphyte Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys (Bromeliaceae).

Background And Aims: The monoecious, bird-pollinated epiphytic Tillandsia achyrostachys E. Morr. ex Baker var.