A new genus and eight new species of the subtribe Anillina (Carabidae,Trechinae, Bembidiini) from Mexico,with a cladistic analysis and some notes on?the?evolution of the genus

One new genus and eight new species of anilline carabids are described from southern Mexico. The new genus, Zapotecanillus gen. n., is established for Z. oaxacanus (type species) sp. n., Z. nanus sp. n., Z. iviei sp. n., Z. ixtlanus sp. n., Z. montanus sp. n., and Z. kavanaughi sp. n. from the Sierra Madre de Oaxaca, Z. pecki sp. n. from the Sierra Madre del Sur, and Z. longinoi sp. n. from the Sierra Madre de Chiapas. A taxonomic key for all described species of Zapotecanillus and a cladistic analysis, based on morphological data, are provided. Morphological, behavioral and biogeographical aspects of the speciation in the genus obtained from the resulting cladogram are discussed.     

Two new remarkable Nolinaceae from Central Mexico

Two new species of Nolinaceae are described and illustrated. The first is a ponytail palm,Beaucarnea compacta, occuring in xerophytic scrub in the Sierra Madre Oriental near Atarjea, Guanajuato. The second new species isCalibanus glassianus, adding the second species to the genusCalibanus. This new species is found in the transition between tropical deciduous forest to subontane scrub in the Sierra Madre Oriental near Xichú, Guanajuato.

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Se describen e ilustran dos nuevas especies de Nolinaceae. La primera es una pata de elefante o palma petacona,Beaucarnea compacta. Se distribuye en matorrales xerófitos de la Sierra madre Oriental cerca de Atarjea, Guanajuato. La segunda nueva especie esCalibanus glassianus, que adiciona una especie más al géneroCalibanus. Esta nueva especie se encuentra en la transición de bosques tropicales caducifolios con matorrales xerófilos de la sierra Madre Oriental en los alrededores de Xichú, Guanajuato.

     

Does the Trans‐mexican Volcanic Belt represent a natural biogeographical unit? An analysis of the distributional patterns of Coleoptera

Aim We analysed the geographical distribution of beetle species of the families Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae from the Trans‐mexican Volcanic Belt (TVB) through a track analysis and a parsimony analysis of endemicity (PAE), in order to test its naturalness and determine its affinities. Location The area analysed corresponds to the TVB, which is a biogeographical province of the Mexican Transition Zone. Methods The panbiogeographical analysis was based on the comparison of the individual tracks of 299 species of Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae (Coleoptera). The TVB was divided into 1^o × 1^o grid cells and we also included in the analysis the remaining Mexican biogeographical provinces. Parsimony analysis of endemicity with progressive character elimination (PAE‐PCE) was applied to classify areas by their shared taxa according to the most parsimonious cladograms. The nested sets of areas were represented as generalized tracks. Results Three generalized tracks were obtained: (1) grid cells 9C, 9D, 10D, 10E, Sierra Madre Oriental, Chiapas, Mexican Gulf and the Sierra Madre del Sur; (2) grid cells 3B, 3C, 4B, 4C, 5C, 6C, 7C, Sierra Madre Occidental, Sierra Madre del Sur, Balsas Basin and the Mexican Pacific Coast, and (3) grid cells 8D, 9C, 9D, 10D, 10E, Yucatán Peninsula, Chiapas, Sierra Madre Oriental and the Mexican Gulf. Main conclusions We conclude that the TVB does not represent a natural biogeographical unit because it shows different relationships with other biogeographical provinces, being clearly transitional between the Nearctic and Neotropical provinces. Some parts of the TVB are related to Neotropical provinces (Chiapas, Mexican Gulf and Mexican Pacific Coast) and others to the remaining provinces of the Mexican Transition Zone (Sierra Madre Oriental, Sierra Madre del Sur, Sierra Madre Occidental and Balsas Basin).     

Prioritizing conservation areas and vulnerability analyses of the genus Pinus L. (Pinaceae) in Mexico

Mexico hosts the highest species richness of pines (Pinus, Pinaceae) worldwide; however, the priority areas for their conservation in the country are unknown. In this study, the ecological niche of the 50 native pine species was modeled. Then, through a multi-criteria analysis, the priority areas for the conservation of the genus Pinus were identified according to the spatial patterns of richness, geographic rareness, irreplaceability, the level of vulnerability of their habitat and the status of legal protection. The results revealed that the regions with high species richness differed from those with high endemism. Also, most pine species have undergone processes of habitat degradation, having been the endemic species the most affected. The priority areas covered regions with high species richness, high endemism, and highly degraded forests, located at mountainous portions of the Baja California Peninsula, the Sierra Madre Occidental, the Sierra Madre Oriental, the Trans-Mexican Volcanic Belt, and the Sierra Madre del Sur. A low proportion of priority areas overlapped with protected areas or terrestrial regions considered priorities for biological conservation. These results suggest that conservation efforts for this genus should be focused beyond regions with high species richness and current protected areas. Besides, the priority areas identified in this study can be the basis to create biological corridors and new protected areas, which could contribute significantly to the conservation of this genus in Mexico.     

Studies on Mexican Cactaceae. VI. A new species of Weberocereus (Cactaceae) from Oaxaca,Mexico

Weberocereus alliodorus, a new cactus species from the southern slopes of the Sierra Madre del Sur, Oaxaca, Mexico, is described, illustrated, mapped, and compared to its putative closest relative, W. glaber. The new species is characterized by its three-winged stems with rigid and setose, relatively long spines, relatively large flowers, and fruits with a penetrating onion-like odor.     

A new Species of <Emphasis Type="Italic">Ceratozamia</Emphasis> (Zamiaceae) from the Sierra Norte of Puebla,Mexico

Recent collections of Ceratozamia from the Sierra Norte of Puebla, Mexico, point to a new undescribed species, which was previously subsumed under the concept of C. mexicana. Identification of this new species resulted from a review of three associated species: C. mexicana, C. tenuis, and C. delucana. Here we describe Ceratozamia totonacorum and provide information regarding its distribution and natural history. The Ceratozamia species from the Sierra Madre Oriental, Mexico, are circumscribed using morphological characters, including a detailed evaluation of reproductive structures such as the apex, position, color and shape of the ovulate strobilus.     

A new species of Malaxis (Orchidaceae) from Guerrero, Mexico

Malaxis molotensis, a new orchid species from a wet cloud forest of the Sierra Madre del Sur, Guerrero, Mexico is described and illustrated. In habit and floral structure it resembles the widespread M. histionantha but differs in the elliptic labellum with incurved distal margin, and elongate, oblong-falciform pollinaria.     

Una nueva especie de <Emphasis Type="Italic">Miconia</Emphasis> (Melastomataceae) de la Sierra Madre del Sur de Guerrero y Oaxaca,México

Miconia rzedowskii, which is characterized by its sharply tetragonal distal branches and its mainly sessile trichotomous inflorescences with many flowers, is described from the Sierra Madre del Sur in Guerrero and Oaxaca, Mexico. The new species is illustrated and compared with M. glaberrima, another Mexican species of section Cremanium.     

Assessing occupancy and habitat connectivity for Baird’s tapir to establish conservation priorities in the Sierra Madre de Chiapas,Mexico

Baird’s tapir (Tapirus bairdii) is the largest native mammal that inhabits the Neotropics, and it is enlisted as Endangered by the IUCN Red List. The historic distribution of this species included the area from southern Mexico to northern Colombia. However, its distribution and populations have been reduced drastically during the past 30 years. The main threats for Baird’s tapir are the direct persecution for subsistence hunting, habitat destruction, and habitat fragmentation. In this study, we used camera traps and occupancy models to identify the landscape characteristics that were associated with the occurrence of tapirs in the Sierra Madre de Chiapas, which is one of the most important populations of the species in Mexico, with the aim to identify areas with habitat suitability for the species. We used our best occupancy model to generate a resistance matrix to develop a model of habitat connectivity using Circuit Theory. According to the best occupancy model, the most suitable areas for this species were the forested areas located at the highest elevations of the mountain ranges that provided rugged terrain. We identified three critical corridors to allow for the connectivity of tapir populations in the Sierra Madre de Chiapas, and one of these corridors provides connectivity between this population and the population in the Ocote Biosphere Reserve. With this approach, we propose a conservation strategy for the species that incorporates a more realistic and detailed scheme of Baird’s tapir occurrence in the Sierra Madre de Chiapas region. Priority actions to conserve tapirs in the Sierra Madre de Chiapas over the long term include ensuring the complete protection of prime habitat for the species, improved connectivity by protecting forest cover, implementation mitigation measures in areas where paved roads interrupt connectivity of populations, and eradicating poaching of the species in the region completely.     

Ephemeral Pleistocene woodlands connect the dots for highland rattlesnakes of the Crotalus intermedius group

Aim To test how Pleistocene climatic changes affected diversification of the Crotalus intermedius species complex. Location Highlands of Mexico and the south‐western United States (Arizona). Methods We synthesize the matrilineal genealogy based on 2406 base pairs of mitochondrial DNA sequences, fossil‐calibrated molecular dating, reconstruction of ancestral geographic ranges, and climate‐based modelling of species distributions to evaluate the history of female dispersion. Results The presently fragmented distribution of the C. intermedius group is the result of both Neogene vicariance and Pleistocene pine–oak habitat fragmentation. Most lineages appear to have a Quaternary origin. The Sierra Madre del Sur and northern Sierra Madre Oriental are likely to have been colonized during this time. Species distribution models for the Last Glacial Maximum predict expansions of suitable habitat for taxa in the southern Sierra Madre Occidental and northern Sierra Madre Oriental. Main conclusions Lineage diversification in the C. intermedius group is a consequence of Pleistocene climate cycling. Distribution models for two sister taxa in the northern and southern Sierra Madre Occidental and northern Sierra Madre Oriental during the Last Glacial Maximum provide evidence for the expansion of pine–oak habitat across the Central Mexican Plateau. Downward displacement and subsequent expansions of highland vegetation across Mexico during cooler glacial cycles may have allowed dispersal between highlands, which resulted in contact between previously isolated taxa and the colonization of new habitats.     

Historical biogeography of the genus Rhadinaea (Squamata: Dipsadinae)

Multiple geological and climatic events have created geographical or ecological barriers associated with speciation events, playing a role in biological diversification in North and Central America. Here, we evaluate the influence of the Neogene and Quaternary geological events, as well as the climatic changes in the diversification of the colubrid snake genus Rhadinaea using molecular dating and ancestral area reconstruction. A multilocus sequence dataset was generated for 37 individuals of Rhadinaea from most of the biogeographical provinces where the genus is distributed, representing 19 of the 21 currently recognized species, and two undescribed species. Our analyses show that the majority of the Rhadinaea species nest in two main clades, herein identified as “Eastern” and “Southern”. These clades probably diverged from each other in the early Miocene, and their divergence was followed by 11 divergences during the middle to late Miocene, three divergences during the Pliocene, and six divergences in the Pleistocene. The ancestral distribution of Rhadinaea was reconstructed across the Sierra Madre del Sur. Our phylogenetic analyses do not support the monophyly of Rhadinaea. The Miocene and Pliocene geomorphology, perhaps in conjunction with climate change, appears to have triggered the diversification of the genus, while the climatic changes during the Miocene probably induced the diversification of Rhadinaea in the Sierra Madre del Sur. Our analysis suggests that the uplifting of the Trans‐Mexican Volcanic Belt and Chiapan–Guatemalan highlands in this same period resulted in northward and southward colonization events. This was followed by more recent, independent colonization events in the Pliocene and Pleistocene involving the Balsas Basin, Chihuahuan Desert, Pacific Coast, Sierra Madre Occidental, Sierra Madre Oriental, Sierra Madre del Sur, Trans‐Mexican Volcanic Belt, and Veracruz provinces, probably driven by the climatic fluctuations of the time.     

Genetic diversity, mating system, and conservation of a Mexican subalpine relict, Picea mexicana Martínez

Mexican spruce (Picea mexicana Martínez), an endangered species of the highest sky islands in México's Sierra Madre Oriental and Sierra Madre Occidental, is threatened by fire, grazing, and global warming. Its conservation depends on whether it also is threatened by inbreeding and loss of genic diversity. We used 18 isozyme markers in 12 enzyme systems to assay genic diversity, characterize the mating system, and test for recent bottlenecks in three known populations. Unbiased, expected heterozygosity (H _e ) averaged 0.125. Despite a separation of 676 km between populations in the Sierra Madre Oriental and the Sierra Madre Occidental, Wright's F _ST , the proportion of total genic diversity among populations, was only 6.9%. Nei's genetic distance was 0.001 between the populations in the Sierra Madre Oriental and more than an order of magnitude greater, 0.019, between the Sierra Madre Oriental and Sierra Madre Occidental. However, both values point to relatively recent divergence. Mating systems were predominantly outcrossing, but with significant selfing. Multilocus estimates of selfing varied from 19% to 41%, and the means of single-locus estimates were higher, suggesting that additional inbreeding occurred by mating among relatives. Despite significant inbreeding, observed heterozygosity was as high as or higher than H _e ; Wright's fixation index, F _IS , was –0.107. Under the observed level of selfing, positive values of F _IS were expected. Therefore, selection against inbreds and homozygotes must be intense. Cornuet-Luikart tests indicate recent bottlenecks in at least two of the three populations. The results suggest that Mexican spruce is a genetically viable species, and threats are primarily environmental.     

Trisetum curvisetum (Poaceae: Aveneae), a new species from Mexico

Trisetum curvisetum is a new species from high Sierra Madre Oriental in Nuevo León, Mexico. Its soft rather than liquid endosperm is new for the genus, and its lemma awn is thin and flexuous, easily distinguishable from that of other North AmericanTrisetum.     

<Emphasis Type="Italic">Echeveria perezcalixii</Emphasis> (Crassulaceae), una especie nueva del occidente de México

Based on collections from the southern part of the Sierra Madre Occidental, in the states of Jalisco, Nayarit, and Zacatecas, Echeveria perezcalixii is described as a new species. It is compared with E. fulgens, from which it differs by its acaulescent habit, pruinose leaves with hyaline margins, and longer pedicels and sepals.     

A biosystematic study of Pacific Northwestern blue-eyed grasses (Sisyrinchium,Iridaceae)

Thirteen species of blue-eyed grasses had been described for the Pacific Northwest prior to this study. Contemporary taxonomic treatments vary; some authors recognize several of the taxa as valid species, others recognize only one highly variable, widely distributed species. Work has been directed to achieve an understanding of the biological integrity of all previously described species within the northwest. Living plants from natural populations were utilized in controlled artificial hybridization experiments, analysis of breeding systems, and cytological investigations. Hybrids of intraand interspecific crosses were examined for pollen fertility, and investigated cytologically for meiotic behavior. Eight genetically compatible groups are indicated from these experiments. Additional information gained from cytological analysis, breeding systems, ecology, distribution, and morphological studies substantiates the recognition of each genetically compatible group at the specific level, including the new species,S. hitchcockii, from southern Oregon. The following taxa are recognized for the Pacific Northwest: tetraploids (n = 16)S. bellum S. Wats.,S. halophilum Greene,S. septentrionale E. P. Bicknell; octoploids (n = 32)S. idahoense E. P. Bicknell (including the vars.segetum,macounii, andoccidentale), andS. hitchcockii D. Henderson; duodecaploids (n = 48)S. idahoense E. P. Bicknell var.idahoense, S. littorale Greene,S. montanum Greene, andS. sarmentosum Suksd. ex Greene.     

A new species of Castilleja (Orobanchaceae) from the central Sierra Madre Occidental, Mexico, and an annotated key to the Castilleja species of that region

Castilleja holmgrenii is described from several collections made in the Sierra Madre Occidental in southeast Sinaloa and adjacent southwest Durango, Mexico. The new species is a member of subgenus and sectionCastilleja. This apparently rare species is presently known from two small, geographically restricted populations. Also provided are a list of theCastilleja species of this region with notes on their status and distribution, a key for their identification, and nomenclatural and taxonomic notes concerning some of the species.     

A new species of Ponthieva (Orchidaceae, Cranichidinae) from Veracruz, Mexico

Ponthieva rinconii, a new orchid species from the foothills of the Sierra Madre Oriental in Veracruz, Mexico, is described and illustrated. It is similar in overall appearance to the wide-ranging upland speciesP. schaffneri, but differs from it in habitat preferences (tropical semi-evergreen forest at 650 m elevation), presence of a loose raceme, and three-lobed labellum with a basal cavity.     

A new species of Govenia (Orchidaceae) from Chiapas, Mexico

Govenia rubellilabia, a new terrestrial orchid from Sierra Madre de Chiapas, Mexico, is described and illustrated. Diagnostic characters of this new species are compared with other species ofGovenia. Govenia rubellilabia is similar in appearance toG. matudae, but it can be distinguished from this species by a shorter inflorescence with fewer flowers, green-yellowish tepals, a reddish lip lacking spots in the margin of the apex, and by a shorter anther beak.     

Do the Oaxacan Highlands represent a natural biotic unit? A cladistic biogeographical test based on vertebrate taxa

Aim  We analysed the distributional patterns of six terrestrial vertebrate taxa from the Oaxacan Highlands (Sierra Mazateca, Nudo de Zempoaltépetl and Sierra de Juárez) through a cladistic biogeographical approach, in order to test their naturalness as a biotic unit.
Location  The Oaxacan Highlands, Mexico.
Methods  The cladistic biogeographical analysis was based on the area cladograms of the Pseudoeurycea bellii species group (Amphibia: Plethodontidae), the genus Chlorospingus (Aves: Thraupidae), the genera Microtus , Reithrodontomys and Habromys , and the Peromyscus aztecus species group (Mammalia: Rodentia). We obtained paralogy-free subtrees, from which the components were coded in a data matrix for parsimony analysis. The data matrix was analysed with N ona through W in C lada .
Results  The parsimony analysis resulted in a single general area cladogram in which areas were fragmented following the sequence Sierra Madre Occidental, Trans-Mexican Volcanic Belt, Chiapas, Sierra Madre Oriental + Sierra Mazateca, Sierra Madre del Sur, Nudo de Zempoaltépetl and Sierra de Juárez.
Main conclusions  The general area cladogram shows that the Oaxacan Highlands do not constitute a natural unit. The Sierra Mazateca is the sister area to the Sierra Madre Oriental, whereas the Nudo de Zempoaltépetl and the Sierra de Juárez are closely related to the Sierra Madre del Sur. The events that might have caused these patterns include cycles of expansion and contraction of mountain pinyon, juniper and oak woodlands during the Pleistocene.