Sierra Madre Occidental Research Articles

Abundance, color pattern variation, life cycle, and reproduction of the triploid parthenogenetic lizard Aspidoscelis uniparens (Squamata: Teiidae) in Chihuahua, Mexico

Abundance, color pattern variation, life cycle, and reproduction of the triploid parthenogenetic lizard Aspidoscelis uniparens (Squamata: Teiidae) in Chihuahua, Mexico. We have observed the triploid parthenogenetic lizard Aspidoscelis uniparens in syntopy with many congeners, as well as allopatric to them, within a distribution area in parts of Arizona, New Mexico, and Texas (USA), and Chihuahua and Sonora (Mexico). In July 2000, we discovered arrays (= groups) of A. uniparens with distinctive dorsal color patterns, allopatric to congeners, at a cluster of three sites in northwestern Chihuahua. These arrays were distinguishable based on strikingly different dorsal color patterns. Thus, we designated specimens from two mapped sites in the Municipality of Casas Grandes and from one nearby mapped site in the Municipality of Nuevo Casas Grandes as vividly striped lizards (VSL). Specimens from other mapped sites were designated normally striped lizards (NSL). We observed that the three VSL sites along the base of foothills of the eastern slope of the Sierra Madre Occidental were ecologically different from NSL sites such as El Sueco and Pradera de Janos in central and northwestern Chihuahua, respectively. All VSL specimens possessed wider and more vividly hued primary stripes, whereas the stripes were of normal width and low-contrast color hues in samples NSL-1 and NSL-2. We used samples NSL-1, NSL-2, and VSL for statistical comparisons of means ± 1 SE for the following characters: snout‒vent length (the three arrays had similar maximum SVL measurements and mean differences attributable to the year-class structure of samples); number of granular scales between the paravertebral stripes at midbody (revealing signifcant differences between some samples); percent of granular scales around midbody situated between the paravertebral stripes at midbody (revealing signifcant differences between all samples); percent of the vertebral feld with a vertebral stripe (revealing signifcant differences between some samples); and clutch size (revealing signifcant differences between some samples). We concluded that qualitative characters diagnostic of the VSL sample of A. uniparens were not accompanied by unique quantitative characters.

Effects of density and structure on production in the communal forests of the Mexican Sierra Madre Occidental

The Sierra Madre Occidental in the Mexican State of Durango, is home to about 5 million ha of species-rich forest ecosystems. Local communities depend on these forests for their livelihood. The preservation of the species richness and productivity of this unique resource requires improved understanding of the effects of forest structure and density on production. The community structure was analysed for three species groups (all species; 12 species of Pinus; and 16 species of Quercus). Based on data gathered in 580 remeasured observational field plots, the main results of this study were as follows: (1) two distinct clusters were identified in each species group, (a) the dominant species with a smaller range of growth rates, and (b) the remaining species which have a smaller maximum size and a greater variation of growth rates. (2) Density (expressed as basal area per hectare) and the percentage contribution to the total basal area of all pine species have a significant effect on forest production (expressed as volume increment per hectare per year). (3) Potential production is surprisingly high (in excess of 20 m3 ha−1 y−1 for some stands) in these forests, but the high potential cannot be realised in many areas because of reduced basal areas caused by overharvesting. (4) The available evidence does not confirm the findings of a recent study that suggests a continuous increase in production with increasing richness. Our observations show that production attains a potential maximum at intermediate levels of richness (between 7 and 9 species per 0.25 ha) and declines with further increases in species richness. This study represents a comprehensive analysis of the effects of density and structure on the community forests of the Sierra Madre Occidental based on a large set of permanent field plots where all trees have been mapped.

TIZÓN SUIZO (Phaeocryptopus gaeumannii (Rhode) Petrak) EN Pseudotsuga menziessi var. glauca (Beissn.) Mayr


 
 
 En México se localizan poblaciones nativas de Phaeocryptopus gaeumannii como colonizadoras de Pseudotsuga menziesii var. glauca. Este hongo es causante del tizón suizo (Swiss Needle Cast), enfermedad que causa defoliación prematura y reducción en el crecimiento. P. gaeumannii se distribuye en el bosque natural de la Sierra Madre Occidental, la Sierra Madre Oriental y en la Sierra Madre del Sur, así como en diversas plantaciones de Árboles de Navidad del centro del país. Los objetivos del presente trabajo fueron identificar y caracterizar molecularmente al patógeno en distintas áreas geográficas y esclarecer algunos aspectos de su ciclo biológico. Para ello, se recolectó follaje de P. menziesii var. glauca con pseudotecios maduros en ocho estados de la república mexicana y se obtuvo una muestra procedente de Oregon (Estados Unidos de América); se aislaron en agar - agua 1.5 % (AA) y se mantuvieron en un medio de cultivo de papa – dextrosa - agar (PDA) durante 60 días. Para identificarlas se consideraron características morfológicas así como los resultados de la amplificación de genes nucleares, a través de la PCR - ITS, que presentó de 99 a 100 % de identidad. El crecimiento se dio de forma radial, color verde olivo a gris, sin formar estructuras reproductivas. Las ascosporas alcanzaron su madurez en marzo y son detectables en la atmósfera; la dispersión principal ocurre entre junio y julio, en relación con las condiciones climáticas y de la localidad; en septiembre y octubre disminuye la cantidad.
 
 

Red dendrocronológica de pino triste (Pinus lumholtzii B.L. Rob. & Fernald) en la Sierra Madre Occidental para reconstrucción de lluvia estacional

Se desarrolló una red de siete cronologías de Pinus lumholtzii en la Sierra Madre Occidental para el desarrollo de reconstrucciones históricas de precipitación estacional. Los valores de los parámetros dendrocronológicos en general fueron similares a los de series de crecimiento desarrolladas con otras coníferas en esta región: sensibilidad media (0.25 - 0.38), inter-correlación entre series (0.52 - 0.66), relación señal/ruido (1.16 - 18.51) y autocorrelación de primer orden (0.01 - 0.30). El primer componente (PC1) que incluyó las cronologías involucradas se utilizó para realizar una reconstrucción de precipitación acumulada noviembre-junio en el período común de las series (1890-2001), donde el crecimiento anual explicó más de 80% de la precipitación ocurrida en dicho período; asimismo, se utilizó la cronología residual del sitio Sauz para reconstruir la precipitación acumulada de los últimos 346 años (1668-2013), la cual detectó períodos extremadamente secos (1665-1688, 1695-1718, 1767-1778, 1890-1896, 1948-1963). La respuesta de las cronologías de esta especie a fenómenos atmosféricos de circulación general, como El Niño Oscilación del Sur (ENSO, por sus siglas en ingles), también fue similar a la obtenida con cronologías de especies con probado potencial dendroclimático. La ventaja de extender la red dendrocronológica de P. lumholtzii se fundamenta en que su potencial dendroclimático es equiparable con el de especies tradicionalmente usadas con este fin; su amplia distribución y el poco disturbio antropogénico que han sufrido sus poblaciones favorece la posibilidad de encontrar individuos longevos. Por su excelente sensibilidad climática, la red dendroclimática de P. lumholtzii es fundamental para estudios dendroclimáticos, particularmente en regiones donde se carece de registros climáticos instrumentales.

Systematics of the frogs allocated to Sarcohyla bistincta sensu lato (Cope, 1877), with description of a new species from Western Mexico.

A new species of hylid frog is described from the southwestern edge of the Mexican Plateau from the states of Morelos and Mexico through Michoacán and Jalisco, reaching the Sierra Madre Occidental in Sinaloa and western Durango. The new species is part of the widespread Mexican hylid Sarcohyla bistincta (sensu amplo) complex, comprised of S. bistincta, S. pentheter, S. calthula, and S. ephemera. One subspecies of S. bistincta (labeculata) was proposed for an isolated population in Oaxaca. We restrict the group's nominal species, S. bistincta (sensu stricto), to the Sierra Madre Oriental of Mexico and southward into the Sierra Madre del Sur of Guerrero and Oaxaca. Examination of type material places S. calthula and S. ephemera in the synonymy of S. labeculata (new combination). The species allied to S. bistincta, namely, S. bistincta, S. labeculata, S. pentheter, and the new species described herein, are diagnosed and described following recent suggested taxonomic changes and new available material.

Molecular systematics and historical biogeography of the genus Gerrhonotus (Squamata: Anguidae)

AbstractAimMultiple geological and climatic events have created geographical or ecological barriers associated with speciation events, playing a role in biological diversification in Mexico. Here, we evaluate the influence of Neogene geological events and of Pleistocene climate change in the diversification of the genus Gerrhonotus using molecular dating and ancestral area reconstruction.LocationMexico and south‐central United States.MethodsA multilocus sequence dataset was generated for 86 individuals of Gerrhonotus from most Mexican biogeographical provinces and belonging to five of the seven currently recognized species, as well as two putative undescribed species. Phylogeographical structure was explored using Poisson‐Tree‐Processes molecular species delimitation. Divergence events were estimated based on the fossil record using a relaxed uncorrelated lognormal clock. Ancestral areas were estimated at divergence events across the tree using a probabilistic Bayesian approach.ResultsExtensive geographical structure was evident within three well‐supported clades. These clades probably diverged from each other in the early to mid‐Miocene, and their divergence was followed by six divergences in the late Miocene and eight divergences in the Pliocene. The ancestral origin of Gerrhonotus with keeled dorsal scales (keeled‐scale Gerrhonotus) was reconstructed to be across the Pacific Coast Province. Our phylogenetic analyses did not support the monophyly of Gerrhonotus.Main conclusionsMiocene and Pliocene geomorphology, perhaps in conjunction with climate change, appears to have induced allopatric divergence on a relatively small spatial scale in this genus. The late Miocene–Pliocene reduction in the highlands along the Tehuantepec fault probably created a large marine embayment that led to an early divergence in a clade of Gerrhonotus. Our analysis suggests uplifting of the Trans‐Mexican Volcanic Belt during this same time period resulted in additional diversification. This was followed by more recent, independent colonization events in the Pliocene from the Mexican Plateau to the Sierra Madre Oriental, Sierra Madre Occidental, Tamaulipas and Edwards Plateau provinces. A genus Gerrhonotus with the keeled‐scale species in addition to Coloptychon rhombifer (= G. rhombifer) is strongly supported. Inclusion of the smooth dorsal‐scale species in the genus is uncertain and maintained only tentatively.

The Rocky Mountains as a dispersal barrier between barn owl (Tyto alba) populations in North America

AbstractAimGeological barriers within a species range play a key role in shaping patterns of genetic variation by restricting gene flow. Mountain ranges are particularly imposing barriers responsible for creating genetic differentiation across multiple taxa, from small amphibians to large mammals and birds. Here, we examined the population structure of North American barn owls (Tyto alba) and investigated whether the Rocky Mountains influence gene flow and dispersal at the continental scale.LocationContinental North America.MethodsWe collected 292 museum samples covering the species range, genotyped them at 20 microsatellite markers and sequenced 410 bp of the mitochondrial gene ND6. Population and landscape genetics tools were used to study range‐wide patterns of structure and identify gene flow barriers. Ring recapture data were also analysed to investigate individual movement patterns and frequency of exchanges between both sides of the Rocky Mountains.ResultsWe found faint overall genetic structure, which is consistent with barn owl's high mobility across its continuous range. Nonetheless, we identified two distinct genetic groups on the western and eastern regions of the Rocky Mountains with a likely contact point through the narrow southern pass between them and the Sierra Madre Occidental in Mexico. Accordingly, most recaptured barn owls remain on the same side of the mountains. The Rockies appear to significantly isolate the populations in the west, which, as a consequence, display lower genetic diversity than their counterparts to the east.Main conclusionsThe Rocky Mountains appear to constrain barn owl dispersal and gene flow. Our study supports the hypothesis that regional landscape barriers can shape gene flow and population structure even in highly mobile organisms.

Phylogenomic insights into the diversification of salamanders in the Isthmura bellii group across the Mexican highlands

Mountain formation in Mexico has played an important role in the diversification of many Mexican taxa. The Trans-Mexican Volcanic Belt in particular has served as both a cradle of diversification and conduit for dispersal. We investigated the evolutionary history of the Isthmura bellii group of salamanders, a widespread amphibian across the Mexican highlands, using sequence capture of ultraconserved elements. Results suggest that the I. bellii group probably originated in southeastern Mexico in the late Miocene and later dispersed across the Trans-Mexican Volcanic Belt and into the Sierra Madre Occidental. Pre-Pleistocene uplift of the Trans-Volcanic Belt likely promoted early diversification by serving as a mesic land-bridge across central Mexico. These findings highlight the importance of the Trans-Volcanic Belt in generating Mexico’s rich biodiversity.

Perils of recovering the Mexican wolf outside of its historical range

The Mexican wolf (Canis lupus baileyi) was included in the 1973 Endangered Species Act listing of the gray wolf (C. lupus), but then listed separately as a subspecies in 2015. Early accounts of its range included the Sierra Madre Occidental of Mexico, southeastern Arizona, southwestern New Mexico, and sometimes western Texas, supported by ecological, biogeographic, and morphological data. There have been multiple unsuccessful attempts to revise the original 1982 recovery plan and identify areas suitable for Mexican wolf reintroduction. Despite the fact that 90% of its historical range is in Mexico and widespread suitable habitat exists there, previous draft recovery plans recommended recovery mostly outside of Mexico and well north of the subspecies' historical range. Planning recovery outside historical range of this subspecies is fraught with problems that may compromise, thwart, or impede successful recovery. Dispersal of Mexican wolves northward and continued movements southward by Northwestern wolves (C. l. occidentalis), along with allowing establishment of Mexican wolves north of their historical range before they are recovered, may lead to premature and detrimental intraspecific hybridization. Interbreeding of Northwestern wolves from Canadian sources and Mexican wolves does not represent the historical cline of body size and genetic diversity in the Southwest. If Northwestern wolves come to occupy Mexican wolf recovery areas, these physically larger wolves are likely to dominate smaller Mexican wolves and quickly occupy breeding positions, as will their hybrid offspring. Hybrid population(s) thus derived will not contribute towards recovery because they will significantly threaten integrity of the listed entity. Directing Mexican wolf recovery northward outside historical range threatens the genetic integrity and recovery of the subspecies, is inconsistent with the current 10(j) regulations under the ESA, is unnecessary because large tracts of suitable habitat exist within historical range, is inconsistent with the concepts of restoration ecology, and disregards unique characteristics for which the Mexican wolf remains listed.

Clasificación geomorfométrica del relieve mexicano: una aproximación morfográfica por densidad de curvas de nivel y la energía del relieve

At present the geomorphometric studies of relief and the digital mapping are an essential geomorphological platform for delimitation of natural synthetic units, so indispensable to the territorial organization, and others applied researches as the optimization of agricultural land use, microlocalization of settlement human, designation of forest programs and even for military strategic plans, among many social and productive utilities. Thus, this article aims to provide detailed information on analytical geomorphological methods and interpretations of morphography and energy for Mexico’s relief, considering two calculations according to unit area: density contour (km/km2) and maximum difference of heights (m/km2) - both relief índices -, with the support of GIS ArcView, ArcGIS, and ArcInfo software. A review of existing national atlases revealed that not all countries have morphometric data on their reliefs. Indeed, mapping of this type was only found, in chronological order, in the National Atlas of Cuba (1970), the Atlas of the Slovak Socialist Republic (Slovak Cartography (1983), the National Atlas of Hungary (Geographic Research Institute of the Hungarian Academy of Sciences (1989), the New National Atlas of Cuba (1989), and the National Atlas of Mexico (1990), all on a small scale. In other national atlases, there are only hypsometric and slope steepness maps. The stages for mapping the geomorphometric units of Mexico’s relief were: (1) Construction of the morphographic map: a) Calculation of density contours, b) Data analysis and reclassification, c) Spatial generalization by minimum mappable area, and d) Smoothing of geographic limits; (2) Obtaining a relief ’s energy map: a) Construction of the Digital Elevation Model (DEM), b) Calculations for the relief ’s energy map, c) Data reclassification, and d) Spatial generalization; (3) Production of a map of the relief ’s geomorphometric units: a) Overlaying of the morphographic and relief ’s energy maps, b) Spatial statistics, and c) Map of geomorphometric relief units: and 4) Definition, according to morphographic contour, of the two predominant classes of the relief ’s energy. The morphographic map (density of contours in km/km2) shows nine range classes: less than 1.0, from 1.0 to 2.0, from 2.1 to 3, from 3.1 to 4, from 4.1 to 5, from 5.1 to 6, from 6.1 to 7, from 7.1 to 8.0, and more than 8.0. On the other hand, the map of the relief ’s energy has 9 ranges (m/km2): less than 10.0, from 10.1 to 20.0, from 20.1 to 50.0, from 50.1 to 100.0, from 100.1 to 200.0, from 200.1 to 300.0, from 300.1 to 400.0, from 400.1 to 500.0, and over 500.0. An analysis of this country’s territory reveals that very highly dissected mountainous relief, with dissection values ranging from 501 to 1 300 m/km2, evidences a monolithic location pattern associated with major breakups due to erosion in the central portion of the Sierra Madre Occidental and, in a more isolated way, in its southern portion; in the central sector of the Sierra Madre del Sur in the State of Guerrero; in the sierras of Miahuatlán and Juárez, in the State of Oaxaca; and in very scattered sectors of the southwestern part of the Sierra Madre de Chiapas and the Sierra Madre Oriental. These orogenic regions have land areas characterized by greater ascending widths and intensities in terms of neotectonic movements responsible for the formation of Mexico’s modern relief. In contrast, morphometric units belonging to the vertical dissection category from 21 to 50 m/km2 exhibit moderately dissected, hilly relief typical of high and mid plains formed by a weaker neotectonic process. Lastly, morphometric units with dissection values between 0 and 20 m/km2 stretch along the plains of the coastal states on the Gulf of Mexico, including karstified plains in the Yucatán Peninsula. Units in this category also stretch along the coastal plains of the Baja California Peninsula, the states of Sonora and Sinaloa, and the Pacific Coast in the State of Chiapas. They can also be found in isolated patches on the coastal plains of the Sierra Madre del Sur, on the plains of the Central Mexican Plateau, and along depressed areas of the Trans-Mexican Neovolcanic Belt, where they occupy countless graben depressions, as well as among volcanic edifices throughout the region. The present methodology for determining geomorphometric unities in Mexico’s relief at a scale of 1:250 000, supported by a GIS platform, using density contours as the morphographic parameter for the country’s relief, provided rather precise results consistent with the relief ’s mathematical-statistical and geomorphological realities. The cartographic expression at a 1:250 000 scale included 122 map sheets of Mexico representing several different levels of data, as morphographical, morphometric (relief ’s energy) and topographic, all of great significance for the preparation of other issues geomorphological mapping.

Synopsis of the spurred species of Lobelia section Stenotium (Campanulaceae) in Sierra Madre Occidental, Mexico, and the description of two new species

The genus Lobelia is cosmopolitan and comprises 423 species in 18 sections. Lobelia sect. Stenotium is the most diverse group with 153 species, has a wide distribution in continental North America and is segregated into two subgroups based on the presence of spurred flowers. There are 16 spurred Lobelia species that occur in streamside or seep areas, throughout pine and oak mixed forests from USA to Costa Rica, but they are frequent along the Pacific slopes of the Sierra Madre Occidental (SMO), Mexico, where 10 species grow. In this paper we present a synopsis of the spurred species of Lobelia in the SMO and propose two new taxa. First, Lobelia rzedowskii is morphologically similar to L. ayersiae, L. cordifolia and L. endlichii but differs by its rosulate leaves, blades 0.5–1.5 × 0.4–1 cm, subsessile, racemose to paniculate inflorescences, with (4–)10–35(–191) flowers, flowers 4–6 mm long including hypanthium, spur 0.5–1 × 0.5–0.8 mm, with the lower two calyx lobes positioned at the middle portion of the spur, white corolla with a yellow spot above lobe sinuses on the throat and staminal tube 1.3–2.5 mm long. Second, Lobelia saturnini is morphologically similar to L. knoblochii, L. macrocentron, L. mcvaughii and L. villaregalis, but differs from them by leaves (2–)4–14(–17) mm long, petioles 2–6(–17) mm long, solitary flowers, flowers 12–16 mm long including hypanthium, hypanthium 1.2–2.5 mm long, spur 2–3 mm long, pedicels (1.3–)2–9(–12) cm long and anthers 1–2.2 mm long. We include an identification key for spurred species of Lobelia in the SMO, photographs, distribution notes with a map, and illustrations.

Notes on the origin of extensive endorheic regions in central and northern Mexico, and some implications for paleozoogeography

The recent discovery of a fossil of Enhydritherium terraenovae in upper Miocene fluvial deposits in Juchipila (Mexico), nearly 200 km away from the nearest coast, together with other known occurrences of the same species in Florida and California, made possible to envision an alternative to the Panamanian and Polar routes of migration through fluvial systems in Mexico. In order to cross from one ocean to the other, individuals of E. terraenovae must have passed the continental divide, which is a physiographic feature that separates surface waters that flow into the Atlantic and Pacific versants.Two vast endorheic regions, which together span more than 400,000 km2 in area, currently dominate drainage systems in northern and central Mexico. The endorheic regions are broadly bounded by two mountain ranges and coincide with the arid and semi-arid regions of the Chihuahuan desert. These closed basins are an additional obstacle for migration. However, drainage systems are constantly varying and adjusting to changing conditions imposed by climate, tectonic activity, volcanism, and pronounced asymmetries in topography and rainfall distribution. The migration route across Mexico for Enhydritherium terraenovae in the late Miocene (≥6 Ma) could have been facilitated by one or more river captures that inverted the flow direction near the headwaters of a drainage system that debouched either into the Gulf of Mexico or the Pacific coast.Biologists studying fresh water fish faunas in the southern part of the United States and in northern and central Mexico have documented several living species that occur in both the Rio Grande and in the Mezquital rivers, two drainages that are not presently connected, drain in opposite directions (i.e. towards the Gulf of Mexico and the Gulf of California, respectively) and are separated by the endorheic regions. Furthermore, systematic studies of fresh water fish faunas in the region has numerous examples of endemicity and allopatric speciations that are interpreted as evidence of several events of drainage system rearrangement either by stream capture, beheading, or river diversion or by fragmentation caused by formation of closed basins by faulting, volcanic activity or isostatic rebound in the footwall block of normal faults.The western boundaries of the extensive endorheic regions in Mexico are controlled mainly by a highland produced by intense felsic volcanism during the Sierra Madre Occidental activity (Eocene – Miocene), and the eastern hydrological divide coincides with mountains associated with the fold and thrust belt produced by the Hidalgoan orogeny in early Cenozoic time. Normal faulting associated with Basin and Range extension formed additional closed basins. Another major factor in the formation of the endorheic regions is the terminal Miocene climate change, which caused runoff reduction and lowered the rivers capacity of erosion.Opening of the Gulf of California changed the overall slope of rivers draining into the Pacific in northwestern Mexico triggering the capture of rivers formerly confined to the closed basins or draining to the Gulf of Mexico. Quaternary normal faults have been documented a few tens of kilometers from the hydrological divides of the endorheic regions, suggesting that in some regions there is an active tectonic component in their formation.The location of the crossing point for the otters is uncertain as the fossil record is scant and investigation on the evolution of drainage systems through time in Mexico is in the early stages. However, it is argued that there is a fair chance that the crossing occurred via the Mezquital river capture near Durango city. Isotopic age of the sediments where the Enhydritherium terraenovae fossil was collected, imply that the capture must have occurred in the late Miocene.

Distribution of Prunus serotina Ehrh. in North America and Its Invasion in Europe

Black cherry (Prunus serotina Ehrh.) is a native North American plant species. It includes five subspecies and is currently invasive in Europe. Since pre-Hispanic times, black cherry has been known and used by American inhabitants, and its botanical use was reported in the 19th century. The present study describes the taxonomic richness and taxonomic diversity of the species based on data from 554 taxonomically confirmed collection sites. Additionally, 19 climatic parameters were used to estimate the current and future potential distribution patterns of black cherry applying a climate change model to North America and Europe. Regions of northeast Mexico, northwestern Mexico, the Great American Basin, and the Mississippi River-Great Lakes region in the USA are shown as areas where taxa of P. serotina are present. The potential distribution model of black cherry in North America shows a continuous pattern starting in the Center of Mexico and following both main Mexican mountain ranges (Sierra Madre Oriental and Sierra Madre Occidental). The pattern extends following two different paths throughout northern Mexico toward the Rocky Mountains and the Appalachians in the USA. Based on the NOAA-CCM3 climatic change model, decreased rainfall in wetlands will result in changes in future patterns in America. When applied to Europe, our model shows more extensive regions and more accurately than previous estimations; thus, the current potential distribution of the species includes important areas in the western part of the continent. The potential effect of climate change on P. serotina distribution suggests new and wider areas of possible invasion of this species throughout the continent mainly in France, Germany, and Italy. We suggest take into account the whole American taxa included in this species in the end to study its potential invasion in Europe and establishing suitable control strategies.

New species of Elateridae (Coleoptera) from Sonora, Mexico, with new country and state records, new taxonomic changes and a classificatory checklist

The click beetles (Elateridae) of Sonora, Mexico reported here are based on published historical records and recent sampling efforts in discrete Sky Island mountain ranges in the Madrean Archipelago north of the Sierra Madre Occidental. Sixty-three (63) species are listed from Sonora of which 41 are newly recorded. Anoplischius murrieta new species, Aptopus opata new species, and Aptopus purica new species are described. Aptopus allita Aranda is treated as a new synonym of A. subcarinatus Schaeffer. Conoderus texanus Candèze is removed from synonymy with C. vespertinus (F.) and reinstated as a valid species. Orthostethus caviceps Schaeffer is a new synonym of O. pectinicornis Champion. Aeolus livens (LeConte) is the senior homonym of A. livens Candèze, which is changed to A. ticuna new name. A summary checklist of recorded click beetle taxa from Sonora is provided.

Diversity and distribution of Phanaeini (Coleoptera: Scarabaeidae: Scarabaeinae) in Mexico.

In this study, we systematized available distribution data, obtained from biological databases and relevant literature, for Mexican species belonging to the tribe Phanaeini. The main objectives were to provide an overall description of the distribution records in biological collections, to detect potential sampling biases, to describe the seasonality of collections and to obtain species distribution models using the Desktop GARP algorithm. A total of 5,562 records, corresponding to 32 species in Mexico, were compiled, including the recently described Phanaeus zoque Moctezuma & Halffter, 2017. This compilation includes 784 unique collection records at 325 localities. These records were mainly distributed along the Trans-Mexican Volcanic Belt, the Sierra Madre Oriental and Sierra Madre Occidental mountain ranges and throughout the states of Chiapas and Veracruz. The Mexican High Plateau, the state of Tlaxcala and the Yucatan Peninsula are lacking in records. Distribution maps were created for species of three genera (Phanaeus MacLeay, 1819, Coprophanaeus Olsoufieff, 1924, and Sulcophanaeus Olsoufieff, 1924) and for 29 species present in Mexico. These species distributions are largely delimited by geomorphological features and vegetation types and coincide with expert descriptions of this tribe; some species show expanded distribution ranges. These maps provide a starting point for further analyses, the planning of future field studies, and the verification of possible new species in the Mexican territory.

Structural characterization of the trees of a forest ejido of northwest Mexico

The objective of this study was to characterize the composition and structure of a forest ejido in the state of Durango. To this end, 10 sampling sites of 2500 m2 were established, within which a census was conducted of all tree species. On each individuals measurements of normal diameter (d1,30), total height (h), of crown diameter (dcopa) were made and the species to which each individual belonged was recorded. For each species the index of value importance family (IVIF), index of value importance (IVI), index value forestry were obtained and the total volume calculated. The Shannon (H´) and Margalef indices (DMG) were also calculated. In total 13 species, five genders and five families were recorded. This forest area had a density of 787 ind ha-1, a dominance (basal area) 22,93 m2 ha-1 and a crown cover of 8838 m2 ha-1. Pinus durangensis had the highest value of importance index with 35,69% of IVIrel and the largest value forestry index with 48,96% IVFrel. With all of the above, quantitative elements of the timberline in a heterogeneous forest of the Sierra Madre Occidental were provided.

Updated checklist and conservation status of Cactaceae in the state of Durango, Mexico

An updated and annotated checklist of Cactaceae in the Mexican state of Durango is provided, supported by a thorough examination of specialized literature and herbarium specimens, as well as field work. Additionally, geographical distribution, endemism and conservation status of the species were analyzed based on a compiled data matrix with 2326 georeferenced records. Cactaceae comprises 137 species and 29 genera in Durango, which represent a high proportion of the Mexican cactus flora: 46−58% at the generic level and 20−23% at the specific level. The estimated richness according to Chao-2 and Jackknife-1 is 143 and 151 species respectively, which means that the inventory we present here for the Cactaceae of Durango is complete in 91 to 96%. Since no herbarium specimens nor registers in reliable data bases were found to support their presence in the area, 46 taxa were excluded; even so, this inventory increases by 30% the cacti richness previously reported for Durango and provides new information on the distribution range of many species. The richest genera are Mammillaria, Opuntia, Coryphantha and Echinocereus. The highest concentration of species occurs in the arid and semiarid zone of eastern Durango, although there are also some spots with significant richness in the tropical region on the western slopes of the Sierra Madre Occidental. 75% of the species are endemic to Mexico, 41% are regional endemics and 5% are restricted to Durango. New records and relevant novelties are also discussed.

Emplacement dynamics and hydrothermal alteration of the Atengo ignimbrite, southern Sierra Madre Occidental, northwestern Mexico

The Sierra Madre Occidental is a thick continental arc related to the subduction of the Farallon plate beneath North America resulting in a very intense and widespread Cretaceous to Cenozoic magmatic and tectonic activity. The 28 My old Atengo ignimbrite outcrops in the southern Sierra Madre Occidental, northwestern Mexico. From 12 sites that belong to various pyroclastic and lava flows emplaced during two pulses in the Oligocene (ca. 32–28 Ma) and Early Miocene (ca. 24–20 Ma), 97 rock specimens were drilled. The mineralogical and rock magnetic properties of the Atengo ignimbrite are compared with the surrounding volcanic rocks to identify the eruption mechanism, and with the El Castillo Ignimbrite, Veracruz, Mexico, to understand the depositional conditions. The comparisons reveal that the Atengo ignimbrite erupted from a single source, but less violently than the El Castillo ignimbrite, and cooled rapidly, inhibiting the formation of subhedral grains. The source of the Atengo Ignimbrite was a Plinian-type eruption, and the characteristic mineralogical and textural properties of each flow are related to different stages of the Plinian-type eruption. Further more, hydrothermal fluids were active during the last stages of volcanism, and caused moderate to intense alteration, especially in the ignimbrites, where high permeability aided the movement of hydrothermal fluids.

Compatible System for Predicting Total and Merchantable Stem Volume over and under Bark, Branch Volume and Whole-Tree Volume of Pine Species

Accurate quantification of branch volume in trees is important for sustainable forest management, especially as these fractions are increasingly used for bioenergy, and for precise forest CO2 quantification. Whereas a large focus has been placed on the compatible estimation of tree taper and bole volume with and without bark, little effort has been made to develop models that allow a simultaneous prediction of these variables together with tree branch volume. In this study, 595 Pinus cooperi trees and 700 Pinus durangensis trees were sampled in pine-oak forests in the Sierra Madre Occidental, Mexico. A compatible system for predicting two segmented taper functions, over and under bark; the corresponding merchantable volumes; coarse branch volume and whole-tree volume was fitted using a modified continuous autoregressive structure to account for autocorrelation. The proposed compatible equations explained more than 97% of the observed variability in diameter over and under bark, volume over and under bark, and total tree volume and more than 64% of the observed variability in branch volume in both species. The method described can theoretically be replicated for any tree species, thus providing a better understanding of the patterns of volume distribution by components, potentially improving carbon accounting system and forest bioenergy planning.

New metallogenic model of telescoped Eocene-Miocene Au-U epithermal mineral deposit in the Placer de Guadalupe district, Chihuahua, Mexico

The chronological repartition of mineral deposits in Mexico and the southern USA coincides with the distribution of the three main volcanic pulses of the Sierra Madre Occidental. These pulses are Eocene to early Miocene in age, suggesting that a broad migration occurred from northwest to southeast, where the last ignimbrite flare-up occurred. The most fertile event occurred from 36 to 28 Ma and produced all of the largest Ag-Au mining districts. The Placer de Guadalupe Au-U district contain a unique association of metals with high variations in their U/Au ratios that are not common worldwide. The uraninite population dated by Wells (1930) yielded an age of ca. 36 Ma, which is comparable to that of the volcanic intrusions and dykes dated in the district (yielding ages of ca. 36 Ma). Altered uraninite cemented by gold sheets provide an age of 21 Ma, which is interpreted to be the age of the gold epithermal event. Studies of fluid inclusions in the quartz and calcite cements formed in the gold event indicate the presence of immiscible magmatic brines and CO2. Homogenization temperatures by halite melting range from 268 °C to 305 °C and 266.6 °C to 283 °C, with salinities ranging from 35.9 to 38.9 and 36.0 to 37.5 wt% eq NaCl, in the quartz and calcite stages, respectively. C-O isotopic compositions of U and Au calcite cements suggest a trend of low-temperature alteration caused by hydrothermal fluids. These C-O isotopes suggest that during the gold event, water/rock interaction processes occurred between magmatic fluids and the carbonate host-rock. REE enrichment in the U calcite cement suggests that La-Ce enriched carbonatite volcanic formations participated in the mineralizing process. The U mineralization event was controlled by (1) a metal and heat source (in this case, late Eocene volcanism and, in particular, a carbonatite volcanic event); (2) an efficient transport mechanism for the large-scale input of meteoric water, which was channeled, heated and U-enriched into reactivated crustal Eocene faults from a deep U source to a shallow sedimentary chemical trap; (3) an effective trap, which is represented in this study by the presence of an organic matter-rich sedimentary formation. The gold mineralization event was characterized by the Miocene extensional peak coupled with asthenospheric upwelling, which facilitated the melting/metamorphism of the lower crust and the expulsion and transport of large amounts of CO2-bearing fluids to a shallow crustal level through the reactivated crustal Laramide thrust faults. The fluids’ interactions with the entire stratigraphic column, from the Grenvillian to the Late Triassic basement, favored the leaching of gold and the enrichment of CO2-bearing fluids. Gold deposition appears to be related to boiling but was ultimately favored by water-rock interaction with U mineralization and the Upper Plomosas shale. Study of the Au-U Placer de Guadalupe deposit reveals evidence of a new Miocene metallogenic event in central and northern Mexico. Its genetic relationship with the Basin and Range (BnR) and Rio Gande Rift (RGR) in USA and its transition from post-orogenic to Miocene intraplate extension in Mexico provides a new perspective regarding the exploration of Miocene gold epithermal deposits in northern Mexico and the southern USA.