Mexican Transition Research Articles

Taxonomic Revision of Pseudognaphalium (Asteraceae, Gnaphalieae) from North America

The genus Pseudognaphalium Kirp., segregated from Gnaphalium L., is one of the largest genera of the tribe Gnaphalieae (Asteraceae) with about 60 species, most of them found in South, Central, and North America, but some species also occurring in Africa, Asia, Europe, and New Zealand. We present a taxonomic revision of Pseudognaphalium for North America accepting 36 species, mainly distributed in the Nearctic Region and the Mexican Transition Zone, and about one third of the species occurring in the Neotropical Region. The following taxa are newly synonymized: G. oaxacanum Greenm. with P. semiamplexicaule (DC.) Anderb., G. schraderi DC. with P. attenuatum (DC.) Anderb. var. sylvicola (McVaugh) Hinojosa & Villaseñor, P. altamiranum (Greenm.) Anderb. with P. roseum (Kunth) Anderb., and P. beneolens (Davidson) Anderb. with P. thermale (E. E. Nelson) G. L. Nesom. Lectotypes are newly designated for G. oblanceolatum Greenm., G. panniforme S. F. Blake, G. ramosissimum Nutt., G. roseum Kunth var. angustifolium Benth., G. roseum var. hololeucum Benth., and G. roseum var. sordescens Benth. Morphological descriptions are provided as well as taxonomic data on nomenclatural types, including synonymies, illustrations, distribution maps, distribution and habitat, additional material examined, distinguishing characters and taxonomic affinities for each taxon, biogeographical and ecological comments, and a key for their identification.

Correction to: Phylogenomics of alligator lizards elucidate diversification patterns across the Mexican Transition Zone and support the recognition of a new genus

Correction to: Phylogenomics of alligator lizards elucidate diversification patterns across the Mexican Transition Zone and support the recognition of a new genus

Amphibian areas of endemism: A conservation priority in the threatened Mexican cloud forest

Amphibians of the Mexican Cloud Forest have a great diversity but are highly threatened. Forest endemisms are useful for recognizing biodiversity hotspots; furthermore, the interaction of historical and current events has generated areas of endemism that can be used for biological conservation in forest fragments; therefore, their identification is an essential part of the management and planning of biological conservation. Thus, our objective was to identify areas of endemism in the cloud forests of Mexico through the analysis of geographical distribution of 126 species of amphibians, as well as their conservation status to obtain information that supports the selection of priority areas for conservation. For this, the endemicity analysis method was used with three spatial scales, 1°×1°, 0.5°×0.5° and 0.25°×0.25° (lat/long), to achieve more complete results and avoid visual overrepresentation of areas of endemism. Seventeen consensus areas distributed in four of the five provinces of the Mexican Transition Zone were identified. The province of the Sierra Madre del Sur exhibited the highest amount of endemism areas, followed by the Sierra Madre Oriental, the East of the Trans-Mexican Volcanic Belt, and the Altos de Chiapas. Results indicate that the endemic areas of the Sierra Madre Oriental and Sierra Madre del Sur provinces are composed of amphibians included in the IUCN red list and the Official Mexican Standard NOM-059. Thus, the small areas of endemism in eastern and western Sierra Madre del Sur, nested within larger ones may be used to increase the protected areas of cloud forests in Mexico.

Spatial phylogenetics in Hechtioideae (Bromeliaceae) reveals recent diversification and dispersal

Background: Hechtioideae is a group of Bromeliaceae that is distributed in Megamexico III. In recent years, evolutionary relationships within this lineage have been studied, however, the biogeography of these plants have not yet been explored from a phylogenetic framework. The integration of geographic and phylogenetic information in the evolutionary study of organisms has facilitated the identification of patterns, as well as the exploration of new hypotheses that allow understanding the processes that have influenced the evolutionary history of lineages.
 Questions and/or Hypotheses: What is the biogeographic history of this lineage? How Hechtioideae has diversified over time?
 Results: The Neotropical region has the highest species richness of Hechtioideae and the Mexican Transition Zone is the area with the greatest phylogenetic diversity. This lineage presented its highest diversification rate during the late Miocene and Pleistocene (6.5-1 Ma). The ancestral area of the group corresponds to the Neotropical region and the Mexican Transition Zone. In addition, Hechtioideae spread across their current ranges through multiple dispersal events associated with climatic and geological events during the last 10 Ma.
 Conclusions: Hechtioideae is a group of recent origin whose evolutionary history has been strongly influenced by geological and climatic events over the past 10 Ma, such as the glacial and interglacial periods of the Pleistocene and the great tectonic and volcanic activity that led to the formation of the Trans-Mexican Volcanic Belt.

Distribution patterns of Triatominae (Hemiptera: Reduviidae) in the Americas: an analysis based on networks and endemicity.

Triatominae, commonly known as kissing bugs, are a group of approximately 150 species of hematophagous reduviids, some of which are vectors of Trypanosoma cruzi, the etiological agent of the Chagas disease. Distributional patterns of triatomines have been studied based on macroecological and historical biogeographic approaches, but the definition of distributional patterns and areas of endemism are yet to be defined based on objective criteria. We used two methods to identify biogeographic units in the Triatominae: the endemicity analysis based on an optimality criterion (NDM/VNDM software) and a network approach aimed to simplify and highlight the underlying structure in species distributions (Infomap Bioregions). Information on species distributions was obtained from a data paper, comprising 21 815 records for 135 triatomine species occurring in the Americas. The resulting areas of each method were clustered using a meta consensus criterion based on dissimilarities and interpreted as recurrent areas. The NDM areas show a nested structure, presenting greater restrictions to the inclusion of species in a given area, requiring broad sympatry. In contrast, bioregions emphasize spatial patterns with better-delimited areas and species occurrences do not need to be highly congruent. When areas were clustered based on their species composition two clear patterns arose from both methods: (i) areas within the southern Amazon and southeast South America, especially in the Chacoan subregion, formed a cluster, and (ii) areas north of the Amazon, Pacific, Mesoamerica, Mexican transition zone and Nearctic formed another cluster. Moreover, within each of these two clusters, there was a latitudinal gradient of the areas in the Americas showing spatial similarity between the areas found in both methods. Results of both methods show well-bound areas separating the triatomine fauna in the Brazilian subregions, resulting in the recognition of areas corresponding to the biomes Chaco, Pampa, Cerrado, and Caatinga, and, to a lesser extent, the Atlantic Forest.

Bajacanthon, a New Subgenus for the Mexican Deltochilini (Coleoptera: Scarabaeidae: Scarabaeinae) Fauna

In this study, data are presented for the designation of the new subgenus (Bajacanthon) for Canthon obliquus Horn, 1894 (Deltochilini). The new subgenus Bajacanthon is described based on a multiple evidence approach using morphological and molecular characters. This new subgenus has some unique characters, and is the remnant of an old South American migratory movement into the Mexican Transition Zone. This beetle species has survived in isolation in the south half of the peninsula of Baja California (Mexico). Results based on molecular clock inference showed that the split between the lineages leading to the subgenus Bajacanthon and Boreocanthon took place nearly 16 Mya, whereas the radiation within Bajacanthon was dated to 3.7 Mya.

Updated checklist of the fireflies (Coleoptera: Lampyridae) of Mexico.

An updated checklist of fireflies (Coleoptera: Lampyridae) from Mexico is presented. The checklist includes the following valid taxa: the subfamilies Amydetinae Olivier in Wytsman, 1907, Chespiritoinae Ferreira, Keller and Branham, 2020, Photurinae Lacordaire, 1857, Pterotinae LeConte, 1861, and Lampyrinae Rafinesque, 1815, in addition to 8 tribes (including incertae sedis), 2 subtribes, 25 genera, and 232 species. We also propose Photinus cubilguitzi Prez-Hernndez Zaragoza-Caballero nom. nov. as a replacement name for Photinus moestus (Gorham, 1884) nec Photinus moestus (Perty, 1830). At least 152 documented species (65.6% of the total) are restricted to Mexico, another 21 have also been recorded in Canada and the United States of America, and 59 in different Latin American countries. Remarkably, Photinini contains 64.6% (150 species) of the Mexican lampyrid fauna, and at least 54.7% (127 species) belong to the Photinus genus. The Mexican Transition Zone had higher Lampyridae species richness and endemism than the Nearctic and Neotropical biogeographic regions in the country, while the Transmexican Volcanic Belt, Veracruzan and Balsas Basin biogeographic provinces harbor the highest overall species richness and endemism. Veracruz and Oaxaca are the richest states in terms of lampyrid genera and species, while Aguascalientes, Quertaro and Zacatecas have only one or no species recorded each. To date, 10% of the global firefly fauna has been recorded in Mexico, and the country has a large number of endemic species. It is essential to intensify the study and fieldwork throughout the country to increase our knowledge of the group, with special focus on poorly explored regions and endemic species, and from other perspectives in addition to taxonomy.

First record of the genus Lainius Navás, 1913 (Neuroptera: Chrysopidae) in Mexico, with notes on the distribution of Apochrysinae

The species Lainius constellatus Navás is recorded for the first time from Mexico; thus this report represents the northernmost record of the genus and species for the Americas. In addition, it provides data on the variation in color marks and a description of the hypandrium internum. A brief summary of the distribution of the species belonging to the subfamily Apochrysinae is provided, with emphasis on the three American genera, which share distribution mostly in the Pacific domain of the Brazilian subregion, ranging from the Mexican transition zone to possibly the Chacoan subregion.

Geodispersal of the Typical Neotropical cenocron from South America to the Mexican Transition Zone: a cladistic biogeographical test

Abstract Analysis of the biotic assembly of the Mexican Transition Zone (MTZ) is challenging because of the convergence of taxa with different origins and biogeographical histories. The typical Neotropical cenocron corresponds to genera widespread in South America that might have dispersed to the MTZ in the Pliocene–Holocene. It has been exemplified with distributional patterns of several plant and animal taxa; however, their historical congruence has not been tested. We examined the historical relationships among the areas of endemism where Typical Neotropical taxa are found through a cladistic biogeographical analysis to determine whether they have dispersed simultaneously, showing a geodispersal pattern. We searched for Neotropical clades that dispersed to the MTZ from the Pliocene to the present. The distribution of nine animal clades in seven areas of endemism was analysed by cladistic biogeography. Redundant areas and widespread taxa were treated with paralogy-free and transparent methods. Patterns of area relationships were searched using a parsimony analysis of paralogy-free subtrees. The parsimony analysis found a single resolved tree showing a general pattern of area relationships: (Chacoan ((South Brazilian (Boreal Brazilian + Lesser Antilles)), (South American Pacific (Mesoamerican-Central America + Western Mexico)))). Distributional and phylogenetic information on the groups analysed contrast with a previous cladistic biogeographical analysis that has shown different area relationships, thus supporting the general hypothesis of a geodispersal event of the Typical Neotropical cenocron in the MTZ. Additionally, the analysis provided evidence of vicariant events related to the lifting of the Northern Andes and climatic changes during the Pleistocene.

Phylogenomics of alligator lizards elucidate diversification patterns across the Mexican Transition Zone and support the recognition of a new genus

AbstractGenomic data continue to advance our understanding of species limits and biogeographic patterns. However, there is still no consensus regarding appropriate methods of phylogenomic analysis that make the best use of these heterogeneous data sets. In this study, we used thousands of ultraconserved element (UCE) loci from alligator lizards in the genus Gerrhonotus to compare and contrast species trees inferred using multiple contemporary methods and provide a time frame for biological diversification across the Mexican Transition Zone (MTZ). Concatenated maximum likelihood (ML) and Bayesian analyses provided highly congruent results, with differences limited to poorly supported nodes. Similar topologies were inferred from coalescent analyses in Bayesian Phylogenetics and Phylogeography and SVDquartets, albeit with lower support for some nodes. All divergence times fell within the Miocene, linking speciation to local Neogene vicariance and/or global cooling trends following the mid-Miocene Climatic Optimum. We detected a high level of genomic divergence for a morphologically distinct species restricted to the arid mountains of north-eastern Mexico, and erected a new genus to better reflect evolutionary history. In summary, our results further advocate leveraging the strengths and weaknesses of concatenation and coalescent methods, provide evidence for old divergences for alligator lizards, and indicate that the MTZ continues to harbour substantial unrecognized diversity.

Systematics and Biogeography of the New World Genus Plumolepilius (Coleoptera: Curculionidae)

Plumolepilius Barrios-Izás & Anderson, 2016 is a leaf litter weevil genus that inhabits montane broadleaf forests from southern Mexico to northern Panama. The genus consists of 27 species, 22 distributed in the Chiapas Highlands province (Mexican Transition Zone) and 5 found in the Pacific dominion (Neotropical region) in Costa Rica and Panamá. Here, we analyze the phylogenetic relationships of the species of Plumolepilius based on 20 external body characters and 9 characters from the genitalia. The first dichotomy of the cladogram separates two species from the Pacific dominion from the remaining species of Plumolepilius from the Chiapas Highlands province and three species restricted to the Pacific dominion. We hypothesize that redundant distributions in the taxon-area cladogram of the genus may be due to dispersal events, probably during the Pleistocene glaciations.

Echeandia cholulensis (Asparagaceae), una especie nueva del centro de México

Antecedentes y Objetivos: El género Echeandia (Asparagaceae) agrupa geófitas que caracterizan la flora de México. El grupo es endémico de América e incluye 85 especies, 74 de las cuales han sido encontradas en México y 63 son endémicas de este país. Su riqueza se concentra en la Zona de Transición Mexicana, incluido el Eje Volcánico Transmexicano (EVT). En este trabajo, se nombra y se describe a una especie nueva de Echeandia recolectada en el EVT en los estados de Puebla y Tlaxcala.Métodos: Recolectas en campo y revisión de ejemplares de herbario permitieron el descubrimiento de una especie nueva de Echeandia. Analizamos la morfología de ocho ejemplares de herbario y plantas vivas de dos poblaciones para describir el nuevo taxón y diferenciarlo de E. michoacensis y E. robusta. Por último, evaluamos su estado de conservación mediante el cálculo de la extensión de ocurrencia (EOO) y el área de ocupación (AOO) con la herramienta GeoCAT y basándonos en las categorías y criterios de la Lista Roja de la IUCN.Resultados clave: Describimos Echeandia cholulensis como una especie nueva de México. Se caracteriza por desarrollar los engrosamientos de las raíces alejados del cormo. Las hojas son lanceoladas, onduladas y glaucas. Produce flores ascendentes con tépalos blancos, filamentos clavados y muricados y anteras libres con dehiscencia longitudinal. Se conoce de tres poblaciones en el centro de México, en los estados de Puebla y Tlaxcala.Conclusiones: En el EVT, el volcanismo ha generado variación topográfica y climática que favorece la especiación y persistencia de las plantas. El descubrimiento y descripción morfológica de Echeandia cholulensis ejemplifican lo anterior. La exploración botánica y la revisión de los ejemplares de herbario podrían resultar en el descubrimiento de especies nuevas que aumenten la riqueza florística del EVT.

Biogeographic analysis of the American genus Echeandia (Asparagoideae, Asparagaceae)

Echeandia (Asparagaceae) is an American genus of herbaceous geophytes. Its distribution is heterogeneous but concentrates along the Mexican Transition Zone (MTZ). We analyzed the species richness distribution and endemism of the group. We compiled a data base of 2,078 records obtained by revision of herbarium specimens, scientific publications, and electronic databases. Species richness was quantified under 4 different criteria. Also, we estimated the weighted endemism and the corrected weighted endemism index to detect centers of endemism. We identified 85 species and registered 74 in Mexico. The MTZ had 61 species and the Sierra Madre del Sur province was the most diverse with 39. The richest cell was located in the Transmexican Volcanic Belt and contained 12 species. In addition, 63 species (85.1%) present in Mexico were endemic. Weighted endemism showed 5 cells in the Sierra Madre del Sur and Balsas Basin in Mexico. In contrast, almost all the high valued cells of corrected weighted endemismindex were located in South America. The results were congruent with the patterns of the geophytes and endemic angiosperms of Mexico. The MTZ has a complex tectonic, volcanic and climatic history. These factors have promoted the diversification of several angiosperm lineages, including Echeandia.

The Mexican Transition Zone The Historical Transition Process

The Mexican Transition Zone The Historical Transition Process

Assessing spatial patterns of phylogenetic diversity of Mexican mammals for biodiversity conservation

Phylogenetic diversity is a biodiversity measurement that describes the amount of evolutionary history contained by the taxonomic units in a region. It has proven to be an important metric for determining conservation priorities. Mammalian phylogenetic diversity patterns have been suggested as potential surrogates of biodiversity for establishing priority areas for conservation. This study aims to identify areas of high mammalian phylogenetic diversity in Mexico, a megadiverse country with high mammalian richness, and to assess how well protected areas encompass the phylogenetic diversity. IUCN distribution data for 479 Mexican mammals were used to estimate species richness. Data for the molecular markers cytB, 12S and COI, was gathered from GenBank and from laboratory extractions for reconstructing a maximum-likelihood phylogenetic tree. Spatial patterns in phylogenetic diversity were estimated by summing the branch lengths of the phylogenetic tree representing species presence across grid cells. The results were compared with the distribution of protected areas in Mexico in order to assess if phylogenetic diversity is effectively conserved. The southeastern part of Mexico was found to be the most diverse. The breadth of the phylogenetic tree was well represented within the protected areas. Beta-diversity analyses showed that the species composition between protected and unprotected areas is very similar. Protected areas group based on the phylogenetic composition of mammal species into three clusters corresponding to the Nearctic, Neotropical, and Mexican Transition Zone biogeographical regions, which suggests that protected areas could be managed based on these clusters.

Toward a biogeographic regionalization of the Nearctic region: Area nomenclature and digital map.

We provide a preliminary nomenclatural proposal and a digital map of the Nearctic region, based on published regionalizations, especially Dice (1943), and applying the International Code of Area Nomenclature. The Nearctic region is comprised of three subregions (one of them with two dominions), one transition zone and 29 provinces. The Arctic subregion, in northern North America and Greenland, includes the Eskimoan, Hudsonian, Aleutian and Sitkan provinces. The Western subregion, in western North America, includes the Californian dominion, with the Californian and Oregonian provinces; and the Rocky Mountain dominion, including the Montanian, Saskatchewan, Palusian, Artemisian, Coloradan, Kansan, Mohavian, Navahonian, Sonoran, Chihuahuan, Comanche, and Baja California provinces. The Alleghany subregion, in eastern North America, includes the Illinoian, Canadian, Carolinian, Texan, Austroriparian, and Tamaulipan provinces. The Mexican Transition Zone, situated in the area of overlap with the Neotropical region, includes the Sierra Madre Occidental, Sierra Madre Oriental, Transmexican Volcanic Belt, Sierra Madre del Sur and Chiapas Highlands provinces.

Diversity, species richness distribution and centers of endemism of Lycianthes (Capsiceae, Solanaceae) in Mexico

Spatial patterns of plant diversity matter. Identifying areas of high species richness and endemism are crucial for understanding the evolution of plant diversity and community assemblages as well establishing sustainablility and conservation priorities. Lycianthes is the third most species-rich genus in the Solanaceae with 187 taxa (152 species, 10 subspecies and 25 varieties) native to the Americas and Asia-Pacific region. However, the distributions of the taxa are uneven and usually concentrated along mountain ranges in the Neotropic. In Mexico, the main mountain chains are known as the Mexican Transition Zone (MTZ), so we expected the highest species richness and endemism to be found there. Our aims were twofold; first, to determine the Lycianthes species richness in Mexico; and second, to analyze the spatial patterns. We used 2305 georeferenced records obtained from specimens examined in herbaria, electronic specimen databases and specimens cited in the literature. Then, we analyzed species richness and endemism using a grid-cell of 50 × 50 km, political divisions, biogeographic provinces, vegetation types, and elevation. In addition, endemism was quantified using weighted endemism (WE) and corrected weighted endemism (CWE). In Mexico, there were 48 taxa of Lycianthes, which included 44 species and four varieties. Of these, 20 species and two varieties were endemic. We found 14 cells of high species richness and eight centers of endemism, all located across the MTZ. The pine-oak forest resulted in the richest plant community followed by the cloud forest along an elevational gradient of 1000–2000 m. Likewise, endemism was found within the pine-oak forest of the MTZ, between 1000–2000 m of elevation. The geological history and climatic conditions of the MTZ could explain the diversity of Lycianthes there.

Three new species of Botanophila Lioy (Diptera: Anthomyiidae) from the Mexican Transition Zone.

The genus Botanophila Lioy has several species distributed in North America, but none had been recorded from Mexico. Here we describe three new species of Botanophila from the highlands of the Mexican Transition Zone. We include images of habitus, drawings of the terminalia and a key to facilitate the identification of species. Remarkably, the male of the new species has dichoptic eyes, an unusual characteristic in Anthomyiidae.

Phylogenetic analysis and evolutionary morphology of wings in the genus Cenophengus LeConte, 1881 (Coleoptera: Phengodidae: Mastinocerinae) based on morphological characters

The genus Cenophengus LeConte (1881) includes 27 species, distributed from southern United States to northern Costa Rica. In order to test the monophyly of Cenophengus, a cladistic analysis based on 81 morphological characters, 28 species of Cenophengus and 27 outgroup species was conducted. A clade supported by three synapomorphies corresponds to Cenophengus as a monophyletic group according to the relationships obtained under both equaland implied weights. The systematic relevance of the coding of the characters from the wing is discussed and the sequence of the character state transformations for the veins (radial twenty [r3], posterior radial twenty [RP] size, and anterior cubital veins [CuA]) is optimized in the cladogram obtained under implied weights. Cenophengus species are distributed in the Nearctic and Neotropical regions, and particularly in the Mexican Transition Zone, where their greatest diversity is found.

Biogeographical evaluation and conservation assessment of arboreal leafhoppers in the Mexican Transition Zone biodiversity hotspot

AbstractAimsMexico harbours a diverse fauna comprising more than 1,400 leafhopper species, 60% of which appear to be strictly endemic, with many apparently restricted to particular habitats and host plants. The aims of this study were to identify areas of high species richness and endemism, and determine the biogeographic affinities of species in the diverse arboreal tribe Athysanini to provide data useful for conservation prioritization.LocationMexico.MethodsA data set of 643 historical occurrence records based on authoritatively identified specimens from museums, recent fieldwork, literature and digital repositories was analysed. Analyses of species richness and areas of endemism were conducted using geographic information systems.ResultsA total of 164 species belonging of 50 genera were included, of which 145 species of 31 genera are considered to be endemic. The Mexican state of Guerrero yielded the most species records (48%). The highest numbers of taxa and endemic species were concentrated along the Mexican Transition Zone (MTZ) within which the Trans‐Mexican Volcanic Belt (TVB) province had the most species records. Endemicity analyses showed two different geographical patterns but similar species richness weights with overlapping values over the MTZ. Distribution across vegetation types was not uniform, with most athysanine species concentrated in the dry tropical forest (65%). Species were documented at elevations between sea level and 3,200 m a.s.l. with three altitudinal preference classes. Conservation assessments applying IUCN criteria categorized a majority of species (145) as endangered or critically endangered.Main conclusionsOur findings suggest that most identified areas of high species richness throughout the territory have predominantly endemic taxa. Distributional patterns found are non‐random, influenced by richness and endemism values over the TVB province and in the MTZ with a variable dispersion among species. Data highlight a greatly threatened status by habitat loss, remarking an urgent need for an improved conservation framework.