Concordant Biogeographic Patterns among Multiple Taxonomic Groups in the Mexican Freshwater Biota

In this paper we analyse the degree of concordance in species richness and taxonomic distinctness (diversity) patterns among different freshwater taxonomic groups in order to test three long held patterns described in Mexican freshwater biogeography: 1. The aquatic biota of Mexico includes two distinct faunas, a rich Neotropical component in the south and a south-eastern region and a less rich Nearctic component towards central and northern latitudes of the country. 2. A hotspot of species richness and diversity has been recorded in the Usumacinta, including the Yucatan Peninsula. 3. The presence of two distinct biotas in Mexico, an eastern one distributed along the Gulf of Mexico slope, and a western one associated to the Pacific versant. We use species richness and taxonomic distinctness to explore patterns of diversity and how these patterns change between zoogeographical regions. This paper points out a clear separation between Neotropical and Nearctic drainage basins but also between eastern (Gulf of Mexico) and western (Pacific) drainage basins. Present data gives additional empirical support from freshwater biota for three long held beliefs regarding distributional patterns of the Mexican biota. The neotropical basins of Mexico are generally host to a richest and more diversified fauna, that includes more families, genera and species, compared to the less rich and less diverse fauna in the nearctic basins.     

Biogeography of helminth parasites of freshwater fishes in Mexico: the search for patterns and processes

Aim To uncover and describe patterns of biogeography of helminth parasites in freshwater fishes of Mexico, and to understand processes that determine them. Three predictions about host‐specificity, faunal exchange in transitional areas, and the biogeographical ‘core’ fauna, are evaluated, all of which follow from a fundamental hypothesis: that parasites show characteristic associations with particular host clades. The parasite fauna of the southern Mexican cichlids and of the fishes of the Mesa Central are examined as case studies that reflect Neotropical and Nearctic historical influences. Location The region covered in this study includes most of Mexico, with emphasis on six biogeographical areas: the Yucatán Peninsula (area 1), the Grijalva‐Usumacinta drainage (area 2), the Papaloapan and Pánuco drainages (area 3), the Balsas drainage (area 4), the Lerma‐Santiago drainage (area 5), and the Bravo drainage (area 6). Methods A parasite data base containing all the records of helminth parasites of freshwater fishes of Mexico was filtered to extract records of adult helminth parasites in freshwater fishes from the six biogeographical areas designated in this study. Jaccard's similarity coefficients and cluster analyses (using upgma ) were used to analyse the extent of faunal similarity between the designated biogeographical areas and between host (fish) families. Taxonomic composition of parasite assemblages in different host groups was also qualitatively compared from summary data. These data were used to test the three main predictions. Results To date, 184 species of helminths (120 as adults) have been recorded from 127 freshwater fishes in Mexico (almost 33% of the total fish diversity of Mexico). Of these parasite species, 69 are digenetic flukes, 51 are nematodes, 33 are monogeneans, 25 are tapeworms, and only six are acanthocephalans. The data and analyses from the six biogeographical areas corroborate the predictions that: (1) the adult parasite fauna is largely circumscribed by higher levels of monophyletic host taxa (families, orders, etc.), and that this pattern is independent of areas; (2) areas within a certain biogeographical region, and consequently with similar fish composition (e.g. areas 1, 2 and 3) have more similar parasite faunas compared to areas with less similar fish faunal composition; and (3) ‘core’ parasite faunas persist to some extent in transitional areas with limited host‐sharing. Main conclusions Helminth biodiversity in Mexican freshwater fishes is determined by the historical and contemporary biogeography of their hosts. Host lineage specificity, mainly at the level of the host family, appears to be an important factor in the distribution of the parasites. Most fish families (Characidae, Cichlidae, Pimelodidae, Ictaluridae, Catsotomidae, Goodeidae, Atherinidae) possess their own characteristic ‘core’ helminth fauna, with limited host‐sharing in transitional areas (e.g. areas 3 and 4). A re‐evaluation of the helminth fauna of Mexican cichlids questions the hypothesis that cichlids lost parasites during the colonization of Mexico from South America. The evidence supports the idea that they acquired new parasites by host switching, possibly from marine or brackish‐water percomorphs. In contrast, the parasite fauna of the Mesa Central remains enigmatic and reflects the region's history of endemicity with historical marine and Nearctic connections.     

A Review of the Ant Genus <Emphasis Type="Italic">Dolichoderus</Emphasis> Lund, 1831 (Hymenoptera,Formicidae: Dolichoderinae) of Mexico

Mexican ants of the genus Dolichoderus are revised. Five species of the genus are recorded: D. bispinosus (Olivier, 1792), D. diversus Emery, 1894, D. lutosus (Smith, 1858), D. mariae Forel, 1885 and D. plagiatus (Mayr, 1870). Dolichoderus tridentanodus Ortega-De Santiago et Vásquez-Bolaños, 2012 is synonymized with Camponotus mucronatus Emery, 1890. Early records of D. germaini Emery, 1894 and D. lugens Emery, 1894 from Mexico are misidentifications and those species are excluded from the list of the Mexican fauna. Dolichoderus mariae Forel, 1885 is newly reported for the fauna of Mexico. Identification key to Mexican Dolichoderus species is given.     

A checklist of the littoral cladocerans from Mexico,with descriptions of five taxa recently recorded from the Neovolcanic Province

By 1996 an inventory of Mexican cladocerans hadrecorded 48 species of which 22 belonged toChydoridae, Macrothricidae and Ilyocryptidae.Unfortunately, most of the surveys were made beforeresearchers knew that these crustaceans are notentirely cosmopolitan. For this reason and the lack ofdeposited type material, many of these records aredoubtful and need detailed analyses. In this study,material from 18 water bodies located in theNeovolcanic Province of Mexico is analyzed andcompared with the literature. Also, males of Camptocercus dadayi Stingelin and Leydigialeydigi (Schoedler) and new records Eurycercus longirostris Hann and Biaperturaintermedia (Sars) are described. Half of thetotal number of species recorded are American endemicsand represents a mixture of the North and SouthAmerican fauna, suggesting that Mexico constitutes atransition between Nearctic and Neotropicalzones.     

A general assessment of the conservation status and decline trends of Mexican amphibians

We present a review on the conservation status and population trends of the 372 amphibian species currently recognized for Mexico. We based our analyses on the information gathered by the International Union for the Conservation of Nature-the Global Amphibian Assessment (IUCN-GAA) as well as on available literature about imminent or potential threats to these organisms in Mexico. This country has the fifth largest amphibian fauna in the world and almost 58% of the species that inhabit this country are considered as threatened. We highlight the proportion of species per order, family, and genus that are currently under severe risk in Mexico. In addition, we prepared a detailed list of the main factors that are threatening amphibians in this country. Evidence is provided that the six main mechanisms that are globally leading amphibians to extinction (alien species, over-exploitation, land use change, global changes, pollution, and infectious diseases) are indeed currently operating in Mexico. We discuss the relative importance of each of these causes. We also highlight the paucity of quantitative studies that support the current conservation status of Mexican amphibian species.     

The non-volant mammal fauna of Mexico:species richness in a megadiverse country

The mammalian fauna of Mexico is one of the world's richest. Mexico can be considered a true country of megadiversity because it has more species of non-volant mammals than any other country in the New World, even after taking account of the effect of size. A comparison with other political units of the New World showed that the country as a whole harbours more non-volant mammals than expected for its size, whereas individual Mexican states have about the number of species that would be expected for their area. Beta, or differentiation diversity and environmental heterogeneity, rather than alpha or within-habitat diversity, are the key factors that determine the unusually high species richness of the country.     

Review of the Eustrophinae (Coleoptera, Tetratomidae) of America north of Mexico

The Nearctic fauna (north of Mexico) of Eustrophinae is reviewed, and consists of the following five genera and 12 species: Pseudoholostrophus (Pseudoholostrophus) impressicollis (LeConte), Pseudoholostrophus (Holostrophinus) discolor (Horn), Holostrophus bifasciatus (Say), Eustrophus tomentosus Say, Eustrophopsis confinis (LeConte), Eustrophopsis bicolor (Fabricius), Eustrophopsis brunneimarginatus (Dury), Eustrophopsis indistinctus (LeConte), Eustrophopsis arizonensis (Horn), Eustrophopsis ornatus (Van Dyke), Eustrophopsis crowdyisp. n., and Synstrophus repandus (Horn). A lectotype is designated for Eustrophus brunneimarginatus Dury. A key is given to separate genera and species, supplemented with illustrations of relevant features, including aedeagi of all Nearctic species of Eustrophopsis. Detailed distribution (including Mexican records) and natural history data are provided.     

Parsimony Analysis of Endemicity (PAE) of Mexican hydrological basins based on helminth parasites of freshwater fishes

Aim The distributional patterns of helminthological fauna of freshwater fishes were analysed to postulate a general hypothesis on the relationships of some Mexican hydrological systems. Location Eight hydrological systems of central and eastern Mexico were studied and compared with records from Nicaragua. Methods A Parsimony Analysis of Endemicity (PAE) was applied to the presence/absence of ninety‐two helminth parasite taxa (Monogeneans, Digeneans, Cestodes, Acanthocephalans and Nematodes) of freshwater fishes, from eight Mexican hydrological systems, using the Hennig86 program. Results The results represent the first attempt for a biogeographical analysis through application of the PAE method to the distributional patterns of helminth parasites of freshwater fishes in Mexico. A single most parsimonious cladogram was obtained, which grouped all the Neotropical systems in accordance with previous proposals based on other plant and animal taxa. Main conclusions The most basal systems were Santiago and Lerma basins, which exhibited Nearctic affinities. The remaining areas of the cladogram showed Neotropical affinities. All the southeastern systems were grouped in a clade with the Nicaragua system, providing support for a ‘Mesoamerican province’ based on helminth parasites of cichlids. The cladogram also suggests that the treatment of the Lerma‐Santiago basin as a single biogeographical unit is inaccurate and that they should be treated as separate systems.     

The mosquitoes (Diptera: Culicidae) of Tabasco,Mexico

To document and update the mosquito species of Tabasco, Mexico, field collection trips were conducted in the two physiographic regions of Tabasco: the coastal plain of the southern gulf and the mountains of Chiapas and Guatemala. Mosquitoes were collected as immature and adult stages during the dry and rainy seasons from 2014 through 2015. Additionally, the Reference Collection of Arthropods of Medical Importance (CAIM‐InDRE) containing mosquitoes of Tabasco was re‐examined. In total, 4,913 specimens were collected and examined, which are divided into seven tribes, 18 genera, 27 subgenera, and 104 species. Of these, one genus (Shannoniana Lane and Cerqueira), two subgenera (Georgecraigius Reinert, Harbach and Kitching, and Carrollia Lutz), and 21 species are new records for the mosquito fauna of Tabasco. Culex metempsytus Dyar is a new record for Mexico and Wyeomyia jocosa (Dyar and Knab) is removed from the Mexican mosquito fauna. Seventeen species historically reported were not found in the field collections conducted here. Taxonomic notes, new distribution limits, and comments about the medical importance of species of mosquitoes of Tabasco are discussed. Tabasco is the second state in Mexico with the largest mosquito richness (104 species), followed by Veracruz with 139 species.     

Une discordance ante albienne datée par une fauned'Ammonites et de Brachiopodes de type téthysien au Mexique central

North of Leon (Guanajuato), a major unconformityis described under a shallow marine carbonate horizon overlying a strongly folded volcanic and detritical series. The Late Albian age of the limestone is indicated by a small assemblage of ammonites including the genera Eohypoturrilites, Pseudouhligella, Salaziceras and Eutrephoceras and Terebratulinidae of the genus Moutonithyris. The emplacement of this fauna demonstrates the westward extension of the Lower Cretaceous carbonates of the eastern Mexican platform. This unconformity shows the importance of pre-Albian tectonics as far as central Mexico.     

Entrapment Bias of Arthropods in Miocene Amber Revealed by Trapping Experiments in a Tropical Forest in Chiapas,Mexico

All entomological traps have a capturing bias, and amber, viewed as a trap, is no exception. Thus the fauna trapped in amber does not represent the total existing fauna of the former amber forest, rather the fauna living in and around the resin producing tree. In this paper we compare arthropods from a forest very similar to the reconstruction of the Miocene Mexican amber forest, and determine the bias of different trapping methods, including amber. We also show, using cluster analyses, measurements of the trapped arthropods, and guild distribution, that the amber trap is a complex entomological trap not comparable with a single artificial trap. At the order level, the most similar trap to amber is the sticky trap. However, in the case of Diptera, at the family level, the Malaise trap is also very similar to amber. Amber captured a higher diversity of arthropods than each of the artificial traps, based on our study of Mexican amber from the Middle Miocene, a time of climate optimum, where temperature and humidity were probably higher than in modern Central America. We conclude that the size bias is qualitatively independent of the kind of trap for non–extreme values. We suggest that frequent specimens in amber were not necessarily the most frequent arthropods in the former amber forest. Selected taxa with higher numbers of specimens appear in amber because of their ecology and behavior, usually closely related with a tree–inhabiting life. Finally, changes of diversity from the Middle Miocene to Recent time in Central and South America can be analyzed by comparing the rich amber faunas from Mexico and the Dominican Republic with the fauna trapped using sticky and Malaise traps in Central America.     

Gastrointestinal helminths of the Mexican duck, Anas platyrhynchos diazi Ridgway, from north central Mexico and southwestern United States

Twenty-five species of helminths, recovered from the gastrointestinal tracts of 129 Mexican ducks from Mexico and the United States, were all new host records. The species included: Echinoparyphium recurvatum, Echinostoma revolutum, Hypoderaeum conoideum, Notocotylus attenuatus, Prosthogonimus cuneatus, Zygocotyle lunata, Anomotaenia ciliata, Cloacotaenia megalops, Diorchis bulbodes, Diorchis sp., Drepanidotaenia lanceolata, Echinocotyle rosseteri, Fimbriaria fasciolaris, Fimbriarioides sp., Hymenolepis sp. 1, Hymenolepis sp. 2, Sobolevicanthus gracilis. Corynosoma constrictum, Polymorphus minutus, Amidostomum acutum, Echinuria sp., Epomidiostomum crami, Hystrichis varispinosus, Rusguniella arctica, and Tetrameres sp. Fimbriarioides sp. occurred predominantly in ducks from south-central Chihuahua, Mexico. The distributions for the other 24 species of the helminths were not significantly different among the four collecting areas. The helminth fauna for the 32 complete specimens and 97 intestinal tracts was distributed relatively evenly among the hosts with a calculated mean evenness of 0.77 +/- 0.15 and 0.89 +/- 0.03 respectively. The parasite fauna was more similar to those of the black duck Anas rubripes Brewster of eastern North America (53%), the mallard, Anas platyrhynchos (L.) (49%), and the mottled duck, Anas fulvigula Ridgway, from Florida (45%), than to the green-winged teal, Anas crecca (L.) (36%), the gadwall, Anas strepera (L.) (30%), and the American wigeon, Anas americana Gmelin (26%), collected in the Southwest.     

Diversity and distribution of freshwater copepods (Crustacea) in southeastern Mexico

Plankton and littoral samples were obtained from several ponds and lagoons of different environments in the Mexican state of Tabasco. These systems are located in the Grijalva-Villahermosa or the Usumacinta basins. Twenty-two copepod species were recorded, most of them cyclopoids with neotropical and Caribbean affinities. Physical and chemical data associated with the species, as well as morphometric parameters of the surveyed systems were measured and analyzed. A correlation was found between diversity and parameters related to the productivity and the shoreline development (D _L) of the systems; therefore the littoral heterogeneity could be used to predict the species number in shallow tropical systems. At a regional level, the Tabasco copepod fauna is similar to that known from the Yucatan Peninsula, but different from the faunal associations of central Mexico. Distributional patterns differed slightly between both basins and appear to be correlated with climatic variations. This first survey of the freshwater copepod fauna in the state of Tabasco shows it to be constituted mainly by neotropical forms.     

Echinoids (Echinodermata: Echinoidea) from the Gulf of Mexico

The echinoid fauna of the Gulf of Mexico collected during three research cruises (20-1260 m depth) was surveyed from samples were taken at 43 stations. A total of 190 individuals were identified (eight orders, 11 families, 15 genera and 18 species). Six species are new records for the Gulf of Mexico: Stylocidaris lineata, Phormosoma placenta placenta, Plesiodiadema antillarum, Plethotaenia spatangoides, Brissopsis atlantica and Hypselaster limicolus. This adds to the little information available on the echinoid fauna of Tamaulipas, Veracruz, Tabasco, Campeche and Yucatan states in Mexico.     

Track analysis of the Mexican species of Buprestidae (Coleoptera): testing the complex nature of the Mexican Transition Zone

Aim  We analysed the geographical distributions of species of Buprestidae (Coleoptera) in Mexico by means of a panbiogeographical analysis, in order to identify their main distributional patterns and test the complex nature of the Mexican Transition Zone, located between the Nearctic and Neotropical regions.
Location  Mexico.
Methods  The geographical distributions of 228 species belonging to 33 genera of Buprestidae were analysed. Localities of the buprestid species were represented on maps and their individual tracks were drawn. Based on a comparison of the individual tracks, generalized tracks were detected and mapped. Nodes were identified as the areas where generalized tracks converged.
Results  Thirteen generalized tracks were obtained: one was restricted to the Mexican Transition Zone and five to the Neotropical region (Antillean and Mesoamerican dominions), a further two occurred in both the Nearctic region (Continental Nearctic dominion) and the Mexican Transition Zone, and a further five in both the Neotropical region (Mesoamerican dominion) and the Mexican Transition Zone. Seven nodes were identified at the intersections of the generalized tracks – in the Mesoamerican dominion (Mexican Pacific Coast, Mexican Gulf and Chiapas biogeographical provinces) and the Mexican Transition Zone (Trans-Mexican Volcanic Belt, Balsas Basin and Sierra Madre Oriental biogeographical provinces).
Main conclusions  We conclude that the geographical distribution of Buprestidae is mainly Neotropical, corresponding to the Mesoamerican dominion and the Antillean dominion of the Neotropical region, and the Mexican Transition Zone. Most of the generalized tracks and nodes correspond to the Mexican Transition Zone, thus confirming its complex nature. We suggest that the nodes we have identified could be particularly important areas to choose for conservation prioritization.     

Affinities of the marine flora of the Revillagigedo Islands,Mexico

The benthic algal flora reported for the Revillagigedo Islands comprises 205 specific infraspecific taxa: 42 Chlorophyta, 29 Phaeophyta and 134 Rhodophyta. This insular flora shares 131 taxa (54%) with other regions of the Mexican Pacific and 74 (36%) are restricted apparently to the islands. One hundred three taxa (50%) are shared with areas of the Mexican tropical Pacific, 69 (34%) with warm temperate Pacific Mexico and 66 (32%) with La Paz, the transitional zone between tropical and warm temperate Pacific Mexico. Considering more general regions, the Revillagigedo Islands flora includes apparently restricted distribution (34 spp., 16.6%), exclusively tropical (51 spp., 25%) and widely distributed eastern Pacific (33 spp., 16%) taxa. Even though we consider that the inventory of the Revillagigedo Islands and to a lesser degree the eastern tropical Pacific flora is still incomplete and in need of further taxonomic study, the floristic comparison shows a greater affinity of the Revillagigedo Islands flora with the Mexican tropical Pacific than with any other part of Mexico.     

Bathymetric distribution and diversity of deep water polychaetous annelids in the Sigsbee Basin, northwestern Gulf of Mexico

The deep water polychaete fauna is analyzed in this study particularly regarding its composition and variations with depth in the Sigsbee Basin, northwestern region of the Gulf of Mexico. Samples were taken at 10 stations along a bathymetric gradient with depth ranges from 200 to 3760 m with a USNEL (0.25 m²) corer. A total of 287 individuals were identified, from 21 families and 65 species. The most important families, both in terms of abundance and species richness, were: Paraonidae (65.4 ind./0.25 m², 9 spp.), Cirratulidae (28.93 ind./0.25 m², 7 spp.) and Spionidae (18.07 ind./0.25 m², 7 spp.). In general, density tended to decrease with depth with minima at around 2000 m, although two abundance peaks were detected at 3700 and 3760 m, making the pattern seem an inverted parabolic curve. The Shannon-Wiener diversity values varied from 0.54–0.92 at around 2000 m to 3.39 at 3620 m and 3.34 at 3760 m. These results contrast with what is already reported from the North Atlantic and the Tropical Pacific deep benthic communities, where highest diversities are found at 2000 m. Faunal changes evaluated through Beta Diversity (0.08–0.1) and the low similarity found between the stations, emphasized the high variability in the composition of the fauna in the Sigsee Basin, meaning that the faunal composition is practically different at all the sampling stations. Ten species are newly recorded for the Mexican fauna.     

Using anthropometric indicators for Mexicans in the United States and Mexico to understand the selection of migrants and the "Hispanic paradox"

Anthropometric measures including height provide an indication of childhood health that allows exploration of relationships between early life circumstances and adult health. Height can also be used to provide some indication of how early life health is related to selection of migrants and the Hispanic paradox in the United States. This article joins information on persons of Mexican nativity ages 50 and older in the United States collected in the National Health and Nutrition Examination Survey IV (NHANES IV 1999-2002) with a national sample of persons of the same age living in Mexico from the Mexican Health and Aging Survey (MHAS 2001) to examine relationships between height, education, migration, and late-life health. Mexican immigrants to the United States are selected for greater height and a high school, rather than higher or lower, education. Return migrants from the United States to Mexico are shorter than those who stay. Height is related to a number of indicators of adult health. Results support a role for selection in the Hispanic paradox and demonstrate the importance of education and childhood health as determinants of late-life health in both Mexico and the United States.     

'India Shopping': Indian Grocery Stores and Transnational Configurations of Belonging

The cost of health services within the USA has increased in recent years, limiting access for many Americans. In response, a growing number of Americans are traveling to medical border towns in Mexico to meet their needs. However, many US patients feel uncomfortable traveling to Mexico for healthcare because they are unsure how the system works and believe that Mexico is dangerous, unregulated, unsanitary, and premodern. To reconcile these beliefs with the need for quality medical care, Mexican medical providers appropriate aspects of the US medical system to encourage patronage and alleviate the concerns of patients. This paper examines how some Mexican dentists, pharmacists and physicians in the Mexican border town of Nuevo Progreso have broadened their appeal to American patients by (a) associating their procedures with US biomedical standards, (b) building facilities that shadow US counterparts, and (c) facilitating access to the Mexican medical system.     

Definition and insertion of the GSPC in the political context of Mexico

Mexico as a megadiverse country houses between 6 and 8% of the world's flora. However, the Mexican flora is facing challenges, including the presence of at least 981 threatened plant species and 618 exotic plant species, habitat loss, pollution, overexploitation of natural resources and the adverse effects of climate change, which are compromising its conservation and sustainable use. Mexico has been actively involved in the development and update of the Global Strategy for Plant Conservation (GSPC) adopted by the Convention on Biological Diversity (CBD). As a party to CBD, Mexico has established a Coordinating Committee for the Mexican Strategy for Plant Conservation (MSPC), which has adapted the GSPC to fit national needs and drafted a number of projects, indicators, means of verification and actors to ensure that the MSPC, as a public policy tool, really drives conservation and sustainable use actions among all sectors and lasts beyond the current administration. An agenda is being developed with activities that include the following: approaching Congress, identifying the relevance of the MSPC in the National Development Plan and the Mexican Biodiversity Strategy, making use of current environmental policies and an aggressive awareness programme. The MSPC includes simultaneous programmes of technical and political work.