State Of Nayarit Research Articles

Redescription of Centruroides noxius and description of a closely related new species from western Mexico (Scorpiones: Buthidae)

In the present contribution, we redescribe the scorpion species Centruroides noxius Hoffmann, 1932, highly toxic and endemic to western Mexico (state of Nayarit). Its diagnosis is updated according to the modern standards for the genus, and enhanced with a photographic complement that depicts its main diagnostic characters. A new closely related species is also described from the same state, and some comments on the taxonomy and distribution of both taxa are given.

Use of herbarium data to evaluate weediness in five congeners.

It is often desirable to quantify a plant's relative weediness or synanthropy, that is, the degree to which a species associates with human-caused disturbance, in order to study and understand the biology, ecology and evolution of weeds and invasive plants. Herbarium specimens are among the most accessible and verifiable sources of data on distribution and habitat. However, the habitat distribution of species may not be reflected accurately by herbarium specimen data, due to well-known biases in plant collection. Here, we assess how well herbarium specimens reflect species' weediness, when compared with direct field surveys. We used five species of Melampodium (Asteraceae) and classified their degree of weediness with a modification of Nuorteva's synanthropy index, based on herbarium specimens. We then modelled the distribution of our focal species in Mexico using MaxEnt and identified a polygon of ∼3000 km(2) in the state of Nayarit, Mexico, where there was a high probability of finding all five species. Systematic field searches in the target area documented all visible populations of four species along major and minor roads. Then we, again, classified their degree of weediness with the synanthropy index, based now on field data, and compared. We found that herbarium data were an accurate predictor of a species' weediness relative to its congeners despite the well-documented skew of herbarium data towards natural areas, which our data reflected as well. So, herbarium data can be used to classify species' weediness relative to each other, but not in absolute terms, if the specimens were correctly identified and none of the species were subject to particular collection bias. This study is the first attempt to compare herbarium and field data on this subject and may be relevant for other types of investigations based on herbarium data. Our work also highlights the usefulness of distribution models based on herbarium specimens.

Nuevo registro y datos de Rhodocollybia popayanica (Agaricales: Omphalotaceae) de México

Se describe a Rhodocollybia popayanica como nuevo registro de la micobiota mexicana en los estados de Chiapas, Hidalgo, México, Michoacán y Nayarit. Los especímenes estudiados concuerdan con las descripciones de Colombia y Costa Rica. Con este registro México llega a ser el límite septentrional de la distribución neotropical de esta especie.

Meteorus arizonensis Muesebeck, 1923 (Hymenoptera: Braconidae): nuevo registro para México

Braconidae is one of the more diverse families of Hymenoptera with almost 20,000 species worldwide. Meteorus has 316 species and is almost cosmopolitan. Previously, seven species of this genus have been recorded from Mexico. In this note, Meteorus arizonensis Muesebeck is recorded for the first time for the country, obtained from the fall armyworm, Spodoptera frugiperda (J.E. Smith), with materialfrom Santa Maria del Oro, locality in the State of Nayarit.

Identification of the Appropriate Leaf Sampling Period for Nutrient Analysis in ‘Hass’ Avocado

This research was carried out from 2004 to 2005 in two commercial ‘Hass’ avocado orchards cultivated under rainfed conditions in a hot subhumid climate of the state of Nayarit, Mexico. The objectives of this study were to: 1) establish the patterns in nutrient concentrations during the lifespan of winter and summer vegetative flush leaves; and 2) validate a methodology based on mathematical functions to identify the appropriate period for leaf sampling to diagnose plant nutrition in avocado considering its two major vegetative flushes. Leaf samples were taken monthly for each vegetative flush, starting when leaf length was 5 cm or greater and concluding at leaf abscission. Starting at vegetative budbreak, winter and summer leaves lived 12.5 and 7.8 months, respectively. Summer flush leaves grew faster and attained greater length than winter leaves. A mathematical model based on the concentration of macro- and micronutrients through the lifespan of avocado leaves was evaluated. This model was used to determine the period when nutrient concentrations became stable and, consequently, to identify the proper leaf sampling period. For the ‘Hass’ avocado in Nayarit, the period for sampling winter flush leaves corresponded to 6.6- to 7.9-month-old leaves (4 Sept. to 13 Oct.). For summer leaves the optimum period was shorter and occurred when leaves were 3.9 to 4.9 months old (5 Dec. to 5 Jan.). The procedure and sampling time obtained here should be tested in other regions.

Timing of rifting in the southern Gulf of California and its conjugate margins: Insights from the plutonic record

The Gulf of California is a young example of crustal stretching and transtensional shearing leading to the birth of a new oceanic basin at a formerly convergent margin. Previous studies focused along the southwestern rifted margin in Baja California indicated rifting was initiated after subduction and related magmatism ceased at ca. 14–12.5 Ma. However, the geologic record on the Mexico mainland (Sinaloa and Nayarit States) indicates crustal stretching in the region began as early as late Oligocene. The timing of cooling and exhumation of pre- and synrift plutonic rocks can provide constraints on the timing and rate of rifting. Here, we present results of a regional study on intrusive rocks in the southern Gulf of California sampled along the conjugate Baja California and Nayarit-Sinaloa rift margins, as well as plutonic rocks now exposed on submerged rifted blocks inside the gulf. Forty-one samples were dated via U/Pb zircon and 40Ar/39Ar mineral ages, providing emplacement age and thermochronological constraints on timing and rate of cooling. We found an extensive suite of early and middle Miocene plutons emplaced at shallow depths within the basement Cretaceous–Paleocene Peninsular Range and Sinaloa-Jalisco Batholiths. Early Miocene granitoids occur in an elongated WNW-ESE belt crossing the entire southern gulf from southern Baja California to Nayarit and Sinaloa. Most have an intermediate composition ( 75 SiO2 wt%) was emplaced 20.1–18.3 Ma, near the end of the early Miocene. Age span and chemical composition of the early Miocene silicic plutons essentially overlap ignimbrites and domes exposed in the southern Sierra Madre Occidental and in southern Baja California, suggesting that eruptive sources for the early Miocene ignimbrite flare-up may also have been located within the southern Gulf of California. Early Miocene plutons cooled below the 40Ar-39Ar biotite closure temperature (350–400 °C) in less than 2.5 m.y., which we interpret as evidence of a regional extensional event leading to the opening of the Gulf of California. A less widely distributed suite of intermediate-composition, middle Miocene granitoids (15–13 Ma) was sampled from the central-western part of the gulf, west of the Pescadero Basin, and these correspond to an episode of scarce volcanism recorded by the middle and upper members of the onshore Comondu Group in Baja California. Our widely spaced sampling of the generally sediment-covered igneous crust suggests that middle Miocene primary volcanic rocks are much less abundant than implied by previous models in which the gulf was the site of a robust Comondu arc. Thermobarometry data also indicate a very shallow depth (<5 km) of emplacement for the middle Miocene plutonic rocks. Some of these rocks also show a distinctive inequigranular texture indicative of at least two crystallization stages at different pressure. Early and middle Miocene granitoids away from the gulf axis yielded 40Ar-39Ar cooling ages very close to U-Pb zircon ages, demonstrating rapid cooling to <350 °C, which we attribute to their shallow emplacement and, possibly, to exhumation soon after intrusion. Since Comondu-age and middle Miocene magmatism in the gulf region coincided with rapid cooling of young plutons that predate the end of subduction, we suggest that intense crustal stretching controlled the pattern and timing of Comondu-age magmatism, rather than the middle Miocene magmatism controlling the locus of <12 Ma extension.

Identification of Coastal Erosion Causes in Matanchén Bay, San Blas, Nayarit, Mexico

Martínez, R.; Silva, R., and Mendoza, E., 2014. Identification of coastal erosion causes in Matanchén Bay, San Blas, Nayarit, Mexico.This work presents an analysis of the erosion processes in Matanchén Bay based on the available historical records; the possible causes were identified and discussed. The bay is located on the Pacific coast of Nayarit state, Mexico; its northern tip is a highly dynamic system that has undergone intense morphological modifications over the last 80 years. At the beginning of the 1940s an unexplained growth in the beach at the northern tip of the bay was observed, while 40 years later, and up to date, erosion processes began adversely affecting small businesses in the area. The primary causes of the erosion are the anthropogenic modifications in the bay and its surroundings, which include the construction of a hydroelectric dam system, new transport infrastructure, tourist facilities, a harbor and several dredging works in the existing port. In this paper the evolution of the coastline at Matanchén Bay and its surroundings is analyzed for the first time and the actual coastline is compared to that predicted under the assumption that no countermeasures against the erosion are adopted.

Occurrence of ‘Candidatus Phytoplasma asteris’ in citrus showing Huanglongbing symptoms in Mexico

Huanglongbing (HLB), one of the most devastating citrus diseases in the world, was detected in Mexico in 2009. Currently, HLB is associated with the bacteria Candidatus Liberibacter spp., although several phytoplasmas have been found from trees showing HLB-like symptoms in Brazil and China. The aim of this study was thus to determine if, in addition to ‘Ca. L. asiaticus’ (CLas), phytoplasma species are also associated with HLB-like symptoms in citrus groves of Mexico. Citrus plants exhibiting symptoms such as diffuse chlorosis, blotchy mottle and vein yellowing were collected in the Mexican States of Nayarit, Colima and Sinaloa between August 2011 and September 2012. Samples were then evaluated for phytoplasmas and CLas by PCR, using primers that respectively target the genes for the 16S ribosomal RNA and 50S ribosomal protein of the β operon (rplA-rplJ). Out of 86 HLB-symptomatic citrus plants, 54 were positive for CLas, 20 were positive for phytoplasmas, 7 were found in mixed infections with both pathogens and 19 samples were negative for CLas and phytoplasmas. Actual and virtual RFLP analyses of the 16S rDNA sequences enabled us to classify two HLB phytoplasma strains as members of the aster yellows group (16SrI) ‘Candidatus Phytoplasma asteris’, which was confirmed by phylogenetic analysis. The HLB phytoplasma strain identified from Nayarit (HLBpc-Nay-IB) belongs to subgroup B (16SrI-B), and the strains identified from Colima (HLBpc-Col-IS) and Sinaloa (HLBpc-Sin-IS) belong to subgroup S (16SrI-S). The partial ‘Ca. L. asiaticus’ rplA-rplJ gene sequences were 100% identical to the ‘Ca. L. asiaticus’ strains isolated from several countries affected by HLB. These results confirm the association of ‘Candidatus Phytoplasma asteris’ with HLB-like symptoms in citrus groves in Mexico. Nonetheless, further studies are required to fully describe the ‘Ca. L. asiaticus’ and ‘Ca. P. asteris’ interactions in citrus, which will greatly assist the design of efficient management strategies.

Discovery of Hyptis pseudolantana in Jalisco and Michoacán, and description of H. cualensis and H. macvaughii (Ocimeae, Lamiaceae), two new species from western Mexico

The distribution of Hyptis pseudolantana is documented in the states of Jalisco and Michoacán, species previously reported exclusively from the state of Guerrero, Mexico. An expanded description, distribution map and photographs are provided for it. Hyptis cualensis and H. macvaughii are also described and illustrated by photographs, as two new species from the Mexican states of Jalisco and Nayarit, respectively. Also, an identification key to species of tribe Hyptidinae in western Mexico is provided.

Evidence of oceanic dispersal of a disjunctly distributed amphidromous shrimp in Western North America: first record of Macrobrachium occidentale from the Baja California Peninsula

Six morphological species of the genus Macrobrachium occur in the Baja California Peninsula (M. americanum, M. digueti, M. hobbsi, M. michoacanus, M. olfersii, and M. tenellum). Their presence is an interesting topic for the systematics of the group, given that their distribution shows a distinct disjunct on the coastal plains of the northern part of the Gulf of California slope. Extensive collection of freshwater shrimp of the peninsula allowed us to discover individuals whose morphology corresponds to Macrobrachium occidentale Holthuis, 1950. This species, described in 1950 from the Pacific slope of Central America has received little atention. The type locality is in Guatemala, but it is also found in Mexico, El Salvador, Costa Rica, and Panama. In Mexico it has been reported in the states of Sinaloa, Nayarit, Guerrero, and Oaxaca. The aim of the present work is to contribute to the systematics of M. occidentale through two approaches. First, by reviewing the geographical distribution in Mexico, using taxonomic morphological revision of extensive field collections, as well as material deposited in three scientific collections. Second, through molecular genetic analysis of fragments of the mitochondrial genes 16S rRNA and cytochrome oxidase I, determine whether individuals from the peninsula belong to the same entity found on the mainland Pacific slope of Mexico or whether they form a distinct lineage. The results indicate the presence of the same genetic entity in both regions and show a disjunct distribution similar to other species of the genus in this region. We present a systematic account for M. occidentale, including a taxonomic treatment of the studied populations and a report of their genetic identity and relationships. Further, we suggest and discuss that the presence of this amphidromous species on the peninsula is explained by the oceanic dispersal hypothesis.

Nuevos registros de distribución para la rana ladrona pigmea Craugastor pygmaeus (Terrarana: Craugastoridae) en el occidente de México

We provide data on 10 new records that expand the geographic range of the pigmy robber frog into the states of Jalisco, Nayarit, and Sinaloa.

Determination of aflatoxin and fumonisin levels through ELISA and HPLC, on tilapia feed in Nayarit, Mexico

A survey of fungal contamination and presence of aflatoxins (AFs) and fumonisins (FBs) in 30 feed samples collected from 10 tilapia farms during three seasons in Nayarit State, located in north-western Mexico, was carried out using ELISA as screening and High-Performance Liquid Chromatography (HPLC) as confirmatory method. Mycobiota included Aspergillus flavus and Fusarium spp. AFs were detected in 63.3% of samples using ELISA, but confirmation by HPLC revealed that all samples were under the detection limit. Regarding to FBs, positive samples were detected using both methods, with 19 positive samples (60% of total) by ELISA and 14 positive samples (46.6% of total) by HPLC and levels ranging from 0.148 to 2.587 mg/kg. Correlation was observed between both methods (r = 0.516, p = 0.004) for FBs results. No sample exceeded the European maximum levels for any of the mycotoxins. Water activity of samples ranged from 0.345 to 0.655, suggesting that mycotoxin occurrence is probably related to raw material contamination.

Noteworthy records of mammals (Mammalia) from Durango and Nayarit states, Mexico

The bats Glyphonycteris sylvestris and Glossophaga leachii, as well as the margay(Leopardus wiedii) and spotted skunk (Spilogale gracilis) are reported for the first time for the states of Durango and Nayarit, respectively. Additionally, the presence of the mouse opossum Tlacuatzin canescens is confirmed in Durango over 100 years after it was recorded for the first time

Elecciones del 3 de julio de 2011. La ausencia del discurso político

&lt;p&gt;El presente trabajo analiza la relación entre la falta de discurso político por parte de ciertos partidos y los resultados en las elecciones estatales y municipales en los estados de Nayarit, Coahuila, Estado de México e Hidalgo en el 2011. La debilidad de las estrategias internas, la falta de fortaleza política de los candidatos de la oposición y el estancamiento de su discurso generó momentos de oportunidad para el PRI que se reflejaron en votos.&lt;/p&gt;&lt;p&gt;Sin embargo, las reflexiones surgidas de éstos resultados no asignan directamente la victoria presidencial al PRI en el 2012, son tan sólo un punto de análisis sobre el camino que las fuerzas políticas tomen.&lt;/p&gt;

Pseudocercospora cruenta on Vigna unguiculata in Mexico

Cowpea is one of the most important grain legume crops worldwide. Although Pseudocercospora cruenta on cowpea was first observed in Mexico in 1976, this is the first documented report of this pathogen in Mexico. The fungus was isolated from symptomatic cowpea leaves collected from Nayarit state, Mexico and identified on the basis of morphology and sequence analysis of the internal transcribed spacer (ITS). Pathogenicity was verified on cowpea plants.

A new species of Peltidium Philippi, 1839 (Crustacea, Copepoda, Harpacticoida) from the Pacific coast of Mexico

During the analysis of phytal meiobenthic samples collected from a rocky-sandy beach in the state of Nayarit, in the Mexican Pacific, several specimens of harpacticoid copepods were obtained and taxonomically examined. These specimens were found to represent an undescribed species of the peltidiid genus Peltidium Philippi, 1839. The new species, Peltidium nayarit sp. n. is described herein. It resembles Peltidium nichollsi Geddes and Peltidium lerneri Geddes from Bahamas but also the widespread Peltidium speciosum Thompson & Scott and Peltidium purpureum Philippi. The new species from the Mexican Pacific differs from its known congeners by its possession of a unique combination of characters, including a modified pectinate seta on the antennary exopod, three terminal setae on the second endopodal segment of leg 1, third exopodal segment of leg 1 with three elements, inner terminal claw twice as long as outer claw, female fifth leg with 5 exopodal setae, exopodal setae I-III stout, spinulose and seta IV being as long as seta V. This is the second species of the family known to be distributed in the Eastern Tropical Pacific and in Mexico. Pending additional data, the distribution of this species appears to be restricted to this area of the Mexican Pacific.

Echeandia novogaliciana and E. crudeniana (Anthericaceae): Two new species from western Mexico

Echeandia novogaliciana and E. crudeniana are described from western Mexico. Echeandia novogaliciana is known from three populations, one in the state of Nayarit and two in Zacatecas. Likewise, E. crudeniana is known from two populations in the municipality of Bahia de Banderas, Nayarit. For both species, illustrations are provided and morphological relationships with similar species are discussed.

Revision of the Mesoamerican Genus &lt;i&gt;Cataractocoris&lt;/i&gt; Usinger (Hemiptera: Heteroptera: Nepomorpha: Naucoridae)

The genus Cataractocoris includes large waterfall-inhabiting insects that occur from Mexico to El Salvador and has received very little attention in the literature. Based on extensive field work during the past three years, we have collected saucer bugs (Heteroptera: Naucoridae) from many localities in central and southern Mexico. We here present detailed distributions and diagnostic information of the two described species of Cataractocoris and the description of a third species that occurs from Nayarit state in Mexico south to Guatemala. An illustrated taxonomic key to identify the species also is presented.

Economic risk associated with white spot disease and stochastic variability in economic, zootechnical and water quality parameters for intensive production of Litopenaeus vannamei

AbstractA bio‐economic model was used to analyse the risks of intensive production of shrimp and to propose alternative schemes of risk management by controlling aeration, pond size, stocking density and duration of cultivation. The model was calibrated from databases of farm operations in the State of Nayarit, Mexico. Improving management allowed us to project an increase in the annual net revenue from $3900 to $26 600 ha−1 and to improve the benefit–cost ratio from 1.14 to 1.55. Managing an early start of aeration, small‐sized ponds, high stocking densities and long cultivation periods maximized economic outcomes. Operating a small farm (consisting of a single 2.5 ha pond) involves more risk than operating a large one (50 ha, consisting of 20 ponds of 2.5 ha each). Improving management also resulted in diminished risk, as indicated by increased values of return per unit risk from 0.14 to 0.21 or from 0.42 to 0.51 (depending on farm size). From sensitivity analysis, we concluded that small ponds are recommended for intensive production of Litopenaeus vannamei and that white spot disease is a major risk factor that can be partly controlled by managing dissolved oxygen levels and aeration.

Potential Distribution in Mexico ofDiaphorina citri(Hemiptera: Psyllidae) Vector of Huanglongbing Pathogen

Huanglongbing (HLB), the citrus disease associated with the bacteria ‘Candidatus Liberibacter asiaticus’, is the most important threat of the Mexican citrus industry. Since 2009, this bacterium has been detected in 11 out of 23 citrus producing states of the country, although with a limited distribution in each state. The Asian citrus psyllid (Diaphorina citri Kuwayama [Hemiptera: Psyllidae]) is the vector of this bacterium; the insect is distributed in all the citrus growing zones of Mexico. Presently, the lime production zone in the Mexican states of Colima, Jalisco, Michoacán, Nayarit, and Sinaloa, near to the Pacific Ocean coast, is the most affected by this disease. One of the main strategies to retard or stop the advance of HLB consists in the regional management of the psyllid populations. In order to contribute to the support of this strategy we analyzed the daily courses of temperature and rainfall all over the country to classify the citrus zones according to the probability of occurrence of favorable conditions for rapid and continuous psyllid reproduction. The results indicate that one of the most important regions of sweet orange production of Mexico, southern Veracruz and the region named “La Huasteca”, where the states of Veracruz, Tamaulipas, San Luis Potosi and Hidalgo converge, represent the zones with the highest risk for an accelerated reproduction of the psyllid. At present these regions remain free of the bacterium and are considered of highest priority for the management of psyllid populations and for preventing the entry and establishment of HLB.