Pacific Coast Of Mexico Research Articles

Description of a new species of Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) a parasite of Dormitator latifrons from Southwestern Mexico based on morphological and molecular characters

Neoechinorhynchus mamesi n. sp. is described from the estuarine fish Dormitator latifrons collected in 3 localities along the coast of Chiapas State in Southwestern Mexico. The new species is characterized by possessing a small trunk, a very small proboscis with relatively very long apical proboscis hooks and small middle and posterior hooks, 2 giant nuclei in the ventral body wall, and males with testes smaller than the cement gland. A multivariate analysis of variance (MANOVA) and a Principal Component Analysis (PCA) of 46 morphometric traits for 21 mature females and 18 males of N. mamesi n. sp., N. brentnickoli and N. golvani, revealed morphological variation among species. DNA sequences of 2 genes, cytochrome oxidase subunit 1 (cox 1) of the mitochondrial DNA and the domains D2 and D3 of the large subunit of the nuclear ribosomal RNA (LSU) were used to corroborate the morphological distinction. The genetic divergence estimated among populations of N. brentnickoli and N. mamesi n. sp. ranged from 10.14 to 10.55% for LSU and from 20.53 to 22.06% for cox 1, whereas the genetic divergence between N. golvani and N. mamesi n. sp. ranged from 20.31 to 21.03% for LSU and from 22.24 to 24.95% for cox 1. Maximum likelihood, maximum parsimony and Bayesian inference analyses were performed for the combined data sets (LSU+cox 1) and each data set alone. All the phylogenetic analyses showed that the specimens from 3 coastal lagoons of Chiapas State in Southwestern Mexico represented a monophyletic clade with strong bootstrap support and Bayesian posterior probabilities. The haplotype network based on the analysis of the cox 1 sequences indicated that N. mamesi n. sp. is separated by 84 substitutions from N. brentnickoli, and with 69 substitutions from N. golvani. The morphological evidence, the multivariate analyses, in combination with the genetic divergence estimated with two genes, the reciprocal monophyly in all the phylogenetic analyses, and the haplotype network, suggested that the acanthocephalans found in the intestine of D. latifrons in Southwestern Mexico represent a new species, named N. mamesi n. sp., and it constitutes the second species of the genus Neoechinorhynchus associated with the Pacific fat sleeper along the Pacific Coast of Mexico.

<p align="left"><strong>A new species of <em>Pyropia</em> (Rhodophyta, Bangiaceae), from the Pacific coast of Mexico, based on morphological and molecular evidence</strong></p>

Pyropia raulaguilarii sp. nov. is described from Michoacán, tropical Mexican Pacific, on basis of comparative morphology and nrSSU, rbcL sequence analysis. It is distinguished from other Pyropia species by the foliose and lanceolate gametophyte, a monoecious thallus and the zygotosporangia in packets of 2x2x4. The phylogenetic analysis showed that the two Pacific Mexican samples, from Caletilla and Carrizalillo (Michoacán), were almost identical and formed a distinctive and well supported clade segregated from other species of Pyropia from Brazil, USA and Mexico. The Mexican entity is morphologically and genetically distinct from other Pyropia species, suggesting that this species should be assigned to a new taxon.

A New Species of Leptogorgia (Cnidaria: Anthozoa: Octocorallia) from the Mexican Pacific Coast

The gorgoniid genus Leptogorgia is found along the Pacific coast of Mexico; 10 species have been reported from Baja California and Acapulco. Leptogorgia ena sp. nov. is a new shallow-water species found at 5-12 m depth at various high energy rocky sites along the coast of San Pedro Pochutla District, Oaxaca. Specimens of the new species were collected by scuba diving and the morphological characters were analyzed and illustrated under light and scanning electron microscopy. The new species can be distinguished from the others by the very small colony, dominance of wide capstans, barrels and double heads, low occurrence of spindles, spindles measuring < 0.10 mm, and presence of tentacular sclerites. With this report, the genus Leptogorgia increases to 11 species for Mexico and 26 for the eastern Pacific.

Juvenile megamouth shark, Megachasma pelagios, caught off the Pacific coast of Mexico, and its significance to chondrichthyan diversity in Mexico

On 16 November 2006, a female juvenile megamouth shark, Megachasma pelagios, was caught off the coast of Mexico in the Pacific Ocean, near Sebastián Vizcaíno Bay. This specimen, that has informally been referred to as “Megamouth No. 38”, measured 2265 mm in total length. It represents the third smallest female recorded for this taxon and the first report of M. pelagios off the Pacific coast of Mexico. The specimen is formally described here with basic anatomical data, and some aspects of this megamouth shark are compared with those of previously reported M. pelagios specimens. The occurrence near Sebastián Vizcaíno Bay is significant because it further emphasizes the high elasmobranch diversity in the area that should be regarded as a key region for shark conservation.

285 A comparative study of the modern dinocyst assemblages from the Pacific coast of Mexico (15° N to 25°N) and the Gulf of Mexico (17° N to 29°N)

285 A comparative study of the modern dinocyst assemblages from the Pacific coast of Mexico (15° N to 25°N) and the Gulf of Mexico (17° N to 29°N)

Population Size of Snowy Plovers Breeding in North America

Snowy Plovers (Charadrius nivosus) may be one of the rarest shorebirds in North America yet a com- prehensive assessment of their abundance and distribution has not been completed. During 2007 and 2008, 557 discrete wetlands were surveyed and nine additional large wetland complexes sampled in Mexico and the USA. From these surveys, a population of 23,555 (95% CI = 17,299 - 29,859) breeding Snowy Plovers was estimated. Com- bining the estimate with information from areas not surveyed, the total North American population was assessed at 25,869 (95% CI = 18,917 - 32,173). Approximately 42% of all breeding Snowy Plovers in North America resided at two sites (Great Salt Lake, Utah, and Salt Plains National Wildlife Refuge, Oklahoma), and 33% of all these were on wetlands in the Great Basin (including Great Salt Lake). Also, coastal habitats in central and southern Texas supported large numbers of breeding plovers. New breeding sites were discovered in interior deserts and highlands and along the Pacific coast of Mexico; approximately 9% of the North American breeding population occurred in Mexico. Because of uncertainties about effects of climate change and current stresses to breeding habitats, the spe-

Genetic Connectivity Patterns of CoralsPocillopora damicornisandPorites panamensis(Anthozoa: Scleractinia) Along the West Coast of Mexico

Abstract: Genetic connectivity was studied in two scleractinian corals, Pocillopora damicornis (branching and broadcast spawner) and Pontes panamensis (massive and brooding type), along the Pacific coast of Mexico. Allelic diversity between adults and juveniles, the latter recruited after the El Nino—Southern Oscillation (ENSO) 1997–1998 event, was determined, and level of genetic connectivity among populations was assessed. There were no significant differences in allelic diversity between adults and juveniles from the same location. Seascape spatial genetic analysis suggested two or three clusters, depending on the species: (1) Bahias de Huatulco, (2) south of the Baja California Peninsula and Bahia de Banderas, and (3) locations in the Gulf of California. The most important barrier to gene flow was detected between Bahia de Banderas and Bahias de Huatulco and corresponds with a major coastal stretch of sandy beaches and lagoons. Moderate to high gene flow was found inside and at the entrance of the Gul...

The Economic Effects of Intense Rainfall in Central States of the Pacific Coast of Mexico: Global Warming Impacts on Agriculture

The Economic Effects of Intense Rainfall in Central States of the Pacific Coast of Mexico: Global Warming Impacts on Agriculture

Population connectivity among geographic variants within the Lutjanidae (Pisces) of the Mexican Pacific coast through fish scale shape recognition

Fish scale shape was used to identify geographic variants among Lutjanidae ( Lutjanus argentiventris, L. guttatus and L. peru ). Specimens were collected from three different geographic areas, north to south of the tropical Pacific coast of Mexico: Puerto Vallarta (PV), Manzanillo (MA) and Caleta de Campos (CC). Configuration of landmark coordinates of fish scales were scaled, translated and rotated using generalized procrustes analysis, followed by principal components analysis of resulting shape coordinates. Principal component scores were submitted to cross-validated discriminant analysis to determine the efficacy of scale landmarks for discrimination by geographic variants. This was done with shape and form (shape plus size). PV and MA were recognized as one population different from the CC sampling area. Using only shape (without size), identification rates predicted geographic variant membership much better than chance (91.3%, 70.6% and 85.4% for L. argentiventris, L. guttatus and L. peru , respectively), and taking size into account, classification is somewhat improved (90.6%, 80.1% and 87.5% for L. argentiventris, L. guttatus and L. peru , respectively). Consistency of the two populations for the three species shows non-fortuitous events. Population discrimination confirmed previous genetic studies that show a zoogeographic barrier between the North Equatorial Current and the California Current. The method is non-destructive, fast and less expensive than genetic analysis, thus allowing screening of many individuals for traceability of fish.

Extreme wave deposits on the Pacific coast of Mexico: Tsunamis or storms? — A multi-proxy approach

Historical and instrumental data show that the Pacific coast of Mexico has been exposed to destructive tsunamis over at least the past 500 years. This coast is also affected by hurricanes generated in the eastern Pacific. The great 1985 Mexico earthquake and its aftershock generated tsunamis that affected the Ixtapa–Zihuatanejo and Michoacán coast. The purpose of our study was two-fold — a) to determine whether storm and tsunami deposits could be distinguished, and b) whether tsunami deposits from historical events are preserved in the tropical environments of the Ixtapa–Zihuatanejo coast. Two anomalous sand units in the Ixtapa estuary are interpreted to be the result of high-energy marine inundation events that occurred in the last century. Several lines of evidence using a multi-proxy approach (historical studies, interviews with local witnesses, geomorphological and geological surveys, coring and trenching, laboratory analyses including grain size, micropaleontology, geochemistry, magnetic susceptibility and radiometric dating, and numerical modeling) indicate the occurrence of two tsunamis that we link to local events: the 21st September 1985 Mexico and possibly the 14th March 1979 Petatlan earthquakes. We thereby provide the first onshore geological evidence of historical tsunamis on the Pacific coast of Mexico.

Epibionts Associated with the Nesting Marine Turtles Lepidochelys olivacea and Chelonia mydas in Jalisco, Mexico: A Review and Field Guide

ABSTRACT The diversity and frequency of epibiota collected over three years (2001, 2002, 2008) from sea turtles (Lepidochelys olivacea and Chelonia mydas) nesting on Teopa Beach in Jalisco State, Mexico, are described. This diversity is compared to epibiotic assemblages procured from these same turtle species nesting on other Mexican beaches, and the role these turtles play in the conservation and dispersal of these epibiota is discussed. Given the increased awareness of epibionts and the desire of many researchers to make positive identifications, specific diagnoses, photographs and a collecting protocol will serve as a basic aid to the collection and accurate identification of epibionts found on turtles living along the Pacific coast of Mexico.

Deep-water Asteroidea (Echinodermata) collected during the TALUD cruises in the Gulf of California, Mexico

During a series of cruises aboard the R/V “El Puma” aimed at collecting the deep-water benthic and pelagic fauna off the Pacific coast of Mexico, in the eastern Pacific, samples of Asteroidea were collected below 500 m depth (587-1 526 m). A total of 335 specimens were collected, belonging to 18 species, 14 identified to species, 3 to genus, and 1 previously undescribed species. New records are provided for Dipsacaster laetmophilus Fisher, 1910, Myxoderma sacculatum (Fisher, 1905), Peribolaster biserialis Fisher, 1905, Ampheraster chiroplus Fisher, 1928, Ampheraster hyperoncus (H. L. Clark, 1913), Anteliaster coscinactis Fisher, 1923, Nearchaster aciculosus (Fisher, 1910), Ceramaster leptoceramus (Fisher, 1905), Mediaster transfuga Ludwig, 1905, and Lophaster furcilliger Fisher, 1905. All species were collected below the oxygen minimum zone that extends throughout the central and southern Gulf of California, or within the threshold zone where severe to mild hypoxic conditions prevail. Epibenthic dissolved oxygen concentrations associated with the capture of the specimens show support for strong tolerance to severe hypoxia (<1.0 ml O2/l) for most species, but only mild hypoxia for Ctenodiscus crispatus (Retzius, 1805), and Nymphaster diomedeae Ludwig, 1905. A checklist of all species of Asteroidea occurring below 500 m depth off the Pacific coast of Mexico is included.

Evidencias ambientales de cambios de nivel de la costa del Pacífico de México: terremotos y tsunamis

The study of prehistoric earthquakes and tsunamis using environmental evidence of coastal level changes, where sudden changes from terrestrial to marine environments, and vice versa, and where tsunami deposits are preserved, has provided valuable information in the earthquake and tsunami hazard assessment. The Pacific coast of Mexico is tectonically active and has experienced numerous large magnitude earthquakes (M > 7.5) in historical times, frequently accompanied by coastal-level changes and tsunamis (> 50 tsunamis recorded since 1732). Using the case study of tropical lagoons and marshes on the Guerrero coast, it is shown the feasibility of recording tectonically induced coastal level changes through the proxy method that integrates geomorphic, stratigraphic, geochemical, microfossil, and radiometric data. The applied method confirms evidence for environmental changes indicative of coastal subsidence and a potential great earthquake and tsunami by ca. 3400-3500 yr BP. In general, most of the Holocene relative sea-level changes observed obscure any climatic signal in this period on the Mexican Pacific coast

Demography, Development and Control of the Coastal Space on the Pacific Coast of Mexico

During the four final decades of the last century, demographicgrowth in Mexico slowed significantly. This trend continued during the firstdecade of the 21st century, in tune with current expectations in the country.However, during precisely the same decades, the opposite phenomenon hasbeen occurring in the country’s coastal territories, i.e. demographic growthresulting not from an increase in average birth rates, which have followedmore or less the same trends as among the rest of the country’s inhabitants,but from immigration into these areas. This phenomenon is of itself reliableproof of the growth in investment of both public and private capitalin coastal territories. The only exception to this trend is provided by threecoastal municipalities in the state of Sinaloa, created in the early 1990s andtaken over, literally, by drug-trafficking activities. The vast majority of thesenew inhabitants of the Mexican coastlines are people who have arrivedfrom inland in search of jobs, in the hope of improving their lives. For thenew «costeños», life in these latitudes is completely different to that whichthey had experienced in their previous homes, whether in the plateau orthe central plain, the deserts of the north, the limestone country of the interiorof the Yucatán peninsula or the tortuous hillsides of the mountains:new rhythms and ways of working, different local eating habits and modesof dress, unknown climatic phenomena and their consequences for dailylife, strange idiomatic expressions, and finally the exotic affection of the native «costeños» for their countryside and their local flora and fauna. Toanalyse the case study, we propose the concept of the «coastal region». Weuse demographic information both at national level and from the coastalstates and municipalities, taken from national censuses of population andhousing done in the decades from 1950 to 2010, published by the InstitutoNacional de Estadísticas, Geografía e Informática (National Institute ofStatistics, Geography and it, inegi), as well as photographs from variousarchives and from the author’s collection. It is not appropriate to talk of an«experimental design» in this work, since it is not an «experiment» but anattempt to explain what has been happening among the inhabitants of theMexican coasts on the basis of the developing situation over some 50 yearsof constant colonisation.

Two New Species of the Marine Littoral Springtail Genus Spinactaletes (Collembola: Actaletidae) from Costa Rica

Spinactaletes is a genus of obligatory marine littoral springtails characterized by marked sexual dimorphism. males of most Spinactaletes species have spur- like sclerotized structures on the metathoracic legs, and many modified setae on the antennae that form the basis for almost all species level diagnostic characters. females of most species have been impossible to identify when collected in isolation. The current distribution of the genus is restricted to the antilles, Venezuela, and the pacific coast of mexico. however, this distribution is undoubtedly an artifact of collection effort. in this contribution, we report Spinactaletes for the first time from central america (costa rica) and draw attention to the utility of the chaetotaxy of the internal metatibiotarsal face in the identification of females. we collected costa rican Spinactaletes at three localities on the caribbean coast and at one locality on the pacific coast. The material from the caribbean coast includes new species, Spinactaletes campylorachis sp. nov. and Spinactaletes deltalus sp. nov., herein described. from the pacific coast, we collected two females and a juvenile showing unique metatibiotarsal chaetotaxy, but formal description of the species is deferred until their males are found. phylogenetic analysis of actaletidae species, using morphological data, supports the basal position of actaletes neptuni giard, 1889 and Spinactaletes nemyops (soto-adames, 1987), but it cannot resolve relationships among species of Spinactaletes with metatibiotarsal spur. we suggest that molecular data will be needed to provide the phylogenetic backbone required to study character evolution and biogeography in this group.

Field survey report on the 11th March 2011 tsunami in Pacific coast of Mexico

On March 11 of 2011, an earthquake of magnitude 9.0 at 05:46:23 UTC triggered a basinwide tsunami in the Pacific Ocean with a wave height of 10 m or more. The maximum inundation limit was approximately 6 km or more in the east coast of Japan causing the death of more than 10,000 people. This mega earthquake mechanism was caused in the reverse fault region with WNW-ESE compressional axis, and it characterized by an inverse fault with slip of 30–40 m. Its epicenter was located at a distance of 129 km east of Sendai (Honshu, Japan) at a depth of 32 km (http://earthquake.usgs.gov/earthquakes/ eqinthenews/2011/usc001xgp/#details). Subsequently, after the earthquake, the tsunami hit the east coast of Japan and a worldwide alert was issued to more than 24 countries all along the Pacific coast. The tsunami waves travelled a distance of more than 10,000 km to reach west coast of Mexico in Pacific Ocean. The tidal gauge monitors of Institute of Geophysics, National Autonomous University of Mexico (UNAM) reported that the tsunami waves arrived at 19:12 h GMT at Mazatlan (Sinaloa state), 19:41 h GMT at La Paz (Baja California Sur state), 19:58 h GMT at Zihuatanejo (Guerrero state), and 20:12 h GMT at Acapulco (Guerrero state). The maximum wave amplitude identified from the tidal gauge monitors were 0.5 m at La Paz, 0.4 m at Mazatlan, 3.2 m at Zihuatanejo, and 1.8 m at Acapulco.

Deep-water Holothuroidea (Echinodermata) collected during the TALUD cruises off the Pacific coast of Mexico, with the description of two new species

Research cruises aboard the R/V “El Puma” were organized to collect deep-water benthic and pelagic specimens off the Pacific coast of Mexico. Seventy four specimens of Holothuroidea were collected off the Pacific coast of Mexico in depths of 377-2 200 m. The collection includes representatives of 5 of the 6 orders of Holothuroidea, 3 Dendrochirotida, 2 Dactylochirotida, 2 Aspidochirotida, 4 Elasipodida and 2 Molpadiida. Apodida were not represented. Of the 13 species recognized, 11 were identified to species level and 2, belonging to the genera Ypsilocucumis Panning, 1949, and Mitsukuriella Heding and Panning, 1954, are new to science. Five species represent new geographic or depth records. A list of Mexican localities previously and newly reported for each species are plotted on distribution maps. Environmental data, i.e., depth, temperature, and dissolved oxygen measured at the bottom level during the survey are provided. When compared with other areas of the world, the reduced number of specimens collected during this survey could be linked to the limiting effect of the Pacific Mexico Oxygen Minimum Zone. An updated checklist of species of Holothuroidea recorded below 350 m depth along the Pacific coast of Mexico is also provided totaling 31 species: 13 of these occur in the California Current area, 20 in the Gulf of California, and 15 (16) along the SW coast of Mexico.

Discordant patterns of geographic variation between mitochondrial and microsatellite markers in the Mexican black iguana (Ctenosaura pectinata) in a contact zone

To delimit the distribution of matrilines of the black iguana (Ctenosaura pectinata), detect potential contact zones between them, and test the hypothesis of geographic concordance in the structuring of matrilines with respect to genetic structuring across the nuclear genome. Pacific coast of Mexico in the states of Nayarit, Jalisco, Colima, Michoacan in the lowlands adjacent to the western end of the Mexican Volcanic Belt. Tissue samples were obtained every 10–20 km along a transect across the range of three previously described mitochondrial DNA (mtDNA) clades of C. pectinata. Iguanas were genotyped with 11 nuclear microsatellites and maternal lineages were inferred based on mtDNA sequences. Geographic structure and geographic concordance between biparentally and maternally inherited markers were analysed with clustering methods, FST and NST indexes as well as haplotype networks. Geographic structure was evident for both markers and the existence of contact zones confirmed. Nevertheless, the distribution of nuclear and mtDNA genetic variation is not geographically concordant. Four matrilines exist in the area, whereas only two nuclear clusters occur. A contact zone between nuclear clusters extends along a distance of c. 60 km, and introgression is evident in individuals from several localities. High levels of genetic diversity were detected on the western coast of Mexico. Historical and contemporaneous processes seem to shape the distribution of genetic variation in C. pectinata. There are no evident geographic, environmental or ecological barriers that coincide with genetic subdivisions, and the observed mtDNA structure is likely to be the result of past climatic changes. The less structured distribution of nuclear genetic variation is consistent with the homogenizing effect of male-biased dispersal. Our findings have implications for the taxonomy and conservation strategies for this threatened species, and highlight the fact that geographic analyses of both cytoplasmic and nuclear genetic variation are important for the meaningful inference of evolutionary and demographic histories.

Metal concentrations in water and sediments from tourist beaches of Acapulco, Mexico

A survey on the metal concentrations (As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, Zn) in beach water and sediments is reported from the tourist destination of Acapulco city on the Pacific coast of Mexico. The concentration of dissolved trace metals (DTMs) in beach water and acid leachable trace metals (ALTMs) in sediments indicated that they are anthropogenic in nature due to the increased tourist activities in the crowded beach locations. The statistical analysis indicates Fe and Mn play a major role as metal scavengers in both the medium (water and sediment) and the higher value of other metals is site specific in the study area, indicating that they are transported from the local area. Comparison results suggest that the beach water quality has deteriorated more than the sediments and special care needs to be taken to restore the beach quality.

Oceanographic anomalies and sea-level rise drive mangroves inland in the Pacific coast of Mexico

Question: Although mangrove forests are generally regarded as highly threatened, some studies have shown that mangrove canopies in the Pacific coast of Mexico have been increasing in recent decades. We investigated the possible causes driving this reported mangrove expansion. Location: The mangrove lagoons of Magdalena Bay in Baja California, Mexico. Methods: We used 50-year-old aerial photographs and 24-year-old satellite images to compare long-term vegetation change, surveyed a coastal vegetation transect to analyse flooding levels, compiled six decades of tidal and oceanographic information, as well as hurricane data to analyse changes in storm frequency or sea-level conditions, and used isotopic analysis to date the age of trees along the gradient. Results: A significant increase in mangrove cover has occurred in backwaters of the lagoons during the last 40 years, and especially during the El Niño anomalies of the 1980s and 1990s, while at the same time the mangrove fringe has been receding. Conclusions: The observed change can be attributed to the combined action of the warm surface waters of El Niño events and sea-level rise. Jointly, these two effects are sufficient to flood large areas of previously non-flooded salt flats, dispersing mangrove seedlings inland. The inland expansion of mangroves, however, does not ease conservation concerns, as it is the seaward fringes, and not the inland margins, that provide the most valuable environmental services for fisheries and coastal protection.