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Theridiidae is a family of spiders with the fourth highest richness of extant species worldwide. Fossil Theridiidae is also the family of spiders with the largest number of Cretaceous, Eocene, and Miocene representatives. Phycosoma Pickard-Cambridge, 1880 is a theridiid genus without a fossil representative. In this study, we describe a new fossil species of Phycosoma, P. icti† n. sp., from an adult male specimen found in a piece of amber from the lower Miocene (ca. 23 Ma), from the Montecristo mines near Simojovel de Allende, Chiapas, Mexico. Phycosoma icti† n. sp. can be distinguished from all other Phycosoma males except P. corrugum by the long embolus partly covered by the conductor. In addition, it can be distinguished from P. corrugum by the oblique and constricted median apophysis; the narrow and pointed conductor; the long, curved, and bent theridiid tegular apophysis in its distal portion; and the prosoma ringed in the middle and along the ventral margin. Phycosoma icti† n. sp. represents the oldest recovered record of the genus. Extant Phycosoma species are still present in Chiapas, suggesting an extended evolutionary history of the genus in the region despite major geological changes over this time span in North America.UUID: http://zoobank.org/28d74f14-0f80-405d-a165-f24749e15d05

Introduction: The specialized root systems of mangroves provide protection and food resources for young and small fish, and it is known that they are reflected on some health condition and growth characteristics of the fish, but much remains to be learned about this subject in the tropics. Objective: To estimate length-weight relationships for ten bony fish species in two tropical mangroves and to compare the allometry and health condition for three species shared among those mangroves. Methods: Between May and November 2019, we collected 1 500 fish specimens from the roots of two mangroves in Chiapas, Mexico (1 322 fishes in stilt-roots and 188 in pneumatophores). We estimated Length-Weight relations with W=aSLb, and the regression parameters (a and b) were calculated by least-squares; as well as univariate analyses to compare standard length, regression slopes, and relative condition among individuals of Poecilia nelsoni, Poeciliopsis fasciata and Dormitator latifrons. Results: The standard length for all species ranged between 0,7 and 21,5 cm and weight between 0,01 and 209,34 g; the regression b-values varied from 2,844 for P. fasciata and 3,847 for Poeciliopsis pleurospilus. TDetermination coefficients were >0,9 for eight species in stilt-roots and for three species in pneumatophores. Specimens of three species collected in both microhabitats were smaller in pneumatophores than in stilt-roots and also differed in b-values; however, the relative health condition was higher only in P. fasciata. Conclusion: The intrinsic conditions of stilt-roots and pneumatophores influence the average size and allometry of fishes at this site. The relative condition does not vary between microhabitats for most species, but may reflect development strategies associated with the environment. Introducción: Los sistemas radiculares de los manglares brindan protección y recursos alimenticios para peces jóvenes y pequeños, y se sabe que se ven reflejados en algunas condiciones de salud y características de crecimiento de los peces, pero queda mucho por aprender sobre este tema en los trópicos. Objetivo: Estimar las relaciones talla-peso de diez especies de peces óseos en dos manglares tropicales y comparar la alometría y el estado de salud de tres especies compartidas entre esos manglares. Métodos: Entre mayo y noviembre de 2019 recolectamos 1 500 ejemplares de peces de las raíces de dos manglares en Chiapas, México (1 322 peces en raíces aéreas y 188 en neumatóforos). Estimamos relaciones Longitud-Peso con W=a SLb, y los parámetros de regresión (ayb) por mínimos cuadrados; y usamos análisis univariados para comparar la longitud estándar, las pendientes de regresión y la condición relativa entre individuos de Poecilia nelsoni, Poeciliopsis fasciata y Dormitator latifrons. Resultados: La longitud estándar para todas las especies osciló entre 0,7 y 21,5cm y el peso entre 0,01 y 209,34g; los valores b de la regresión variaron de 2 844 para P. fasciata hasta 3 847 para Poeciliopsis pleurospilus. Los coeficientes de determinación fueron >0,9 para ocho especies en raíces aéreas y para tres especies en neumatóforos. Los especímenes de tres especies recolectados en ambos microhábitats fueron más pequeños en neumatóforos que en raíces aéreas y también difirieron en los valores de b; sin embargo, el estado relativo de salud fue mejor solo en P. fasciata. Conclusión: Las condiciones intrínsecas de las raíces aéreas y los neumatóforos influyen en el tamaño promedio y la alometría de los peces en este sitio. La condición relativa no varía entre microhábitats para la mayoría de las especies, pero puede reflejar estrategias de desarrollo asociadas con el ambiente.

Diadromous fishes can exhibit interesting evolutionary and population-level patterns given their use of freshwater and marine environments as part of their life histories. The River goby genus Awaous are prominent members of riverine ichthyofaunas and occur throughout Atlantic and Pacific slopes of the Americas from the southern United States to Ecuador and Brazil. Here we study the widespread and polymorphic Awaous banana complex to assess phylogeographic patterns and test previous hypotheses that all populations of this species in the Americas belong to the same species. Analysis of sequence data based on the mitochondrial cytochrome oxidase I gene shows multiple clades within the Atlantic and Pacific basins, which correspond to previously described species. Additionally, haplotype analysis demonstrates unique and unconnected networks between these species. Within these clades we document biogeographic patterns that are congruent with results of other co-occurring diadromous species, as well as a novel biogeographic pattern for the region. Our results support the recognition of distinct species of Awaous in the Atlantic (A. banana and A. tajasica) and Pacific (A. transandeanus) basins. These results are concordant with previously established morphological characters permitting the separation of these species.

To accurately identify the species that make up the assemblage of the family Cichlidae in the Mexican state of Chiapas, we first updated the total species account (36 species) for the state and then created an identification key. For the distribution maps, the geographic records were projected using a geographic information system considering the layers of the two largest basins in the state (Grijalva and Usumacinta) and the Chiapas coast basin. The dichotomous key includes meristic, morphometric and coloration patterns that facilitate species identification present in the state. Rheoheros coeruleus (Stawikowski and Werner 1987) and Vieja breidohri Werner and Stawikowski 1987 are included in a key for the first time. The distributions of Paraneetroplus gibbiceps Steindachner 1864a, Rheoheros coeruleus, and Vieja zonata Meek 1905 in the state are mapped for the first time, and the range of 16 species was expanded. By updating and creating tools of great taxonomic use, we contribute to the study of this complex family with high morphological diversity.

Studies have been devoted to describing the diet of D. monticola. However, knowledge of how D. monticola utilizes food resources through ontogeny remains unknown. We characterized D. monticola general dietary patterns and tested for ontogenetic diet shifts. We also inferred on juvenile recruitment patterns. We examined the stomach contents of 120 specimens ranging in size from 20 to 154 mm in standard length (SL). To infer on recruitment periodicity, we examined the size of specimens deposited in museum collections to compile size frequencies by month. We assume that the occurrence of smaller-size class categories will shed light on their recruitment time. Our results show that D. monticola is an omnivore that largely feeds on aquatic insects but also includes detritus, terrestrial material, fishes and crustaceans. Our analysis did not detect strong changes in diet through ontogeny, instead some changes were detected but mainly on the percentage of some food items included at different size category classes. In regards to the recruitment periodicity, we found younger D. monticola (20–40 mm SL) throughout most of the year, suggesting that they may be reproducing for longer periods of time than those previously reported from Honduras.

The role of interspecific interactions in structuring low‐diversity helminth communities is a controversial topic in parasite ecology research. Most parasitic communities of fish are species‐poor; thus, interspecific interactions are believed to be unimportant in structuring these communities.We explored the factors that might contribute to the richness and coexistence of helminth parasites of a poeciliid fish in a neotropical river.Repeatability of community structure was examined in parasitic communities among 11 populations of twospot livebearer Pseudoxiphophorus bimaculatus in the La Antigua River basin, Veracruz, Mexico. We examined the species saturation of parasitic communities and explored the patterns of species co‐occurrence. We also quantified the associations between parasitic species pairs and analyzed the correlations between helminth species abundance to look for repeated patterns among the study populations.Our results suggest that interspecific competition could occur in species‐poor communities, aggregation plays a role in determining local richness, and intraspecific aggregation allows the coexistence of species by reducing the overall intensity of interspecific competition., The results of this work suggest that interspecific competition can occur in species‐poor, nonsaturated communities among specialist dominant species. Our analyses suggest also that aggregation is an important factor to determine local richness of parasites in fish populations and that intraspecific aggregation allows the coexistence of species in the same host population by means of reducing the overall intensity of competition.

Profundulus adani, new species, is described from the upper reaches of the Papaloapan River in the Mexican state of Oaxaca. The uniqueness of this new species is supported by morphological and molecular evidence. A combination of color patterns and counts separate P. adani, new species, from its congeners. Profundulus adani, new species, is distinguished from all congeners by the absence of a humeral spot in individuals larger than 45 mm SL. It can further be distinguished from P. balsanus, P. chimalapensis, P. kreiseri, P. oaxacae, P. parentiae, and P. punctatus based on the absence of series of dark dots on the sides of the body. Profundulus adani, new species, shows a faded dark band that extends from the tip of the operculum to the end of the caudal peduncle; this band is absent in P. balsanus and P. parentiae. The new species is described using specimens collected in the upper reaches of the Papaloapan River in the Mexican state of Oaxaca; geographically this represents a significant range expansion and extends the Atlantic slope northernmost limit of the Profundulidae.

The Central Chiapas Mud Turtle (Kinosternon abaxillare) is one of the least-studied turtles in Mexico. It is considered a microendemic, with a limited distribution in the Central Depression of Chiapas. In this article, we summarize its population ecology and provide a new assessment of its morphology from Villa Hidalgo, Chiapas, Mexico. We captured 168 individuals with 64 recaptures (232 total captures), and we report a population size of 231 individuals with a density of 700 turtles/ha (189 kg/ha standing crop biomass). The population showed a female-biased sex ratio (1:1.5) and the population structure was largely composed of adults. Finally, we provide a set of morphological measurements for all size classes and sexes of K. abaxillare for the first time. The plastral formula (relative lengths of midline plastral seams) was identical in all size classes and sexes (Ab > An > Gu > Hu > Fe > Pe). Females and males reached similar carapace length but not body mass. Further studies are needed to determine the overall conservation status of this range-restricted species.

Introduction:TheCyprinodontiformesare a group of secondary freshwater fishes widely distributed in El Salvador. Currently, many species of this group are usually incorrectly identified for lack of adequate tools. Additionally, their taxonomy and distribution have changed in recent years.Objective: To provide updated information about the taxonomy and distribution of El SalvadorCyprinodontiformesthrough identification keys, distribution notes, and general descriptions for all species.Methods: We carried out an extensive review of the literature, electronic databases, and museum specimens to generate a list of valid species present in El Salvador.Results:Eleven species in three families are confirmed:Profundulidae(two species),Anablepidae(one species), andPoeciliidae(eight species). We also include distribution data, both vertical and by main basins, and an illustrated guide.Conclusions: There are 11 species ofCyprinodontiformesin El Salvador and they can be found and identified with this article. Introducción:Losciprinodontiformesson un grupo de peces secundariosde agua dulce ampliamente distribuidos en El Salvador. Actualmente hay errores de identificación por falta de herramientas adecuadas; además, su taxonomía y distribución han cambiado en los últimos años.Objetivo:Proporcionar información actualizada sobre la taxonomía y distribución de losCiprinodontiformesde El Salvador a través de claves de identificación, notas de distribucióny descripciones generales para todas las especies.Métodos:Realizamos una revisión extensa de la literatura, bases de datos electrónicas y especímenes de museo para generar una lista de especies válidas presentes en El Salvador.Resultados:Se confirman once especies en tres familias:Profundulidae(dos especies),Anablepidae(una especie) yPoeciliidae(ocho especies). También incluimos datos de distribución, tanto vertical como por cuencas principales, y una guía ilustrada.Conclusiones:Existen 11 especies deCyprinodontiformesen El Salvador y se pueden encontrar e identificar con este artículo.&nbsp

Systematics of the genus Vieja is complex, with many morphologically similar species that have little genetic differentiation. Examination of additional morphological traits can be useful for clarifying their taxonomic status and evolutionary history. We analyzed morphological variation of bones in the oral jaw and lower pharyngeal jaw to determine if these structures permit delimitation of species and to study possible functional implications. Morphological differences were quantified from canonical variates analysis, MANOVA, and paired comparisons. Differences in the number of pharyngeal teeth in the lower pharyngeal jaw were determined using an ANCOVA. The shape of the premaxilla and lower pharyngeal jaw are best for differentiating between these closely related-species. Although the morphological variation between V. breidohri and V. hartwegi were most similar, the shape of the lower pharyngeal jaw contrasts in morphospace. Vieja bifasciata possesses more teeth in the lower pharyngeal jaw. Variation in this bones may effect jaw biomechanics. Morphological differences are in contrast with the little genetic differentiation observed. The geographic isolation of V. bifasciata is likely related to its morphological differentiation. The common ancestry of V. breidohri and V. hartwegi probably explains their small morphological divergence.

The data presented in this article are related to the research article entitled “Competition from sea to mountain: interactions and aggregation in low diversity monogenean and endohelminth communities in twospot livebearer Pseudoxiphophorus bimaculatus (Teleostei: Poeciliidae) populations in a neotropical river.” accepted for publication in Ecology and Evolution. The data describes the communities of helminth parasites in 11 populations of a small poeciliid freshwater fish Pseudoxiphophorus bimaculatus (Heckel, 1848) sampled along the La Antigua river basin in Veracruz, Mexico. We examined 19 P bimaculatus from one locality, 21 from another locality, and 20 from each of the other nine locations sampled in June 2016. A total of 220 individual fish were examined, and in this paper we provide the data for 18 helminth parasite taxa recorded from them. The material in this Data paper comprised the raw data on the abundance, i.e. the number of helminth individuals of each of 18 taxa found in each one individual of P. bimaculatus from each of 11 localities. The data set is contained in a single text-table including one matrix containing each of the 220 host P. bimaculatus examined from 11 localities (lines). Measures for each host P. bimaculatus include total length, standard length, maximum deep and sex, documented for everyone fish examined, plus data of the number of individual helminth of each taxa collected by each examined fish are placed in the columns. These data might be used to examine spatial distribution of helminth parasite taxa. These data might be reused to examine the spatial variation in community structure of helminth parasites of freshwater fish. This kind of data could be used to provide an assessment of human environmental impacts, or for public awareness of conservation objectives.

Here we report the first record of the Mayan cichlid, Mayaheros urophthalmus, occurring on an offshore island 70 km from the mainland, the most distant record from the mainland to date. Specimens were collected during several ichthyological surveys on the island of Guanaja, Honduras in November 2019. Mayan cichlids are euryhaline fishes that perform very well in fresh, brackish and marine waters. It has been hypothesized that their high tolerance to salinity and potential of using costal waterways has facilitated the colonization and expansion of M. urophthalmus.

Loricariidae is the largest catfish family, with over 1000 species and 80 genera (Fricke & Eschmeyer, 2019). Sailfin catfishes of the genus Pterygoplichthys are armored catfishes, native to temperate and tropical areas of South America, especially the Amazon (Wakida-Kusunoki & del Angel, 2011). Two species of this genus (Pterygoplichthys pardalis (Castelanu, 1855) and P. disjunctivus (Weber, 1991)) are naturally distributed in South America along the lower, middle and upper basin of the entire Amazon River (Wakida-Kusunoki & del Angel, 2008). These armored catfishes, typified by the presence of ossified plates through the body, are considered very successful invaders of rivers and lakes outside their natural range. Their invasion success has been attributed to their morphology, behavior and life history. For instance, their ability to withstand droughts and cold weather by using burrows in river and lake banks they can survive in the moist habitat even when water levels decrease below the opening of the burrows, these survival characteristics of harsh conditions enable them to thrive in native and non-native grounds (Burgess 1989; Hoover & Killgore 2004; Nico & Martin 2001; Sandoval-Huerta et al. 2012). Furthermore, their rapid growth during their first years of life, their reproductive traits such as an extended reproductive period, high egg yield (Rueda-Jasso et al. 2013), and the capability of achieving reproductive maturity at smaller size (Wei et al. 2017) allow introduced populations to become abundant in a short period of time.

Despite their incredible diversity, relatively little work has been done to assess impacts of climate change on tropical freshwater organisms. Chortiheros wesseli is a species of Neotropical cichlid (Cichlidae: Cichlinae) restricted to only a few river drainages in the Caribbean-slope of Honduras. Little is known about this species and few specimens had been collected until recently; however, our work with this species in the wild has led to a better understanding of its ecology and habitat preferences making it an excellent model for how freshwater fishes can be affected by climate change. This study assesses the distribution and habitats of Chortiheros wesseli using a combination of field data and species distribution modeling. Results indicate this species is largely limited to its current range, with no realistic suitable habitat nearby. Empirical habitat data show that this species is limited to narrow and shallow flowing waters with rapids and boulders. This habitat type is highly influenced by precipitation, which contributed the greatest influence on the models of present and future habitat suitability. Although several localities are within boundaries of national protected areas, species distribution models all predict a reduction in the range of this freshwater fish based on climate change scenarios. The likelihood of a reduced range for this species will be intensified by adverse changes to its preferred habitats.

The Middle American killifish genus Profundulus occurs in most Pacific and Atlantic drainages from the Mexican state of Guerrero to the Chamelecon River in Honduras, with highest species diversity in southern Mexico. In this study, we describe a new member of the genus, Profundulus parentiae, new species, from the Mexican state of Oaxaca. It is distinguished from P. guatemalensis and P. kreiseri by having rows of dots on the sides of the body. Profundulus parentiae, new species, can be distinguished from P. oaxacae by having 33 lateral scales, versus 29–31 in P. oaxacae. Profundulus parentiae, new species, can be distinguished from P. balsanus, P. oaxacae, and P. mixtlanensis by the presence of long epiotic processes that extend beyond the epipleural ribs of the first vertebra, versus short epiotic processes not reaching the epipleural ribs of the first vertebra. Profundulus parentiae, new species, can be differentiated from P. punctatus by the presence of a dorso-ventrally compressed Meckel's cartilage w...

Introduccion: El estado de Chiapas ha ostentado el primer lugar de pobreza extrema en Mexico. La mayor parte de la poblacion de los municipios de Chiapas es indigena, vive en condiciones de marginacion y padece de diarrea de etiologia desconocida. Este trabajo evaluo el estado nutricional, la presencia de parasitos intestinales y patogenos bacterianos comunes, ademas de cepas DEC (Escherichia coli diarreogenica) en 178 ninos menores de cinco anos, provenientes de una localidad con alto grado de marginacion (rural) y de una con moderada marginacion (urbana). Metodos: Se obtuvieron los puntajes Z de los indices antropometricos de los ninos. Los parasitos intestinales se investigaron con el metodo coproparasitoscopico directo y un metodo de concentracion. Las cepas DEC se detectaron mediante reaccion en cadena de la polimerasa. Resultados: La prevalencia de desmedro en ninos de la zona rural y urbana fue de 79.8 y 7.5%, respectivamente. Unicamente los ninos de la zona rural estuvieron parasitados (72.6%), y los mas prevalentes fueron Ascaris lumbricoides y Entamoeba histolytica/Entamoeba dispar (57.1 y 38.1%, respectivamente). Mas de la mitad de los infantes exhibieron ascariasis moderada. Estos parasitos, ademas de Giardia intestinalis, se asociaron con el desmedro. En ambas regiones, la prevalencia de DEC fue similar. Conclusiones: Solo los ninos de los Altos de Chiapas (zona rural) exhibieron alta prevalencia de desmedro y parasitos intestinales. Para evitar las consecuencias adversas entre los infantes, es necesario reevaluar los programas de desarrollo social para combatir el desmedro y la parasitosis intestinal, principalmente en las regiones rurales de Chiapas

Pacific and Atlantic-slope rivers of the Isthmus of Tehuantepec in Mexico contain two cichlid species of the genus Vieja relevant to the current study, V. zonata and V. coatlicue, respectively. The Atlantic-slope species was initially considered a population of uncertain taxonomic status and recently described as a distinct species based on three putatively diagnostic morphological characters. The objective of this study was to combine new and existing genetic data, along with reanalysis of morphological characters, to test the distinctiveness of V. coatlicue. Little genetic variability and no geographic structuring were recovered. Additionally, putatively diagnostic morphological character states were present across both species, failing to separate the forms. The synthesis of molecular and morphological data supports the recognition of V. coatlicue as a junior synonym of V. zonata. RESUMEN Dos especies del género Vieja se encuentran distribuidas a lo largo Istmo de Tehuantepec en México; V. zonata se distribuye en los ríos de la vertiente del Pacífico y V. coatlicue en los ríos de la vertiente del Atlántico. La especie que se distribuye en la vertiente del Atlántico era considerada como una población de estado taxonómico incierto, pero recientemente fue descrita como nueva especie en base a tres caracteres morfológicos diagnósticos. El objetivo de este estudio fue utilizar datos moleculares nuevos con datos moleculares previamente publicados en combinación con una reanálisis de los caracteres morfológicos para testear la validez taxonómica de la especie V. coatlicue. Nuestros análisis moleculares no recobran estructura geográfica y además muestran baja variabilidad genética. Además, los tres caracteres morfológicos diagnósticos se encontraron presentes en individuos de ambas especies, nuestro trabajo sugiere que estos caracteres morfológicos diagnósticos no proven información que permita separar a las formas que se distribuyen en la vertiente del Pacífico y la vertiente del Atlántico. Nuestra síntesis de datos moleculares y morfológicos provee evidencia para reconocer a V. coatlicue como una sinónima mas reciente de V. zonata.

Introduction: Due to its colors, shape, size, and simplicity of care, the neotropical fish Poecilia reticulata (guppy) is popular in the aquarium trade. It is also valued as mosquito control and is now found in most of the world. Objective: To report its presence in southern Mexico. Methods: Fish were captured with seine nets in a tributary of the Grijalva River, Chiapas, in August 2019, and March 2020. Results: Two hundred and fifty individuals of P. reticulata were captured. Conclusion: The species, found in México in 1971, has extended its range to the Grijalva Usumacinta river system. RESUMEN. “Primer registro del pez introducido Poecilia reticulata (Cyprinodontiformes: Poeciliidae), en Chiapas, sur de México”. Introducción: Debido a sus colores, forma, tamaño y simplicidad de cuidado, el pez neotropical Poecilia reticulata (guppy) es popular en el comercio de acuarios. También se valora como control de mosquitos y ahora se encuentra en la mayor parte del mundo. Objetivo: Informar su presencia en el sur de México. Métodos: Se capturaron peces con redes de cerco en un afluente del río Grijalva, Chiapas, en agosto de 2019 y marzo de 2020. Resultados: Se capturaron 250 individuos de P. reticulata. Conclusiones: La especie, hallada en México en 1971, ha extendido su ámbito geográfico al sistema fluvial Grijalva Usumacinta.

A new nematode species, Rhabdochona juliacarabiasae sp. n. is described from specimens recovered from the intestine of the freshwater Mexican mojarra, Eugerres mexicanus (Steindachner) (Gerreidae) captured in the Lacantun River, Chiapas, Mexico. Rhabdochona juliacarabiasae sp. n. is characterized by possessing a prostom armed with 12 anterior teeth (excepcionally 11), small bifurcated deirids with a markedly long base, an unusual tetrafurcate tip of the larger (left) spicule, a smaller (right) spicule without dorsal barb on its distal tip, and eggs with 1 short filament on each pole. In addition, in order to assess the phylogenetic relationships of the new species, and further demonstrate its distinctiveness against close related congeners, specimens of R. juliacarabiasae sp. n, R. xiphophori, R. salgadoi, R. kidderi, R. canadensis, and R. mexicana were sequenced for the cox1 gene, and the sequences were aligned with other nematode sequences available in GenBank ( R. adentata, R. ahuhuellensis, R. ictaluri, and R. osorioi ). Maximum likelihood and Bayesian inference analyses indicated that this new nested in a well-supported clade with high posterior probability. The molecular analyses support the validity of the new species. R. juliacarabiasae sp. n. was recovered as sister to the clade formed by R. kidderi and R. ictaluri , and shows genetic divergence that range between 11.18 and 14.89% (P- distances) compared with other congeners.

Conservation planners use a variety of decision-making tools, many of which require identifying and prioritizing spatial units based on their biodiversity and levels of imperilment. Turtles are highly imperiled, but present schemes for determining global priority areas are focused mostly on broad regional scales. We conduct the first global evaluation of turtle biodiversity and imperilment at a sub-basin level to identify geographically smaller areas of high conservation value, and compare with these existing prioritizations. We employed two spatial analyses—bivariate maps and local indicator of spatial association (LISA)—to identify and prioritize sub-basin clusters based on multiple biodiversity and conservation metrics in addition to species richness. Most high-priority sub-basin clusters were located along tropical and subtropical coastlines. A new area of global significance for turtle conservation was identified in southwest India. Many sub-basins of the Indomalayan Realm were clustered as high or intermediate priority, with large clusters of high-priority sub-basins also in tropical Australasia. Other high and intermediate priority sub-basin clusters were found in the Afrotropical, Neotropical, and Nearctic realms, often in previously recognized turtle biodiversity hotspots. Many conservation-priority sub-basins with high turtle-species richness and endemism are in lowland and coastal areas where endemics (some from ancient lineages) are imperiled in association with a high human footprint. Our findings reiterate the global significance of Asia as a key area of chelonian conservation need, while identifying focal areas across the globe where the need for targeted turtle conservation is especially great.

An updated checklist of the distribution of fishes that inhabit the continental waters of the Mexican state of Chiapas is presented. The state was compartmentalized into 12 hydrological regions for the purpose of understanding the distribution of fish fauna across a state with large physiographic variance. The ichthyofauna of Chiapas is represented by 311 species distributed in two classes, 26 orders, 73 families, and 182 genera, including 12 exotic species. The families with the highest number of species were Cichlidae, Poeciliidae, Sciaenidae, Carangidae, Ariidae, Gobiidae, and Haemulidae. This study attempts to close gaps in knowledge of the distribution of ichthyofauna in the diverse hydrological regions of Chiapas, Mexico.

Our study investigates how factors, such as latitude, productivity, and several environmental variables, influence contemporary patterns of the species richness in North American turtles. In particular, we test several hypotheses explaining broad-scale species richness patterns on several species richness data sets: (i) total turtles, (ii) freshwater turtles only, (iii) aquatic turtles, (iv) terrestrial turtles only, (v) Emydidae, and (vi) Kinosternidae. In addition to spatial data, we used a combination of 25 abiotic variables in spatial regression models to predict species richness patterns. Our results provide support for multiple hypotheses related to broad-scale patterns of species richness, and in particular, hypotheses related to climate, productivity, water availability, topography, and latitude. In general, species richness patterns were positively associated with temperature, precipitation, diversity of streams, coefficient of variation of elevation, and net primary productivity. We also found that North America turtles follow the general latitudinal diversity gradient pattern (i.e., increasing species richness towards equator) by exhibiting a negative association with latitude. Because of the incongruent results among our six data sets, our study highlights the importance of considering phylogenetic constraints and guilds when interpreting species richness patterns, especially for taxonomic groups that occupy a myriad of habitats.

Summary The effect of the preserver on the length-weight relationship and condition factor were estimated using 50 specimens of Tlaloc labialis; a small stream fish from the Grijalva River basin, Mexico. They were measured at different stages of preservation: freshly collected, fixed in 10% formalin and preserved in 70% ethanol for over a 2 years period. All fish decreased in weight and condition factor, with very significant differences compared to the fresh material. The value of the coefficient (b) increased and stabilized from the second month of preservation in ethanol.

Scombroclupea javieri sp. nov. is erected based on the description of well-preserved specimens collected in the lower Cenomanian marine outcrop at the El Chango quarry, near Ocozocoautla de Espinosa, Chiapas State, southeastern Mexico. This new species shows the distinctive feature of the superorder Clupeomorpha, the presence of the abdominal scute series, as well as the diagnostic characters of Scombroclupea, as the lack of the dorsal scutes and the presence of two supramaxillae, the comb-like dentition in the maxilla, the horizontal laminae in the anterior caudal vertebrae, the flat epineurals and epipleural in caudal region of the trunk, and the finlets present along the anal fin, and differs from the other three nominal species of this genus in meristic data of the fins and vertebrae. Scombroclupea was previously thought as an incertae sedis members of the order Clupeiformes; however, S. javieri displays two primitive features never recorded before in this clupeomorph order and commonly observed in the order Ellimmichthyiformes, this new species has a large beryciform foramen piercing the anterior ceratohyal and its parietal bones are sutured to each other. The review of specimens of S. occidentalis and S. macrophthalma confirms that these species share the presence of a large beryciform foramen in the anterior ceratohyal. These characters make it difficult to include Scombroclupea as a member of any of the orders Clupeiformes and Ellimmichthyiformes. This record of Scombroclupea, the oldest in America and the second in Mexico, widens the geographical Cenomanian distribution of the genus along the Tethys Sea, from Middle East to southern North America.

Defaunation in the Anthropocene has created a need to focus limited conservation resources on geographically-explicit areas with high conservation significance. Priority conservation areas are often defined as those with high biodiversity – hotspots. While these conservation areas are critical to securing global biodiversity, prevailing approaches for their delineation are often qualitative. Here, we demonstrate the benefits of a clade-specific approach that improves conservation. We use the distinct, imperiled clade of turtles (tortoises and freshwater turtles) to delineate biogeographical regions and characterize their comparative levels of biodiversity and conservation values. We produce a quantitative, revisable map of 63 global turtle regions and identify several turtle regions, mostly in the Indomalayan turtle realm, that are high-priority conservation regions. While our high-priority turtle regions include those previously reported in the literature as turtle hotspots, we also describe a new priority conservation region in Southeast Asia (Yangtze-Huang He-Xi Yiang) which has both high species and endemism richness. Although not considered a high or intermediate conservation priority, our analyses delineated another previously unidentified turtle hotspot – the Kalahari Basin-Rift Valley. Additionally, we identify several turtle regions, largely in Central America, with intermediate conservation priority. Our results reveal that many turtle hotspots represent complex biogeographical areas with high inter-regional β-diversity, and several of these turtle-hotspots occur in transition zones with high biogeographical complexity. In these cases, inter-regional conservation efforts will be necessary to ensure turtle biodiversity conservation.

Vieja hartwegi was described by Taylor and Miller in 1980 based on 45 juvenile and sub-adult specimens, but this species shows an enormous variation in coloration patterns during ontogenic development and between individuals. Additionally, morphological data have demonstrated the existence of two forms in V. hartwegi: the typical morph of a moderately deep to slightly elongated body shape with midlateral band, and a rheophilic morph with an elongated to slightly deep body shape and lack of midlateral band. Herein we redescribe V. hartwegi adding adults and individuals from broad geographic ranges, as well as a rheophilic morph recently discovered in the upper reaches of the Grijalva River basin in Mexico. The set of characters include coloration, meristic, morphometric and osteological features. Vieja hartwegi is a polymorphic species whose forms may be segregating because of habitat preferences and food habits.

Although the conterminous USA has a long history of ichthyological exploration, the description of biogeographical provinces has been ad hoc. In this study we quantitatively determined fish faunal provinces and interpreted them in the context of the geological history of North America. We also evaluated influences of major river basin occupancy and contemporary environmental factors on provincial patterns. Our data set comprised 794 native fishes, which we used to generate a presence and absence matrix for U.S. Geological Survey (USGS) four-digit hydrologic units. Three nested data sets were analysed separately: primary freshwater families, continental freshwater families (including primary and secondary families) and all freshwater families (including primary, secondary and peripheral families). We used clustering analysis to delimit faunal breaks and one-way analysis of similarity (ANOSIM) to determine significance among clusters (i.e. provinces). We used an indicator-species analysis to identify species that contributed most to province delineations and a similarity-percentage (SIMPER) analysis to describe the relative influence of representatives from each category (i.e. primary, secondary, peripheral) on provincial boundaries. Lastly, we used a parsimony redundancy analysis to determine the roles of historical (i.e. major river basin) and contemporary environmental factors in shaping provinces. Analysis of the nested data sets revealed lessening provincial structure with inclusion of more families. There were 10 primary freshwater provinces, 9 continental freshwater provinces and 7 all freshwater provinces. Major basin occupancy, but not contemporary environmental factors, explained substantial variance in faunal similarities among provinces. However, provincial boundaries did not conform strictly to modern river basins, but reflected river-drainage connections of the Quaternary. Provinces represent broad-scale patterns of endemism and provide a starting point for future studies. Relative malleability of province boundaries in the continental interior highlights this region as biogeographically diverse and dynamic. Interior-core provinces of this region (Central Gulf Coastal Plains, Northern Interior) have not been recognized previously and warrant further study.

As part of a revision of the cichlid genus Archocentrus, a new genus, Amatitlania, was erected comprising four species: A. nigrofasciata (the type species), A. siquia, A. kanna, and A. coatepeque. Amatitlania coatepeque is an endemic and an eponym of Lago Coatepeque in the interior highlands of western El Salvador. This species was diagnosed by a Y-shaped pattern formed by the ventral fusion of bars four and five on the body; a triple-spined, squarish, or blunt appearance of the dentigerous arm of the dentary; the presence of a posterior projection at the dorsal corner of the lower lip; the presence of a double medial-loop in the gut; sparsely uniform pigmentation of the peritoneum, and 5–5.5 scale rows from the lateral line to the origin of the dorsal fin. Here we examined the taxonomic status of A. coatepeque using molecular and morphological characters. We found that A. coatepeque is phylogenetically nested within the clade of A. nigrofasciata. Additionally, our re-examination of the reported diagnosti...

The ichthyofauna of the Río Acahuapa was analyzed sampling 17 sites that included the basin main channel and its tributaries. Fish were collected using dip-nets, seine-nets and electrofishing. Fish standard length and species abundance were recorded. Species origin and salinity tolerance criteria were used to classify fish species. Water physicochemical variables, habitat structure and sampling sites elevation were recorded. A total of 33 fish species were registered, 12.1% are primary, 45.5% are secondary and 42.4% are of marine derivation. Fish species richness declined with increase of elevation (R2=0.55, p=0.0006). Two assemblages of fishes were identified: the first one associated to sites of low elevations (19-184 masl), composed mainly of secondary and marine-estuarine fish species related with high temperature, water velocity, river width, dissolved oxygen and low sand and silt substrate cover; the second one associated to sites of middle and higher elevations (185-519 masl), composed by primary and secondary freshwater fishes related with high pH, logs and rocks substrate cover. In summary, elevation and environmental variables contributed to the composition and distribution of fish in the Río Acahuapa. RESUMEN La ictiofauna del Río Acahuapa fue analizada en 17 sitios que incluyen el canal principal de la cuenca y sus tributarios. Los peces fueron recolectados utilizando chinchorros, redes de mano y electropesca. Se registró la longitud estándar y la abundancia por especie. El criterio de origen y tolerancia a la salinidad de las especies fue utilizado para clasificar a los peces. Las variables fisicoquímicas del agua, estructura del hábitat y elevación se registraron en cada sitio. Un total de 33 especies fueron registradas, cuyo 12.1% son primarias, 45.5% secundarias y 42.4% son de derivación marina. La riqueza de especies de peces disminuyó con el aumento de la elevación (R2=0.55, p=0.0006). Dos ensamblajes de peces fueron identificados: el primero está asociado con sitios de bajas elevaciones (19-184 msnm), compuesto principalmente de especies de peces secundarias y marino-estuarinas relacionadas con altas temperaturas, velocidad del agua, ancho de río, oxígeno disuelto y baja cobertura de sustrato de arena y limo; el segundo está asociado con sitios de mediana y alta elevación (185-519 msnm), compuesto por peces dulceacuícolas primarios y secundarios relacionados con altos valores de pH y cobertura de sustrato de troncos y rocas. Se determina que la elevación y las variables ambientales contribuyen a la composición y distribución de peces en el Río Acahuapa.

The inland fish fauna of El Salvador and its distribution was originally described in 1925 by Samuel Hildebrand. That work has been the main source of information for freshwater fishes of El Salvador up to today. Based on the combination of an intensive literature review, electronic database searches, re-identification of museum specimens, and fieldwork, we hereby provide an updated checklist of the inland fishes of El Salvador. This checklist provides distributional data at the Salvadoran hydrographical and political (by department) levels. The checklist is systematically arranged at the ordinal and familial level and then alphabetically therein. The freshwater fish fauna of El Salvador includes 101 species divided into 64 genera, 29 families, and 14 orders. According to their supposed tolerance to salinity, 73% of these species are peripheral, 23% secondary, and only 4% are primary freshwater fishes. One species is endemic to the country, Amatitlania coatepeque. The low number of primary freshwater fishes and endemics is comparable to the Central American Pacific slope in particular, as well as northern Central America in general.

The distributions of many Northern Hemisphere organisms have been influenced by fluctuations in sea level and climatic conditions during Pleistocene interglacial periods. These cycles are associated with range contraction and refugia for northern-distributed organisms as a response to glaciers. However, lower sea levels in the tropics and sub-tropics created available habitat for expansion of the ranges of freshwater organisms. The goal of this study was to use ecological niche modeling to test the hypothesis of north to south range expansion of Vieja maculicauda associated with Pleistocene glacial cycles. Understanding the biogeography of this widespread species may help us better understand the geology and interconnectivity of Central American freshwaters. Occurrence data for V. maculicauda was based on georeferencing of all museum records of specimens recovered from FishNet2. General patterns of phylogeographic structure were assessed with mtDNA. Present day niche models were generated and subsequently projected onto paleoclimatic maps of the region during the Last Interglacial, Last Glacial Maximum, and mid-Holocene. Phylogenetic analysis of mtDNA sequence data showed no phylogeographic structure throughout the range of this widespread species. Present day niche models were congruent with the observed distribution of V. maculicauda in Central America. Results showed a lack of suitable freshwater habitat in northern Central America and Mexico during the Last Interglacial, with greatest range expansion during the Last Glacial Maximum and mid-Holocene. Results support the hypothesis of a north to south range expansion of V. maculicauda associated with glacial cycles. The wide distribution of this species compared to other closely related cichlids indicates the latter did not respond to the degree of V. maculicauda in expansion of their distributions. Future work aimed at comparisons with other species and modeling of future climatic scenarios will be a fruitful area of investigation.

Profundulus balsanus was described by Ahl in 1935 and later placed in synonymy with P . punctatus . Recent molecular studies have demonstrated that specimens identified as P. balsanus belong to a distinct taxon. Herein we used a combination of morphometric, meristic, coloration and osteological data in order to demonstrate the distinctiveness of P. balsanus . Additionally, we used molecular data to reconstruct a phylogeny to place P. balsanus in a systematic context. Profundulus balsanus belongs to the punctatus clade within the genus Profundulus . It can be distinguished from P. oaxacae based on scale count in the lateral line and from P. punctatus based on differences in coloration in the anal fin. We provide a taxonomic key to all Mexican species of Profundulus .

We investigate phylogeographic patterns and delimit species boundaries within Amatitlania, a genus of Central American cichlid fishes. Phylogenetic analyses of mitochondrial DNA sequences from 318 individuals spanning the geographical ranges of all three currently recognized Amatitlania species strongly supported one major clade, with a relatively diverged subclade corresponding to A. kanna samples from eastern Costa Rica and Panama. Gene trees and networks revealed marked incongruences between phylogeographic structure and morpho-species taxonomy as a result of species-level polyphyly. Bayes factor comparisons of species delimitation models accounting for incomplete lineage sorting under the multispecies coalescent decisively supported the recognition of two distinct species within Amatitlania corresponding to Amatitlania nigrofasciata and A. kanna lineages. The only clearly genetically and morphologically diagnosable species was A. kanna. These results strongly suggest that incomplete lineage sorting provides the best explanation for the polyphyly of A. kanna, whereas the polyphyly of A. siquia is likely a result of an imperfect taxonomy. Additional insights from coalescent-dating, network, and historical demographic analyses suggested that the two species of Amatitlania diversified only since the early Pleistocene, and that A. nigrofasciata experienced population expansions from approximately 200 000 years ago in the mid-late Pleistocene onward. We discuss implications of our results for the taxonomy and evolutionary history of Amatitlania and, more broadly, of Central American freshwater fishes.