Search

We studied the fish fauna of the Rio Sain Alto (Rio Aguanaval endorheic basin) in Zacatecas, Mexico, during the dry (May) and wet (October) seasons of 2011 in order to evaluate changes in the distribution of the species and its relationship with environmental variables. A total of 12 fish species (6 native and 6 exotic) were registered. The longitudinal distribution of the species in the river during both seasons combined was 2 native species (Gila conspersa and Catostomus nebuliferus) with ample distribution in the river (upper, middle and lower zones), 2 native species (Campostoma ornatum and Notropis nazas) in 2 zones of the river (middle and lower), 4 species (2 native: Astyanax mexicanus and Etheostoma pottsii, and 2 exotic: Cyprinus carpio and Oreochromis sp.) in the middle zone of the river, and 4 exotic species (Gambusia affinis, Lepomis cyanellus, Lepomis macrochirus, and Micropterus salmoides) with distribution confined to the lower zone of the river, especially in reservoirs. Species richness decreased with altitude and after a flooding event. The factor analysis model determined that both altitude and flow velocity were the factors that best explained the variation in the distribution of fish species during the rainy season, especially for the exotic component.

The name killifish refers to the oviparous secondary freshwater fishes in the order Cyprinodontiformes. Killifishes are abundant in Mexico and are represented by four extant families, Rivulidae, Profundulidae, Fundulidae and Cyprinodontidae, comprising > 50 species in a wide variety of habitats. This paper reviews the current classification of the killifishes of Mexico, as well as aspects of their distribution, biology, ecology and current population conservation status.

Resumen El Río Presidio, ubicado en el sur de Sinaloa, México, pertenece a la zona de transición zoogeográfica NeárticoNeotropical, donde su fauna de peces podría manifestar cambios en la abundancia y distribución de las especies durante los períodos de lluvias y de secas. El objetivo principal de este estudio fue describir la composición taxonómica y la abundancia espacial y temporal de la fauna de peces de la parte baja y media del Río Presidio, mediante muestreos bimestrales de abril 2008 a febrero 2009. Cuarenta especies (39 nativas y 1 exótica) pertenecientes a 32 géneros y 19 familias fueron registradas, siendo las familias Gerreidae y Poeciliidae las más diversas con cinco y cuatro especies, respectivamente. Seis especies: Lile stolifera, Oreochromis aureus, Awaous banana, Gobiomorus maculatus, Anchoa analis y Atherinella crystallina, en ese orden de importancia contribuyeron con casi el 49 % de la abundancia íctica total. La riqueza de especies y la salinidad demostraron una relación directa y ambas tuvieron una relación inversa con la altitud. Con base en la disimilitud de especies entre sitios, dos tipos de ensambles de peces fueron distinguidos a través de un gradiente de salinidad y turbidez en el río, el primero representado por especies de derivación marina (periféricas) en la parte baja, y el segundo por especies dulceacuícolas secundarias en la parte media. La mayor similitud de especies se dio en agosto y septiembre y estuvo asociada a condiciones de altos flujos del periodo de lluvias. Veintisiete especies tienen afinidad a la Región del Pacífico oriental, seis a la Región Neotropical, dos a la Región Neártica (Dorosoma smithi e Ictalurus cf. pricei), una Anfiatlántica (Mugil curema), una Circumtropical (M. cephalus), dos Anfiamericanas (Agonostomus monticola y Gerres cinereus) y una exótica (O. aureus). Abstract The Rio Presidio in the southern Sinaloa, Mexico belongs to Nearctic-Neotropical zoogeographical transition zone, where its fish fauna could manifest changes in the abundance and distribution of the species during rainy and dry periods. The main objective of this study was to describe the taxonomic composition and spatial and temporal abundance of the fish fauna from the lower and middle Rio Presidio, by means of bimonthly samplings from April 2008 to February 2009. Forty fish species (39 native and 1 exotic) belonging to 32 genera and 19 families were registered. Two families (Gerreidae and Poeciliidae) contained the highest numbers of species (five and four, respectively). Six species (Lile stolifera, Oreochromis aureus, Awaous banana, Anchoa analis, Gobiomorus maculatus and Atherinella crystallina) in this order of importance contributed with almost 49 % of the total fish abundance. Species richness and salinity showed a direct relationship and an inverse relationship with the altitude. Based on the coefficient of similarity of species among sites two fish assemblages were identified. The first assemblage formed by species from marine derivation (peripheral) occurring in the lower part of the river, and the second assemblage by secondary freshwater species in the middle part. The higher fish species similarity observed in August and September was under the influence of the highest flows of the rainy period. Twenty-seven 27 species showed affinity to the Tropical Eastern Pacific Region, six species to the Neotropical region and two to the Nearctic region (Dorosoma smithi and Ictalurus cf. pricei ); one species has an Amphiatlantic distribution (Mugil curema), another is circumtropical (Mugil cephalus), two species have Amphiamerican distribution (A. monticola and G. cinereus), and one is exotic (O. aureus). Rev. Biol. Trop. 66(2): 848-862. Epub 2018 June 01.

We access the evolutionary history of the genus Herichthys based on a phylogenetic reconstruction using a mitochondrial fragment of gene Cox1. We evaluate its morphological variation, its correspondence with molecular differentiation and suggest a biogeographical scenario based on a molecularclock and demographic history. Furthermore, we describe Nosferatu new genus, composed of Nosferatupame (assigned as type species),N. molango,N. pratinus, N. bartoni, N. labridens, N. pantostictus, and N. steindachneri. Genus is characterized by a transition to prolongation in the size of the symphysial pair of teeth relative to that of the other teeth in the outer row of the upper jaw; breeding pigmentation that consists of darkening of ventral area extending over nostrils, opercular series, or pectoral fins; depressed dorsal fin rarely expands beyond anterior third of caudal fin; and an elongated, elastic, smooth caecum adhered to a saccular stomach. We also describe Herichthys tepehua n. sp. found in the Pantepec, Cazones, Tenixtepec, Tecolutla, and Solteros rivers, in Veracruz, Mexico. Moreover, we provide re-descriptions for some of the species in Herichthys and propose a biogeographic hypothesis for both genera, based on available information on the geological and climate history of the area of study, associated to dating retrieved in our phylogenetic analysis., We also thank the funding support derived from the projects CGL2006-1235-BOS and CGL2010-15231-BOS.

Pupfishes (genus Cyprinodon) are iconic of biodiversity and endemism in the desert southwest of North America. Most of these species are imperiled, primarily because of excessive exploitation of water resources in this arid region. The critically endangered Julimes pupfish, Cyprinodon julimes, is restricted to a small, isolated, and highly modified desert spring in Chihuahua, Mexico. We evaluated effective population size (microsatellites) and genetic variation (microsatellites and mitochondrial DNA) to determine the conservation genetic status of this species. The effective population size was critically low and indicated that this pupfish is at genetic risk of extinction through loss of adaptive variance and, potentially, from inbreeding depression. Mitochondrial variation was also extremely low, and haplotype frequency was biased heavily in favor of one of two variants. The uncommon haplotype was derived from a past hybridization event with the closely related C. eximius; whether cessation of introgressive hybridization is relevant to conservation management of Julimes pupfish is unknown but may be important to consider. Minimally, C. julimes is compromised genetically. Baseline population genetic information provided by this study will be vital to long-term monitoring of this highly imperiled species.

A morphometric comparison was performed on specimens of blue catfish (Ictalurus furcatus) from northern (Lower Rio Bravo) and southern (Chiapas) Mexico in order to identify diagnostic characters that allow their discrimination. The discriminant function analysis determined three characters to be highly diagnostic to separate the two groups of specimens: the southern group [SG] has a shorter anal base (mean = 3.4 times in standard length [SL], range = 3.1 to 3.7) vs northern group [NG] (mean = 2.9 times in SL, range = 2.7 to 3.1), a lesser head width (mean = 6.0 times in SL, range 5.1 to 6.8) vs NG (mean = 5.6 times, range = 5.3 to 6.0), and a lower number of anal rays (mean = 26, range = 24 to 28) vs NG (mean = 31, range = 29 to 34). Additionally, 14 other characters were also different (P < 0.01) between both groups. All these characters support the taxonomic validation of Ictalurus meridionalis (Gunther 1864) for the individuals of SG that are currently included in I. furc...

The Mexican freshwater fish that are at risk orextinct are listed by family, state,basin/region, and causes of risk. Of the 506known species, 168 are at some level of risk,and 25 are believed to be extinct. States withthe most reports are: Chihuahua (46); Coahuila(35); Nuevo Leon (20); Sonora (19); Durango(18); and Tamaulipas (15). With the exceptionof Sonora, these states are largely located inthe Rio Bravo region, and are all arid orsemiarid. Most extinctions have occurred inNuevo Leon (8) and Coahuila (7). The maincauses of risk reported are: habitat reductionor alteration (86); water depletion (83);presence of exotics (76); small or decliningpopulation (73); and small habitat (57). Allof which result in very local endemism. Thesecauses of risk develop easily when thedistribution is small. The critical factor isaridity, which is associated withdesertization. Water conflicts were to beexpected, and the result is resource nonsustainability.

Clearly defined changes in the fishesof the Lower Rio Grande/Rio Bravo, Texas andMexico, have been documented since 1953. Morerecent surveys show that the originalfreshwater fish fauna has been retreating fromthe lower reaches and is being replaced bybrackish and marine invaders. A total of 13localities between Colombia (Nuevo Leon,Mexico) and the delta (580 km) weresurveyed, with a total fish fauna of 142species, which include native, exotic, andintruding species. Changes were analysed bylocality. These changes show a loss of themajority of freshwater species, replacement oflow to higher salinity forms. This shift isvery clear in marine invaders, with somespecies penetrating the whole areainvestigated. Those changes are morenoticeable in the lower-most localities, anddiminish upstream. Data suggest that thechanges in the basin, reflecting shifts inwhole-basin ecology, include elevatedtemperature, salinity, turbidity, and lowerrunoff levels. There are indications of higherlevels of pollution as well. Informationobtained in this study is being incorporated inan Index of Biological Integrity to appearelsewhere.

We report an apparently successful effort to restore native fishes to a pool in the Cuatro Cienegas Bolson, Coahuila, Mexico. The results demonstrate the feasibility, in small, confined systems, of eliminating a recently introduced nonnative fish, the spotted jewelfish (Hemichromis guttatus), and transplanting a native fish assemblage from nearby areas. We recommend that similar removal and restoration activities be conducted to protect the unique, highly endemic Cuatro Cienegas fish fauna.

Como resultado de 26 expediciones de colecta y observaciones visuales efectuadas entre 2007 y 2009 en 644 localidades del Sistema Arrecifal Lobos-Tuxpan, se presenta un inventario ictiofaunístico. Se revisaron un total de 1 024 ejemplares capturados con diferentes artes de pesca y se realizaron 511 censos visuales aleatorios. En total se obtuvieron peces de 74 familias, 155 géneros pertenecientes a 282 especies de las cuales, 24 son nuevos registros para los arrecifes del norte de Veracruz. Las familias con mayor diversidad fueron: Serranidae, Gobiidae y Carangidae, con 24,16 y 14 especies respectivamente. A nivel de arrecife, la mayor riqueza ictiológica se presentó en Lobos, con 248 especies. La diversidad de peces registrada para los arrecifes del norte de Veracruz es un elemento importante para la denición de los planes de manejo, no solo por su riqueza sino también por la presencia de las dos especies endémicas veracruzanas: Elacatinus jarocho y E. redimiculus.

The northern and central part of Veracruz, Mexico, as herein delimited, is inhabited by 121 species of fish, in 83 genera and 47 families. Four species and 3 families are Nearctic, 28 species and 6 families are Neotropical, and 1 species is circumtropical. Ecologically, 8 species and 4 families are primary, 25 species and 6 families are secondary, 30 families are peripheral, and 7 families are marine, many of them marine accidentals. A mountainous area near Punta del Morro almost reaches the sea, and acts as a filter for primary and secondary species. Its importance had not been described in detail. From the north, the following species range to Punta del Morro or less:astyanax mexicanus, Dionda ipni, Ictalurus cf.furcatus, I. cf.punctatus, Lucania parva, Cyprinodon variegatus, Gambusia affinis, G. vittata, Heterandria sp.,Poecilia formosa, P. latipinna, Xiphophorus birchmani, X. variatus, Cichlasoma cyanoguttatum, C. labridens andC. sp.. From the south, the species that approach or reach Punta del Morro are:Astyanax aeneus, Hyphessobrycon compressus, Rhamdia guatemalensis, R. laticauda, Rivulus cf.robustus, Belonesox belizanus, Poeciliopsis gracilis, Xiphophorus andersi, X. maculatus, andOphisternon aenigmaticum. Eight species including one peripheral are present on both sides and constitute short penetrations across the barrier. At least nine species represent introductions, purposeful or accidental.

We collected 12 mountain clingfish Gobiesox fluviatilis in the Rio Tamazula that represent the first record of the species in both the Rio Culiacan basin and the state of Sinaloa, Mexico. We compared proportions of body and counts of fin rays of the new specimens with those previously reported for this species.

Background Climatic and sea-level fluctuations throughout the last Pleistocene glacial cycle (~130-0 ka) profoundly influenced present-day distributions and genetic diversity of Northern Hemisphere biotas by forcing range contractions in many species during the glacial advance and allowing expansion following glacial retreat ('expansion-contraction’ model). Evidence for such range dynamics and refugia in the unglaciated Gulf-Atlantic Coastal Plain stems largely from terrestrial species, and aquatic species Pleistocene responses remain relatively uninvestigated. Heterandria formosa, a wide-ranging regional endemic, presents an ideal system to test the expansion-contraction model within this biota. By integrating ecological niche modeling and phylogeography, we infer the Pleistocene history of this livebearing fish (Poeciliidae) and test for several predicted distributional and genetic effects of the last glaciation. Results Paleoclimatic models predicted range contraction to a single southwest Florida peninsula refugium during the Last Glacial Maximum, followed by northward expansion. We inferred spatial-population subdivision into four groups that reflect genetic barriers outside this refuge. Several other features of the genetic data were consistent with predictions derived from an expansion-contraction model: limited intraspecific divergence (e.g. mean mtDNA p-distance = 0.66%); a pattern of mtDNA diversity (mean Hd = 0.934; mean π = 0.007) consistent with rapid, recent population expansion; a lack of mtDNA isolation-by-distance; and clinal variation in allozyme diversity with higher diversity at lower latitudes near the predicted refugium. Statistical tests of mismatch distributions and coalescent simulations of the gene tree lent greater support to a scenario of post-glacial expansion and diversification from a single refugium than to any other model examined (e.g. multiple-refugia scenarios). Conclusions Congruent results from diverse data indicate H. formosa fits the classic Pleistocene expansion-contraction model, even as the genetic data suggest additional ecological influences on population structure. While evidence for Plio-Pleistocene Gulf Coast vicariance is well described for many freshwater species presently codistributed with H. formosa, this species demography and diversification departs notably from this pattern. Species-specific expansion-contraction dynamics may therefore have figured more prominently in shaping Coastal Plain evolutionary history than previously thought. Our findings bolster growing appreciation for the complexity of phylogeographical structuring within North America’s southern refugia, including responses of Coastal Plain freshwater biota to Pleistocene climatic fluctuations.