Checklist of the continental fishes of the state of Chiapas, Mexico, and their distribution

Diversity of Cichlid Fishes (Cichliformes: Cichlidae) in Chiapas, Mexico: A practical identification key with updated distribution maps

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.  

Genetic diversity and structure of one of the most endangered freshwater fish species in Mexico: Tlaloc hildebrandi (Miller, 1950) and recognition of its evolutionarily significant units

The endangered Chiapas killifish Tlaloc hildebrandi is an endemic freshwater species that lives in four subbasins of the Grijalva and Usumacinta basins, and one of the most geographically restricted species of the Produndulidae family. The species was originally described as endemic to springs in the high limestone plateau in San Cristóbal de Las Casas in the Río Amarillo subbasin (upper Grijalva basin). However, it was recently recorded in the Jataté and Tzaconejá subbasins in the upper Usumacinta basin, thereby expanding its known distribution range. The discovery of these populations is relevant not only for the conservation of the species but also for a better understanding of its evolutionary history. Currently, the scarce populations of T. hildebrandi, found in only a few localities in the Grijalva and Usumacinta basins, are fragmented and living under unfavorable conditions. Here, we analyzed three mitochondrial (mt-atp8&6 and mt-nd2) and one nuclear (nuc-s7) marker in order to assess the genetic diversity and population structure of T. hildebrandi. We found that, in comparison with other endangered freshwater fish species from Mexico, T. hildebrandi showed a lower level of genetic diversity (mt-nd2: h = 0.469, π = 0.0009; mt-atp8&6: h = 0.398, π = 0.001; and nuc-S7: h = 0.433, π = 0.001). Moreover, the analyzed populations exhibited a strong genetic structure in accordance with their geographic distribution, and can be placed into three genetic clusters: (1) Amarillo plus Chenhaló in the upper Grijalva basin, (2) Jataté, and (3) Tzaconejá, both in the upper Usumacinta basin. On the basis of our results, we propose the recognition of at least three evolutionarily significant units (ESUs) for the species and the urgent implementation of ex situ and in situ conservation and management efforts that consider the genetic background of the species.

A new record of the exotic Guapote jaguar, Parachromis managuensis (Günther, 1867) (Cichliformes, Cichlidae) in a tropical coastal lagoon of the Mexican Pacific slope

The presence of Parachromis managuensis has been reported for the first time in the Tres Palos Lagoon, State of Guerrero, on the coastal Lagoon of the Mexican Pacific slope. Two specimens (189 mm and 215 mm standard length) were caught by local fishermen from the community of San Pedro de Las Playas. A description of the morphological and meristic characters of the specimens is provided. The natural distribution of the species is from Honduras to Costa Rica and, as it is predatory and highly territorial, in conjunction with other introduced species, it can present a risk to native species and alter the biological dynamics in the lagoon system.