Miriam Soria-Barreto

Diferencias Osteológicas entre los Subgéneros Profundulus y Tlaloc (Teleostei: Profundulidae)

El genero Profundulus es uno de los grupos de peces mas antiguos, distribuidos al norte de America Central en Mexico, Guatemala y Honduras. No obstante, son pocos los trabajos que se han realizado para conocer el numero de especies que lo conforman y sus relaciones filogeneticas. Historicamente se reconocio que este taxon estaba conformado por dos grupos naturales, actualmente considerados como los subgeneros Profundulus y Tlaloc. Recientes investigaciones geneticas han revelado un alto grado de diferenciacion entre ambos taxones y algunas de sus especies, lo cual probablemente este asociado a cambios morfologicos. De esta manera, se realizo la comparacion osteologica entre seis especies de los subgeneros Profundulus y Tlaloc (Cyprinodontidae: Profundulidae). Se revisaron 17 huesos ubicados en el craneo y la cintura pelvica, se encontraron diferencias cualitativas en el mesetmoides, vomer, lacrimal, premaxilar, articular, cuadrado, interoperculo y basipterigio. Los patrones de variacion observados permiten diagnosticar ambos subgeneros, corroborando lo encontrado en estudios morfologicos y moleculares. Las evidencias permiten suponer que ambos taxones podrian ser reubicados como generos, como previamente se habia establecido.

Fishes in the lower San Pedro Mezquital River, Nayarit, Mexico

The San Pedro Mezquital River is the seventh largest river in Mexico, and flows through the Sierra Madre Occidental into the Marismas Nacionales Biosphere Reserve, on the coast of the state of Nayarit. The present study is to conform a systematic checklist of fishes in the lower basin of the San Pedro Mezquital River. In total, 52 species were collected from 24 families. Four native species were collected (Atherinella crystallina, Poecilia butleri, Poeciliopsis latidens and Poeciliopsis prolifica) that are federally protected. Five of the collected species were new records for the state of Nayarit. This checklist constitutes a first approximation of the fish fauna present in the San Pedro Mezquital River. However, the construction of the Las Cruces dam upstream, will modify the basin hydrology, worsen the introduction of exotic species and create habitat loss, which can have immediate negative impacts on the fish communities in this region.

Preliminary observations on the effect of temperature on growth, condition and survival in Cichlasoma beani in culture conditions

The Mexican Cichlid, Cichlasoma beani has potential to be a candidate for the aquarium trade and the food industry. However, there are no studies regarding the effect of environmental factors on the species in culture conditions. The aim of this study was to examine the effect of temperature on growth, condition and survival of C. beani cultured in 26, 28 and 30 °C, for six weeks in recirculation systems. Fish were fed 2.4 mm pellets (40 % protein, 15 % fat) at a ration rate of 5 % body weight per day (dry weight food: wet weight fish).The final weight and specific growth rate at 30 °C was significantly greater ( P