Gustavo Ernesto Quintero-Díaz

Effects of copper addition to laboratory maintained microcosms of Presidente Calles Reservoir organisms (Aguascalientes, Mexico)

Abstract We studied the effects of five different concentrations of copper (0.05, 0.20, 0.45, and of 0.05 added continuously up to 0.45 mg l-1) in 30 l aquaria containing water and organisms from Presidente Calles reservoir, the biggest reservoir in the State of Aguascalientes, Mexico. Large reductions in zooplankton density, species diversity and total chlorophyll were found when we compared the different treatments against controls. Initial addition of a greater amount of copper has a more adverse effect than constant additions of small amounts of copper as suggested by smaller reductions in zooplankton density and chlorophyll. This result agrees with the previous reports on the effects of other metals in different aquatic microcosms. The most dramatic effect of copper addition on zooplankton density was found three days after copper addition. Lethal effects on cladocerans, copepods, and rotifers were found at a concentration of 0.45 mg l-1. These results are important for regulatory agencies in Mexico ...

Lithobates magnaocularis Frost & Bagnara, 1974, the Northwest Mexico Leopard Frog (Anura: Ranidae): new state records for Aguascalientes and Zacatecas, Mexico

We report an adult female and subadult specimen of the frog Lithobates magnaocularis Frost & Bagnara, 1974 from tropical deciduous forest habitat in the Municipality of Calvillo, Aguascalientes and Valparaiso, Zacatecas, Mexico. These vouchers represent the first state records of L. magnaocularis for Aguascalientes and Zacatecas, and extend the known distribution of the species through the northeastern portion of the tributaries of the Rio Grande de Santiago basin.

First records of the Chihuahuan Black-headed Snake, Tantilla wilcoxi Stejneger, 1902 (Squamata: Colubridae), in the Mexican state of Jalisco

Based on three specimens, we document the occurrence of Tantilla wilcoxi in the Mexican state of Jalisco. This species was found at two localities, 2.9 km apart, both in the ecotone between xerophytic scrub and oak forest in the arid plains of the municipality of Ojuelos de Jalisco in the northeastern portion of the state.