Knowledge of the population dynamics of tropical trees has expanded considerably in the past 20 years. An important observation deriving from these investigations is the confirmation that population behaviour varies both in time and space. A tool recently developed to…

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Tillandsia magnispica Espejo & López-Ferrari, known only from the state of Oaxaca, Mexico, in the municipalities of San Pedro el Alto and San Pedro Pochutla, is described and illustrated. The new taxon is compared with T. jaliscomonticola Matuda, a morphologically…

The name Didymaea alsinoides (Schltdl. & Cham.) Standl. has been incorrectly applied to a common and wide-ranging Mexican and Central American species whose correct identity is Didymaea Mexicana Hook. f. In this paper a lectotype is selected and designated for…

Significant changes in the isotopic composition of groundwater in the upper catchment of Rio Guanajuato, Mexico, were detected in two independent sets of samples for 3 % of the 1600 high-production wells in the area. Sampling was done in December…

In this paper we report the oldest geologic world record of Ptychodus mortoni, from the Vallecillo Member (Agua Nueva Formation), at Vallecillo, Nuevo León, northeastern Mexico. The presence of the ammonite Watinoceras coloradoense, allows the placement of the sediments of…

A complete description of Vallecillichthys multivertebratum Blanco and Cavin, 2003, is provided. This ichthyodectiform fish was collected in the Vallecillo Member of the Agua Nueva Formation (Upper Cretaceous: lower Turonian) at Vallecillo, Nuevo León State, northeastern Mexico. On the basis…

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