It has frequently been reported that species with strong niche conservatism will not be able to adapt to new climatic conditions, so they must migrate or go extinct. We have evaluated the shifts in climatic niche occupation of the species Astrophytum coahuilense and its potential distribution in Mexico. We understand niche occupation as the geographic zones with available habitats and with the presence of the species. To assess shifts in climatic niche occupation, we used niche overlap analysis, while potential distribution modeling was performed based on the principle of maximum entropy. The results indicate that this species presents a limited amplitude in its climate niche. This restriction of the climatic niche of A. coahuilense limits its ability to colonize new geographical areas with different climatic environments. On the other hand, the potential distribution models obtained from the present study allow us to identify potential zones based on the climatic requirements of the species. This information is important to identify high priority areas for the conservation of A. coahuilense.

Catfishes of the genus Ictalurus (Ictaluridae) range geographically from southern Canada to northern Guatemala and Belize. The systematics of this genus remain unresolved, with recent studies suggesting the presence of cryptic diversity. This is the case for a potentially undescribed catfish species distributed in the Nazas River basin, which has been recorded to date as a population of Ictalurus pricei. Recent phylogenetic studies suggest that it represents an independently evolving lineage that is distinct from I. pricei. This study aimed to determine the diagnostic characters that differentiate the Nazas River basin lineage and to describe this lineage as a new taxon. Morphological comparisons were made using meristic and morphometric characters. The study identified useful meristic and morphometric characters for diagnosing Ictalurus nazassp. nov., which differentiate it from I. pricei.

We describe two new species and a new record of stygobitic gastropods from small groundwater-fed springs in Candela, Coahuila, northern Mexico. Phreatomascogos garciasaucedoi n. sp. is described based on shell morphology and is the second species of this formerly monotypic genus. According to the current classification, we have transferred this genus to Cochliopidea. Phreatodrobia candelensis n. sp. is described, and represents the first record of the genus in Mexico extending its known range more than one hundred kilometers to the south. Also found with the new stygosnails was Coahuilix hubbsi Taylor, 1966, which was previously known only as an endemic species from the neighboring Cuatro Ciénegas valley. The reported new subterranean snails are restricted in their distributions to two small water sources only a few meters long which flow directly into a touristic zone with swimming pools and other recreation areas. Using NatureServe Ranking, both new species were assigned as critically imperiled. The very limited distribution and negative anthropogenic impacts within the sites should draw special conservation attention for the reported stygobionts.

This paper describes a new genus and species of stygobitic gastropod from a small groundwater-fed spring in Los Chorros, Coahuila, northern Mexico. Microphreatus saltillensis gen. et sp. nov. is described based on shell morphology, because so far, no living individuals could be obtained. Conchologically, the new genus can be well distinguished from all other subterranean genera by a unique combination of characteristic proto- and teleoconch features. We also reassigned into the new genus Balconorbis coronae (Hershler, 1987), a subterranean snail from Southwestern Texas, so that the new genus consists of two species. One of the most striking features of the new snail is its extremely small shell (about 0.73 mm shell width, 0.36 mm shell height) making the species probably the world’s smallest known freshwater gastropod. Microphreatus saltillensis gen. et sp. nov. is restricted in its distribution to a small water source in a touristic recreation area. This limited distribution and increased anthropogenic impacts make conservation efforts urgently necessary.

Durante el reconocimiento de la diversidad de insectos y otros invertebrados acuáticos del río Nazas en el Cañón de Fernández en Lerdo, Durango, México, en la época de lluvias (agosto y septiembre) del 2023 se realizó una campaña de muestreo multi hábitat. Se encontraron cinco larvas de Climacia chapini (Parfin y Guney) (Neuroptera: Sisyridae) asociadas a esponjas de agua dulce Eunapius sp., y Ephydatia sp. Esto representa el primer reporte de C. chapini en estas esponjas en el Neártico. Dada la ubicación geográfica de los sitios muestreados se sugiere que C. chapini se puede distribuir a lo largo de todo el río en esta área natural protegida.