Collaborators: Jairo Arroyave (UNAM), C. Patricia Ornales-García (UNAM) & Elizabeth S. Alter (York College)
This newly established research project takes me to the land of the Mayans, the Yucatán Peninsula of Mexico (Fig. 1). The karstic landscape of the peninsula was formed by the dissolution of an underlying limestone platform, resulting in a region devoid of rivers, and with a scattered network of hundreds of water-filled cenotes, or sinkholes. These cenotes vary in environmental conditions, notably with respect to their connections to groundwater flow. Additionally, some are open to the air (Fig. 2), while others are fully contained within cave systems (Fig. 3).
Little is known of the degree to which subterranean waterways facilitate connectivity of populations among cenotes. In collaboration with investigators from the U.S. and Mexico, I am researching the morphology and phylogeography of cenote fishes. Ichthyofaunal communities within individual pools are low in diversity, and while some species are patchily distributed, others are consistently found across the peninsula.
Initially, we are focusing on species that we expect to differ in their abilities to migrate between cenotes. For example, one species of interest is the the mostly surface-dwelling, trans-andean catfish, Rhamdia guatemalensis (Fig. 4), which contrasts the troglodytic blind brotula, Typhliasina pearsei (Fig. 5), that is endemic to southern Mexico. We will be using both morphometric and molecular methods to understand patterns of connectivity and local adaptations of these species and others occurring in cenotes within the states of Yucatán and Quintana Roo.
Arroyave J, Martinez CM, Martínez-Oriol FH, Sosa E & Alter SE. In Press. Regional-scale aquifer hydrogeology as a driver of phylogeographic structure in the Neotropical catfish Rhamdia guatemalensis(Siluriformes: Heptapteridae) from cenotes of the Yucatán Peninsula, Mexico. Freshwater Biology.
Theodore Roosevelt Memorial Grant (AMNH)