Inland dunes fauna and flora from Paleolake Irritila in the Comarca Lagunera, Coahuila, northern Mexico

Resumen

For over a decade the
Chihuahuan Desert has been considered as a hotspot of biodiversity.
The diverse aquatic ecosystems, especially, are (and were) rich in
mollusk species. The dunes of the Comarca Lagunera, Coahuila,
Mexico, are of major importance due to the well-preserved remains of
animals and plants in a paleolake that covered a vast area in the
region. This paper is the first report of the paleolimnological
investigations of the Paleolake Irritila ecosystems in northern
Mexico. We determined more than 28 species of gastropods, bivalves,
ostracods, algae and one aquatic plant. The dunes contain one of the
richest and most diverse fauna of the late Quaternary of northern
Mexico. The fossils indicate a permanent but shallow lake with
moderate salinity and alkalinity (pH) higher than 8.5, most likely
around 10. Most of the mollusks are distributed outside Mexico and
restricted to northern latitudes (northern United States and
Canada). Several of them are endemic to the southern United States
(Florida, Nevada, and Texas). For the first time in North America,
using the local fauna and flora preserved in dune sediments, we try
to reconstruct the paleoenvironmental conditions in northern Mexico
during the late Quaternary.