Phylogeographical convergence between Astyanax cavefish and mysid shrimps in the Sierra de El Abra, Mexico

The Sierra de El Abra is a long (120 km) and narrow (10 km) karstic area in northeastern Mexico. Some studies have suggested independent evolutionary histories for the multiple populations of blind cavefish Astyanax mexicanus that inhabit this mountain range, despite the hydrological connections that may exist across the Sierra. Barriers between caves could have prevented stygobitic populations to migrate across caves, creating evolutionary significant units localized in discrete biogeographical areas of the Sierra de El Abra. The goal of the present study was to evaluate if there is a correspondence in phylogeographical patterns between Astyanax cavefish and the stygobitic mysid shrimp Spelaeomysis quinterensis. Astyanax mtDNA and mysid histone H3 DNA sequences showed that in both species, cave populations in central El Abra, such as Tinaja cave, are broadly different from other cave populations. This phylogeographical convergence supports the notion that the central Sierra de El Abra is a biogeographical zone with effective barriers for either cave to cave or surface to cave gene flow, which have modulated the evolutionary history across species of its aquatic stygobitic community