| A phylogeny of the genus Uma was reconstructed from a maximum parsimony analysis of DNA sequence data from two mitochondrial genes. All species of fringe-toed lizards were included. Comprehensive geographic sampling was undertaken to determine genetic variation among geographically isolated populations. In total, 1630 combined base pairs were sequenced for 175 individuals from 56 populations. The fringe-toed lizards grouped into seven primary clades, or phylogenetically diagnosable and exclusive species. Five clades were already recognized as species, one clade was a subspecies, and the seventh was unknown and represented cryptic biodiversity. Both newly designated species occurred within the U. notata group.; Fringe-toed lizards are philopatric and populations are naturally fragmented on sand dunes and ramps. In the southwestern deserts, direct and indirect impacts of anthropogenic activities threaten the survival of fringe-toed lizards. Major threats include agriculture, development, habitat destruction, off-road vehicle use, and the introduction of windbreaks that reduce or eliminate natural sand corridors. Because of this intrinsic vulnerability, populations within nominal species were evaluated phylogenetically and prioritized for conservation management. All species are designated at various levels of being at risk of extinction by federal or regional governments. The Coahuila fringe-toed lizard, Uma exsul, is currently listed as rare in Mexico but should be considered endangered. Present efforts involve the creation of the first wildlife sanctuary at Bilbao Dune to protect this flagship species. In California, two genetically distinctive clades occur within the Mojave fringe-toed lizard, Uma scoparia. One clade includes populations in and adjacent to Death Valley National Park, with a secondary clade from nearby Red Pass Dunes. These lizards should be protected due to ongoing habitat degradation. This area has high endemicity and is a potential biodiversity hotspot. Further research into the conservation and management of the fringe-toed lizards is essential due to ongoing threats to survival and slow recovery times of desert habitats. |
