Mitochondrial and nuclear assessment of Ferruginous Pygmy-Owl (Glaucidium Brasilianum) Phylogrography

Sequences of the cytochrome b gene and genotypes from 11 polymorphic microsatellite loci were used to assess phylogeographic variation in ferruginous pygmy-owls (Glaucidium brasilianum) from Arizona, Mexico, and Texas. Analysis of mtDNA indicated that pygmy-owl populations in Arizona and Texas are unique, with no shared haplotypes. Populations from Sonora and Sinaloa, Mexico, were distinct from remaining populations in Mexico and grouped closest to haplotypes in Arizona. Nested clade analysis of mtDNA sequence data indicated past fragmentation separated pygmy-owls into two major groups: 1) Arizona, Sonora and Sinaloa, Mexico, and 2) southwestern (Nayarit and Michoacan), south-central (Oaxaca and Chiapas), and eastern Mexico, along the eastern slope of the Sierra Madre Oriental from Texas to Central America. In addition, analysis of mtDNA variation in several species of Glaucidium support the recommendation that populations of G. brasilianum from Mexico, Texas, and Arizona represent a phylogenetically distinct group from populations occurring in South America. The level of separation between the North and South Americanpopulations justifies granting species status (G. ridgwayi) to the North American population. Analysis of distance matrices derived from genotypes of 11 polymorphic microsatellite loci supports restricted gene flow between pygmy-owl populations in Arizona-Sonora and Sinaloa, and Texas-Tamaulipas and the remainder of states in Mexico. The Arizona-Sonora population showed signs of a recent genetic bottleneck, an observation supported by low population estimates for Arizona (13-117 individuals). Heterozygosity in Arizona, however, was equal to levels recorded throughout Mexico and Texas. Congruent patterns revealed by both mtDNA and nuclear DNA (microsatellites) indicate Arizona and Texas populations are distinct subspecies that require the design and implementation of separate management plans for recovery and conservation efforts.