Phylogeographic and diversification patterns of the white-nosed coati (Nasua narica): Evidence for south-to-north colonization of North America.

White-nosed coatis (Nasua narica) are widely distributed throughout North, Central, and South America, but the patterns of temporal and spatial diversification that have contributed to this distribution are unknown. In addition, the biogeographic history of procyonid species in the Americas remains contentious. Using sequences from three mitochondrial loci (Cytochrome b, NAHD5 and 16S rRNA; 2201 bp) and genotypes from 11 microsatellite loci, we analyzed genetic diversity to determine phylogeographic patterns, genetic structure, divergence times, and gene flow among Nasua narica populations throughout the majority of the species' range. We also estimated the ancestral geographic range of N. narica and other procyonid species. We found a high degree of genetic structure and divergence among populations that conform to five evolutionarily significant units. The most southerly distributed population (Panama) branched off much earlier (∼3.8 million years ago) than the northern populations (<1.2 million years ago). Estimated gene flow among populations was low and mostly northwards and westwards. The phylogeographic patterns within N. narica are associated with geographic barriers and habitat shifts likely caused by Pliocene-Pleistocene climate oscillations. Significantly, our findings suggest the dispersal of N. narica was south-to-north beginning in the Pliocene, not in the opposite direction during the Pleistocene as suggested by the fossil record, and that the most recent common ancestor for coati species was most likely distributed in South or Central America six million years ago. Our study implies the possibility that the diversification of Nasua species, and other extant procyonid lineages, may have occurred in South America.

Rabies in hooded and striped skunks in Arizona.

Arizona is home to four species of skunks, and rabies is enzootic in the region in which their ranges overlap. Examination of state health data from 1985 to 2004 revealed an irregular 4-10 yr periodicity in the number of cases annually, which may be related to past precipitation patterns. The number of rabid skunks peaked during springtime. Locations of rabies epizootics changed over time, but there was no evidence of a large-scale geographic spread. Skunks live-trapped during 1996-2002 had a low prevalence of rabies-virus neutralizing antibodies. This study was the first to document rabies in hooded skunks (Mephitis macroura).

Identification of skunk species submitted for rabies testing in the desert southwest.

Skunks usually are identified by their common name (skunk) when submitted for rabies testing. In the desert southwest (Arizona, New Mexico, Texas, USA; and northern Mexico), there are five species of skunks; four of which can occur in sympatry. To better understand the ecology of skunk rabies in these areas, it is imperative that species be properly identified. We used the displacement loop (d-loop) of the mitochondrial genome to identify to species 24 skunk brain samples submitted for rabies testing in New Mexico from 2001 to 2002. Most were identified as striped skunks (Mephitis mephitis), but hooded (Mephitis macroura) and hog-nosed (Conepatus leuconotus) skunks were also found.

Multitaxonomic diversity patterns along a desert riparian-upland gradient.

Riparian areas are noted for their high biodiversity, but this has rarely been tested across a wide range of taxonomic groups. We set out to describe species richness, species abundance, and community similarity patterns for 11 taxonomic groups (forbs & grasses, shrubs, trees, solpugids, spiders, scarab beetles, butterflies, lizards, birds, rodents, and mammalian carnivores) individually and for all groups combined along a riparian-upland gradient in semiarid southeastern Arizona, USA. Additionally, we assessed whether biological characteristics could explain variation in diversity along the gradient using five traits (trophic level, body size, life span, thermoregulatory mechanism, and taxonomic affiliation). At the level of individual groups diversity patterns varied along the gradient, with some having greater richness and/or abundance in riparian zones whereas others were more diverse and/or abundant in upland zones. Across all taxa combined, riparian zones contained significantly more species than the uplands. Community similarity between riparian and upland zones was low, and beta diversity was significantly greater than expected for most taxonomic groups, though biological traits explained little variance in diversity along the gradient. These results indicate heterogeneity amongst taxa in how they respond to the factors that structure ecological communities in riparian landscapes. Nevertheless, across taxonomic groups the overall pattern is one of greater species richness and abundance in riparian zones, coupled with a distinct suite of species.

Percutaneous aortic valve replacement: gross anatomy and histological findings after transapical and endoluminal resection of human aortic valves in situ.

OBJECTIVE: Transluminal resection of the aortic valve was already successfully carried out by our group. The aim of this study was the analysis of the gross anatomy and the histology of the surrounding tissue after resection. METHODS: Aortic valve resection was performed in postmortem human hearts (endoluminal (EL) n=9, transapical (TA) n=4). After deployment of the aortic valve isolation chamber, the leaflets were resected with a Thullium:YAG laser scalpel (cw, 20W). After resection, the hearts were analyzed to check for lesions caused by resectioning the associated tools. Therefore, gross anatomy and histological analysis were performed (H&E staining). RESULTS: Lesions of the aortic annulus were seen in 3/9 (EL) (depth: 583+/-186 microm) and 2/4 (TA) (120 microm and one complete perforation), lesions of the aorta (ascending-arch-descending) in 4-9-0/9 (EL) and 0-0-0/4 (TA), lesions of the mitral valve in 0/9 (EL) and 0/4 (TA), lesions of the papillary muscle in 0/9 (EL) and 2/4 (TA) (depth: 400 microm and 450 microm), lesions of the endomyocardium in 0/9 (EL) and 4/4 (TA) (depth: 258+/-102 microm). The coronary ostia remained unaffected. CONCLUSIONS: This study shows fewer severe lesions in the aorta after transapical antegrade access compared to the transluminal retrograde approach. Especially noteworthy is that the aortic arch remains unaffected by the transapical procedure. These data demonstrate the transapical approach as less hazardous.