In this paper, I present a model of community assembly in the salamander genus Desmognathus based on a survey of assemblage composition throughout the range of the genus. The 21 species of Desmognathus can be sorted into three life-history categories, namely, stream, streamside, and forest, based on duration of the larval phase and a suite of other life-history and morphological traits that are correlated with habitat use of the several life-history stages. In most assemblages having all three life-history categories, stream species are larger than streamside species, and the latter species are larger than forest species. An evaluation of the literature on interspecific competition and predation (i.e., intraguild predation) in Desmognathus indicates that these processes are important in structuring assemblages of these salamanders. Thus, niche assembly, as opposed to dispersal assembly (i.e., neutral model), seems to be a valid model of community assembly in Desmognathus. Only streamside species occur throughout the range of the genus, and these forms alone are found around the periphery of the range. One to three streamside species form the base of extant assemblages of Desmognathus, with stream and forest species contributing to the more diverse assemblages of the southern Appalachian region. The maximum numbers are two or three streamside species, two or three stream species, and two forest species, although assemblages of more than six species are undocumented. I suggest that the rapid evolutionary diversification in body size and life history in Desmognathus that has generated the complex assemblages of this genus in the Appalachians has been facilitated by a high level of life-history symmetry in these salamanders.

The Mexican Plestiodon brevirostris species group (Squamata: Scincidae) is composed of seven nominal species. The wide-ranging P. brevirostris is a polytypic species composed of five subspecies: P. b. brevirostris, P. b. bilineatus, P. b. dicei, P. b. indubitus, and P. b. pineus. A tree-based approach for species delimitation with mtDNA data was used to test the traditional species-level taxonomy of P. brevirostris preliminarily. A haplotype phylogeny for all of the species and subspecies in the P. brevirostris group, except P. colimensis, was inferred. The mtDNA data consisted of sequences encompassing the genes encoding 16S rRNA (part), ND1, and associated tRNAs (1355 base pairs), which were analyzed with Bayesian methods. Then, a search for diagnostic morphological characters for the putative species delimited by this approach was performed. The results indicate that the P. brevirostris group is paraphyletic with respect to P. lynxe, and that P. brevirostris actually is composed of at least five distinct lineages disguised by traditional taxonomy: P. b. brevirostris, P. b. bilineatus, P. b. dicei, and the eastern populations of P. b indubitus (from Morelos, Guerrero, and México) represent distinct species, whereas the western populations of P. b. indubitus (from Colima and Jalisco) represent an undescribed species. The data cannot resolve whether P. b. pineus is conspecific with P. b. dicei or P. b. dicei is a paraphyletic ( = nonexclusive) species relative to an exclusive P. b. pineus. Thus, the status of P. b. pineus remains uncertain. The haplotype phylogeny also suggests that P. b. brevirostris may represent more than one species.

We studied the spatial ecology of Common Side-blotched Lizards (Uta stansburiana) in the northern Great Basin desert of eastern Oregon. Over 3 yr (2007–2009) we collected 3675 coordinates from 51 males and 60 females during the breeding season (mid-May to early July). We found significant variation among years and between the sexes in home-range size, but contrasting evidence for a relationship between body size and home-range size. Lizard home ranges overlapped those of other lizards extensively and the number of overlapping home ranges within and between the sexes as well as the percentage of unique home range varied among study years. However, we found no evidence that lizards are minimizing their overlaps with the same sex and maximizing their overlaps with the opposite sex. By studying home ranges over multiple years we found that lizards exhibit strong year-to-year fidelity in home-range location, which may be a consequence of relatively high interannual survival. We also present long-term data on the home ranges of Common Side-blotched Lizards from a population in central California that were studied for 8 (females) or 10 (males) consecutive yr as well as new analyses of Tinkle's (1967a,b) 6-yr dataset from west Texas. We found that winter rainfall, population density, and lizard sex were significant predictors of home-range size across years within both sites, though the effects of density and sex appear to be more robust than rainfall. By combining data on home-range ecology from nine study populations of Uta stansburiana, we tested for the effects of latitude of origin, rainfall, population density, and lizard sex on home-range size across the geographic distribution of this species. Similar to our results within sites, rainfall, density, and sex have significant effects on home-range size when comparing sites, but again the effects of density and sex appear to be more robust than rainfall. Latitude of origin also appears to explain variation in home-range size independent of ecosystem productivity (i.e., rainfall, density). Thus, we conclude that ecosystem productivity is an important determinant of density and spatial ecology of lizard populations and that even modest fluctuations in productivity may influence population density and home-range ecology, but that latitude of origin remains important independent of these factors.

With robust new datasets from morphology and DNA sequences, we review the limbed, nonpentadactyl species of the Brachymeles samarensis complex (now known to include B. cebuensis, B. minimus, and B. lukbani), and describe five new species in this highly limb-reduced, endemic Philippine clade of scincid lizards. For more than four decades, B. samarensis has been recognized as a single “widespread” species. This perception of the species' peculiar geographic range has persisted as a result of weak sampling and similar gross morphology (body sizes, scale pigmentation) among populations. However, previous authors have noted morphological variation between different island populations, and our new data build on these observations and extend them to delimit new proposed species boundaries. Our data indicate that the “widespread” species B. samarensis is actually a complex of six distinct lineages, some of which are not each others' closest relatives, and each of which is genetically unique. The taxa we define possess allopatric geographic ranges and differ from their congeners by numerous diagnostic characters of external morphology, and therefore should be recognized as full species in accordance with any lineage-based species concept. Species diversity in the genus has doubled in the last 3 yr, with these six taxa increasing the total known number of species of Brachymeles to 30.

The common, terrestrial teiid lizards of the Ameiva ameiva complex have a broad Neotropical distribution from Costa Rica and Panama to Paraguay and northern Argentina. These lizards have also been reported from the Lesser Antilles, Trinidad, Tobago, Providencia, and the Swan Islands. The group has a complicated taxonomic history and has not been comprehensively reviewed. With the use of external morphology, we reviewed this complex in Venezuela. We conclude that A. ameiva (sensu lato) in Venezuela comprises at least four evolutionary species and recommend elevating A. ameiva (sensu stricto), A. atrigularis, and A. praesignis to species. On the other hand, we synonymize A. ameiva fischeri, A. a. ornata, and A. a. vogli, with A. praesignis; we synonymize A. a. laeta and A. a. petersii with A. ameiva; and we synonymize A. a. melanocephala with A. atrigularis. We designate a lectotype of A. atrigularis. Populations from savannahs of southern Monagas represent a new species described in this work. Both A. ameiva and A. praesignis exist as apparently viable breeding populations in southern Florida, USA.