We use data from external morphology and mitochondrial gene sequences to provide the basis for a taxonomic revision of two polytypic, pentadactyl Philippine species of scincid lizards of the genus Brachymeles. Although previous studies have noted significant morphological variation among island populations, the similarities in body size and scale pigmentation and pattern have led to the continued recognition of these two “widespread species.” A third, widespread, pentadactyl species, Brachymeles talinis, is known from Jolo Island and the central and northern Philippine islands. We evaluate both morphological and genetic data to define species limits in B. boulengeri, B. schadenbergi, and B. talinis. Our molecular and morphological data indicate each of the four subspecies of B. boulengeri, and both subspecies of B. schadenbergi, are genetically distinct, with ranges biogeographically circumscribed, differ from their congeners by numerous external morphological features, and therefore should be recognized as full species. Our morphological and genetic data necessitate the recognition of northern populations of B. talinis (from Luzon Island) as a new species and also reveal an unanticipated new species from Masbate Island. Finally, morphological data require the recognition of the B. talinis population from Jolo Island as a unique, new species. These 10 taxa elevate the total known number of species of Brachymeles from 18 to 25.

We review the taxonomic status of Philippine bent-toed geckos previously referred to Cyrtodactylus agusanensis. We delineate four evolutionary lineages within the C. agusanensis complex from the southeastern islands of the archipelago and describe three of these lineages as new species. The new species and true C. agusanensis are identified by numerous, nonoverlapping morphological characters and by allopatric ranges on separate islands. Our morphology-based taxonomic conclusions are bolstered by biogeographic evidence and marked interspecific divergence between monophyletic groups defined by mitochondrial and nuclear DNA sequences. To compliment these descriptions and enable future taxonomic work on Philippine Cyrtodactylus, we rediagnose and redescribe C. agusanensis. Because the holotype of C. agusanensis was destroyed in World War II, we designate a neotype for this species and restrict its geographic range to north central Mindanao Island. Our phylogenetic estimate suggests that the C. agusanensis complex originated in Mindanao and spread progressively north, diversifying incrementally with colonization of successive islands in a south-to-north pattern of biogeographic expansion and allopatric speciation.

The endangered iguana Cyclura cornuta stejnegeri is endemic to Mona Island, Puerto Rico. Factors accounting for its protected status include low adult densities and relatively low abundance of juveniles. We studied the spatial ecology, territoriality, and philopatric behavior along a gradient of human-disturbed areas to increase our understanding of its unusual demography. We used the minimum convex polygon (MCP) method to estimate the home range of radiomarked iguanas, the degree of inter- and intrasex home-range overlap, and the temporal patterns of space use by 42 iguanas (19 males and 23 females, including 4 juvenile individuals) during the nonbreeding (October–November) and mating season (June) at three Mona Island localities with different levels of human disturbance. Juvenile iguanas had larger home ranges and move across the home ranges of several adults. Adult males had larger home ranges than females and no significant temporal differences in size or pattern of usage (Cole index) were detected between the study periods. Females, despite reducing their home-range size during the mating season, changed the usage patterns, resulting in increased interactions with neighboring males. Home-range overlap was minimal between males, followed by female–female overlap and maximal between males and females. Our results suggest that Mona Island iguanas are highly territorial throughout the year; particularly males in the mid- and undisturbed areas where almost all home-range areas appear to be equivalent to the defended territory. In the most disturbed area, where supplemental feeding by humans exists, home ranges are smaller and there is larger intersex home-range overlap. Previously, the low density of the population was attributed to lack of recruitment into adult stages due to predation of juveniles by nonnative mammals. However, the high levels of territoriality documented in this study may be an additional factor explaining the low densities exhibited by this population. Our data suggest that the three study sites may be at or close to carrying capacities for males, because there appear to be no vacant areas for additional males. Furthermore, the large and highly overlapping home ranges exhibited by four juvenile iguanas suggest that they are or will become floaters in search of unoccupied space.

Cnemidophorus nigricolor consists of at least three species rather than a single taxon distributed throughout the Venezuelan Caribbean islands. We describe two new species, one from Isla La Blanquilla and another from Isla La Tortuga. Both species were previously confused with C. nigricolor. The species from Isla La Tortuga is critically threatened by recent plans to develop the island for tourism. We comment on similarities among the two new species, C. nigricolor, and other insular Cnemidophorus. The whiptails from the southern Caribbean are revised and diagnoses are given for species inhabiting Aruba, Curaçao, Bonaire, and the Los Roques Archipelago. Additionally, Cnemidophorus ruthveni (formerly C. murinus ruthveni) is recognized as a full species.

We revised the taxonomic status of Atractus species occurring in the eastern slopes of Central Cordillera, Magdalena Valley, and west slopes of Eastern Cordillera of Colombia on the basis of morphological characters (meristics, morphometrics, color patterns, and hemipenes). A lectotype is designated for Atractus obtusirostris. Additional specimens of A. melanogaster are reported for the first time and a neotype is designated for the species. The status of A. werneri is restricted to include only specimens from the western slopes of the Eastern Cordillera. Three new species are described from the eastern slopes of the Central Cordillera. Additionally, we provided a key for species distributed from the eastern Central to the western Eastern Cordilleras of Colombia, and propose a new species group for Atractus based on the sharing of exclusive morphological features.

We studied the population biology of Sonora mud turtles (Kinosternon sonoriense) for 10 yr in an extremely hot and dry desert stream habitat in central Arizona. Adults made up 34.4% of the population. Modeling with Program MARK indicated that both age class (adult vs. juvenile-hatchling) and season contributed significantly to the probability of capture. The presence of exotic crayfish (Orconectes virilis) and age class were significant contributors to turtle survival, supporting the hypothesis that exotic crayfish are important predators on hatchlings. Population density estimates indicated low density over the range of water availability. Both adults and juveniles made long-distance movements along the dry stream bed between pools of water. Males and females were both likely to make long-distance movements and were sometimes absent from the study site for years at a time. In addition to terrestrial estivation in foresummer drought, turtles apparently hibernated on land in winter when standing water was available. Growth fit a von Bertalanffy model very well. We make the first report of growth rates for hatchling K. sonoriense. Growth rates estimated from shell annuli were consistent with similar estimates for older turtles in other studies. Measured growth rates, however, were much higher than annuli-based estimates. In contrast to other populations, we determined that hatchlings and juveniles in our study added 1–3 plastron annuli each year, making age estimation from annuli difficult. Understanding relationships between habitat use, invasive predators, and demographics is essential for effective management of low-density populations.