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We quantified reproductive phenology for three lizard species collected in northeastern Costa Rica over a 14-month sampling period from November 1973 to December 1974. Two species, a gecko (Lepidoblepharis xanthostigma) and a skink (Sphenomorphus cherriei), reproduced continuously at this site, whereas an anole (Norops limifrons) showed a slight decline in reproduction during the dry season. The decrease in reproduction of N. limifrons may reflect a response to moisture stress during the driest part of the year. When seasonal patterns of reproduction among 32 populations of Neotropical lizards with small clutch sizes were analyzed with the effect of phylogenetic relatedness removed, we found that seasonality of reproduction was strongly related to mean annual rainfall but not to number of dry season months.
A new species of Philautus is described from Ponmudi Hill in the Western Ghats of India. It can be distinguished from all other members of the genus by the combination of its rather robust body, relatively large snout–vent length, rounded snout, protruding eyes, and vermiculated coloration of the posterior surface of the tibia. It is one of the largest species of the genus in the Western Ghats (adult males of type series up to 38.9 mm). It is currently known only from the type locality, where it is essentially an inhabitant of the canopy.
One or both sexes exhibit territorial behavior in all dendrobatids that have been studied. Two types of territoriality are identified. In some Colosthethus species only females or both sexes defend small nonreproductive territories that offer access to water, food, and shelter. In other species, only males defend large reproductive territories against conspecific calling males, suggesting that females are the limited resource. However, in no case has the defended resource been unambiguously identified. I hypothesize that, in at least some species, males compete for calling sites in areas with high female density and with favorable sound transmission features. I found little support for the hypothesis that dendrobatids exhibit resource defense polygyny. More research is necessary to understand the function of territoriality and to identify limiting resources in poison frogs.
We tested whether the presence of an iridovirus (Ambystoma tigrinum virus; ATV) could alter patterns of larval life histories in Arizona Tiger Salamanders (Ambystoma tigrinum nebulosum). Viral epidemics cause extreme mortality in natural populations and, thus, impose a strong selective force. We tested how exposure to ATV during larval development influences survival, growth, and frequency of cannibalism by manipulating the presence of ATV in replicated experimental tanks. ATV significantly reduced survival and larval growth. Propensity to become cannibalistic was not related to ATV exposure, suggesting that salamanders cannot facultatively respond to the presence of diseased conspecifics by reducing cannibalism. Our results demonstrate that viral pathogens may have both a direct and indirect effect on A. tigrinum fitness by reducing survival and growth rate.
Eleutherodactylus heterodactylus was rediscovered in Cerrado montane forest of eastern Bolivia, 250–300 km airline from its type locality in Brazil, in similar habitat. The advertisement call is described for the first time. This species shares morphological features with species of the Eleutherodactylus binotatus and Eleutherodactylus discoidalis groups but is not assigned to either group pending further study. We confirm that Eleutherodactylus crepitans and Eleutherodactylus dundeei are valid species easily distinguishable from Eleutherodactylus fenestratus. Bolivian populations of the Andes previously assigned to E. dundeei correspond to an undescribed species allied to Eleutherodactylus peruvianus.
A new species of Clelia Fitzinger, 1826, is described on the basis of 37 specimens. It differs from all other Clelia by having two loreals and a higher number (21 vs. 19) of dorsal scale rows in the neck region. The species is probably endemic to the Bolivian inter-Andean dry valleys.
Geographic variation in the presence/absence of generation glands in female lizards of the cordylus-niger-oelofseni complex was described and correlations with climatic variables investigated. Preserved and live specimens from 95 localities in the area south of 32°30′S and west of 19°45′E in the Western Cape, South Africa, were examined for the presence or absence of generation glands. A GIS analysis was performed to determine mean annual minimum temperature, mean annual maximum temperature, potential evaporation, mean annual precipitation, mean annual fog, and mean annual cloud cover for each locality. Discriminant function and canonical analyses showed highly significant correlations between presence and absence of generation glands and five of the six climatic variables. Females from western coastal localities and from the Cape Fold Mountains generally lacked generation glands, whereas females from inland lowland localities generally possessed glands.
I evaluated the life history of Florida Sand Skinks (Neoseps reynoldsi), fossorial lizards endemic to central Florida. Based on museum specimens, literature records, and field captures, sand skinks have a single mating period each year, lasting from February through May. Females produce a single clutch each year between May and June, although some reproduce biennially or less frequently. Mean clutch size from counts of enlarged follicles and eggs was 2.2 (range two to three; if only oviducal eggs are counted, clutch size was two). Mark-recapture data indicate that sand skinks do not reproduce before 19–23 months of age and that sand skinks can live to at least eight to 10 years of age. The suite of life-history traits shown by sand skinks (low frequency of reproduction, small clutch size, late maturity, and long lifespan) is similar to those of other fossorial lizards.
We studied the cryptic fossorial legless lizard (Anniella pulchra) in a 1.57-ha area of sand dune on the coast of central California. This is the largest and most dense population of A. pulchra (N = 3,582; 0.228/m2) known to date. We documented distribution of animals through systematic removal and relocation of lizards at the site and with GIS analyses. Lizard density was high near shrubs and where soil moisture was greater but lower in disturbed soils and in iceplant. We also conducted time-constrained searches and coverboard surveys to analyze the efficacy of standard survey methods for legless lizards. Moderate-impact time-constrained searches were more effective in establishing presence of lizards when compared to low-impact time-constrained searches and coverboard surveys. Our data show that standard methods may not be effective in establishing presence or absence of this lizard at low densities. None of the survey methods was effective in predicting the density of lizards actually present.
West Indian rock iguanas (genus Cyclura: Iguanidae) are among the most endangered lizards in the world, and many species will need to occupy human-modified and -occupied habitats to escape extinction. The Grand Cayman Blue Iguana, Cyclura lewisi, is critically endangered with fewer than 25 wild iguanas remaining. To aid the conservation of this and other iguanas, we investigated the spatial ecology of a captive-bred, released population of C. lewisi occupying a botanic park on Grand Cayman. Iguanas were monitored using transect walks and radio telemetry during the summer and fall of 2002. Males used larger areas and had greater movement distances than females during tracking periods in the summer but not in the fall. Overall home ranges for both seasons combined were larger in males than in females. Some home-range estimates were greater than any previously reported in Cyclura. Several iguanas, especially males during the breeding season, used areas outside the park where they are vulnerable to increased predation, death by vehicle, and hunting or collection by humans. This, combined with the large average home-range sizes for this species, indicate that future reserves for C. lewisi should be large and surrounded by buffer zones or fences.
A new species of Telmatobius is described from humid paramo of southeastern Peru and western Bolivia. Males of the new species differ from those of Telmatobius sanborni, the only other species of Telmatobius in the area, mainly by lacking hypertrophied forearms and having smaller nuptial spicules; in addition, color patterns are different. The apparent low diversity of forest Telmatobius in southern Peru may be an artifact of lack of research on this group of frogs in this region.
I reared four species of anurans (Rana sphenocephala [Southern Leopard Frog], Rana blairi [Plains Leopard Frog], Rana clamitans [Green Frog], and Bufo woodhousii [Woodhouse's Toad]) for seven to 12 months in small, outdoor terrestrial enclosures (1 × 2 m) to examine the consequences of larval competition (via density) and contaminant exposure (via the insecticide carbaryl). I added six Rana clamitans, eight Rana sphenocephala, eight Rana blairi, and 10 Bufo woodhousii to terrestrial enclosures shortly after metamorphosis and recaptured them during the following spring. All anurans from low-density ponds were significantly larger than those from high-density ponds, but these size differences did not significantly affect survival to or size at spring emergence. However, R. sphenocephala, R. blairi, and R. clamitans that survived to spring had been larger at metamorphosis on average than those that did not survive; in contrast, B. woodhousii that survived the winter were smaller at metamorphosis on average than those that did not survive. Carbaryl exposure affected mass at metamorphosis of R. clamitans and B. woodhousii that were added to enclosures, but this difference disappeared or did not increase by spring emergence. Overall, exposure to carbaryl during the larval period did not have any apparent effects on survival or growth during the terrestrial phase. In my study, anurans were able to offset small size at metamorphosis with terrestrial growth, although there was a trend of reduced overwinter survival for ranid species that metamorphosed at a smaller size.
A new species of Crytodactylus from Pulau Aur in the Seribuat Archipelago off the southeast coast of Peninsular Malaysia is differentiated from all other Sundaland species in having a unique suite of characteristics involving tuberculation, scale counts, and color pattern. This increases the total number of endemic species in the Seribuat Archipelago to at least 18 and is the second endemic gecko known from Pulau Aur.
We analyzed variation in growth in the lizard Xenosaurus grandis in a seasonal tropical environment in Veracruz, México. We used the logistic-by-length model to represent the growth pattern of these lizards. Males and females did not differ in estimated asymptotic size or the characteristic growth parameter. Estimated growth curve predicted an age at maturity of 28 months for males and 32 months for females. Size independent growth rates were higher during the wet season, and did not differ among years. The interaction among body mass, food abundance, and maximum, minimum, and average temperatures significantly affected growth rates. Our results suggest that variation in body growth is predominantly driven by seasonal resource limitation.
Anolis porcatus is a tropical lizard endemic to Cuba. Monthly samples of lizards were obtained from the urban area surrounding Havana, Cuba. Testicular size and weight in males, and oocyte diameter and the presence of oviductal eggs in females, varied with season. Histological examination of gonads indicated a seasonal pattern in mature gametes for both sexes. In males, the spermatogenic process began with early gonadal recrudescence in November and the testes attained maximal spermatogenic activity between March and August. Spermatogenesis diminished during September and ceased in October. In females, only previtellogenic follicles were observed in the ovaries from November through February, and vitellogenesis began in March, and the first oviductal eggs were observed during late April. Vitellogenesis and oviductal eggs were observed from April to October. The timing of the gametogenic events indicates that male and female gonadal cycles are synchronized, corresponding to prenuptial spermatogenesis.
Vocalizations are important in anuran communication, especially during the breeding season. Calling affects spatial organization of males at breeding sites, promotes attraction of new individuals to the chorus, and attracts mature females for reproduction. We describe four distinct vocalizations (advertisement calls, sporadic calls, and two types of aggressive calls) emitted by adult males of Scinax fuscomarginatus. With the exception of the advertisement call, the remaining descriptions are novel. We also describe calling sites, calling season, and nightly calling activity. Fieldwork was made in a fragment of Cerrado (Estação Ecológica de Itirapina), Municipalities of Itirapina and Brotas, State of São Paulo, southeastern Brazil. At this ecological station, S. fuscomarginatus exhibits a complex acoustic repertoire, social interactions and a prolonged reproductive pattern similar to observations of congeneric species at other localities.
A new species of ranid frog of the genus Nyctibatrachus is described from Castle Rock, Karnataka State, Southwest India. The new species is compared with all known congeners and is diagnosed by the following combination of characters: head wider than long; snout projecting beyond mouth; supratympanic fold poorly defined; webbing on toes reaching base of disks except on Toe IV, where it reaches distal subarticular tubercle; tips of digits on fingers and toes flattened to form disks with distinct grooves separating dorsum of disks from venter; and femoral gland present. The largest specimen in the type series has a snout-vent length of 43.2 mm. Nyctibatrachus hussainiKrishnamurthy, Reddy and Gururaja, 2001, is shown to be an invalid nomen, for lack of typification.
A new species of Stenocercus is described from the eastern slopes of the Andes in central Peru, Departamentos Ayacucho and Huancavelica. It differs from other Stenocercus by the combination of the following characters: scales on posterior surface of thighs granular, lateral body scales imbricate and keeled, vertebral row of enlarged scales present, gular scales unnotched, neck folds present, three caudal whorls per autotomic segment, postfemoral mite pocket absent, dorsal ground color gray or brown, without a black shoulder patch in males. Specimens of the new species have been misidentified as Stenocercus variabilis, which occurs allopatrically in Departamento Junín.
Removal of vegetation directly surrounding a breeding pond has the potential to significantly alter the environmental conditions experienced by larval amphibians during development and, therefore, may affect the life history of this and subsequent life stages. In this study, we investigated growth, development, and survivorship of Litoria ewingii as a result of different shading conditions in a commercially logged forest in Tasmania, Australia. We specifically investigated responses in two types of breeding ponds available to the species: permanent ponds, and smaller ephemeral ponds. Increased shading in permanent ponds resulted in reduced survival. Larval growth and development did not respond significantly to shading treatment in permanent ponds but were significantly affected by pond elevation. In ephemeral ponds, increased shading resulted in decreased developmental rate and a higher coefficient of variation for size at metamorphosis. Our findings suggest that the larval success of L. ewingii is not likely to be enhanced by vegetative buffer zones around permanent pond margins but may be enhanced by ensuring heterogeneity of shading conditions around ephemeral ponds.
Green Salamander (Aneides aeneus) habitat has been described traditionally as rock outcrop formations that contain moist, but not wet, crevices. Early studies of Green Salamander natural history claimed arboreal habitat was used secondarily to rock outcrops and in situations where more suitable habitat was unavailable. Although arboreal behavior of western Aneides has been well established, arboreal habitat has been deemed “not typical” for Green Salamanders. This study examined the extent to which Green Salamanders use arboreal habitat. Surveys were conducted between August 2001 and July 2004 at a study area in Pickens County, South Carolina. Salamander size influenced arboreal habitat use, but gender and reproductive condition did not. There was a positive relationship between tree diameter at breast height (DBH) and Green Salamander observations and a negative relationship between tree distance to rock outcrop and salamander observations. Tree selection did not reflect tree species relative dominance, and salamanders favored hardwoods over conifers. Seasonal use of arboreal habitat was distinct, implying that salamanders overwinter in rock outcrops and move into trees and logs at the onset of spring. Salamanders observed during summer were primarily arboreal, but they returned to rock outcrops in late fall. Researchers have largely overlooked arboreal habitat use by Green Salamanders, and consequently, the importance of arboreal habitat near rock outcrops has been underestimated. Arboreal habitat appears to be an important component of the life history of this declining species, and future survey and monitoring efforts should include searches of arboreal habitat.
Five specimens of Lepidophyma radula were collected recently near San Pablo Villa de Mitla, Oaxaca. The species had not been collected since its description in 1942. A redescription of the holotype is presented, including new and important taxonomic characters proposed by other workers.
Although many lizard species detect and respond to conspecific chemical cues, variation in this ability among populations of the same species from different habitat types is less well understood. We compared chemoreceptive behaviors and head-bobs in response to conspecific chemical cues by Ornate Tree Lizards (Urosaurus ornatus) between populations from an upland forested habitat and a lowland desert habitat. Under this experimental design, U. ornatus from different habitats performed chemoreceptive behaviors and head-bobs at similar rates. Rate of chemoreceptive behaviors and head-bobs in response to chemical cues deposited by same- and opposite-sex conspecifics was higher than that of cues deposited by the subject in their home tank, demonstrating that U. ornatus has the ability to detect cues from conspecifics. Head-bob rate was also higher in same- and opposite-sex tanks compared to home tanks, demonstrating that chemical cues alter the rate of a social display behavior. Urosaurus ornatus exhibited chemosensory behavior at rates similar to rates reported for this species and lower than those reported for other phrynosomatid lizards, suggesting a lower reliance on chemical cues in social interactions.
Phylogenetic relationships of Corallus caninus phylogeny were examined with DNA samples from five geographically disparate localities from across the range of the species (Guyana, Venezuela, Brazilian states of Pará and Rondônia, and Peru). The Peruvian sequence was the most divergent (16.2%) and the closest relative of a clade including Brazilian, Guyanan, and Venezuelan populations. Within the latter clade, the most basal lineage was from the state of Pará, followed by the state of Rondônia, which was the closest relative of populations from the Guiana Shield. Preliminary morphological data paralleled molecular results, and it is likely that a separate species of Corallus currently included in C. caninus occurs in the upper Amazon.
Aspects of the ecology of the semiarboreal lizards Enyalius bilineatus and Enyalius brasiliensis were studied in a montane Atlantic forest region of Espírito Santo State, southeastern Brazil. Individuals of E. bilineatus were collected mainly in a coffee plantation, whereas E. brasiliensis was found only in the forest proper. Enyalius brasiliensis was significantly larger (up to 106 mm snout—vent length, SVL) than E. bilineatus (up to 90 mm SVL). Both species were sexually dimorphic in body size, with females larger than males. The two species consumed a broad spectrum of prey but differed quantitatively in their diet composition. Ants and orthopterans dominated the diet of E. bilineatus, whereas E. brasiliensis preyed mainly on cockroaches and caterpillars. Clutch size of E. bilineatus varied from 2–6 (mean = 4.4) and that of E. brasiliensis from 8–14 (mean = 11.5). Ecological differences between the two species may result in differential susceptibilities to habitat perturbation, with E. bilineatus being more tolerant of disturbed areas and perhaps even benefitting from anthropic action, unlike the forest-dependent E. brasiliensis.
We examined museum specimens of the Common Barking Gecko (Ptenopus garrulus) from the Kalahari and Namib Deserts to assess sexual size dimorphism, reproductive status, and diet. Males had significantly wider heads than females of the same body size; however, P. garrulus showed no sexual dimorphism in any other morphological character. The smallest mature male was 36 mm snout–vent length, whereas the smallest female was 31 mm. Peak reproductive activity for both sexes was in September and October. Clutch size was fixed at one large egg (average size = 5.9 × 4.4 mm); all eggs were in the right ovary, but more than one clutch may be laid in a single breeding season. Ptenopus garrulus, when compared with other geckos, produces very large offspring and thereby invest heavily in a single offspring. We recorded 15 arthropod orders in the diet of P. garrulus. Termites dominated their diet both numerically and volumetrically. Males and females ate prey of similar taxa and sizes, suggesting that trophic partitioning is absent. Therefore, the evidence suggests that the evolution of head width differences is driven by male contest competition.
Eggs from five clutches of Chamaeleo calyptratus were incubated at 25, 28, and 30°C during the period of sex determination. Sex ratios were slightly biased toward females at all temperatures but did not differ statistically from the expected 1:1 ratio of males and females. Egg survival was sufficiently high that sex-biased temperature-induced mortality cannot account for the lack of departure from 1:1 sex ratios. I conclude that the veiled chameleon has genetic sex determination (GSD) and that anecdotal accounts of temperature-dependent sex determination (TSD) for this species, and other chameleons are likely to reflect reporting or statistical bias.
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