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We describe a new microhylid frog of the endemic Malagasy subfamily Cophylinae and designate a lectotype for Plethodontohyla notosticta. Plethodontohyla mihanika sp. n. has enlarged terminal disks on all fingers and toes, a distinct border between its dorsal and lateral coloration, and a pointed snout. The new species is recognized by its longer hind limbs, smaller body size (SVL 26–31 mm), and advertisement call. Together with P. notosticta and possibly Plethodontohyla inguinalis, the new species forms a partially arboreal subgroup within the otherwise terrestrial Plethodontohyla. The eggs of the new species are most likely laid in strings, which may be a preadaptation to egg transport by the parents. Males cohabit with eggs, tadpoles, and recently metamorphosed juveniles, suggesting parental care as known from other cophylines.
We describe a new species of Austrochaperina from the Bewani Mountains of northwestern Papua New Guinea. The new species is a member of Zweifel's (2000) “Large” group of Austrochaperina closely related to A. hooglandi, from which it differs in size, color pattern, call parameters, and ecology. It differs from its other 23 congeners in a variety of morphological and color pattern attributes, and in advertisement call.
We assessed relative abundance, demographic, and reproductive success data for two lizard species in a Northern Arizona ponderosa pine forest, a fire-dependent system unnaturally modified by fire suppression over the past century. During May to October 1997–1999, we employed up to 70 pitfall arrays to sample lizards over 6990 array-days. At each array, we described macro-vegetative cover, stand, and microhabitat characteristics. Sceloporus graciosus responded to habitat variation at all three spatial scales. Adult S. graciosus were widely distributed among cover and stand types. However, reproductive success and hatchling abundance were highest in the most open cover (meadow) and stand (savannah) types, and lowest in pure ponderosa cover and dense ponderosa stands. Adult females replaced themselves annually only in meadows, savannahs, and forest with a deciduous component. Eumeces skiltonianus adults and juveniles were least abundant in meadows, but females replaced themselves each year in meadow and ponderosa-pinyon-juniper vegetative cover and in savannahs. Hatchlings were least abundant in intermediate- and high-density ponderosa stands, whereas juveniles of both species were most abundant in areas containing a deciduous tree component. Both species were present in plots having lower percent duff groundcover than at plots containing no lizards. Increased tree densities, canopy closure, and litter accumulation influenced distributions of both lizards. Furthermore, abundance and reproduction in these lizards were generally optimized in habitat with features most similar to that present prior to fire suppression activities and in areas containing a deciduous tree component.
Bothrops moojeni is a member of the atrox group that occurs in central and southeastern Brazil and adjacent Paraguay and Argentina. We describe habitat use, diel and seasonal activity, biometry, feeding habits, and reproduction of B. moojeni, based on field studies and analysis of 207 preserved specimens. Bothrops moojeni predominantly uses riparian vegetation in the Cerrado (central Brazilian savannas), such as gallery forests and adjacent wet grasslands, although they occasionally use drier interfluvial areas. Sexes are dimorphic in snout–vent length, relative tail length, relative mass, and relative head length. Main prey types were mammals, frogs, and lizards. There is an ontogenetic dietary shift from ectotherms to endotherms. Prey-predator mass ratio ranged from 0.008–1.079, and prey mass was positively correlated with predator mass. Although prey absolute mass was positively correlated with snake mass, large snakes did not eliminate small prey from their diets. There was an ontogenetic decrease in prey relative mass. Females consumed more endothermic prey than males, and this difference probably reflects size differences. The reproductive cycle is lengthy and seasonal, with recruitment restricted to the rainy season. Fecundity is positively correlated with female body size. Life-history characters of B. moojeni are similar to those of other members of the atrox group, even though B. moojeni occurs in the Cerrado, a drier and more seasonal biome.
Amphibians in general, and plethodontid salamanders in particular, are highly susceptible to cutaneous water loss. We compared behavior, habitat use, and physiology of Batrachoseps attenuatus (Eschscholtz) and Ensatina eschscholtzii (Gray) in Humboldt County, California, to identify adaptations of water economy. Both species lost more body water in a dry environment than in a wet one. In the field, sites with salamanders had higher relative humidity than sites without salamanders. In behavioral experiments, both species used water-conserving postures; they positioned themselves deep in leaf litter in dry environments while remaining on the surface of leaf litter in wet environments. The slender morphology of B. attenuatus may aid in habitat partitioning by plethodontid salamanders; in the field we found B. attenuatus closer to the surface of the leaf litter than E. eschscholtzii. The evolution of a slender body shape appears to be unconstrained by microclimates typically encountered by this species.
We examined the relationships between ambient temperature, activity level, and vegetation structure of microhabitats used by Ornate Box Turtles; vegetation structure of these habitats should influence microclimatic conditions and, thus, the thermoregulatory value of microhabitats. Thirty-four Ornate Box Turtles (Terrapene ornata ornata) were radio-tracked during 1997 and 1998 in the Nebraska Sandhills. Activity level was negatively related to ambient temperature. Active turtles used areas with more bare ground in both years, and more forb cover in one year, whereas inactive turtles used areas with more shrub and litter cover. Providing habitat components that function as thermoregulatory cover may be an important consideration for land management plans in areas where this species is found.
Although effects of temperature on sprint performances of lizards are well documented, influences of slope are much less well known, and few studies have examined comparable effects on stamina. We monitored locomotor performance of Eastern Fence Lizards, Sceloporus undulatus, at temperatures from 15–40°C and slopes from 0–45° using two types of nonmotorized tracks. Body size did not significantly affect performance, but both sprint performance and stamina were significantly affected by temperature and slope. The optimal temperature for performance is approximately 30°C. As slope increased, both sprint speed and stamina progressively decreased. Mean incline speeds were significantly greater than mean decline speeds at all slopes other than 0°. There was a direct relationship between sprinting ability and stamina; lizards that ran faster tended to run for longer periods of time and distances. Neither sprint speed nor stamina data support the hypothesis that running velocity of lizards is limited by mechanical power output.
Sixty-nine telemetered Phrynosoma mcallii from the Colorado Desert in California were relocated for up to nine months to examine activity patterns, home-range sizes and overlap, distance traveled between relocations, and onset and duration of hibernation. Total area used by the lizards ranged from 651–59,237 m2. Males had significantly larger mean summer home ranges and traveled significantly further than females. The duration of winter dormancy for eight telemetered lizards was 85 ± 8 (mean ± SE) days. Nearly all telemetered lizards were underground by mid-November and emerged as early as late December. Telemetered P. mcallii were out in the open or underneath a shrub throughout the day during spring and fall. They retreated into burrows to escape the midday summer heat. When out in the open, males perched on an elevated surface 19.0% of the time, whereas females perched 4.3%. Telemetered lizards exhibited considerable overlap among their home ranges; males shared 11% of their home ranges with females, whereas females shared 42% of their home ranges with males.
The reproductive cycle of the tropidurid lizard, Eurolophosaurus nanuzae, was studied at the montane habitat of Serra do Cipó, Minas Gerais State, Brazil, from June 1996 to June 1997. Reproductive activity of E. nanuzae was cyclic, occurring from the middle of the dry season to the end of the wet season. Female reproductive activity was influenced by photoperiod and by long term precipitation and temperature. Males exhibited sperm in their testes throughout the year, and their reproductive activity was not related with any of the climatic factors analyzed. Fat storage varied inversely with reproductive activity and was more accentuated in females. Mean clutch size was 2.06 (±0.36 eggs) and was not related to female body size. The effects of precipitation on the reproductive cycle of E. nanuzae could be related to the microclimatic conditions necessary for embryo development and hatchling survivorship, as well as to the greater food availability for hatchlings during the wet season.
We describe the ecology of the gecko Gymnodactylus geckoides amarali in the Cerrado of central Brazil and using published data, compare it with the conspecific Gymnodactylus geckoides geckoides from the Caatinga of northeastern Brazil. Gymnodactylus geckoides amarali is rupicolous, living primarily in rock crevices in “campos rupestres” (rocky fields), which are highly patchy in Cerrado. Field body temperatures were low and associated with environmental temperatures, suggesting thermoconformity. Termites were the most important food item, and consumption was greatest during the dry season. We suggest that access to termites is facilitated by the shallow soils used by G. g. amarali and by its well-developed chemosensory apparatus. Reproduction was concentrated in the dry season, a pattern known for very few Cerrado squamates, possibly because of the higher availability of termites during that period. Clutch size was significantly correlated with female size, a pattern unknown in any other gecko, and there was no association between egg size and female size. Gymnodactylus geckoides amarali produced larger clutches of smaller eggs relative to G. g. geckoides, presumably because of the high climatic unpredictability of the Caatinga. We detected a significant sexual dimorphism in both body size and shape: females were larger and had smaller heads than males. We suggest that large female size is likely a plesiomorphic character of gekkonids and that large head size in males results from sexual selection theory.
A new dendrobatid frog of the genus Colostethus is described from the Cordillera El Sira, an isolated mountain ridge in the upper Amazon basin of central Peru. It has bright yellowish dorsolateral stripes thus resembling Colostethus exasperatus, Colostethus sp. (cf. exasperatus), and Colostethus nexipus, all from the upper Amazon basin of Ecuador and Peru. In morphology, the new species is most similar to Colostethus mcdiarmidi from the eastern Andean slopes of Bolivia and Colostethus alessandroi from the eastern Andean slopes of Peru. The new species can be distinguished from all these taxa on the basis of coloration including the color of the ring around pupil in life, adult male size, length of Finger I relative to Finger II, and toe webbing extension. The advertisement call and aspects of the skeleton of the new species are described.
We describe the sequence of cranial ossification in the Tailed Frog, Ascaphus truei, and examine intraspecific variation in the timing and sequence of cranial development. Because tadpoles of A. truei lack the subarticular tubercles that normally delineate Gosner stages 39 and 40, we provide a modified Gosner staging system more appropriate for this species. Ossification sequence was highly variable among the populations and greater than that reported for other anuran species. In general, early ossification events in A. truei are similar to that reported for other anuran species. However, compared with other taxa, both onset of initial ossification events and appearance of specific elements appear relatively later in the development of Ascaphus.
The hemipenes of seven species of Atractus (Atractus emigdioi, Atractus major, Atractus mariselae, Atractus poeppigi, Atractus torquatus, Atractus univittatus, and Atractus ventrimaculatus) are described. Hemipenial morphology in this poorly known genus of snakes is found to be particularly variable among the species studied. Additionally, the primitive unicapitate hemipenal condition is more widespread among Atractus than was previously thought. Given the drastic variation in hemipenal morphology observed in Atractus, it is likely that characters derived from studying this organ may prove especially useful for future work on intrageneric relationships among members of this genus.
We studied the ecology of a population of Sceloporus undulatus speari from the Transmontane Sand Dune region of northern Chihuahua, México. Most of the individuals in our population used fence posts or yucca plants as perches and were only rarely seen on the ground. The majority of individuals in our population were seen in full sun, although a substantial number were in shade. Mean body temperature in our population was 35.2°C. Individuals first seen in full sun had lower Tbs than individuals first seen in shade. Lizards using different microhabitats (e.g., yucca vs. fence post) had different body temperatures. Clutch size in our population was 5.23 eggs per clutch. Clutch size in our population was not statistically significantly related to female body size; however, the trend was for an increase in clutch size with SVL, with the smallest females having the smallest clutches. We found no evidence for sexual dimorphism in body size (SVL) in our population of S. undulatus, but males had larger heads. Coleopterans (particularly tenebrionids) and hymenopterans (particularly formicids) were the most important prey items.
The fall-winter food habits of the Texas river cooter (Pseudemys texana) were investigated at Spring Lake, Hays County, Texas, by examination of stomach contents. Samples were collected from 33 live turtles by flushing stomach contents with water (Fields et al., 2000). Four aquatic macrophytes composed 91.6% of the diet. Aquatic macrophyte availability at Spring Lake was estimated using the Daubenmire technique (Daubenmire and Daubenmire, 1968) and compared to occurrence in the diet to assess selectivity in foraging. Cooters actively selected Carolina fanwort (Cabomba caroliniana), a plant low in fiber and high in total digestible nutrients. Hydrilla (Hydrilla verticilata), an invasive exotic aquatic plant, was an important food item due to the large amount present in the lake.
Juvenile Nerodia sipedon sipedon possess a striking dorsal pattern, whereas adults often have a more uniform dorsal coloration. Past researchers have hypothesized that this color shift occurs through a darkening of the ground color, but this hypothesis has never been tested quantitatively. Analysis of digital images of the dorsum and venter of N. s. sipedon individuals of all sizes from islands in Lake Michigan indicated that as snakes increase in length, the dorsal ground color darkens, but the coloration of dorsal blotches and ventral pattern does not change. Potential costs and benefits of a change in dorsal coloration while ventral pattern remains relatively constant are discussed in relation to variation in size.
Terrestrial salamanders of the genus Plethodon live in a world dominated by chemical-mediated senses. Little is known, however, about the histochemistry of the integumentary glands that produce chemicals used for communication and predator defense. We used histochemical staining techniques to identify the caudal integumentary glands in both male and female Plethodon cinereus. Our research suggests that there are three types of caudal integumentary glands, including nongranular mucous glands, and two types of granular serous glands. The two serous glands are histochemically and morphologically distinct, are concentrated in different areas around the tail's circumference, and are believed to have different function.
We studied the helminth fauna of the digestive tract of the lizard, Eurolophosaurus nanuzae, from the Serra do Cipó, Minas Gerais State, Brazil and tested for sexual, ontogenetic, and seasonal differences in prevalence (proportion of infected individuals) and intensity of infection (number of parasites per host). We also analyzed the distribution patterns of the helminths along the digestive tract of E. nanuzae. We found the nematodes Physaloptera lutzi, Subulura lacertilia, Parapharyngodon sceleratus, and Strongyluris oscari and the cestode Oochoristica vanzolinii. Males and females differed in prevalence for P. lutzi, S. lacertilian, and O. vanzolinii. None of the helminth species differed in intensity of infection between sexes. Prevalence was significantly higher in adults than in juveniles for P. lutzi and S. lacertila; however, this difference was not observed for P. sceleratus. Only adults were infected by S. oscari and O. vanzolinii. Intensity of infection increased with lizard body size for P. lutzi, S. lacertilian, and S. oscari but not for P. sceleratus and O. vanzolinii. Only P. lutzi differed in prevalence between seasons, with lizards being more parasitized during the wet season. Physaloptera lutzi and S. lacertilia differed in infection intensity between seasons. For both species the mean intensity of infection was higher in the dry season than in the wet season. Physaloptera lutzi used the stomach and the other helminths used the intestines.
We studied the helminth fauna of the digestive tract of the lizard, Eurolophosaurus nanuzae, from the Serra do Cipó, Minas Gerais State, Brazil and tested for sexual, ontogenetic, and seasonal differences in prevalence (proportion of infected individuals) and intensity of infection (number of parasites per host). We also analyzed the distribution patterns of the helminths along the digestive tract of E. nanuzae. We found the nematodes Physaloptera lutzi, Subulura lacertilia, Parapharyngodon sceleratus, and Strongyluris oscari and the cestode Oochoristica vanzolinii. Males and females differed in prevalence for P. lutzi, S. lacertilian, and O. vanzolinii. None of the helminth species differed in intensity of infection between sexes. Prevalence was significantly higher in adults than in juveniles for P. lutzi and S. lacertila; however, this difference was not observed for P. sceleratus. Only adults were infected by S. oscari and O. vanzolinii. Intensity of infection increased with lizard body size for P. lutzi, S. lacertilian, and S. oscari but not for P. sceleratus and O. vanzolinii. Only P. lutzi differed in prevalence between seasons, with lizards being more parasitized during the wet season. Physaloptera lutzi and S. lacertilia differed in infection intensity between seasons. For both species the mean intensity of infection was higher in the dry season than in the wet season. Physaloptera lutzi used the stomach and the other helminths used the intestines.
We analyzed the frugivorous diet of the lizard Gallotia galloti, a Canary Island endemic, in relation to season and fruit availability in a xeric habitat from Tenerife. Gallotia galloti was omnivorous throughout the year (including >59% of plant material by volume in fecal pellets); only in the winter months (December and January) did invertebrates dominate the diet (>73% in volume). The most remarkable aspect of the diet was the high level of consumption of fleshy fruits, showing pronounced seasonal variation (from 30% in January to 95% in April in frequency of occurrence). Variation in fleshy fruit consumption was associated with seasonal patterns of fruits availability. A total of 4710 seeds were found in 1120 droppings analyzed during the entire year corresponding the majority to Rubia fruticosa and Plocama pendula (Rubiaceae). The extensive consumption of fleshy fruits during seven months of the year (>50% by volume) suggests G. galloti is an important seed disperser in the Canary Islands. These results contrast with the majority of continental lacertids that are insectivorous.
At the extreme southwestern part of its range in southeastern Arizona, annual surface activity of the Desert Box Turtle (Terrapene ornata luteola) is limited primarily to the three-month summer monsoon. Turtles emerging at the beginning of the monsoon are severely dehydrated. We examined the effects of dehydration on the critical thermal maximum (CTMax) of T. o. luteola. Compared to normally hydrated turtles, the CTMax of dehydrated turtles was depressed about two degrees from 41.0–39.0°C.
Drought-related survival strategies were examined in a population of Sonoran Mud Turtles (Kinosternon sonoriense) inhabiting an ephemeral stream in the Peloncillo Mountains, New Mexico. Behavioral responses to seasonal drying of the habitat were investigated via radiotelemetry and repeated sampling of the resident population. All transmittered turtles were observed engaging in terrestrial dormancy for periods of 11–34 days. Two nontransmittered turtles remained in a small puddle through the drought, and no turtles were observed migrating to permanent bodies of water. Our results indicate that estivation is the dominant drought-survival strategy employed by K. sonoriense in our study population.
We assessed the reproductive characteristics of the type population of Colostethus marchesianus on the banks of the Uaupés River (upper Rio Negro basin, Amazonas, Brazil). Colostethus marchesianus occupied floodplain forest areas on the river margin, and the peak of the reproductive season coincided with the peak of the rainy season. Sexual size dimorphism was not detected and adult size ranged from 15.0–17.0 mm snout–vent length. Males were territorial and employed three types of vocalization, two high-intensity advertisement calls and a lower intensity courtship call. Duration of courtship and mating behavior was less than 30 min and involved 2–3 sequential cephalic amplexi. From 1–5 egg clutches were found within each of several oviposition sites within male territories. Number of eggs in 63 clutches ranged from 10–29. Only males were observed to carry tadpoles (stage 25) to water on their backs. The mean number of transported tadpoles was similar to the mean clutch size. Additional descriptive information on reproduction and general behavior, which is highly variable among Colostethus species, is needed to confirm the specific status of other populations identified as C. marchesianus throughout the Amazonian basin.
Using starch gel electrophoresis, we examined proteins specified by 41 presumptive loci representing two breeding populations of Rana subaquavocalis, a recently described species of leopard frog from Arizona. Individual and population levels of heterozygosity were low. Mean number of alleles detected (1.2) and mean levels of individual heterozygosity were higher at the Barchas Ranch location (0.042) compared with those from Ramsey Canyon (0.029). Nine loci among the 41 surveyed were polymorphic. Four of these were common to both populations. Each population was polymorphic for the remaining three loci, and each possessed one unique allele. Both populations went extinct by 1996.
The endangered Pygmy Blue Tongue Lizard, Tiliqua adelaidensis, occupies narrow vertical burrows, probably constructed by spiders. We assessed the fitness of female lizards in artificial burrows added to a 1-ha plot within a natural population, over a three-year period. Compared with females in natural burrows, females in artificial burrows had significantly better body condition and produced larger offspring with better body condition. We discuss possible explanations for these differences but conclude that adding artificial burrows was not detrimental to reproductive females in a population and could be used in the conservation management of this species.
The rain-forest frogs Mantidactylus bicalcaratus and Mantidactylus punctatus have only been collected from Pandanus and other water-holding plants in Madagascar. In both species, eggs are laid on the surface of Pandanus leaves above water-filled leaf axils, where tadpoles develop. Although some egg masses (26%) were not attended, adults were often found straddling or directly adjacent to egg masses for up to eight days after oviposition. In both species, eggs were attended by either the male or the female parent but not both. This amphisexual egg attendance is known from only three other anurans and an antipredator function for it is hypothesized.
I examined sexual dimorphism in the lacertids Gallotia atlantica atlantica and Gallotia atlantica mahoratae from Lanzarote and Fuerteventura Islands, respectively. Mean body size was smaller in G. a. mahoratae than in G. a. atlantica. Sexual size dimorphism was greater in G. a. atlantica than in G. a. mahoratae, but relative size of several morphological traits was not different between the two populations. In both subspecies, head and body traits scaled to SVL, with head size of males having a positive allometry, indicating a disproportionate increase of this trait with the increase in body size. Relative size in hind-limb length was greater in males than in females in G. a. atlantica but not in G. a. mahoratae.
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