A new ranid frog of the genus Cacosternum Boulenger, 1887 is described from the semiarid Karoo region of South Africa. This species is the putative sister species of Cacosternum namaquense Werner, 1910, but differs in that the two characteristic longitudinal dorsal glands of the latter species are absent and the musculus cutaneous pectoris is present. The two species differ further in their advertisement calls and substratum preferences. A discussion of the ecology and breeding biology of the two species is presented and their distributions mapped. Observational data suggest that growth to metamorphosis is rapid in these arid-adapted frogs, which are cued to breed primarily by rainfall events, not temperature or seasonality.

Conservation efforts for two endangered lizard species, the chevron skink (Oligosoma homalonotum) and the striped skink (Oligosoma striatum), have been hindered by a lack of knowledge on their habitat preferences. Reports of some individuals being found in moist microenvironments has led to speculation that both species may be physiologically restricted to such habitats. Estimates of water loss in these two species were compared with water loss in two relatively common species, the speckled skink (Oligosoma infrapunctatum) and Falla's skink (Oligosoma fallai), that are inhabitants of semiarid habitats. When the effect of body size was accounted for using analysis of covariance, results indicated that chevron and striped skinks lost 34% more water through evaporation than the semiarid inhabiting species did. When compared to water loss rates in lizards elsewhere, all New Zealand species had relatively high rates of loss for their size. It is predicted that high rates of water loss in chevron and striped skinks would lead to these species preferentially inhabiting moist sites. Recommendations include that future survey effort for both species should be focused on areas with high moisture content. The results also raise implications for land management on Great Barrier Island and provide insight into the current distribution of chevron and striped skinks.

A new species of the genus Echinosaura is described from the Pacific drainages of northern Ecuador and adjacent Colombia. Evaluation of variation among congeners justifies their recognition as distinct species instead of subspecies as previously proposed. The new lizard occurs in close proximity to Echinosaura horrida and Teuchocercus keyi.

The Bolitoglossa macrinii species group (restricted geographically to southern Oaxaca and southwestern Guerrero, México) is a monophyletic assemblage of five species, B. macrinii, Bolitoglossa riletti, Bolitoglossa hermosa, Bolitoglossa oaxacensis sp. nov., and Bolitoglossa zapoteca sp. nov. DNA sequences totaling 1164 base pairs for the mitochondrial genes 16S ribosomal RNA and cytochrome b were analyzed to generate a phylogenetic hypothesis for the relationships within the group. Our hypothesis is in agreement with previous morphological and allozyme analyses. Divergence within the group is great (to 18.6% for cytochrome b, to 7.0% for 16S rRNA) and two clades are well supported: one including B. riletti, B. hermosa, and B. zapoteca and the other including B. macrinii and B. oaxacensis. These clades likely diverged beginning in mid-Miocene times. We describe two new species, B. oaxacensis, for inland Oaxacan populations previously assigned to B. macrinii, and B. zapoteca for the easternmost populations of the clade. The new species are diagnosed by less interdigital webbing, distinctive coloration (each with subdued or no white spotting but differing from each other in pattern and hue) and by extensive differentiation in allozymes (B. oaxacensis) and mitochondrial DNA sequences (both species). The new taxa are the third and fourth species of Bolitoglossa endemic to the State of Oaxaca.

A new species of Hemisus is described from the Barotse floodplain, Zambia. The advertisement call of this species differs in pulse structure from all other known species of Hemisus. This cryptic species is similar to Hemisus guineensis and Hemisus marmoratus but can be separated from these by differences in body proportions.

A new scansorial frog species of Mantidactylus (subgenus Phylacomantis) is described from Andasibe, a midaltitude locality in central, eastern Madagascar. The new species is similar to the sympatric Mantidactylus cornutus but differs by smaller size, presence of a chevron-like dorsal ridge, more distinct supraocular dermal spines, throat coloration, and advertisement call. Its discovery emphasizes the importance of midaltitude rain forests in central, eastern Madagascar as a center of anuran diversity.

Early spring population parameters and activity of wild Namaqualand speckled padlopers (Homopus signatus signatus) were monitored using mark-recapture and thread-trailing methods. Eighty-three tortoises were studied between 22 August and 22 September 2000. The maximum number of scute rings counted was 14, with females appearing to have longer lives than males. Tortoises were encountered on rock slabs, on a rocky hill slope, and frequented adjacent, gently sloping fields with many flowering plants. The frequent use of shallow concealed crevices as hiding places may be, in part, caused by greater availability of such refuges. Single specimens were usually found in refugia, but occasionally male-female pairs were observed. The shelter types identified (rock and spaces under shrubs) were rarely used for more than one night. Activity was unimodal. Activity area and daily movements were lower in H. s. signatus than in other tortoise species, possibly because of their smaller body size, cooler ambient spring temperatures during this study, a short measurement period, smaller habitat requirement of H. s. signatus, or some combination of the four.

Surveys for amphibians along large rivers pose monitoring and sampling problems. We used canoes at night to spotlight and listen for anurans along four stretches of the Rio Grande in Big Bend National Park, Texas, in 1998 and 1999. We explored temporal and spatial variation in amphibian counts and species richness and assessed relationships between amphibian counts and environmental variables, as well as amphibian-habitat associations along the banks of the Rio Grande. We documented seven anuran species, but Rio Grande leopard frogs (Rana berlandieri) accounted for 96% of the visual counts. Chorus surveys along the river detected similar or fewer numbers of species, but orders of magnitude fewer individuals compared to visual surveys. The number of species varied on average by 37% across monthly and nightly surveys. We found similar average coefficients of variation in counts of Rio Grande leopard frogs on monthly and nightly bases (CVs = 42–44%), suggesting that canoe surveys are a fairly precise technique for counts of this species. Numbers of Rio Grande leopard frogs observed were influenced by river gage levels and air and water temperatures, suggesting that surveys should be conducted under certain environmental conditions to maximize counts and maintain consistency. We found significant differences in species richness and bullfrog (Rana catesbeiana) counts among the four river stretches. Four rare anuran species were found along certain stretches but not others, which could represent either sampling error or unmeasured environmental or habitat differences among the river stretches. We found a greater association of Rio Grande leopard frogs with mud banks compared to rock or cliff (canyon) areas and with seepwillow and open areas compared to giant reed and other vegetation types. Canoe surveys appear to be a useful survey technique for anurans along the Rio Grande and may work for other large river systems as well.

A new species of Atractus is described from the Cordillera de Mérida, Venezuela. The new species can be distinguished from all other congeners by the combination of 15 dorsal scale rows at midbody and a color pattern consisting of two pale dorsolateral stripes on a dark ground color. Additionally Atractus pamplonensis is reported for the first time for Venezuela.

We studied movement patterns, activity, and home range of the eastern spiny softshell turtle (Apalone spinifera) in northern Lake Champlain (Québec, Canada; Vermont) from 1996 to 1999. This turtle population is at the northern limit of its range and considered threatened. Of the 30 individuals captured and marked, 15 females and eight males were equipped with radio-transmitters and monitored from two weeks to 29 months. Mean annual home range size for females (32.06 km², N = 11) was significantly larger than for males (2.75 km², N = 4). Home ranges generally consisted of a spring-summer concentration area (0.90 km²) and a fall-winter concentration area (1.80 km²), plus the area traversed between these concentration areas. In general, movements did not vary significantly from May to September, but turtles were less active after mid-September. Three hibernacula and three nesting sites were identified. Seventy five percent of the radio-tracked individuals were concentrated in a small area surrounding one hibernaculum from September to April. We hypothesize that habitat fragmentation, both natural and resulting from human activities, was in part responsible for the large home range and long movements observed. Results indicate that, to conserve this spiny softshell turtle population, the seasonal concentration areas need strict protection, although a lakewide approach promoting the preservation of natural habitats is also necessary.

We quantified the flight trajectories of Ptychozoon kuhli dropped from distances of 300 and 825 cm and the effects of removing the cutaneous flaps and binding the feet. Analyses suggested there is a threshold speed of approximately 650 cm/sec below which the lift generated does not significantly retard acceleration of the animal or permit shallow glide angles. Removal of cutaneous flaps from specimens gliding at airspeeds below 650 cm/sec had no effect on the flight; above 650 cm/sec the presence of the cutaneous flaps significantly slowed the specimen and produced shallower glide angles. Binding of the feet eliminated all maneuverability and led to a significant increase in airspeed as well as a significant decrease in glide angle. We propose that the webbed feet of Ptychozoon play a key function in gliding and that aerial locomotion in this taxon may be more similar to “flying” treefrogs than to other reptilian gliders.

Body size, age, and growth were studied in samples of Nile monitor lizards from variably exploited populations. One sample originated from the central Niger delta, in Mali, and the other two from Lake Chad. Snout–vent length, mean age, and longevity were reduced in the most exploited animals. These exhibited a characteristic pattern of somatic growth: size increased up to an age of 30 months and then dropped steeply to a negligible level after 54 months. Conversely, in the less exploited populations, initial growth was slower but remained at a sustained level within the limits of individual longevity. With reference to available data on sexual maturation and reproductive output in harvested Varanus niloticus, these results suggest that rapid growth and early sexual maturity both contribute to a demographic accommodation in exploited monitor populations.

In 1982, B. Rose pointed out that home-range area could easily be underestimated unless sufficient numbers of sightings were obtained for each individual, and recommended a population-specific test to determine the minimum sample size at which home-range area can be accurately measured. This recommendation has been generally ignored. We explore how sample size affects interpretation of space use data in male lava lizards, Microlophus albemarlensis, and male eastern collared lizards Crotaphytus collaris. Using the criteria established by Rose, the minimum sample sizes for collared lizards and lava lizards were 45 and 84 sightings, respectively. These are much larger samples than we anticipated and reinforce the need for empirical determination of minimum sample size. Our data suggest that lizard movement rate is a better predictor of minimum sample size than home-range area. Collared lizard home ranges were over 10 times larger than lava lizard home ranges, yet the higher movement rates of collared lizards resulted in a minimum sample size that was about one-half that of lava lizards. Restricting data collection to any one-quarter of the total study period would have markedly underestimated home-range area and home-range overlap in both species. Every lizard of both species had a core area within their home range, suggesting the absence of major temporal shifts during the study. On average, lava lizard core areas occupied 21.7 ± 2.8% of total home-range area, yet core areas included 78.8 ± 3.1% of all lizard sightings. Collared lizard core areas averaged 25.4 ± 2.4%, with a lower percentage of collared lizard sightings occurring within core areas (66.3 ± 3.0%). There was only one incidence of core overlap in either species. Lava lizards may be defending core areas but in an unusual manner, what amounts to “sit-and-wait territoriality.” This unusual mode of space use would not be detectable from a smaller number of sightings per individual.

New material of Emydoidea hutchisoni from Nebraska shows the species lived in the North American Miocene from medial Barstovian (approximately 14.5–13 million BP) to Clarendonian (approximately 11.5–9 million BP) times. Previously unknown plastra, limb girdle elements, and limbs of E. hutchisoni have provided new characters that have led to a revised diagnosis of the species. Derived characters shared by E. hutchisoni and Emydoidea blandingii include an elongated nuchal bone, ovoid plastral shape, short and broad femoral scute overlap, very wide xiphiplastral shelf, xiphiplastral striations, and an angular coracoidal border. But E. hutchisoni is distinct from E. blandingii in being smaller and having an akinetic shell with a shorter nuchal area, and it probably was more aquatic. The plastral lobes of a complete E. hutchisoni plastron are firmly fused together by dovetail sutures and a second, less complete plastron, has dovetail sutures on the anterior surface of the hypoplastron. Moreover, the pectoral abdominal scute sulcus occurs well anterior to the hyo-hypoplastral suture and expanded plastral buttresses are present on both plastra, furthur demonstrating a completely akinetic shell in E. hutchisoni. Two Terrapene sp. plastra from the same late Barstovian horizon in Nebraska as E. hutchisoni, however, are as kinetic as recent species of the genus, thus making the often proposed “Emydoidea-Terrapene clade” questionable. But an Emydoidea sp. indet. hyoplastran from a temporally equivalent Miocene (late Barstovian site) in Nebraska has a weak hinge line, indicating that it may be an advanced form, ancestral to E. blandingii and that E. hutchisoni is primitive. This suggests the possibility that E. hutchisoni may be a sister taxon to Emys, Emydoidea, and Terrapene.

We studied the diet of green sea turtles (Chelonia mydas) at Bahía de los Angeles in the Gulf of California, México. From 1995–1999, we collected esophageal lavage and fecal samples from live-captured turtles and analyzed stomach contents from stranded carcasses encountered in the study area. Foods ingested did not vary with carapace length. Turtles consumed diverse marine algae, with the filamentous red alga Gracilariopsis lemaneiformis the most abundant; other common genera included Gracilaria, Codium, Ulva, and Chaetomorpha. Turtles also augmented their diet with animal matter; 25 nonalga food items were identified, including sponges, tube worms, sea pens, and sea hares. Substratum and anthropogenic debris such as plastic bags and nylon cord were commonly recovered in diet samples.

We describe the diet of Desert Massasauga, Sistrurus catenatus edwardsii, in Arizona, Colorado, and New Mexico using fecal remains and gut contents obtained from field encounters and museum specimens. From these, 165 prey were identified, including 97 (58.8%) lizards, 51 (30.9%) mammals, 15 (9.1%) centipedes (Scolopendra sp.), one (0.6%) anuran, and one (0.6%) snake. Analyses of geographic, sexual and ontogenetic variation within S. c. edwardsii suggest diet is homogeneous among populations and between the sexes but that juveniles consume significantly more lizards and fewer mammals than adults. We assess rangewide variation in diet of Sistrurus catenatus using our data from Arizona, Colorado, and New Mexico (S. c. edwardsii) and previously published studies of populations in Wisconsin (Sistrurus catenatus catenatus), Michigan (S. c. catenatus), Missouri (Sistrurus catenatus tergeminus) and Texas (S. c. tergeminus) as well as new data from Texas (S. c. tergeminus). Significant geographic variation in diet parallels ecological and behavioral variation across the range of S. catenatus. Sistrurus c. edwardsii are xeric grassland-adapted snakes dependent on lizard and centipede prey, whereas both eastern subspecies favor more mesic environs and prey primarily on small mammals with juveniles occasionally feeding on snakes or lizards.

Using visual (VI) and dip net indices (DI) and double-observer (DOE), removal (RE), and neutral red dye capture-recapture (CRE) estimates, we counted, estimated, and censused Couch's spadefoot (Scaphiopus couchii) and canyon treefrog (Hyla arenicolor) tadpole populations in Big Bend National Park, Texas. Initial dye experiments helped us determine appropriate dye concentrations and exposure times to use in mesocosm and field trials. The mesocosm study revealed higher tadpole detection rates, more accurate population estimates, and lower coefficients of variation among pools compared to those from the field study. In both mesocosm and field studies, CRE was the best method for estimating tadpole populations, followed by DOE and RE. In the field, RE, DI, and VI often underestimated populations in pools with higher tadpole numbers. DI improved with increased sampling. Larger pools supported larger tadpole populations, and tadpole detection rates in general decreased with increasing pool volume and surface area. Hence, pool size influenced bias in tadpole sampling. Across all techniques, tadpole detection rates differed among pools, indicating that sampling bias was inherent and techniques did not consistently sample the same proportion of tadpoles in each pool. Estimating bias (i.e., calculating detection rates) therefore was essential in assessing tadpole abundance. Unlike VI and DOE, DI, RE, and CRE could be used in turbid waters in which tadpoles are not visible. The tadpole population estimates we used accommodated differences in detection probabilities in simple desert pool environments but may not work in more complex habitats.

A mark and recapture study was carried out from 1990–1992 for a population of Gekko hokouensis in the southern part of Okinawajima Island, Ryukyu Archipelago. Gonadal states were also examined for 389 preserved specimens from the central part of the island. Results indicate that this species breeds from April to August and that females may lay eggs more than once during a breeding season. Young appeared from July to November, and hatchlings, although they grew somewhat in autumn, scarcely grew in winter. Their growth rate dramatically increased during the next spring and summer. Although some hatchlings grew to the minimum maturity size (43 mm in snout–vent length in both sexes) by the end of the next breeding season, others required a second year to reach maturity. There were no sexual differences in juvenile growth. After reaching maturity, however, growth rate of females was significantly greater than that of males. This seems to account for the significantly greater adult SVL in females than in males.

The effect of caudal autotomy on reproductive investment in females of a viviparous skink, Niveoscincus metallicus, was investigated to examine the relative importance of lipid depletion and energetic diversion to this activity. Although abdominal fat bodies are present, this species stores most of its energetic reserves in the tail. Since caudal fat is preferentially aggregated toward the base of the tail, autotomy and lipid depletion may be mutually exclusive events. Reproductive consequences following tail loss associated with significant loss of caudal fat were compared with those following autotomy involving no fat loss in two groups of females: females that had lost their tail during their most recent vitellogenic period; and females in which tail loss had occurred in a previous reproductive season. Caudal autotomy during vitellogenesis resulted in a significant reduction in litter size, irrespective of the position of tail loss, suggesting that smaller litters were a consequence of the diversion of energetic resources from reproduction to tail regeneration, rather than the loss of fat reserves per se. However, offspring from mothers that experienced tail loss during vitellogenesis without associated loss of fat reserves were significantly larger in size (snout–vent length and mass) and had longer tails than those from any other group. We suggest that this was probably achieved through facultative placental transfer during gestation, although the possibility that more yolk was allocated to each egg cannot be discounted. Sprint speed and the size of abdominal fat reserves at birth and postnatal growth were not correlated with either recency of autotomy or the location of the tail break.