We contrasted the summer and winter field body temperatures of the tropidurid lizard Microlophus peruvianus at the Paracas Peninsula in southern Peru. We also compared our winter data to those gathered by >Huey (1974) at the Illescas Peninsula in northern Peru to test the hypothesis that southern lizards would tolerate lower temperatures than northern lizards. Cloud cover is more persistent in Paracas than it is in Illescas. During the austral winter, lizards at Paracas reduced surface activity to midday hours and had body temperatures below the mean set-point temperature (as measured in a photo-thermal gradient). Lizards from southern Peru were active over a wider range of temperatures than were lizards from Illescas. Mean body temperature of field-active lizards in the cloudy Paracas site was 33.0 ± 0.44 C, significantly lower than the mean field body temperature at the sunnier Illescas site (36.3 ± 0.26 C, t = −6.19, P < 0.001). Although thermal preferences tend to be conserved among related lizard species, we found considerable variation in body temperatures and activity patterns of two populations of this species.

Two new species of the callichthyid catfish genus Lepthoplosternum are described from the Amazon region. Lepthoplosternum stellatum is described from a tributary of Lago Tefé, Amazonas, Brazil, and it is diagnosed from other Lepthoplosternum species by a unique combination of characters: lower lip with pointed, crenulate, triangular fleshy projections lateral to the medial notch, caudal peduncle comparatively shallow (15.7–18.9% SL), and dorsal fin usually with one unbranched and seven branched rays. Lepthoplosternum ucamara is described from the Pacaya-Samiria National Reserve in the lower Ucayali River, Loreto, Peru, and can be diagnosed from other Lepthoplosternum species by the following unique combination of characters: lower lip with short, rounded projections, caudal peduncle comparatively shallow (15.2–17.7% SL), and dorsal fin with two unbranched and six branched rays. The distribution of Lepthoplosternum altamazonicum is extended to include the varzea floodplains of the Solimões River and its tributaries in Brazil. A key to species of Lepthoplosternum is also included.

Duas novas espécies de tamoatás do gênero Lepthoplosternum são descritas da região amazônica. Lepthoplosternum stellatum é descrita de um tributário do lago Tefé próximo a Tefé, Estado do Amazonas, Brasil, sendo diagnosticada das outras espécies de Lepthoplosternum pela combinação única de lábio inferior com projeções triangulares, pontiagudas e crenuladas, laterais à fenda medial, pedúnculo caudal comparativamente baixo (15.7–18.9% SL), e nadadeira dorsal usualmente com um raio simples e sete ramificados. Lepthoplosternum ucamara é descrita da Reserva Nacional Pacaya-Samiria, no baixo rio Ucayali, Loreto, Peru, e pode ser diagnosticada dos outros Lepthoplosternum pela combinação única de lábio inferior com projeções curtas e arredondadas, laterais à fenda medial, pedúnculo caudal comparativamente baixo (15.2–17.7% SL) e nadadeira dorsal com dois raios simples e seis ramificados. A distribuição de Lepthoplosternum altamazonicum é ampliada para incluir as áreas de várzea do rio Solimões e seus tributários no Brasil. Uma chave para as espécies de Lepthoplosternum é também incluida.

The present study examined gonadal development and sexual pattern in two populations of the black-tailed dascyllus Dascyllus melanurus in Madang, Papua New Guinea (5°10′S, 145°48′E) from 31 March to 26 June 1996. Two populations differed in their social organizations. In the Guzem population, small fish occurred in groups of 10–20 around single coral colonies and large fish occurred in groups of 50–100 over a continuous cover of corals. In the Kranket population, fish occurred in groups of a few to 20 around single or clusters of two to three corals. A total of 81 and 119 fish, respectively, were examined histologically. After an initially undifferentiated state, gonads of D. melanurus developed oocytes in the primary growth stage, followed by an ovarian lumen. From this ovarian state or from more developed ovaries, some gonads developed into testes through degeneration of oocytes and development of spermatogenic tissue. No fish had gonads that simultaneously contained both degenerating vitellogenic oocytes and developing spermatogenic tissue, but some fish had gonads that contained both degenerating oocytes in the primary growth stage and developing spermatogenic tissue (termed as mixed-stage gonads). The size distributions of fish with mixed-stage gonads differed between the two populations in a manner that was predicted from the theories of sex allocation and mating systems. In the Guzem population, most fish with mixed-stage gonads were smaller than the smallest mature female, which indicated that functional sex change was infrequent. In the Kranket population, the majority of fish with mixed-stage gonads were within the size range of mature females, which indicated that functional sex change was present and was more frequent than in the former population. Presence of fish with mixed-stage gonads in the size range of mature females indicated that D. melanurus was a protogynous hermaphrodite, but two populations differed in the frequency of functional sex change.

Pseudomystus sobrinus, a new species of bagrid catfish, is described from small coastal streams draining the eastern slope of the Annam Cordillera in central Vietnam. Pseudomystus sobrinus resembles P. siamensis and P. bomboides; all three species are distinguished from congeners by their color pattern of strongly contrasting brown and yellow/cream vertical bands on the body. Pseudomystus sobrinus differs from P. siamensis in having a slightly bulbous snout, shorter adipose-fin base (14.7–19.9% SL vs. 21.3–27.2) and pectoral-fin spine (15.4–18.3% SL vs. 17.8–23.4), and from P. bomboides in having a shorter maxillary barbel (not reaching beyond opercle vs. reaching beyond base of pectoral-fin spine) and one (vs. two) brown bands on the caudal fin.

Small streams with acidic, nutrient-poor waters form a dense hydrological system in Central Amazonia. However, little is known about the fish assemblages that occur in these systems. We investigated the relationships among stream size, substrate, and other physical-chemical factors and fish distributions. Fish assemblages and stream characteristics were sampled in 50-m long sections of streams at 38 sites distributed throughout the 100-km² florestal reserve. Forty-nine species were encountered. The mean richness was similar among sites; however, community composition was correlated with physical and chemical characteristics of the streams. The mean number of species per site (X̄ = 9) was low in relation to the total number of species recorded from the reserve (49) and in relation to the ichthyofauna that has been recorded from small forest streams near the study area. This contrasts with studies in temperate zones where strong patterns of species addition along the river continuum were found, resulting in prominent species richness gradients. The high between-site turnover in species composition and the strong habitat specificity indicate that it will be necessary to create a network of reserves to efficiently conserve the fish fauna of small forest streams in Central Amazonia.

Na Amazônia Central, pequenos riachos de águas ácidas e pobres em nutrientes constituem uma densa rede hidrica. Contudo, pouco é conhecido sobre a riqueza e abundância de sua ictiofauna. Para determinar a composição ictiofaunistica existente, bem como determinar a relação entre o tamanho dos igarapés, substratos presentes nos leitos, e fatores fisico-quimicos e a estrutura da comunidade, nós amostramos trechos de 50-m em 38 locais distribuidos em uma reserva de 100-km². A riqueza média foi semelhante entre os sitios de amostragem. No entanto, a composição de espécies foi relacionada com caracteristicas fisicas e quimicas dos riachos. O número médio de espécies por local (X̄ = 9) foi pequeno em relação ao número total de espécies encontrado na reserva (49) e em relação à ictiofauna que foi encontrada em pequenos riachos próximos à área de estudo. Isto contrasta com estudos realizados em zonas temperadas, onde um padrão muito forte de adição de espécies ao longo das bacias foi encontrado, resultando em um gradiente acentuado de riqueza de espécies. A alta troca na composição de espécies entre locais, e a alta especificidade de hábitat, indica que seria necessário criar uma rede de reservas para conservar eficientemente a ictiofauna de pequenos riachos na região.

Parodon moreirai, new species, is described from headwater streams of the Rio Sapucai basin, tributary of the Rio Grande basin, upper Rio Paraná system, in the southwestern region of the Serra da Mantiqueira, southeastern Brazil. The new species is distinguishable from other species of Parodontidae by morphological, coloration, and karyotypic characters. Some adults of P. moreirai lack dentary teeth. Absence of dentary teeth is the main diagnostic character that traditionally distinguishes Apareiodon from Paradon, and the variability of that character underscores the need for a phylogenetic revision of the Parodontidae.

Parodon moreirai, espécie nova, é descrita a partir de exemplares coletados em riachos de cabeceira da bacia do Rio Sapucai, tributário da bacia do Rio Grande, sistema do alto Rio Paraná, na região sudoeste da Serra da Mantiqueira, sudeste do Brasil. A nova espécie distingue-se das demais espécies de Parodontidae através de caracteres morfológicos, de coloração e citogenéticos. Alguns exemplares adultos de Parodon moreirai não apresentam dentes no osso dentário. A ausência de dentes no dentário é o principal caráter diagnóstico que tradicionalmente distingue Apareiodon de Parodon, e a variabilidade deste caráter enfatiza a necessidade de uma revisão filogenética de Parodontidae.

Roads affect animal survivorship and behavior and thereby can act as a barrier to movement, which exacerbates habitat fragmentation and disrupts landscape permeability. Field experiments demonstrated that interspecific differences in ecology and behavior of snakes affected responses of species when they encountered and crossed roads. The probability of crossing a road varied significantly among southeastern U.S. snakes, with smaller species exhibiting higher levels of road avoidance. Species also differed significantly in crossing speeds, with venomous snakes crossing more slowly than nonvenomous ones. All species crossed at a perpendicular angle, minimizing crossing time. A model incorporating interspecific crossing speeds and angles revealed that some species cannot successfully cross highways with high traffic densities. Individuals of three species immobilized in response to a passing vehicle, a behavior that would further prolong crossing time and magnify susceptibility to road mortality. Identifying direct and indirect effects of roads on snakes is essential for mitigating road impacts and for designing effective transportation systems in the future.

Nominotypical Noturus elegans are herein restricted to the Green River drainage of central Kentucky and north-central Tennessee. Ten specimens and additional new material from the Duck River originally allocated to N. elegans are here described as a new species, Noturus fasciatus, restricted to the Duck River system and two minor tributaries of the lower arm of the Tennessee River, Tennessee. A second new species, Noturus crypticus, is described from the only known extant population in Little Chucky Creek, Greene County, Tennessee. These three taxa are closely related and are distinguished on the basis of modal differences in anal-fin ray numbers, body shape, pigmentation, and genotypic arrays. Noturus crypticus is described from only eight specimens, is clearly uncommon, probably relict, and in need of federal protection and future propagation efforts. All three species are primarily riffle/glide dwellers in small- to medium-sized streams where they may be found in or under gravel, rubble, and slab rock. The limited geographic distributions of the two new species places them at greater risk of extinction, warranting comprehensive evaluation of their life histories, demographic characteristics, recruitment rates, and nesting requirements.

Members of the genus Leptodactylus deposit eggs in foam nests; however, species vary in nest deposition sites, which may be aquatic or terrestrial, and the amount of time larvae remain in the nest. Life history characteristics are hypothesized to have a phylogenetic basis, but data to evaluate this idea are lacking for most species of Leptodactylus. We studied the ecology of tadpoles of Leptodactylus labyrinthicus in the Brazilian Cerrado to gain insight into the reproductive ecology of this species. Foam nests of L. labyrinthicus were deposited on land generally along the periphery of small, shallow ponds. Internal nest temperatures were lower, less variable, and less influenced by the environment than nest surface temperatures. Only a small percentage of eggs in each nest were fertilized, and tadpoles grew and developed within the foam while feeding on unfertilized eggs. Heavy rainfall washed the majority of tadpoles out of nests and into ponds. Tadpoles collected from the ponds had eggs in their guts, and feeding experiments confirmed that free-living tadpoles of L. labyrinthicus eat eggs of other frog species. The reproductive mode of L. labyrinthicus is intermediate between two previously described modes for closely related species. This mode may be adaptive in the unpredictable and seasonal environment in which this species occurs.

Todos os membros do gênero Leptodactylus depositam ovos em ninhos de espuma; se os ninhos são aquáticos ou terrestres e até qual estágio as larvas desenvolvem-se neles, contudo, varia entre espécies. Acredita-se que os modos reprodutivos de anuros têm uma base filogenética, mas para a maioria das espécies não existem dados suficientes para avaliar essa hipótese. Nós estudamos a ecologia dos girinos de Leptodactylus labyrinthicus no Cerrado brasileiro com o intuito de tentar compreender melhor sua ecologia reprodutiva. Os ninhos de espuma de L. labyrinthicus foram depositados sobre o chão ao longo da periferia de poças pequenas e rasas. As temperaturas internas dos ninhos foram mais baixas e variaram menos do que as temperaturas externas. Apenas uma pequena porcentagem dos ovos em cada ninho foi fertilizada e os girinos permaneceram dentro da espuma, crescendo e desenvolvendo-se através da ingestão de ovos. Chuvas fortes dissolveram os ninhos e lavaram os girinos, carregando-os para as poças. Girinos coletados nas lagoas possuiam ovos em seus intestinos, e experimentos confirmaram que girinos de L. labyrinthicus alimentam-se dos ovos de outras espécies após abandonarem os ninhos. O modo reprodutivo de L. labyrinthicus é intermediário a dois outros modos descritos para espécies próximas. Esse modo pode ser adaptativo em ambientes sazonais e imprevisiveis onde essa espécie ocorre.

A new species of Creagrutus from the Rio Magdalena basin, Colombia, is described. This species is distinguished from all congeners by a combination of morphometric, meristic, and morphological features. The species is the first member of the genus known to have breeding tubercles with keratinized caps. The phylogenetic position of the new species and various aspects of its ecology and behavior are discussed.

Es descrita una nueva especie de Creagrutus de la cuenca del Rio Magdalena, Colombia. Ésta especie se distingue de sus congéneres por su combinación de caracteristicas morfométricas, meristicas y morfológicas. Ésta es la primera especie de Creagrutus en la que se hayan observado tubérculos reproductivos con casquetes queratinizados. Se discute la posición filogenética de la nueva especie y se comentan varios aspectos de su ecologia y comportamiento.

We describe a new species of krait (Elapidae: Bungarus) from the Red River drainage in northern Vietnam. The new species differs from all congeners except its sister species Bungarus bungaroides by the combination of divided subcaudals, dorsal scales arranged in 15 rows, black and white rings on body and tail, and in color pattern of the head as well as hemipenis morphology. The new species differs from B. bungaroides, a distantly allopatric species ranging from eastern Nepal to northern Myanmar, in molecular characters and color pattern. We propose a vicariance hypothesis in which speciation coincided with the uplift of intervening mountain ranges in southwestern Yunnan (China) and/or Late Tertiary glaciations.

A new Smoothhound shark, Mustelus hacat, is described from the eastern North Pacific. Four species of the genus Mustelus had been previously recognized in this area: M. californicus, M. henlei, M. lunulatus, and M. dorsalis. Mustelus hacat is described on the basis of 36 specimens caught in the Gulf of California. Among the Smoothhound sharks in the eastern North Pacific, M. hacat is distinguished mainly by having color uniform dark gray-brown above, white below, with conspicuously white tips and trailing edges of dorsal, pectoral, anal, and caudal fins; upper jaw teeth cuspidate and distinctly asymmetric, with low rounded cusp and prominent cusplet present in teeth of juveniles; upper jaw labial folds notably longer than lower jaw labial folds; and inter-nostril and inter-orbital space wide. Because these species have long been misidentified, we present a key to species using morphological and morphometric features found to be useful taxonomic characters to distinguish them.

En este trabajo describimos una nueva especie de tiburón Musola, Mustelus hacat, del Pacifico Noreste. Previamente, en esta área habian sido reconocidas cuatro especies del género Mustelus: M. californicus, M. henlei, M. lunulatus, y M. dorsalis. Mustelus hacat es descrita con base en 36 especimenes que fueron capturados en el Golfo de California. Entre los tiburones del género presentes en el Pacifico Noreste, M. hacat es distinguido principalmente por su patrón de coloración, el cual es café-gris oscuro uniforme arriba, blanco abajo, con puntas y bordes posteriores blancos en aletas dorsales, pectorales, anal y caudal; la forma de sus dientes, los cuales son notablemente asimétricos, con una cúspide redonda, y una cúspide accesoria prominente en los dientes de juveniles; por tener pliegues labiales superiores notablemente más largos que los pliegues labiales inferiores; y espacios inter-narial e inter-orbital amplios. Debido a que estas especies han sido mal identificadas desde hace mucho tiempo, presentamos una clave dicotómica usando caracteristicas morfológicas y morfométricas que han mostrado ser caracteres taxonómicos útiles para distinguirlas.

Glanidium bockmanni, new species, is described from the Rio São Francisco basin in Brazil. The new species is distinguished from its congeners by the reduced ossified suprapreopercular canal. It occurs in sympatry with Glanidium albescens in Minas Gerais; the two species differ in relative adult size, pectoral-fin spine serration, fin ray counts, and numbers of ribs and vertebrae. Within Glanidium, the new species uniquely shares with G. cesarpintoi (Ihering, 1928) a color pattern of small dark dots scattered over the body, a smaller adult size (less than 50 mm in standard length), and absence of first nuchal plate.

Glanidium bockmanni sp. nov. é descrita a partir de material da bacia do rio São Francisco, nos estados brasileiros de Minas Gerais e Bahia. A nova espécie distingue-se de todas as congêneres pela reduzida ossificação do canal suprapreopercular. Em Minas Gerias ocorre em simpatria com Glanidium albescens; as duas espécies diferem quanto ao tamanho relativo dos adultos, aos denticulos no espinho da nadadeira peitoral, contagem dos raios das nadadeiras, e número de costelas e vértebras. Dentro de Glanidium, a nova espécie compartilha de modo exclusivo com G. cesarpintoi (Ihering, 1928) o padrão de colorido formado por pequenos pontos escuros espalhados sobre o corpo, o menor tamanho de adulto (inferior a 50 mm em comprimento padrão), e a ausência da primeira placa nucal.

Hapalogenys nigripinnis (Schlegel in Temminck and Schlegel, 1843) is redescribed on the basis of a lectotype, five paralectotypes, and non-type specimens. Hapalogenys sennin, new species, is described from type and non-type specimens and is currently known only from parts of southern Japan (except the Ryukyu and Ogasawara Islands). It has long been identified as H. nigripinnis, although lacking a scaled maxilla. The type specimens of H. nigripinnis are all conspecific with the holotype of H. nitensRichardson, 1844, which is regarded as a valid species from the East Asian Shelf and also characterized by a scaled maxilla. Accordingly, H. nigripinnis has priority over H. nitens, including junior synonyms of H. aculeatusNystöm, 1887 and H. guentheriMatsubara, 1933 by having the same characters of H. nigripinnis on the basis of their type specimens.

Understanding the mechanisms and patterns of how energy is allocated into the reproductive components of offspring size and number is central to life-history theory. We used X-ray photographs from a long-term mark recapture study of Kinosternon subrubrum, Sternotherus odoratus, and Pseudemys floridana to investigate hypotheses concerning variation in reproductive allocation due to constraint on egg size, within-female variability (within and among clutches), interannual environmental variation, multiple annual clutches, allocation of continuous resources into small integer numbers of offspring (fractional offspring-size problem), and age. Patterns of reproductive allocation varied markedly within and among species. Overall, egg size varied as a function of maternal body size and age, intra-annual clutch frequency, the fractional offspring-size problem, and environmental variation. Clutch size varied with maternal body size, clutch frequency, and environmental variation. We examine how effectively the data support optimal-egg-size and phenotypic-plasticity models of reproductive allocation, and identify limitations of fundamental biological findings necessary to address the issues.

Boa constrictors inhabiting islands off the coast of Belize have been historically collected for the pet trade, and enthusiasts have described these as a dwarfed race. Additionally, it has been suggested that these boas feed on birds, yet no dietary data are available. I initiated a mark-recapture study of five Belizean island populations and have accumulated data on mainland individuals to describe the natural history and population biology of boas in this region. Results indicate that adult island boas from West Snake Cay eat small passerine birds (gray-breasted martins, Progne chalybea) that average 7% of the snake's mass. Fecal samples from boas on other islands contained bird feathers and, although these feathers were unidentifiable, this indicates that other island boa populations also consume birds. Compared to mainland boas, island boas have significantly smaller litters of smaller neonates (lighter and shorter) and have extraordinarily small population sizes (range 8–88 total individuals). According to IUCN criteria, island boas can be classified as Endangered based solely on total population and subpopulation sizes. Collection data, gathered from the literature and unpublished sources, revealed a decline in one island population (Crawl Cay) that is currently estimated to consist of eight free-ranging individuals. Island populations of Belizean boas warrant immediate conservation priority due to their low reproductive output, small population sizes, and continued demand in the pet trade.

Boa constrictors inhabiting islands off the coast of Belize have been historically collected for the pet trade, and enthusiasts have described these as a dwarfed race. Additionally, it has been suggested that these boas feed on birds, yet no dietary data are available. I initiated a mark-recapture study of five Belizean island populations and have accumulated data on mainland individuals to describe the natural history and population biology of boas in this region. Results indicate that adult island boas from West Snake Cay eat small passerine birds (gray-breasted martins, Progne chalybea) that average 7% of the snake's mass. Fecal samples from boas on other islands contained bird feathers and, although these feathers were unidentifiable, this indicates that other island boa populations also consume birds. Compared to mainland boas, island boas have significantly smaller litters of smaller neonates (lighter and shorter) and have extraordinarily small population sizes (range 8–88 total individuals). According to IUCN criteria, island boas can be classified as Endangered based solely on total population and subpopulation sizes. Collection data, gathered from the literature and unpublished sources, revealed a decline in one island population (Crawl Cay) that is currently estimated to consist of eight free-ranging individuals. Island populations of Belizean boas warrant immediate conservation priority due to their low reproductive output, small population sizes, and continued demand in the pet trade.

Air-breathing and non air-breathing gobiids inhabiting mangal tidepools on Pulau Hoga, Sulawesi, Indonesia, displayed differing types and degrees of behavioral and physiological adaptations to mitigate daily thermal and oxic stress. Non air-breathing Dusky Frillfin Goby, Bathygobius fuscus, and an undescribed sandflat goby species, Bathygobius sp., had higher critical thermal maxima, CTMax, (41.2 and 41.6 C, respectively) and lower critical thermal minima, CTMin, (11.0 and 11.4 C, respectively) than amphibious Common Mudskipper, Periopthalmus kalolo (40.8 and 12.8 C, respectively). During hypoxia, Common Mudskipper CTMax decreased significantly (38.8 C) and fish displayed a pronounced escape response, while Dusky Frillfin Goby showed no significant CTMax decrease (40.8 C). Neither bathygobiid attempted to escape during CTM trials. Common Mudskipper, however, attempted escape at temperatures significantly lower than their normoxic and hypoxic CTMax (36.4 and 35.0 C, respectively), and at temperatures higher than their normoxic CTMin (18.7 C). Temperature quotients (ratio of metabolic rates or oxygen consumption at two temperatures) for all species approached unity and ranged from 1.00 to 1.37 when exposed to a temperature increase of 6 C. Oxygen insensitive CTMaxima and a wide thermal scope allow bathygobiids to remain in tidepools during the most extreme conditions. In contrast, amphibious Common Mudskipper use a well developed behavioral escape response to avoid unfavorable environments. A sharply reduced temperature quotient response for these gobies diminishes the metabolic costs typically associated with diel temperature increases.

Air-breathing and non air-breathing gobiids inhabiting mangal tidepools on Pulau Hoga, Sulawesi, Indonesia, displayed differing types and degrees of behavioral and physiological adaptations to mitigate daily thermal and oxic stress. Non air-breathing Dusky Frillfin Goby, Bathygobius fuscus, and an undescribed sandflat goby species, Bathygobius sp., had higher critical thermal maxima, CTMax, (41.2 and 41.6 C, respectively) and lower critical thermal minima, CTMin, (11.0 and 11.4 C, respectively) than amphibious Common Mudskipper, Periopthalmus kalolo (40.8 and 12.8 C, respectively). During hypoxia, Common Mudskipper CTMax decreased significantly (38.8 C) and fish displayed a pronounced escape response, while Dusky Frillfin Goby showed no significant CTMax decrease (40.8 C). Neither bathygobiid attempted to escape during CTM trials. Common Mudskipper, however, attempted escape at temperatures significantly lower than their normoxic and hypoxic CTMax (36.4 and 35.0 C, respectively), and at temperatures higher than their normoxic CTMin (18.7 C). Temperature quotients (ratio of metabolic rates or oxygen consumption at two temperatures) for all species approached unity and ranged from 1.00 to 1.37 when exposed to a temperature increase of 6 C. Oxygen insensitive CTMaxima and a wide thermal scope allow bathygobiids to remain in tidepools during the most extreme conditions. In contrast, amphibious Common Mudskipper use a well developed behavioral escape response to avoid unfavorable environments. A sharply reduced temperature quotient response for these gobies diminishes the metabolic costs typically associated with diel temperature increases.

In the last two centuries, European fire suppression practices have produced increases in vegetation density and canopy cover in many landscapes. Potentially, increases in canopy cover could negatively affect small populations of nocturnal reptiles that use sun-exposed shelters for diurnal thermoregulation. We hypothesized that vegetation encroachment over rock outcrops might partly explain the recent decline of Australia's most endangered snake, the Broad-headed Snake Hoplocephalus bungaroides. To test this hypothesis, we carried out a field study in Morton National Park, southeastern Australia. We removed overhanging vegetation from above shaded rocks and compared their subsequent usage by reptiles to control (shaded) rocks. In spring, one year after canopy removal, experimental rocks were 10.3 C hotter than control rocks and were used as diurnal retreat sites by three species of reptiles, including the endangered Broad-headed Snake and its prey (Velvet Gecko, Oedura lesueurii). By contrast, no reptiles used control rocks as diurnal retreat sites. Our results show that modest canopy removal (15% increase in canopy openness) can restore habitat quality for nocturnal reptiles. Future studies are needed to examine whether controlled burns can maintain an open canopy above sandstone rock outcrops. However, until effective fire management measures are in place, sapling removal from overgrown rock outcrops could help to protect small populations of endangered reptiles.

The developmental environment influences a wide variety of phenotypic traits in the adults of many vertebrates (i.e., developmental plasticity). In this study, we test to see if developmental environment (E_DEV) interacts with the adult behavioral environment (E_BEHAV) in determining behavioral phenotypes. We reared Zebrafish (Danio rerio) from eggs in either continuously hypoxic or normoxic conditions. We then tested aggression and avoidance (i.e., hiding) levels of fish from each developmental treatment in both environments. Developmental environment was a significant source of variation in avoidance behavior while the stimulus environment did not influence avoidance. Without a period of acclimation we found that E_BEHAV and an E_DEV × E_BEHAV interaction were both significant sources of variation. However, when the fish were allowed to physiologically acclimate to the environment for 16 h, aggression level was highest for fish tested in the environment in which they developed. In that case the E_DEV × E_BEHAV interaction was the only significant source of variation. These results demonstrate that a more complete understanding of phenotypic response can be gained by incorporating environmental conditions across multiple time scales.

We assessed Anax junius dragonfly naiad strike frequencies and kill probabilities against Rana sylvatica (Wood Frog) tadpoles. Strikes fell into five categories according to their placement on the tadpole body: anterior head/body, posterior head/body, head/body-tail intersection, anterior tail, and posterior tail. The kill probability was calculated for each category as the number of kills divided by the number of contacts made in that category. These probabilities varied; a higher probability was found for both the anterior and posterior head/body, and values declined for successively posterior categories. Neither the kill probability nor the size of the body zone influenced the number of strikes to that zone. Surprisingly, the dragonfly naiads struck most frequently at the relatively narrow region of the head/body-tail intersection, suggesting that dragonfly naiads may aim at a specific target.

From March 1998 to September 2000, we collected Atlantic Sharpnose Sharks, Rhizoprionodon terraenovae, in the north central Gulf of Mexico between St. Louis Bay, Mississippi and Perdido Bay, Alabama. Collections were typically made in the Mississippi Sound over a 4-day period, one site per day, using a gill net fished from 1500 to 2200 h at each site. We collected sharks each month from March to October of each year of the study. We made a total of 100 collections at approximately 60 different sites. Rhizoprionodon terraenovae were very common and were distributed over the entire study area. We collected 1,344 R. terraenovae of all size classes and both sexes; 276 in 1998, 300 in 1999 and 768 in 2000. The unexpectedly low number of adult females in collections (718 adult males: 9 adult females) suggests that females rarely enter shallow waters after maturation and both pupping and mating occur outside of the Mississippi Sound. Sharks begin to appear inshore in the spring when water temperatures approach 20 to 22 C and begin to move out of the area in fall at 24 to 22 C. In each year of the study, relative abundance (catch rates as catch per unit effort, CPUE, in sharks/1000 meters net/hour) of adult male R. terraenovae was highest in spring and fall and lowest during summer. During summer months, catch rates of adult male R. terraenovae was significantly and inversely related to temperature. We also found a significant effect of season on condition factor of adult males, with shark condition lowest during summer months. These results suggest that the exodus of adult males from inshore waters may be in response to the high temperature/low oxygen conditions of summer. However, a reproductively motivated migration from the Mississippi Sound is likewise a possibility.

Atelognathus patagonicus is a Leptodactylid frog endemic to Patagonia with a very restricted range in and around Laguna Blanca National Park, Neuquén, Argentina. We conducted surveys of A. patagonicus in 15 lakes in and around the park from December 2000 through April 2001 (late austral spring through early fall) and January–February 2002. We found the species in all the lakes except the largest, Laguna Blanca, and conclude that A. patagonicus is gone from that lake, probably related to the introduction of an invasive fish species there. We used transects and quadrats to sample animals near the shoreline of the lakes and found impressive densities of A. patagonicus, up to 1.15 individuals/m² in one transect at one lake and an overall average highest density per lake of 0.58 individuals/m². Densities were highest in late summer (March). Captures were higher in aquatic than terrestrial habitat, although postmetamorphs on land were not uncommon. Littoral and aquatic postmetamorphic forms have been described for this species; most animals we found were the aquatic form (96.8%). Tadpoles were found in January–March. In most populations, we found many dead and moribund tadpoles and frogs, all of which showed clinical signs of an unknown disease. Frequency of affected animals was greater than 40% in eight of the 11 lakes sampled systematically and reached 91.3% in one lake in February 2002. Percent animals encountered dead was usually less than 12%, except for 33% registered in one lake in January 2001. Clinical signs occurred mostly in metamorphosing tadpoles and recent metamorphs, with a peak in February (47%). Populations were mostly asymptomatic (prevalence of 1.4%) by early fall (April) and showed roughly equivalent high densities of animals the next year, as well as high levels of sick animals once again.

Atelognathus patagonicus es una rana Leptodactilida endémica de la Patagonia con una distribución restringida a un área dentro y cerca del Parque Nacional Laguna Blanca, Neuquén, Argentina. Llevamos a cabo muestreos de A. patagonicus en 15 lagos dentro y cerca del parque de diciembre del 2000 a abril del 2001 (finales de la primavera a principios del otoño austral) y en enero–febrero de 2002. Encontramos la especie en todos los lagos excepto en el más grande, Laguna Blanca, y concluimos que A. patagonicus ha desaparecido de ese lago, probablemente en relación a la introducción de una especie invasiva de pez en ese ambiente. Usamos transectas y cuadrados para muestrear animales cerca de la orilla de los lagos y encontramos densidades impresionantes de A. patagonicus, hasta 1.15 individuos/m² en una transecta en un lago y un promedio general de la más alta densidad por lago de 0.58 individuos/m². Las densidades fueron más altas a fines de verano (marzo). Las capturas fueron más frecuentes en hábitats acuáticos que terrestres, a pesar de que los post-metamorfoseados en la tierra fueron relativamente comunes. Formas litorales y acuáticas de post-metamorfoseados han sido descritas para esta especie, la mayoria de los animales que encontramos fueron de la forma acuática (96.8%). Se encontraron renacuajos de enero a marzo. En la mayoria de las poblaciones, encontramos muchos renacuajos y ranas muertos y moribundos, todos con signos clinicos de una enfermedad desconocida. La frecuencia de animales afectados fue más alta que el 40% en ocho de los 11 lagos muestreados sistemáticamente, y alcanzó 91.3% en un lago en febrero, 2002. El porcentaje de animales encontrados muertos fue usualmente menos del 12%, excepto por el 33% registrado en un lago en enero, 2001. Los signos clinicos ocurrieron principalmente en los renacuajos en metamorfosis y en juveniles recién metamorfoseados, con un máximo en febrero (47%). Las poblaciones fueron principalmente asintomáticas (prevalencia del 1.4%) al princ

Despite widespread belief that selection molds thermoregulatory behaviors, direct evidence for fitness effects is extremely rare. We studied the effect of developmental temperature on embryo mortality in a viviparous snake. Seventy-four female Thamnophis elegans were maintained at one of nine constant temperatures during pregnancy (21–33 C). The duration of pregnancy was recorded for each female as well as the sex, snout–vent length, mass, and survival of 504 newborns. Embryo survival was highest at an intermediate temperature (26.6 C). The developmental temperature of maximum survivorship in T. elegans corresponds to the temperature that induces minimum developmental abnormality and the optimum temperature for whole organism performance. These three thermal optima together correspond with the average temperatures imposed on embryos by free-ranging pregnant females (26.6 C). This correspondence implies that thermal optima are coadapted to thermoregulation in T. elegans.