Thermal relationships and exercise physiology in anuran amphibians: Integration and evolutionary implications

Thermal and water balance are coupled in anurans, and species with particularly permeable skin avoid overheating more effectively than minimizing variance of body temperature. In turn, temperature affects muscle performance in several ways, so documenting the mean and variance of body temperature of active frogs can help explain variation in behavioral performance. The two types of activities studied in most detail, jumping and calling, differ markedly in duration and intensity, and there are distinct differences in the metabolic profile and fiber type of the supporting muscles. Characteristics of jumping and calling also vary significantly among species, and these differences have a number of implications that we discuss in some detail throughout this paper. One question that emerges from this topic is whether anuran species exhibit activity temperatures that match the temperature range over which they perform best. Although this seems the case, thermal preferences are variable and may not necessarily reflect typical activity temperatures. The performance versus temperature curves and the thermal limits for anuran activity reflect the thermal ecology of species more than their systematic position. Anuran thermal physiology, therefore, seems to be phenotypically plastic and susceptible to adaptive evolution. Although generalizations regarding the mechanistic basis of such adjustments are not yet possible, recent attempts have been made to reveal the mechanistic basis of acclimation and acclimatization. (C) 2007 Elsevier B.V. All rights reserved.

The evolution of jumping performance in anurans: morphological correlates and ecological implications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Natural history of the South American water snake Helicops leopardinus (Colubridae : Hydropsini) in the pantanal, Central Brazil

The South American water snake Helicops leopardinus is very abundant in the Pantanal wetlands of Central Brazil. We studied the biology of this species based on specimens collected by local workers in the Paraguay River. Females attained greater body lengths and had larger heads than males, but the latter had longer tails. Helicops leopardinus fed on a wide variety of fishes (70% of the total prey items) and frogs, with fishes of the order Gymnotiformes (33.34%) and frogs of the family Hylidae (23.34%) representing the most common prey items. There was relatively lows diet overlap between the sexes and between juveniles and adults. Mean litter size was 6.6 and ranged from 4-11. The reproductive cycle was seasonal, with birth occurring late in the wet season (simultaneous with the flooding of the Paraguay River), facilitating dispersal of young snakes by floating vegetation. Floating vegetation may be a critical habitat for H. leopardinus, and management plans for their maintenance need to be developed.

Hemoparasites of the genus Trypanosoma (Kinetoplastida: Trypanosomatidae) and hemogregarines in Anurans of the São Paulo and Mato Grosso do Sul States - Brazil

Os animais silvestres estão expostos a inúmeros patógenos,dentre eles estão os hemoparasitas. Podem-se destacar espécies do gênero Trypanosoma e do grupo das hemogregarinas,que ocorrem com freqüência parasitando anuros (rãs, pererecas e sapos). Normalmente, a descrição destes hemoparasitas é feita através da morfologia dos estágios observados nosangue periférico do hospedeiro e as pesquisas sobre o ciclobiológico desses hemoparasitas são escassas. Os objetivos dopresente estudo foram avaliar a presença de hemogregarinas eTrypanosoma spp. em anuros capturados nos Estados de São Paulo e Mato Grosso do Sul e fazer a caracterização morfológica e morfométrica dos seus hemoparasitas. As espécies deanuros examinadas foram: Dendropsophus nanus, D. minutus, Leptodactylus chaquensis, L. podicipinus, L. labyrinthicus, L. fuscus, Bufo granulosus, B. schneideri, Phyllomedusahypocondrialis, Trachicephalus venulosus, Scinax fuscovarius e Hypsiboas albopunctatus. Dos 40 animais estudados, foramencontrados quatro (10%) positivos para hemogregarinas e oito(20%) positivos para Trypanosoma spp. Foram observadosgamontes de hemogregarinas com morfologia variável e, alémdas formas intraeritrocíticas, também foram observados gamontes fora das hemácias. As formas de Trypanosoma encontradas eram muito polimórficas, conforme é descrito na literatura, sendo na sua maioria, larga e oval.

Comparative karyotype analysis and chromosome evolution in the genus Aplastodiscus (Cophomantini, Hylinae, Hylidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reproductive biology of Scinax fuscomarginatus (Anura, Hylidae) in south-eastern Brazil

The present study describes the reproductive biology of Scinax fuscomarginatus in a remnant of Cerrado in south-eastern Brazil. Observations were made between September 2002 and March 2004 at Estacao Ecologica de Itirapina, State of São Paulo, south-eastern Brazil. Breeding activities occurred in lentic and temporary bodies of water during the rainy season. Scinax fuscomarginatus exhibited a prolonged breeding pattern and a lek mating system. Males were smaller than females and defended individual calling areas through acoustic and physical interactions. Resident males consistently won encounters, but did not differ in size or mass from intruder males. Satellite behaviour was observed, but no female or amplected pair interception was registered. Scinax fuscomarginatus exhibited low operational sex ratios and the general reproductive mode in which eggs are laid in the water and tadpoles are aquatic. Amplexus was axillary and the eggs were deposited at the bottom of temporary ponds. Details on oocytes, egg masses, and eggs are included.

Tribute to R.G. Boutilier: Skin colour and body temperature changes in basking Bokermannohyla alvarengai (Bokermann 1956)

In amphibians solar basking far from water sources is relatively uncommon since the highly permeable amphibian skin does not represent a significant barrier to the accompanying risk of losing water by evaporation. A South American frog, Bokermannohyla alvarengai (Bokermann 1956), however, spends a significant amount of the day exposed to full sun and relatively high temperatures. The means by which this frog copes with potentially high rates of evaporative water loss and high body temperatures are unknown. Thus, in this study, skin colour changes, body surface temperature, and evaporative water loss rates were examined under a mixture of field and laboratory conditions to ascertain whether changes in skin reflectivity play an important role in this animal's thermal and hydric balance. Field data demonstrated a tight correlation between the lightness of skin colour and frog temperature, with lighter frogs being captured possessing higher body temperatures. Laboratory experiments supported this relationship, revealing that frogs kept in the dark or at lower temperatures (20 degrees C) had darker skin colours, whereas frogs kept in the light or higher temperatures (30 degrees C) had skin colours of a lighter hue. Light exhibited a stronger influence on skin colour than temperature alone, suggesting that colour change is triggered by the increase in incident solar energy and in anticipation of changes in body temperature. This conclusion is corroborated by the observation that cold, darkly coloured frogs placed in the sun rapidly became lighter in colour during the initial warming up period (over the first 5 min), after which they warmed up more slowly and underwent a further, albeit slower, lightening of skin colour. Surprisingly, despite its natural disposition to bask in the sun, this species does not possess a 'waterproof' skin, since its rates of evaporative water loss were not dissimilar from many hylid species that live in arboreal or semi-aquatic environments. The natural history of B. alvarengai is largely unknown and, therefore, it is likely that the herein reported colour change and basking behaviour represent a complex interaction between thermoregulation and water balance with other ecologically relevant functions, such as crypsis.

Comparative cytogenetic analysis on four tree frog species (Anura, Hylidae, Hylinae) from Brazil

A comparative cytogenetic analysis was carried out on four Hylinae tree frogs from Brazil (Aparasphenodon brunoi, Corthomantis greeningi, Osteocephalus langsdorffi and Scinax fuscovarius) using Giemsa staining, BrdU replication banding, Ag-NOR staining, C-banding, DAPI and CMA(3) fluorochrome staining, and fluorescence in situ hybridization (FISH) with an rDNA probe. All the species share closely similar 2n = 24 karyotypes, almost indistinguishable by standard staining. The technique of BrdU incorporation allowed the identification of each pair of homologs and the establishment of extensive homeology for the great majority of the chromosomes, mainly of A. brunoi, C greeningi, and O. langsdorffii. Despite highly conserved replication banding patterns, the use of the other banding techniques disclosed some minor differsences, which reinforces the importance of extensive cytogenctic analyses for the karyotypic characterization of Anuran species. The present cytogenctic data confirm the closer proximity of A. brunoi, C greeningi, and O. langsdorfjii, whereas S. fuscovarius is phylogenetically more distant. Copyright (C) 2003 S. Karger AG, Basel

Two new species of Brachycephalus (Anura : Brachycephalidae) from the Atlantic Forest in Parana State, Southern Brazil

Two new species of brachycephalid frogs are described from Pico Marumbi, municipality of Morretes, and Pico da Igreja, municipality of Guaratuba, Parana State, southern Brazil. The new species share the following attributes: body bufoniform; skin on top of the head, and central part of the back body smooth with no dermal co-ossification; outer metatarsal tubercle distinct; dermal roofing bones of skull unornamented; all paired cranial bones distinct and not fused; quadratojugals, and maxillary odontoids present. The new species from Pico Marumbi is characterized by male SVL = 11.6-12.5 and female SVL = 13.0-14.5 turn; and general color orange with dorsal reddish-brown irregular markings, lateral surfaces with small dark brown spots, and belly with brownish spots and small dots. The new species from Pico da Igreja is characterized by male SVL = 12.6-13.9 and female SVL = 14.6-15.3 mm; and general color orange, lateral surfaces with small dark brown spots, and belly with brownish coalescent spots and small dots. Comparisons with other brachycephalid species and osteological data are provided.

A new and threatened island-dwelling species of Cycloramphus (Anura : Cycloramphidae) from southeastern Brazil

We describe a new species of Cycloramphus of the eleutherodactylus group from the Ilha dos Alcatrazes, southeastern Brazil, with descriptions of advertisement and territorial calls and notes on natural history. Additionally, we describe the advertisement and territorial calls of C. eleutherodactylus. The new species is diagnosed by the following set of characters: snout truncate in lateral and dorsal views; head wider than long; eyes protruding; tibia shorter than thigh; and distinct advertisement call. The new species is known from a single population on the Ilha dos Alcatrazes, a 149 ha island about 35 kin off São Paulo State coast where these frogs are scattered in a small valley. The very restricted range of the new species of Cycloramphus and the declining quality of its habitat qualify this frog as critically endangered.

Diet and habitat use of two sympatric species of Philodryas (Colubridae), in south Brazil

Feeding habits and habitat use of the colubrid snakes Philodryas olfersii and P patagoniensis in southern Brazil are presented here. Philodryas olfersii and P patagoniensis are sympatric in the study area and both dwell in open and forested areas. Specimens preserved in collections and observations of snakes in the field yielded the data. Both species are diet generalists, feeding on small vertebrates, mainly frogs. Philodryas patagoniensis has a broader diet, a less variable frequency of food items, and fed on heavier prey than R olfersii. Seasonal variation in diet occurs in both species. The semi-arboreal Philodryas olfersii is more slender and has a longer tail than the terrestrial R patagoniensis, characters that may reflect differences in microhabitat use. There are a strong relationship between habitat use and frequency of a given food type. Differences in the use of food resources between P. olfersii and P patagoniensis seem to reflect differences in foraging microhabitats used by each species.

Social interactions in Hypsiboas albomarginatus (Anura : Hylidae) and the significance of acoustic and visual signals

Social behavior of Hypsiboas albomarginatus was studied in the Atlantic rain forest, Municipality of Ubatuba, in the north coast of the State of São Paulo, southeastern Brazil. Vocalizations of H. albomarginatus are described, including contexts in which they were emitted and temporal and spectral parameters differentiating advertisement from aggressive calls. Dominant call frequency was inversely correlated with male length and body mass but not with environmental temperature. Number of pulses per note was not correlated with any variable, and advertisement call amplitude was influenced by temperature and time. During chorus aggregation, males interacted acoustically by emitting advertisement calls in antiphony, or by emitting aggressive calls. Some disputes among males culminated in physical combat; males performed kicks and slaps on rivals' heads, in an apparent attempt to dislodge rivals from perches. Visual signals were also displayed during conflicts between males, contributing to an escalation of aggressive behavior. Visual signals were not recorded during courtship between males and females but may help in the accurate localization of the signaling male during aggressive interactions.

Diet of the colubrid snake, Thamnodynastes strigatus (Günther, 1858) from Paraná State, Brazil, with field notes on anuran predation

São apresentados dados da dieta de Thamnodynastes strigatus (Serpentes: Colubridae), a partir da dissecção de 44 espécimes. No tubo digestivo dos exemplares examinados foram encontrados anfíbios anuros (71,4% da amostra), roedores (14,3%), peixes (10,7%) e lagartos (3,6%). A maioria das espécies de anuros (Bufo sp., Leptodactylus sp., Physalaemus cuvieri e Scinax fuscovarius) encontradas no exame de conteúdo estomacal de T. strigatus, utiliza o solo ou o nível d'água como sítio de vocalização. Também são apresentados dados sobre a observação de eventos de predação na natureza.

Hábitos alimentares de serpentes em Espigão do Oeste, Rondônia, Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Skin glands, poison and mimicry in dendrobatid and leptodactylid amphibians

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)