A New Miniature Treefrog of the Scinax ruber Clade from the Cerrado of Central Brazil (Anura: Hylidae)

José P. Pombal Jr., Marcos Bilate, Priscilla G. Gambale, Luciana Sognorelli and Rogério P. Bastos

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Abstract: We describe a new species of treefrog of the Scinax ruber clade related to Scinax fuscomarginatus from southwest of the state of Goia´s in central Brazil. The new species is characterized by its small size (snout–vent length of males, 15.9–18.6 mm; females, 18.1–18.7 mm), very slender body, a snout that is strongly acute in lateral view and subelliptical in dorsal view, two lateral broad blackish stripes from the posterior corner of the eye to inguinal region, reduced toe webbing, and advertisement calls that are a single pulsed note with a pulse period of 2–13 ms and a dominant frequency of 2.51–5.95 kHz. Vocalizations of the new species and S. fuscomarginatus, Scinax parkeri, Scinax squalirostris, and Scinax wandae are provided and discussed.

The Tadpole of Physalaemus moreirae (Anura: Leiuperidae)

Diogo B. Provete, Michel V. Garey, Natacha Y. N. Dias and Denise C. Rosa-Feres

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Abstract: We describe the external morphology of the tadpole of the frog Physalaemus moreirae. We also provide a review of internal oral features, chondrocrania, and a characterization of the genus based on larval traits. The internal oral features and the external morphology of P. moreirae are most similar to P. jordanensis, a species allocated to the P. gracilis group. None of the larval traits supports the current intrageneric arrangement of species, because several features are shared by species belonging to different species groups. We argue for the inclusion of larval traits in future phylogenetic studies in order to understand the evolution of larval characters.

Amphibian Conservation in the Caatinga Biome and Semiarid Region of Brazil

Milena Camardelli and Marcelo F. Napoli

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Abstract: The Brazilian Ministry of the Environment (Ministe´ rio Do Meio Ambiente, MMA) proposed defining priority areas for Brazilian biodiversity conservation in 2007, but to date, no definitions of priority areas for amphibian conservation have been developed for the Caatinga biome or the semiarid region of Brazil. In this study, we searched for ‘‘hot spots’’ of amphibians in these two regions and assessed whether the priority areas established by the MMA coincided with those suitable for amphibian conservation. We determined amphibian hot spots by means of three estimates: areas of endemism, areas of high species richness, and areas with species that are threatened, rare, or have very limited distributions. We then assessed the degree of coincidence between amphibian hot spots and the priority areas of the MMA based on the current conservation units. We analyzed areas of endemism with the use of a parsimony analysis of endemicity (PAE) on quadrats. The Caatinga biome and semiarid region showed four and six areas of endemism, respectively, mainly associated with mountainous areas that are covered by isolated forests and positively correlated with species richness. All areas of endemism coincided with one or more priority areas defined by the MMA. We identify 15 priority areas for amphibian conservation in the Caatinga biome and semiarid region, including the creation of new full-protection conservation units.

Strategies Used By Tadpoles to Optimize Buoyancy in Different Habitats

John H. Gee and Sylvie L. Rondeau

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Abstract: We measured gaseous lift and specific gravity of larval anurans at regular intervals during development to assess their importance in determining buoyancy in eight species. Specifically, we examined the hatchling, larval, and metamorphic stages of tadpoles from still waters (Limnodynastes dumerili, Limn. peronii, Lithobates septentrionalis, and Rhinella marina), intermittent streams (Litoria genimaculata and Lito. lesueuri), and torrent sections of rivers (Lito. nannotis and Nyctimystes dayi). Buoyancy levels and the strategies used to attain buoyancy varied at different phases of development and with the environment occupied. Buoyancy increased rapidly during development in hatchlings of Limn. peronii, Lith. septentrionalis, and R. marina due to a reduction in specific gravity. Lungs were inflated in early larval stages of all species except for Lito. nannotis, N. dayi, and R. marina, which inflated their lungs following metamorphosis. Limnodynastes dumerili and Limn. peronii used gaseous lift to maintain near-neutral buoyancy throughout larval and metamorphic stages. Lithobates septentrionalis, Stages 25–29 (first summer), possessed a high level of gaseous lift, but buoyancy declined as lung gas volume decreased in Stages 31–43 (second summer). Rhinella marina did not inflate lungs prior to transformation but achieved an intermediate buoyancy level due to a very low specific gravity. The intermittent-stream species Lito. genimaculata and Lito. lesueuri used gaseous lift to achieve buoyancy levels similar to those of Lith. septentrionalis (Stages 31– 43) and R. marina. The torrent-dwelling species Lito. nannotis and N. dayi were the least buoyant; their lungs were not inflated prior to transformation and their specific gravity was elevated. Both gaseous lift and specific gravity are important factors in determining buoyancy in larval anurans.

How the Cricket Frog Lost Its Spot: The Inducible Defense Hypothesis

Geraldo L. F. Carfagno, J. Maxwell Carithers, Leah J. Mycoff and Richard M. Lehtinen

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Abstract: Prey may use a variety of strategies to avoid predators, including behavioral modification and inducible defenses. For an inducible defense to evolve, one necessary component is that the defense must be costly; if it is not, then the defense should evolve into one that is always expressed (i.e., a constitutive defense). However, costs of inducible defenses have not been well-documented. Using predator exposure experiments in aquatic mesocosms, we demonstrate that dark tail coloration (or lack thereof) in Blanchard’s Cricket Frog (Acris blanchardi) tadpoles is an inducible defense. Specifically, Acris tadpole tail spots in treatments with dragonfly predators (Anax sp.) were significantly larger when compared to treatments with fish predators (Lepomis macrochirus). However, tadpoles in control tanks (with no predators) had tail spots that were not significantly different in area from the Anax treatment. Therefore, this defense is unique among those known because the presence of fish induces the loss (not the appearance) of this morphology. Because Acris tadpoles express the tail spot in the absence of predation risk, this phenotype also does not appear to have any  substantial allocation cost. We also document predation of Acris tadpoles by a fish predator and demonstrate reduction in movement and differential habitat use in the presence of fish predator cues. Under predation risk, tadpoles became less active and occupied the shallowest regions of their habitats. This combination of plastic morphological and behavioral defenses likely allows these frogs to successfully breed in a broad range of aquatic habitats with different assemblages of predators. While likely effective in reducing vulnerability to Anax attacks, the tail spot may increase vulnerability to fish. Our results suggest that the antagonistic effects of predator-specific inducible defenses may represent another type of cost relevant to the conditions under which inducible defenses are expected to evolve.

Factors Affecting Aggression during Nest Guarding in the Eastern Red-Backed Salamander (Plethodon cinereus)

Jan K. Tornick

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Abstract: Defending young against intruders is a potentially risky behavior, and is energetically costly. Yet female eastern red-backed salamanders, Plethodon cinereus, guard their clutches for many weeks and aggressively defend eggs against predators and conspecifics. I examined the effect of clutch age, clutch size, and attendant size on the level of aggression attained during nest defense by staging conspecific invasions of nests of brooding female P. cinereus in the laboratory. I predicted that older and larger clutches would elicit increased aggression from the guarding females, and that larger females would be more aggressive when defending. The females were significantly more aggressive when guarding older clutches (6 wk postoviposition) than younger clutches (4 wk postoviposition). However, there was no difference in aggressive behavior when females guarded large (10-egg) or small (4-egg) clutches. There was also no relationship between body size and level of aggression; females were aggressive regardless of their size. These results suggest that females are able to evaluate the age (or developmental stage) of their eggs and adjust expenditure accordingly, but are not differentially responsive to clutch size.

Dispersal Versus Site Tenacity of Adult and Juvenile Red- Backed Salamanders (Plethodon cinereus)

Brittany H. Ousterhout and Eric B. Liebgold

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Abstract: In many species of amphibians that display territoriality, it is unclear at what life stage and to what extent dispersal occurs. We examined whether differences existed between life stages in dispersal and homing in red-backed salamanders (Plethodon cinereus) in continuous habitat. In a mark–recapture study, we found that juvenile and adult movements between years were not significantly different. The median distances moved by both adults (0.85–0.88 m) and juveniles (1.14–1.22 m) of P. cinereus between years were similar to the diameter of adult home ranges in this area (1.15 m). In a homing experiment, we found that, although the probability of recapture of translocated individuals under their original cover object increased with body size, both adults and juveniles successfully orientated toward their original cover objects when displaced over short distances (1.5 m and 6.25 m), but their orientation was random when displaced long distances (12.5 m and 25 m). Despite the current assumption that juveniles of P. cinereus lack territorial behaviors, our results suggest that regardless of life stage, site tenacity accounts for lack of movements.