Salamanders are the top predators in many fishless headwater streams, and intraguild interactions among stream salamanders are well documented. However, little is known about the top-down effects of salamanders on stream food webs or how intraguild interactions mediate these effects. To investigate the effects of salamanders on macroinvertebrate communities of headwater streams, we conducted an experiment in stream mesocosms to test for effects of two stream salamander species, namely, Eurycea bislineata and Gyrinophilus porphyriticus, alone or in combination, on benthic and emerging macroinvertebrate density, biomass, and community composition. We also assessed intraguild interactions between these salamander species by comparing Eurycea bislineata survival and G. porphyriticus growth in single-species versus two-species treatments. Gyrinophilus porphyriticus reduced benthic macroinvertebrate densities when alone but not when co-occurring with E. bislineata. There were no effects of salamanders on benthic macroinvertebrate biomass or community composition and no effects on emerging macroinvertebrate density, biomass, or community composition. Eurycea bislineata survival decreased and G. porphyriticus weight increased in two-species treatments, suggesting that intraguild predation was occurring. Overall, although some of our findings are equivocal, these results suggest that salamanders can exert top-down control on macroinvertebrate communities in fishless headwater streams, decreasing benthic macroinvertebrate density. But this effect is dependent on the salamander species present, and can be removed by intraguild interactions between salamander species.

Patterns of interspecific differences in the diets of nonavian reptiles may be complicated by intraspecific dietary diversity that is related to variation in body size and trophic morphology. Graptemys pearlensis and Graptemys gibbonsi are sister map turtle species endemic to adjacent Gulf Coastal river drainages and both are candidates for federal listing. Little has been reported about the diet of either species. We examined fecal samples collected from turtles captured throughout their respective ranges in the Pearl and Pascagoula river drainages. Females of both species primarily consumed invasive Asian clams (Corbicula spp.), with adult females being nearly exclusively molluscivorous while juvenile females also consumed softer-bodied prey items. Adult males and unsexed juveniles primarily consumed insects; males in particular specialized on trichopteran larvae and also ate more mollusks than did unsexed juveniles. In comparisons to each species' sympatric congeneric sawback species, the two focal species' avoidance of sponges caused large interspecific differences. Due to their greater consumption of insect prey than mollusks, unsexed juvenile G. pearlensis and unsexed juvenile and adult male G. gibbonsi were slightly more similar in diet to their respective sympatric congeneric sawbacks than to conspecific large juvenile females and adult females. Scoring of similarity in diet was greatly influenced by strongly predominant prey items found within each class of each species. Future studies of interspecific dietary differences in sympatric species should include consideration of intraspecific variation in diet as it relates to body size and sexual dimorphism.

Seed dispersal through endozoochory is a critical ecosystem function worldwide. Seed gut retention time (GRT; the duration that seeds are retained in the digestive tract) is an important part of the qualitative component of the seed dispersal effectiveness framework. GRT is a major determinant of when and how far away seeds are dispersed, aiding seeds in escaping predation in space as well as in time. In this study, we examined whether the size of the disperser and/or the size of the ingested seeds affect the GRT in Aldabra Giant Tortoises (Aldabrachelys gigantea) on Aldabra Atoll, Seychelles. We selected tortoises of varying body mass (mean ± 1 SD = 48.6 ± 27.2 kg, range = 0.6–104.0 kg) and fed them different-sized artificial seeds (plastic beads; 2, 4.5, and 10 mm diameter). Tortoises defecated the first beads a mean of 12.0 ± 2.7 d after ingestion, and the last beads 20.4 ± 6.0 d after ingestion. Mean GRT was 14.6 ± 3.7 d. We show that neither tortoise body size nor bead size had an effect on the patterns and time of defecation. We discuss the relevance of our result for seed dispersal and for rewilding projects that use Aldabra Giant Tortoises as substitute species for extinct giant tortoises on other oceanic islands.

Animal coloration can benefit fitness via its function in homeostatic regulation, communication, or camouflage. For wide-ranging taxa that are exposed to diverse climatic conditions throughout their range, spatial variation in color morphology might reflect locality-specific adaptive responses to those variable conditions. As a result, these species might vary in their color-climate associations over geographic space. Here, we integrate georeferenced photographs of adult animals with available bioclimatic data to test the hypothesis that dorsal color differences in Eastern Hog-Nosed Snakes (Heterodon platirhinos) reflect ecogeographic divergence. We first assigned each photographed snake into one of four dorsal color phases, namely, black, brown, red-orange, or yellow, and evaluated the spatial dispersion and bioclimatic niche occupancy of each phase by using multiple environmental niche modeling approaches. We then used pairwise comparisons of bioclimatic niche space to explicitly test for niche divergence among the color phases. Overall, black, brown, and red-orange phase H. platirhinos exploited different subsets of the species' geographic range and bioclimatic niche. In contrast, yellow phase snakes partly overlapped with red-orange and brown phase snakes in geographic and bioclimatic space. These findings support our hypothesis, and we discuss some of the possible functions of phase coloration.

Integrative analyses, long-term studies, and access to remote areas in Amazonia have led to new hypotheses and increased resolution of the systematics and taxonomy of the small nurse frog genus Allobates (family Aromobatidae). During anuran sampling in the Middle Tapajós River region, state of Pará, Brazil, we collected data on a new cryptically colored species of Allobates with a cricket-like advertisement call. Here, we name and describe this new species, following an integration of phenotypic, ecological, and molecular analyses. The results of a phylogenetic analysis based on mitochondrial and nuclear DNA placed the new species as the sister taxon of Allobates grillisimilis. Genetic pdistances between the two sister taxa at the 16S region of the mitochondrial DNA ranged from 7% to 9%. A sister-species relationship between the new species and A. grillisimilis is also supported by phenotypic evidence. Adults of the new species are small (snout–vent length 15.2–16.8 mm in males and 16.5–17.7 mm in females), with a dorsum uniformly tan to reddish brown, a dark brown lateral stripe and a white ventrolateral stripe, arms pale tan brown and legs greyish-brown, and venter yellowish colored, with variable extension and shades of yellow, paler on the throat. The advertisement call is a trill with a mean peak frequency of 5830.2 Hz, arranged in series of short, closely spaced, pulses (mean of 24.3 pulses/s), and followed by silent intervals of variable duration. We discuss the putative drivers generating and maintaining the distinctiveness between the new species and the allopatrically distributed sister taxon, and on threats to the persistence of the new species. With this species description, the Middle Tapajós River region is consolidated as having one of the highest alpha diversities for the genus Allobates in Amazonia.

Species in the Adelophryne genus consist of diminutive, agile, and secretive frogs that inhabit forest leaf litter and have direct development. Species richness within Adelophryne was previously underestimated, and several new species have recently been described. Here, we describe a new species of Adelophryne from the Atlantic Forest in the Brazilian states of Alagoas, Pernambuco, and Paraíba. The new species is characterized by its small body size, small and distinct tympanum, toes with subarticular tubercles, fingers mucronate, three phalanges in the Finger IV, and an advertisement call composed of one single pulsed note with a high dominant frequency. The new species is phylogenetically related to other Adelophryne species of the Northern Atlantic Forest Clade and is endemic to the “Pernambuco Endemism Center” in the Atlantic Forest biodiversity hotspot.

Four species of pumpkin toadlets are currently recognized by the extreme condition of hyperossification in the skull and vertebral column within the genus Brachycephalus. In addition to their larger body size, relative to other congeneric species, Brachycephalus darkside, Brachycephalus ephippium, Brachycephalus garbeanus, and Brachycephalus margaritatus share remarkable osteological features, such as the large paravertebral plates forming an ornamented dorsal bone shield, visible through the integument. We add to the current knowledge of this group by analyzing its diversity and describing a new hyperossified species from some important Atlantic Forest remnants in southeastern Brazil, including those bordering São Paulo, the largest and most populous city in South America. The new species is diagnosed by a combination of morphological, osteological, and bioacoustic characters, with further evidence of mtDNA sequences to confirm its distinction from the other congeners. The parotic and paravertebral bone plates externally bordered with a rough and pale contour can readily distinguish the new species from the other hyperossified species within Brachycephalus. The new species is widely distributed along the Serra do Mar mountain range, including the regionally named Serra de Paranapiacaba, in elevations from 700 to 1000 m above sea level (a.s.l.), in the central coast of the state of São Paulo, southeastern Brazil. We discuss valuable morphological characters within this group of species, reinforce the need for further studies, and highlight the relevance of protected areas for biodiversity conservation in metropolitan regions.

We review the taxonomic status of Oligodon waandersi sensu lato after examining all the name-bearing types (including synonyms) and morphological evidence. Oligodon waandersi sensu stricto is widely distributed (up to 1200 m above sea level) throughout the southern, some parts of the central, and the northern slopes of Central Sulawesi Island, Indonesia, whereas a similar species, O. propinquus, is only known from its holotype and considered to have originated from Java. Here, we demonstrate that O. propinquus is a close match with the northern population (North and Gorontalo) of O. waandersi and morphologically distinct; hence, we consider the type locality of O. propinquus as North Sulawesi, not Java. Oligodon taeniurus, long considered a junior synonym of O. waandersi, is a distinct species, but here we synonymize it with the morphologically closely matched O. propinquus, which has priority over O. taeniurus. Oligodon waandersi in Southeast Sulawesi (including some populations of Buton Islet) is morphologically distinct from O. waandersi sensu stricto in South Sulawesi; hence, it requires a new name. The new species is distinguished from congeners by having the following combination of characters: maximum snout–vent length of 340 mm, a single postocular, a single cloacal plate, a completely divided nasal, ventrals 150–169, subcaudals 18–26, temporals 1+2, six supralabials with third and fourth in contact with eye, dorsal scale rows 15-15-15, hemipenes not forked and covered with spines, maxillary teeth 6–7, shorter tail (6.8–11.2% of total length), brownish dorsum with few dark-edged spots on the vertebral line anteriorly, reddish brown vertebral line on the posterior body and tail, mostly a blackish brown blotch below the eye, and whitish collar band interrupted middorsally. We provide a complete redescription for O. waandersi and O. propinquus based on respective holotypes deposited at the Natural History Museum London and the Zoologisches Museum Hamburg.