Temporal and spatial diversification along the Amazonia-Cerrado transition in Neotropical treefrogs of the Boana albopunctata species group

Despite extensive research on biodiversity in Neotropical forests, biodiversity in seasonally dry, open biomes in South America has been underestimated until recently. We leverage a widespread group, Boana albopunctata, to uncover cryptic lineages and investigate the timing of diversification in Neotropical anurans with a focus on dry diagonal biomes (Cerrado, Caatinga and Chaco) and the ecotone between Amazonia and the Cerrado. We inferred a multilocus phylogeny of the B. albopunctata species group that includes 15 of 18 described species, recovered two cryptic species, and reconstructed the timing of diversification among species distributed across multiple South American biomes. One new potential species (B. aff. steinbachi), sampled in the Amazonian state of Acre, clustered within the B. calcara-fasciata species complex and is close to B. steinbachi. A second putative new species (B. aff. multifasciata), sampled in the Amazonia-Cerrado ecotone, is closely related to B. multifasciata. Lastly, we place a recently identified Cerrado lineage (B. aff. albopuncata) into the B. albopunctata species group phylogeny for the first time. Our ancestral range reconstruction showed that species in the B. albopuctata group likely dispersed from Amazonia-Cerrado into the dry-diagonal and Atlantic Forest. Intraspecies demography showed, for both B. raniceps and B. albopunctata, signs of rapid expansion across the dry diagonal. Similarly, for one clade of B. multifasciata, our analyses support an invasion of the Cerrado from Amazonia, followed by a rapid expansion across the open diagonal biomes. Thus, our study recovers several recent divergences along the Amazonia-Cerrado ecotone in northern Brazil. Tectonic uplift and erosion in the late Miocene and climate oscillations in the Pleistocene corresponded with estimated divergence times in the dry diagonal and Amazonia-Cerrado ecotone. Our study highlights the importance of these threatened open formations in the generation of biodiversity in the Neotropics.

Ecological divergence and synchronous Pleistocene diversification in the widespread South American butter frog complex

Phylogeographic studies primarily focus on the major role of landscape topography in driving lineage diversification. However, populational phylogeographic breaks may also occur as a result of either niche conservatism or divergence, in the absence of geographic barriers to gene flow. Furthermore, these two factors are not mutually exclusive and can act in concert, making it challenging to evaluate their relative importance on explaining genetic variation in nature. Herein, we use sequences of two mitochondrial and four nuclear genes to investigate the timing and diversification patterns of species pertaining to the Leptodactylus latrans complex, which harbors four morphologically cryptic species with broad distributions across environmental gradients in eastern South America. The origin of this species complex dates back to the late Miocene (ca. 5.5 Mya), but most diversification events occurred synchronically during the late Pleistocene likely as the result of ecological divergence driven by Quaternary climatic oscillations. Further, significant patterns of environmental niche divergences among species in the L. latrans complex imply that ecological isolation is the primary mode of genetic diversification, mostly because phylogenetic breaks are associated with environmental transitions rather than topographic barriers at both species and populational scale. We provided new insights about diversification patterns and processes within a species complex of broadly and continuously distributed group of frogs along South America.

Variability in anuran advertisement call: a multi-level study with 15 species of monkey tree frogs (Anura, Phyllomedusidae)

Understanding the variability of acoustic signals is a first important step for the comprehension of the evolutionary processes that led to current diversity. Herein, we evaluate the variability of the advertisement call of the phyllomedusid species from the genera Phyllomedusa Wagler, 1830 and Pithecopus Cope, 1866 at different levels: intra-individual, intra-population, inter-population, intra-species, and inter-specific. An analysis of coefficients of variation showed a continuum of variability between the acoustic parameters analyzed, from static to highly dynamic. The majority of the variation was attributed to the inter-specific level, while call parameters at the intra-individual level varied the least. However, each parameter behaved differently with call interval being the most variable across all levels. Most temporal acoustic parameters were affected by environmental temperature, while pulse rate and dominant frequency were strongly influenced by body size. Only pulse rate was correlated to the geographic distance between populations, while all parameters presented a significant phylogenetic signal. Based on these results, we discuss the possible importance of different evolutionary forces and the usage of vocalizations for taxonomic purposes.

Release calls of four species of Phyllomedusidae (Amphibia, Anura)

Anurans emit a variety of acoustic signals in different behavioral contexts during the breeding season. The release call is a signal produced by the frog when it is inappropriately clasped by another frog. In the family Phyllomedusidae, this call type is known only for Pithecophusayeaye. Here we describe the release call of four species: Phyllomedusabahiana, P.sauvagii, Pithecopusrohdei, and P.nordestinus, based on recordings in the field. The release calls of these four species consist of a multipulsed note. Smaller species of the Pithecopus genus (P.ayeaye, P.rohdei and P.nordestinus), presented shorter release calls (0.022–0.070 s), with higher dominant frequency on average (1508.8–1651.8 Hz), when compared to the bigger Phyllomedusa (P.bahiana and P.sauvagii) (0.062–0.107 s; 798.7–1071.4 Hz). For phyllomedusid species, the release call might indicate a phylogenetic signal, because species of the same genus have similar acoustic traits.

Anurans of the Reserva Ecológica da Michelin, Municipality of Igrapiúna, State of Bahia, Brazil

We studied the richness and distribution of anuran species on different breeding sites at the Reserva Ecológica da Michelin (13° 50' S and 39° 10' W, approximately 90-400 m above sea level), Municipality of Igrapiúna, Bahia State, Brazil. The reserve includes fragments of Atlantic Rain Forest varying from 140 to 650 ha. Five types of environments were sampled: leaf litter inside forest fragments, streams inside forest fragments, dam on the edge of forest fragment, temporary pond inside forest, and temporary ponds inside banana and rubber groves along the eastern boundary of the reserve. We used active and passive sampling methods for surveys of amphibians, between March 2007 and December 2008. We captured 48 species distributed in 10 families (number of species in parentheses): Aromobatidae (1), Brachycephalidae (4), Bufonidae (2), Craugastoridae (1), Centrolenidae (1), Cycloramphidae (3), Hylidae (29), Leiuperidae (1), Leptodactylidae (3), and Microhylidae (3). Temporary ponds presented the highest number of species in reproductive activity (19 species in native forested areas, and 21 in plantation areas), while leaf litter presented the lowest (6 species). Two species were found in bromeliads (Phyllodytes melanomystax and P. luteolus). Twenty-two species were exclusive to fragments of forest, 11 were found only in anthropized areas (dam, and rubber and banana plantations) and 15 in both environments. Aplastodiscus cavicola and Dendropsophus giesleri had their geographic distribution extended to the State of Bahia. Phasmahyla timbo and Chiasmocleis cordeiroi known only from their type localities were found in the reserve.