Natan Medeiros Maciel

Late Miocene diversification and phylogenetic relationships of the huge toads in the Rhinella marina (Linnaeus, 1758) species group (Anura: Bufonidae).

We investigated the phylogeny and biogeography of the Rhinella marina group, using molecular, morphological, and skin-secretion data, contributing to an understanding of Neotropical faunal diversification. The maximum-parsimony and Bayesian analyzes of the combined data recovered a monophyletic R. marina group. Molecular dating based on Bayesian inferences and fossil calibration placed the earliest phylogenetic split within the R. marina group at ∼ 10.47 MYA, in the late Miocene. Two rapid major diversifications occurred from Central Brazil, first northward (∼ 8.08 MYA) in late Miocene and later southward (∼ 5.17 MYA) in early Pliocene. These results suggest that barriers and dispersal routes created by the uplift of Brazilian Central Shield and climatic changes explain the diversification and current species distributions of the R. marina group. Dispersal-vicariance analyzes (DIVA) indicated that the two major diversifications of the R. marina group were due to vicariance, although eleven dispersals subsequently occurred.

Composition of indolealkylamines of Bufo rubescens cutaneous secretions compared to six other Brazilian bufonids with phylogenetic implications

The composition of indolealkylamines of Bufo rubescens cutaneous secretions was compared to those from six other Brazilian bufonids. Skin, parotoid and tibial gland secretions were obtained for analysis by thin-layer chromatography. A triple-quadrupole mass spectrometer was used to confirm the indolealkylamines standards (serotonin, 5-HT; bufotenin, BTN; dehydrobufotenin, DHB and bufotenidin, BTD). We observed clear variation in the composition of indolealkylamines of the cutaneous secretions studied and also between those found in the skin and parotoid gland secretions of the same species. We discuss the utility of indolealkylamines to the phylogeny of this group of toads.

A New Species of Chaunus from Central Brazil (Anura; Bufonidae)

Abstract A new species of Chaunus, apparently related to Chaunus arenarum, Chaunus rubescens, and Chaunus achavali is described. The new species occupies Cerrado habitats in southwestern Piauí and Bahia states and in northwestern Minas Gerais state, Brazil. The species is characterized by anterior interruption of the supraocular crest; weakly developed cranial crests; short and robust limbs; several pointed spiculae on dorsum, head, and limbs; male coloration; small to medium size; and by the short and narrow head.

Occurrence of a Calcified Pseudodontoid in Leptodactylus Troglodytes (Anura: Leptodactylidae)

Abstract A calcified pseudodontoid in the mandibular symphysis of Leptodactylus troglodytes was described from fresh, macerated, and cleared/double-stained preparations. Histology confirmed that the pseudodontoid was mineralized and composed of fibrocartilage. This structure was found in all specimens of both sexes, suggesting a role in either prey capture or defense rather than in courtship or combat. The structure in L. troglodytes differed morphologically and histologically from the pseudodontoid observed in other Leptodactylus and in other neobatrachian species. Our sampling indicates that the presence and morphology of the pseudodontoid is synapomorphic to a clade recently named Tinctanura. However, a broader sample is still necessary to strengthen this assessment.

Revealing Two New Species of the Rhinella margaritifera Species Group (Anura, Bufonidae): An Enigmatic Taxonomic Group of Neotropical Toads

Abstract:  The level of species richness of amphibians found in Brazil is the greatest in the world. Despite increasing anthropic pressures on the Brazilian Cerrado and Amazon biomes, several new anuran species are described each year. In this study, two new species of Rhinella found in Brazil are described and assigned to the Rhinella margaritifera species group, based on morphological features. Rhinella sebbeni sp. nov. occurs in forested environments in the Cerrado biome and is characterized by the combination of the following features: snout–vent length (SVL; range  =  48.5–59.7 mm in males, and 54.7–66.7 mm in females); presence of bony protrusion at the angle of jaws and rostral keel at the tip of snout; skin on the dorsum with a few granules, but more concentrated on the flanks; parotoid gland is well delineated and small and elliptical in shape showing a lateral line of tubercles. Rhinella gildae sp. nov. is found in southern Amazonia and is characterized by the combination of following features: SVL (range  =  69.6–76.4 mm in males); cephalic crests poorly developed; parotoid gland without lateral line of tubercles; in dorsal view, supratympanic crest not exceeding the angle of the jaws; and presence of a vertebral line. We discuss data on morphological variation, natural history attributes, and distribution of the two new species.