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The geographic distribution of a species is limited by many factors, including its ecological and evolutionary history. Species distribution modeling has been used to evaluate the effects of climate and other variables on geographic distribution and to measure the degree of niche similarity among co-occurring species. Our goal in this study was to compare the geographic distributions and ecological niches of four closely related species of lined ground snakes, Lygophis dilepis, L. flavifrenatus, L. meridionalis, and L. paucidens. These species are distributed along the South American Dry Diagonal. We found that the four species of Lygophis overlap somewhat along their distributions with a low degree of niche overlap. Lygophis dilepis shows a disjunct distribution with two isolated populations. The break in the distribution of L. dilepis in Central Brazil is filled by L. meridionalis, which is found mostly in the highlands of the Central Plateau. Because of the disjunct distribution of L. dilepis, we performed species distribution modeling on both populations separately. The environmental niches of the two populations of L. dilepis were indistinguishable according to the niche equivalence tests, but the distribution of one of these populations did not predict the distribution of the second one, and vice versa. Our study shows that niche partitioning may allow for the coexistence of Lygophis species. [ABSTRACT FROM AUTHOR]

Based on concordant differences in morphology, male advertisement call, and 16S mtDNA barcode distance, we describe a new species of Proceratophrys from southern Amazonia, in the states of Mato Grosso and Pará, Brazil. The new species is most similar to P. concavitympanum and P. ararype but differs from these species by its proportionally larger eyes and features of the advertisement call. Additionally, genetic distance between the new species and its congeners is 3.0–10.4% based on a fragment of the 16S rRNA gene, which is greater than the threshold typically characterizing distinct species of anurans. Using an integrative approach (molecular, bioacoustics, and adult morphology), we were able to distinguish the new species from other congeneric species. The new species is known only from the type locality where it is threatened by illegal logging and gold mining as well as hydroelectric dams. [ABSTRACT FROM AUTHOR]

A new species of frog of the genus Odontophrynus is described from grassland of the subtropical regions of Argentina, Brazil, and Paraguay based on morphological, osteological, bioacoustical, cytogenetic, and molecular evidence. The new species is characterized by having medium size; rostral and eye-nostril glandular warts well developed; several long glandular ridges, longitudinally oriented, on dorsum; several medium-sized, nearly rounded, dark-brown dorsal blotches; light mid-dorsal stripe continuous and well defined or restricted to the head and the urostyle regions; and mid-dorsal stripe, interorbital, and dorsolateral bands with a moderately whitish highlight, light brown, or reddish coloration. Additionally, the new species has a skull with nasals slightly separated both from each other and frontoparietals, and frontoparietal fontanelle not exposed. The advertisement call consists of a single multipulsed note with a dominant frequency of 820-1,121 Hz and a pulse rate of 99.3-140.7 pulses/s. The chromosomal complement is diploid with 2N = 2X = 22 chromosomes and nucleolar organizer regions on the interstitial regions of the short arm of chromosome pair 4. The phylogenetic analysis allowed us to recover the new species belonging to the O. americanus species group with genetic distances from its congeners ranging from 2.11 to 4.82% in a partial sequence of 16S ribosomal RNA gene. The new species is geographically isolated from the other currently known diploid species of the group, but in some localities is found in sympatry or syntopy with the tetraploid O. americanus. [ABSTRACT FROM AUTHOR]

Recently, Proceratophrys cristiceps was redescribed along with the description of two species from the Caatinga biome: P. aridus and P. caramaschii. However, only a small fraction of the populations related to such species in Northeastern Brazil was examined, and most populations of central Caatinga were not contemplated in this analysis. Comparisons were also based exclusively on external morphology, precluding a more accurate delimitation of such taxa in the light of multiple characters. Such geographic paucity and reliance in only one data source caused the species status of most central Caatinga populations to be uncertain. Thus, the revision of Proceratophrys populations from the Caatinga biome is of utmost importance to establish a solid taxonomic background and to test the validity of the described species. Based on morphologic, morphometric, acoustic, and multilocus genetic data, we define the range of inter‐ and intrapopulation variation in the parameters we analyzed, establishing which ones are useful as diagnostic characters for Proceratophrys in the Caatinga. We found no evidence supporting P. aridus and P. caramaschii as distinct species and thus place them as junior synonyms of P. cristiceps. Our results reinforce the importance of using multiple lines of evidence to avoid taxonomic instability. [ABSTRACT FROM AUTHOR]

The combination of different approaches has successfully delimited new species within many Neotropical species complexes traditionally classified as a single nominal organism. Recent studies have shown that the Amazonian endemic genus Amazophrynella, currently composed of 12 small-sized species, could harbor several additional species. Based on morphology and molecular data, we describe a new species of Amazophrynella from east of the Guiana Shield, in Pará state, Brazil. The new species is characterized by having one of the biggest size of the genus (SVL of males 16.0-17.8 mm and females 22.9-24.4 mm), presence of a large palmar tubercle (occupying 2/4 of the palmar surface), 5.6-8.1% uncorrected p-distance from its sister clade (including A. teko, A. sp.1, and A. manaos) for the 16S mitochondrial gene, and 8.8% for the COI. The new species described here represents a newly discovered lineage. Of the 12 Amazophrynella species currently recognized, two were describe in the last century (A. bokermanni and A. minuta) and the remaining species were recently discovered and described (in the last six years), which underscores the degree to which species richness of Amazophrynella is underestimated. [ABSTRACT FROM AUTHOR]