ABSTRACT
The genus Rhinella is one of the most diverse groups of bufonid toads, currently composed by 93 valid species and naturally distributed throughout different Neotropical ecoregions. Here, we analyze nine Brazilian populations of toads representing species of the Rhinella margaritifera and Rhinella marina groups. These new data include the first description of the R. hoogmoedi and R. proboscidae karyotypes, as well as other taxonomically unresolved forms. Chromosomal analysis of the populations revealed pronounced chromosomal uniformity (2n=22), including the diploid number and chromosomal morphology. Three different NOR-bearing chromosomes were identified: in the subterminal region of pair 10q in R. hoogmoedi, Rhinella sp. 1 and Rhinella sp. 2, in subterminal region of 7p in R. proboscidae and Rhinella cf. margaritifera while in R. henseli and R. icterica was detected in interstitial region of 7p. Karyotypic uniformity of the genus permits the inference of interspecific chromosome homologies and evolutionary changes in the NOR-bearing chromosome may represent an informative character in species group level. The review of the cytogenetic data of the Rhinella species together with the new karyotypes reported here contributes to the understanding of the chromosomal evolution of these toads, which karyotypes are highly conserved despite the ample distribution of many forms.
ABSTRACT
Abstract Amphibian research has grown steadily in recent years in the Amazon region, especially in the Brazilian states of Amazonas, Pará, Rondônia, and Amapá, and neighboring areas of the Guiana Shield. Even so, few data are available for the Amazonian savannas of Brazil. To contribute to the understanding of the diversity of the amphibians of these savannas, we surveyed 15 temporary ponds, six located in open areas, seven on the edge of savanna forest, and two within the forest, in the savanna of the Rio Curiaú Environmental Protection Area (EPA) in Macapá, in the state of Amapá, northern Brazil. Sampling occurred from May 2013 to August 2014 during periods when the ponds contained water. Amphibians were sampled through visual and auditory surveys conducted during both the day- and the nighttime periods on seven days each month over a total of 84 days. A total of 1574 individuals belonging to four families, 12 genera, and 28 species were recorded during the surveys. The cumulative species curve reached the asymptote, indicating that sampling effort was adequate. The number of species was 25% higher than that reported in other studies in Amazonian savannas. Twelve species were recorded for the first time in the savanna of Amapá. Lysapsus boliviana was the most common species (n = 332 of the individuals recorded). The greatest amphibian species richness found in the Rio Curiaú EPA was associated with the savanna mosaic, forest patches, lowland swamp, and temporary ponds. The results of this study contribute to the understanding of the diversity of amphibian species in the Guianan area of endemism in northern Brazil, and also the Amazonian savannas.
Resumo Existe um crescimento constante em estudos sobre os anfíbios Amazônicos especialmente nas regiões do Amazonas, Pará, Rondônia, Amapá e outras áreas no Escudo das Guianas. Porém, poucos estudos são realizados em Savana Amazônica no Brasil. Para diminuir esta lacuna, amostramos anfíbios em 15 lagoas temporárias, sendo seis em área aberta, sete com a borda próxima a mata de savana e 2 com borda interna em contato com a mata de savana na Área de Proteção Ambiental (APA) do Rio Curiaú em Macapá no estado do Amapá, norte do Brasil. As amostragens ocorreram de maio de 2013 a agosto de 2014, nos períodos em que as lagoas continham água, sete dias por mês, totalizando 84 dias de amostragem, através de procura visual e auditiva no período diurno e noturno. Os 1574 indivíduos registrados pertenciam a quatro famílias, 12 gêneros e 28 espécies. A curva de acumulação de espécies atingiu a assíntota, indicando que o esforço amostral foi suficiente. O número de espécies foi 25% maior que o registrado nos outros estudos em Savanas Amazônicas. Doze espécies foram registradas pela primeira vez em Savana Amapaense. Lysapsus boliviana contribuiu com o maior número de indivíduos (n=332). A maior riqueza de anfíbios nesta savana foi associada ao mosaico de savana, ilhas de matas de savana, florestas de várzea e lagoas temporárias existentes na APA do Curiaú. Os dados apresentados contribuem para preencher a lacuna de conhecimento para o Centro de Endemismo Guiana no norte do Brasil e em Savana Amazônica.
ABSTRACT
BACKGROUND: Dendropsophus is a monophyletic anuran genus with a diploid number of 30 chromosomes as an important synapomorphy. However, the internal phylogenetic relationships of this genus are poorly understood. Interestingly, an intriguing interspecific variation in the telocentric chromosome number has been useful in species identification. To address certain uncertainties related to one of the species groups of Dendropsophus, the D. microcephalus group, we carried out a cytogenetic analysis combined with phylogenetic inferences based on mitochondrial sequences, which aimed to aid in the analysis of chromosomal characters. Populations of Dendropsophus nanus, Dendropsophus walfordi, Dendropsophus sanborni, Dendropsophus jimi and Dendropsophus elianeae, ranging from the extreme south to the north of Brazil, were cytogenetically compared. A mitochondrial region of the ribosomal 12S gene from these populations, as well as from 30 other species of Dendropsophus, was used for the phylogenetic inferences. Phylogenetic relationships were inferred using maximum parsimony and Bayesian analyses. RESULTS: The species D. nanus and D. walfordi exhibited identical karyotypes (2n = 30; FN = 52), with four pairs of telocentric chromosomes and a NOR located on metacentric chromosome pair 13. In all of the phylogenetic hypotheses, the paraphyly of D. nanus and D. walfordi was inferred. D. sanborni from Botucatu-SP and Torres-RS showed the same karyotype as D. jimi, with 5 pairs of telocentric chromosomes (2n = 30; FN = 50) and a terminal NOR in the long arm of the telocentric chromosome pair 12. Despite their karyotypic similarity, these species were not found to compose a monophyletic group. Finally, the phylogenetic and cytogenetic analyses did not cluster the specimens of D. elianeae according to their geographical occurrence or recognized morphotypes. CONCLUSIONS: We suggest that a taxonomic revision of the taxa D. nanus and D. walfordi is quite necessary. We also observe that the number of telocentric chromosomes is useful to distinguish among valid species in some cases, although it is unchanged in species that are not necessarily closely related phylogenetically. Therefore, inferences based on this chromosomal character must be made with caution; a proper evolutionary analysis of the karyotypic variation in Dendropsophus depends on further characterization of the telocentric chromosomes found in this group.
Subject(s)
Anura/genetics , Phylogeny , Animals , Anura/classification , Chromosomes , KaryotypingABSTRACT
Anuran larvae, which are otherwise simple in shape, typically have complex keratinized mouthparts (i.e. labial teeth and jaw sheaths) that allow them to graze upon surfaces. The diversity in these structures among species presumably reflects specializations that allow for maximal feeding efficiency on different types of food. However, we lack a general understanding of how these oral structures function during feeding. We used high-speed digital imaging (500 Hz) to observe tadpoles of six species from the anuran family Hylidae grazing on a standardized food-covered substrate. Tadpoles of these species vary in the number of labial tooth rows, belong to two different feeding guilds (benthic and nektonic), and inhabit ponds and streams. We confirmed that the labial teeth in these species serve two functions: anchoring the mouth to the substrate and raking material off of the substrate. In general, tadpoles with a larger maximum gape or those with fewer labial tooth rows opened and closed their mouths slower than tadpoles with smaller gape or more tooth rows. Nektonic feeding tadpoles released each of their tooth rows proportionally earlier in the gape cycle compared with benthic feeding tadpoles. Lastly, we found some support for the idea that deformation of the jaw sheaths during a feeding cycle is predictable based on tadpole feeding guild. Collectively, our data show that anatomical (e.g. number of labial teeth) and ecological features (e.g. feeding guild) of tadpoles significantly influence how tadpoles open and close their mouths during feeding.
Subject(s)
Anura/physiology , Feeding Behavior/physiology , Tropical Climate , Animals , Biomechanical Phenomena/physiology , Jaw/physiology , Larva , Multivariate Analysis , Phylogeny , Principal Component Analysis , Regression Analysis , Species Specificity , Time Factors , Tooth/anatomy & histology , Tooth/physiologyABSTRACT
Efetuou-se levantamento sobre os principais agrotóxicos utilizadospor agricultores da zona rural da Ilha de São Luís (MA), visando analisar os níveis de contaminação de corpos dágua adjacentes aos pólos agrícolas locais. Segundo os critérios avaliados neste estudo, os agrotóxicos investigados apresentam riscos de contaminação doambiente, dos agricultores e da população em geral. Em algumasdas amostras de água foi detectada inclusive a presença deagrotóxico organoclorado, cujo uso agrícola no Brasil foi proibido hámais de duas décadas.
Subject(s)
Environmental Hazards , Natural Hazard , Pesticides , Water PollutionABSTRACT
A non-engorged adult female Amblyomma dissimile and two Amblyomma sp. larvae were found parasitizing the lizard Ameiva ameiva in the municipality of Chapadinha, State of Maranhão. This is the first record in the state of Maranhão and fills a gap in the distribution of A. dissimile in Brazil. The lizard A. ameiva represents a new host for A. dissimile, and also the first record of this tick species infesting lizards of the family Teiidae in Brazil.
Subject(s)
Ixodidae/physiology , Lizards/parasitology , Animals , BrazilABSTRACT
A non-engorged adult female Amblyomma dissimile and two Amblyomma sp. larvae were found parasitizing the lizard Ameiva ameiva in the municipality of Chapadinha, State of Maranhão. This is the first record in the state of Maranhão and fills a gap in the distribution of A. dissimile in Brazil. The lizard A. ameiva represents a new host for A. dissimile, and also the first record of this tick species infesting lizards of the family Teiidae in Brazil.
Uma fêmea adulta não ingurgitada de Amblyomma dissimile e duas larvas de Amblyomma sp. foram encontradas parasitando o lagarto Ameiva ameiva no município de Chapadinha, Estado do Maranhão. Além de representar um novo registro para o Estado do Maranhão, esse trabalho preenche uma lacuna de distribuição geográfica de A. dissimile no país. O lagarto A. ameiva representa um novo hospedeiro para A. dissimile, sendo também o primeiro registro dessa espécie de carrapato infestando lagartos da família Teiidae no Brasil.
Subject(s)
Animals , Ixodidae/physiology , Lizards/parasitology , BrazilABSTRACT
Pseudis paradoxa paradoxa, P. p. platensis, P. bolbodactyla, P. fusca and P. tocantins were analyzed cytogenetically by conventional chromosomal staining, C-banding, silver staining and fluorescent in situ hybridization with an rDNA probe. Pseudis tocantins chromosomes were also stained with distamycin A/DAPI. All of the species had a diploid number of 2n = 24 chromosomes and the nucleolar organizer region (NOR) was located on pair 7. However, the karyotypes could be differentiated based on the morphology of chromosomal pairs 2 and 8, the region that the NORs occupied on the long arms of the homologous of pair 7, and the pattern of heterochromatin distribution. The subspecies P. p. paradoxa and P. p. platensis had identical karyotypes. Heteromorphism in NOR size was seen in P. p. paradoxa, P. p. platensis, P. bolbodactyla and P. fusca. Heteromorphic sex chromosomes (ZZ/ZW) were identified in P. tocantins. The W chromosome was subtelocentric and larger than the metacentric Z chromosomes. The differences observed in the C-banding pattern and in the position of the NOR on the sex chromosomes suggested that inversions and heterochromatinization were responsible for the morphological differentiation of these chromosomes.
