Taxonomic Review of South American Butter Frogs: Phylogeny, Geographic Patterns, and Species Delimitation in the Leptodactylus latrans Species Group (Anura: Leptodactylidae)

Integration of a battery of biomarkers to evaluate the health status of field-collected frogs of Leptodactylus luctator living in ecosystems with different anthropogenic disturbances

Amphibians are the most threatened group of vertebrates because they have certain biological and ecological characteristics that make them sensitive to environmental changes. The aim of this study was to evaluate the health status of field-collected adult frogs of Leptodactylus luctator (Amphibia, Anura) living in sites with different anthropogenic disturbances (florihorticulture, petrochemical industry and sewage discharges) and a reference site without any detectable influence of such activities. To this end, a battery of 21 biomarkers (hematological, biochemical and individual biomarkers) was studied using a multivariate approach that allows us to evaluate the relationship between them and provide information on their usefulness. The frogs at the florihorticulture, petrochemical and sewage discharges sites exhibited several biomarkers far from homeostasis. In addition, we identified 11 of 21 biomarkers that were useful indicators of the health status of the frogs and allowed discrimination between study sites in the following order: lymphocytes (98 %), neutrophils (45 %), hemoglobin (42 %), monocytes (41 %), fat body index (35 %), eosinophils (35 %), hepatosomatic index (33 %), mean corpuscular hemoglobin (32 %), thrombocytes (27 %), catalase in liver (26 %), and GST in liver (26 %). The results suggest that hematological biomarkers contribute the most to site separation, whereas biochemical biomarkers contribute the least. The integral interpretation of the results also allowed us to diagnose the different health status of L. luctator: The frogs from the petrochemical industry were the most negatively affected, followed by the frogs from the sewages discharges and finally the frogs from the florihorticulture and reference sites. This is the first field study with anurans in which so many biomarkers were examined.

SynGenes: a Python class for standardizing nomenclatures of mitochondrial and chloroplast genes and a web form for enhancing searches for evolutionary analyses

BACKGROUND

The reconstruction of the evolutionary history of organisms has been greatly influenced by the advent of molecular techniques, leading to a significant increase in studies utilizing genomic data from different species. However, the lack of standardization in gene nomenclature poses a challenge in database searches and evolutionary analyses, impacting the accuracy of results obtained.

RESULTS

To address this issue, a Python class for standardizing gene nomenclatures, SynGenes, has been developed. It automatically recognizes and converts different nomenclature variations into a standardized form, facilitating comprehensive and accurate searches. Additionally, SynGenes offers a web form for individual searches using different names associated with the same gene. The SynGenes database contains a total of 545 gene name variations for mitochondrial and 2485 for chloroplasts genes, providing a valuable resource for researchers.

CONCLUSIONS

The SynGenes platform offers a solution for standardizing gene nomenclatures of mitochondrial and chloroplast genes and providing a standardized search solution for specific markers in GenBank. Evaluation of SynGenes effectiveness through research conducted on GenBank and PubMedCentral demonstrated its ability to yield a greater number of outcomes compared to conventional searches, ensuring more comprehensive and accurate results. This tool is crucial for accurate database searches, and consequently, evolutionary analyses, addressing the challenges posed by non-standardized gene nomenclature.

Mineral profile and histopathological findings in the liver of white-lipped frog (Leptodactylidae) from the morphoclimatic domain of the Caatingas, Brazil

This study aimed to investigate the mineral profile and histopathological findings in the liver of Leptodactylus macrosternum (white-lipped frog) and to assess the association between melanomacrophage areas and hepatic fungal granuloma with several factors such as weight, snout-cloacal length, sex, hepatosomatic index, season (dry and rainy), and condition factor K. A total of 135 frogs of different ages were collected from three areas in the city of Petrolina, Pernambuco, with varying land use (conventional agriculture, organic agriculture, and Caatinga stricto sensu). The liver of all specimens exhibited changes such as granulomatous lesions, inflammatory cell infiltrate, blood vessel congestion, and sinusoid dilation. The melanomacrophage areas were influenced by weight, snout-cloacal length, and hepatosomatic index. Our findings revealed a positive correlation between body size (weight and snout-cloacal length) and melanomacrophage/hepatic granuloma, while the hepatosomatic index showed a negative relationship. For the condition factor K, only age presents relationship. Eleven elements were quantified for the mineral profile, with aluminum (Al), iron (Fe), and zinc (Zn) being the most abundant in both liver and muscle. Although the histopathological findings and mineral profile of the liver and muscle in this study indicate an effect on the health of L. macrosternum in different collection areas, confirming the relationship between environmental characteristics and these findings requires future studies. Furthermore, long-term studies would be necessary to allow the monitoring of all stages of development of these populations, from tadpoles to adults, for a better evaluation of these effects in L. macrosternum.

Oswaldocruzia franciscoensis n. sp. (Nematoda: Molineidae) in Leptodactylus macrosternum Miranda-Ribeiro, 1926 (Anura: Leptodactylidae) from Caatinga morphoclimatic domain, Brazil: morphological and molecular characterisation

A new species of Oswaldocruzia Travassos, 1917 (Nematoda, Molineidae), parasite of Leptodactylus macrosternum Miranda-Ribeiro, 1926 (Anura: Leptodactylidae), from Caatinga morphoclimatic domain, Brazil, is described based on morphological and molecular data. Oswaldocruzia franciscoensis n. sp. is characterised by an anterior extremity with a cephalic vesicle divided into two portions, a body covered by cuticular longitudinal ridges, and cervical alae. Males of the new species have caudal bursa of type I with a 2-1-2 pattern, spicules divided into a shoe, bifurcated fork, and blade with two unequal branches, in which the longer branch bifurcates at its distal portion end and the smaller branch with three distal processes, each with distal bifurcations. Females have didelphic and amphidelphic uteri, an ovijector divided into vestibule, anterior and posterior sphincters, and anterior and posterior infundibula. The new species differs from its Neotropical congeners that have caudal bursa of type I, based on the presence of cervical alae and by having a spicular blade distally divided into two unequal branches, with the longer branch bifurcating at its distal portion and smaller branch with three distal processes, each distally bifurcated. The partial 18S rDNA sequence generated for Oswaldocruzia franciscoensis n. sp. is the first of a representative belonging to this genus in the Neotropical region.

Discovering the diversity of tadpoles in the mid-north Brazil: morphological and molecular identification, and characterization of the habitat

Brazil stands out for presenting the highest amphibian anuran diversity in the world. However, taxonomic studies that address characteristic of larval stage of anurans are incipient, representing only 62% of known species. We assess the species diversity of tadpoles from eastern Maranhão state, mid-northern region of Brazil based on morphological and molecular identification (i.e., 16S rRNA gene fragment), and we also provide characteristics of the habitats occupied by each species. We carried out 30 field samplings during 13 months in 16 environments along an ecotonal area, over five cities inside the limits of state of Maranhão, between the Maranhão Babaçu Forest and Cerrado ecoregions. We searched for tadpoles in a variety of water bodies, and the tadpoles that reached the developmental stage between 34 to 40 Gosner were morphologically identified. The tadpoles collected herein represent 26 species belonging to five families. The external morphology enabled the identification of 24 species, while the molecular data recognized 22 unique evolutionary units. The most represented family was Hylidae (Hylinae 11 spp., Phyllomedusinae one spp.) followed by Leptodactylidae (Leptodactylinae seven spp., Leiuperinae three spp.), Microhylidae (Gastrophryninae two spp.), and Bufonidae (two spp.). Our results show that oral morphology was the most important character for identifying tadpoles based on morphology, and the specific 16S rRNA primer was suitable for molecular identification. This study pioneers the use of both morphological and molecular data to identify tadpoles in the state of Maranhão. It also provides, for the first-time, habitat characteristic for the species. Our study reveals a high number of anuran species sampled at the larval stage in the region, identifies species that require further taxonomic and systematic attention, and extends the geographic distribution of six species, three of which represent new occurrences for the state. Our results strengthen the hypothesis that the diversity of amphibians from Maranhão is underestimated and highlight the importance of herpetological inventories in poorly sampled areas, decentralizing the knowledge of biodiversity.

Hematologic variables of free-living Leptodactylus luctator with and without hemoparasites and thrombidiform mites in southern Brazil

It has been suggested that anuran amphibian parasites can cause clinical signs in situations of environmental imbalance. In the family Leptodactylidae, information about hematology is scarce, although these are well-known tools for the diagnosis and prognosis in clinical practice and potential bioindicators of environmental stress. The objective of this study is to describe Leptodactylus luctator hematology, to report the occurrence of hemoparasites and thrombidiform mites, and to compare the hematological variables under the presence and absence of these organisms. Ectoparasites and heparinized blood samples from 40 free-living specimens of L. luctator were collected for analysis. Hematologic variables and total plasma protein were compared between groups with and without hemoparasites and intradermal mites. As results, structures compatible with hemogregarines, Lankesterella sp., five morphotypes of Trypanosoma spp., microfilaria, Aegyptianella sp., an unidentified intraleukocytic hemoparasite, and frog erythrocytic virus (FEV) inclusion bodies were identified in the blood samples, besides Hannemania spp. intradermal mites. The hemoparasite occurrence was higher than previously reported in other anuran families and locations. Also, L. luctator has smaller red blood cells (RBCs) and white blood cells (WBCs), and a hyposegmentation of the neutrophil nucleus, when compared to many other amphibians. White blood cell, neutrophil, and monocyte counts were higher in animals parasitized by mites. There was no correlation between the number of parasitized RBCs and hematologic variables. This study provides anuran hematologic information, in addition to indicating a host reaction to infestation by Hannemania spp. mites, besides constituting the first record of the distribution of hemoparasites and intradermal mites in L. luctator of the study region.

The herpetofauna of priority highland areas for conservation of the Caatinga in the state of Rio Grande do Norte, northeastern Brazil

Abstract The Brazilian Caatinga has already lost extensive areas of original vegetation, thus it becomes imperative to perform fauna inventories within this region to fill geographical sampling gaps. Herein, we present a taxonomic list of the herpetofauna of a mountain chain located in the central zone of Rio Grande do Norte (RN) state whose region includes two priority areas for conservation of the Caatinga: “CA087 – Serra de Santana” in the west, and “CA078 – Nascente do Potengi” in the east. The sampling was carried out using methods of visual searching, pitfall traps with drift fences, specimens rescued during vegetation suppression activities in wind energy projects, occasional encounters, and third-party records. We recorded 19 amphibian species and 53 reptile species (23 lizards, 24 snakes, five amphisbaenians and one chelonian). About half of the recorded species have distributions entirely or mostly in the Caatinga. The mountain range sampled in this study harbors virtually all species found in nearby lowlands of the “sertaneja” depression of RN state, plus some relevant species with relictual distributions in the Caatinga, highlighting the importance of these highland areas for conservation of the Caatinga herpetofauna.

Bioaccumulation of pesticides and genotoxicity in anurans from southern Brazil

The expansion of agricultural activities causes habitat loss and fragmentation and the pollution of natural ecosystems through the intense use of pesticides, which may affect the populations of amphibian anurans that inhabit agricultural areas. The present study evaluated the in situ bioaccumulation of pesticides in a population of Leptodactylus luctator that occupies farmland in southern Brazil. We also compared the genotoxicity of L. luctator populations from farmland and forested areas in the same region. We analyzed the micronuclei and nuclear abnormalities of 34 adult anurans, 19 from farmland, and 15 from the forested area. We also assessed the presence of 32 pesticides in liver samples obtained from 18 farmland-dwelling anurans, using chromatographic analysis. We recorded significantly higher rates of nuclear abnormalities in the individuals from the farmland, in comparison with the forest. We detected nine pesticides in the liver samples, of which, deltamethrin was the most common and carbosulfan was recorded at the highest concentrations. The bioaccumulation of pesticides and the higher levels of genotoxic damage found in the anurans from agricultural areas, as observed in the present study, represent a major potential problem for the conservation of these vertebrates, including the decline of their populations and the extinction of species.

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.