Anuran Amphibians Research Articles

First record of microplastic contamination in adult endemic amazonian anuran species

The microplastics (MPs), due to their high dispersion and bioaccumulation rates, have been identified in various animal groups, such as anuran amphibians during both larval and adult stages. However, current studies on adult anuran amphibians focus on assessing only one exposure route, the digestive system, while other routes remain underestimated. Therefore, this present study aimed to evaluate the degree of contamination in the digestive, respiratory, and integumentary systems, in situ, of two endemic Amazonian adult anuran species (Physalaemus ephippifer and Boana multifasciata). From this, we identified and characterized microplastic particles for each exposure route, assessed the effects of morphometric measures on the total MP contamination level and in the gastrointestinal tract (GIT). Additionally, we determined different contamination indices and how they vary according to species and systems. Based on our data, the digestive and integumentary exposure routes showed the highest contamination levels for both species. Additionally, variations in MP contamination levels indicated that P. ephippifer had a higher level of MP contamination. Thus, this study provides the first evidence of microplastic exposure through respiratory and integumentary routes in adult anurans in situ, and it is the first to identify MP contamination in terrestrial biomonitors in the Amazon.

Urodele amphibian newt bridges the missing link in evo-devo of the pancreas.

The pancreas exhibits diverse structures and roles across vertebrates. The pancreas has evolved to include both endocrine and exocrine cells, a change that occurred during the transition from fish to amphibian. This event emphasizes the evolutionary significance of amphibians. However, research has focused predominantly on anuran amphibians, with urodeles, such as newts, remaining underexplored. In this study, we investigated the development of the pancreas using Pleurodeles waltl as a model species of urodele. The newt pancreas consists of a single organ with exocrine tissue characterized by acinar structures and endocrine tissue forming islets. Notably, the newt possesses unique pancreas-like tissues on their intestines. We found that disruption of the newt Pancreatic and Duodenal Homeobox (Pdx) 1 gene resulted in an underdeveloped pancreas. Conversely, disruption of the Pdx2 paralog in newt had no significant impact on pancreatic development. The newt pancreas shows a morphology similar to that of the mammalian pancreas, which includes both exocrine and endocrine tissues. These results highlight the intermediate evolutionary position of the newt in the context of the evolution of pancreatic development. Our findings indicate that characterization of the newt pancreas will be crucial for understanding the evolutionary progression of pancreatic function in vertebrates.

Unraveling the neural basis of behavioral isolation through the lens of audition in anurans.

Background The origin and maintenance of species is a unifying theme in evolutionary biology. Mate choice and selection on sexual signals have emerged as powerful drivers of reproductive isolation-the key pillar of the Biological Species Concept. The mechanistic underpinnings of isolating behaviors lie in the circuit- and cellular-level properties of the brain and yet remain relatively understudied. Summary Here, I argue that temporal auditory selectivity in anuran amphibians offers a window into the proximate mechanisms of reproductive isolation. First, I discuss anuran behaviors as a longstanding neuroethological model with which to examine behavioral reproductive isolation and its neural correlates. Next, I review how modern neurobiological techniques are revealing the proximate mechanisms of the evolution of divergent mate preferences in anurans, highlighting cellular-level neural shifts in temporal coding. Finally, I discuss future research directions to reveal the neural mechanisms through which behavioral isolation is generated and maintained in anuran model systems. Key messages Anurans offer a powerful model for addressing questions about how neural barriers to gene flow arise across biological scales, and how changes in the brain contribute to speciation. Modern evolutionary neurobiology will benefit from applying new tools to this longstanding neuroethological model clade.

Pregametogenesis: The Earliest Stages of Gonad and Germline Differentiation in Anuran Amphibians.

The gonads of amphibians, like other vertebrates, consist of somatic tissues, which create a specific environment essential for the differentiation of germline cells. The earliest stages of gametogenesis still remain underexplored in anuran amphibians. We propose to introduce the term "pregametogenesis" for a specific period of gonocyte proliferation and differentiation that occurs exclusively during the early stages of gonadal development. This review shows the key steps of early gonad differentiation in anuran amphibians and further compares chromatin reorganization in gonocytes of mammals and hybridogenetic water frogs. In mammals, this phase involves resetting genomic imprinting, which is crucial for determining gene expression in offspring. In hybridogenetic Pelophylax water frogs, we highlight the unique phenomenon of genome elimination, where one parental subgenome is eliminated while the other is replicated. This process, occurring at the same developmental phase as imprinting in mammals, underscores the evolutionary importance of pregametogenesis. The study of amphibian gonocytes provides valuable insights into chromatin reorganization and genome plasticity, offering new perspectives on reproductive biology.

Batrachopolyenes: Volatile Norsteroids from Femoral Scent Glands of Frogs

AbstractSteroid hormones are C18‐C21‐sterane derivatives, featuring the typical 6–6–6–5 ring system. Here we report on a novel C18‐steroid ring system named batrachane with a contracted A‐ring resulting in a 5–6–6–5 ring arrangement. The isolation, structural elucidation, and total synthesis of three members of the novel batrachopolyene family occurring in the tropical frog genus Odontobatrachus is reported. The batrachopolyenes represent an entirely new collection of volatile steroidal natural products produced by anuran amphibians. Alongside the contracted A‐ring, each member contains a Δ16‐17 double bond but differs in the central belt of the steroidal structure. To create these atypical structural features, syntheses featuring a combination of Breslow radical chain relay chlorination, Favorskii ring contraction, and Clemmensen reduction proved successful. The occurrence of such compounds in another distal anuran group, the Mantellinae, suggests a more widespread distribution of the batrachane‐type compounds among frogs. The new structural steroid type raises questions concerning steroid biosynthesis and reception, as well as distribution in frogs in general and the structures of their hormones.

Batrachopolyenes: Volatile Norsteroids from Femoral Scent Glands of Frogs.

Steroid hormones are C18-C21-sterane derivatives, featuring the typical 6-6-6-5 ring system. Here we report on a novel C18-steroid ring system named batrachane with a contracted A-ring resulting in a 5-6-6-5 ring arrangement. The isolation, structural elucidation, and total synthesis of three members of the novel batrachopolyene family occurring in the tropical frog genus Odontobatrachus is reported. The batrachopolyenes represent an entirely new collection of volatile steroidal natural products produced by anuran amphibians. Alongside the contracted A-ring, each member contains a Δ16-17 double bond but differs in the central belt of the steroidal structure. To create these atypical structural features, syntheses featuring a combination of Breslow radical chain relay chlorination, Favorskii ring contraction, and Clemmensen reduction proved successful. The occurrence of such compounds in another distal anuran group, the Mantellinae, suggests a more widespread distribution of the batrachane-type compounds among frogs. The new structural steroid type raises questions concerning steroid biosynthesis and reception, as well as distribution in frogs in general and the structures of their hormones.

The impact of neonicotinoid insecticides on amphibians: A comprehensive review and future research challenges.

Neonicotinoid insecticides (NNIs) are widely used in agriculture; however, their effects on anuran amphibians remain poorly explored. This global review critically examines the existing literature, with data obtained from Web of Science and Scopus databases. A total thirty-seven studies were published from 2004 to 2023. Most studies originate from countries with significant scientific investment, with a notable absence of research from Europe, likely due to European Union restrictions on NNIs. Despite these restrictions, NNIs continue to be produced and exported from Europe. Since 1990, four generations of NNIs have been developed, generally characterized by high water solubility and environmental persistence, which increases the risks of groundwater contamination. Imidacloprid (46%), Clothianidin (22%) and Thiamethoxam (20%) were the most studied NNIs. The research predominantly focused on species such as Lithobates sylvaticus, Xenopus laevis, Lithobates pipiens and Pelophylax nigromaculatus. A significant 71.43% of the studies involved tadpoles, due to their vulnerability during early development and importance for population survival. L. sylvaticus, L. pipiens and P. nigromaculatus were extensively studied due to their distribution and X. laevis due to its ease of laboratory handling. The most common experimental approaches included survival tests, which assessed mortality rates, and biochemical tests that revealed cellular damage and concerns regarding lipid peroxidation. Developmental studies indicated both physical and physiological impacts, while genotoxic tests demonstrated damage to genetic material. Notable variability in responses was observed between species and compounds. The biomarkers investigated employed diverse methodologies, suggesting the need for more effective techniques. In the concluding remarks and future perspectives, the study presents the main findings, identifies important gaps in current research, emphasizes key challenges, and outlines strategic directions for future investigations.

Genomic and bioacoustic variation in a midwife toad hybrid zone: A role for reinforcement?

Hybrid zones, i.e., geographic areas where diverging lineages meet, hybridize and eventually mix their genomes, offer opportunities to understand the mechanisms behind reproductive isolation and speciation. Hybrid zones are particularly well suited to study reinforcement, i.e., the process by which selection against hybridization increases reproductive barriers, which, in anuran amphibians, is typically expressed by increased divergence in advertisement calls-the main cue to assortative mating-in parapatric ranges. Using mitochondrial barcoding (16S sequences), population genomics (thousands of SNPs) and bioacoustic analyses (four call parameters), we examine the hybrid zone between two incipient species of midwife toads (Alytes obstetricans and A. almogavarii) in southern France, with the purposes of locating their transition, measuring genetic introgression, and documenting potential signatures of reinforcement. We map range boundaries in the Eastern Pyrenees and the southwestern foothills of the Massif Central, namely along the Ariège valley and the Montagne Noire area. Similarly to another transition between these species in Spain, we found the hybrid zone to be narrow, involving geographically restricted gene flow (~20 km wide allele frequency clines) and barrier loci (i.e., loci resisting introgression), both suggestive of partial post-zygotic isolation (hybrid incompatibilities). The calls of the species overlap less inside than outside the hybrid zone, due to a reduction of their standing variation rather than a shift towards distinctive variants. While neutral causes cannot be excluded, this pattern follows the general expectations of reinforcement, yet without reproductive character displacement. Our study highlights the potential of amphibian hybrid zones to assess the genetic and behavioral drivers of reproductive isolation in statu nascendi and under various evolutionary contexts.

Experimental evidence of aposematic signal in black tadpoles

Aposematism is a widespread defense mechanism in animals. Anuran amphibians are known for their extensive repertoire of defenses, especially in the adult stage. Color-based mechanisms are particularly common in this group, although their use during the larval stage is still understudied. The hypothesis of aposematism in tadpoles has been suggested for several species that present conspicuous coloration and unpalatability. Tadpoles of some bufonid toads have been considered aposematic for decades, as they have a conspicuous black color, are unpalatable, and form aggregations that make them even more visible. However, few empirical studies have tested aposematism in these larvae against visually oriented predators, such as birds. In this paper, we tested whether the uniform black coloration acts as an aposematic signal in anuran larvae. The research was conducted through field predation experiments using artificial replicas of tadpoles of different colors (brown, gray, and black). The survival of black replicas was significantly higher than that of control groups, supporting the aposematism hypothesis. Given that the replicas varied only in color, we conclude that the differential attacks among treatments were carried out by visually oriented predators, probably birds, that had learned to recognize and avoid black tadpoles.

Effects of parental care on skin microbial community composition in poison frogs.

Parent-offspring interactions constitute the first contact of many newborns with their environment, priming community assembly of microbes through priority effects. Early exposure to microbes can have lasting influences on the assembly and functionality of the host's microbiota, leaving a life-long imprint on host health and disease. Studies of the role played by parental care in microbial acquisition have primarily focused on humans and hosts with agricultural relevance. Anuran vertebrates offer the opportunity to examine microbial community composition across life stages as a function of parental investment. In this study, we investigate vertical transmission of microbiota during parental care in a poison frog (Family Dendrobatidae), where fathers transport their offspring piggyback-style from terrestrial clutches to aquatic nurseries. We found that substantial bacterial colonization of the embryo begins after hatching from the vitelline envelope, emphasizing its potential role as microbial barrier during early development. Using a laboratory cross-foster experiment, we demonstrated that poison frogs performing tadpole transport serve as a source of skin microbes for tadpoles on their back. To study how transport impacts the microbial skin communities of tadpoles in an ecologically relevant setting, we sampled frogs and tadpoles of sympatric species that do or do not exhibit tadpole transport in their natural habitat. We found more diverse microbial communities associated with tadpoles of transporting species compared to a non-transporting frog. However, we detected no difference in the degree of similarity between adult and tadpole skin microbiotas, based on whether the frog species exhibits transporting behavior or not. Using a field experiment, we confirmed that tadpole transport can result in the persistent colonization of tadpoles by isolated microbial taxa associated with the caregiver's skin, albeit often at low prevalence. This is the first study to describe vertical transmission of skin microbes in anuran amphibians, showing that offspring transport may serve as a mechanism for transmission of parental skin microbes. Overall, these findings provide a foundation for further research on how vertical transmission in this order impacts host-associated microbiota and physiology.

Wet creatures in a warming world: How climate change will impact the future distribution of anuran amphibians from Brazilian semiarid region?

The world has been going through a climate crisis that has led to a substantial increase in global temperatures. Consequently, amphibians, ectothermic animals that depend on water to survive/reproduce, are under increasing threat. In this research, we compared the influence of climate change on the geographic distribution between anuran species with occurrence restricted to the Brazilian semi-arid region (Caatinga domain) and widely distributed congeneric species, with occurrence in multiple biomes. We hypothesized that climate change would be more harmful for species of restricted distribution than for those widely distributed. For this purpose, using ecological niche modeling, we designed potential distribution models for current and four future climate scenarios, and compared two metrics (climatic suitability and index of extent of occurrence) between restricted and widely distributed species. The results revealed that the climatic suitability did not differ among current climatic conditions and those expected for 2050 and 2090, nor differed between species with distribution restricted to the Caatinga and widely distributed ones. On the other hand, contrary to our predictions, while species with wide distributions would tend to retract their extent of occurrence in future times, species with restricted distributions would expand their ranges. These results suggest that species with current distribution restricted to Caatinga biome might be relatively favored by the climate changes predicted for the next 80 years. However, we discuss that this result should be interpreted with very caution, because many ecological and conservation requirements need to be guaranteed so that these predictions can actually occur. Our findings contributed to the understanding of the effects of climate change on closely related taxa, with different distribution patterns, revealing particularities of the anuran amphibians that occur in semi-arid environments in response to climate changes predicted for this century.

Integrative proteome and metabolome analyses reveal molecular basis of the tail resorption during the metamorphic climax of Nanorana pleskei.

During the metamorphosis of anuran amphibians, the tail resorption process is a necessary and crucial change. One subject that has received relatively little or no attention is the expression patterns of proteins and metabolites in the different tail portions during metamorphosis, especially in highland amphibians. The mechanisms of tail resorption in three portions (the tip, middle and root) of the tail were investigated in N. pleskei G43 tadpole based on two omics (proteomic and metabolomic). Integrin αVβ3 was found to be high expressed in the distal portion of the tail, which could improve the sensitiveness to thyroid hormones in the distal portion of the tail. Muscle regression displayed a spatial pattern with stronger regression in distal and weaker one in proximal portion. Probably, this stronger regression was mainly performed by the proteases of proteasome from the active translation by ribosomes. The suicide model and murder model coexisted in the tail resorption. Meanwhile, fatty acids, amino acids, pyrimidine, and purine which derived from the breakdown of tissues can be used as building blocks or energy source for successful metamorphosis. Our data improved a better comprehension of the tail resorption mechanisms underlying the metamorphism of N. pleskei tadpole through identifying important participating proteins and metabolites.

A comparative account of phototoxicity of anthracene and pyrene in the tadpoles of the anuran amphibian Fejervarya limnocharis using multiple toxicological end points.

Anthracene (Anth) and pyrene (Pyr), two of the priority polycyclic aromatic hydrocarbons (PAHs), being lipophilic in nature, not only accumulate in animals, but also settle in the sediment of water bodies leading to continuous exposure for animals. Anth and Pyr when exposed to sunlight can be photoactivated and have harmful effects on aquatic organisms. A comparative analysis was carried out to assess the acute, sub-chronic, genetic and biochemical toxicity of Anth and Pyr in F. limnocharis tadpoles following short exposures to sunlight on a daily basis. In the bioaccumulation studies, it was found that both Anth and Pyr accumulated in the tadpole tissues in a concentration and time dependent manner. The LC50 values for Anth (under 15 min of daily sunlight exposure) were found to be 2.87, 2.59, 2.28, 1.80 mg/L at 24, 48, 72 and 96 h of the exposures. The corresponding LC50 values for Pyr were 1.03, 0.80, 0.62, 0.42 mg/L. Sublethal exposure of Anth and Pyr affected the survivality, time to metamorphosis as well as morphometric parameters under sunlight exposure. In the genotoxicity assessment studies, particularly the micronucleus test and comet assay, it was found that Pyr led to a higher incidence of micronucleus formation and DNA damage in comparison to Anth. The exposure to PAHs resulted in significant changes in the activity of antioxidant-mediated protective response, specifically the SOD activity, which varied between the groups treated with Anth and Pyr. On the other hand, Pyr treated group showed a higher level of GSH as compared to Anth treated groups. Moreover, the elevation in MDA level in the Anth and Pyr treated groups suggests an increase in lipid peroxidation. Future research should focus on understanding the ecotoxicological risk faced by anuran amphibia due to PAHs that frequently occur in aquatic environments and developing strategies to mitigate these risks.

Adoption of satellite behavior by small male green treefrogs, Dryophytes cinereus, is not associated with age: Implications for the maintenance of alternative behavioral phenotypes

AbstractBody size is often a critical determinant of competitive ability and reproductive behavior. For example, small males characteristically lose contests with larger males and may be metabolically constrained from sustaining energetically demanding reproductive behaviors. Small males thus often utilize alternative reproductive tactics (ARTs) to maximize their reproductive success. How variation in body size among behavioral phenotypes arises can provide important insight into the maintenance of ARTs. For instance, smaller body sizes for males adopting ARTs may simply be a function of age, suggesting that the tactic is maintained by the periodic recruitment of young males into the population. Alternatively, body size differences among behavioral phenotypes that are unrelated to age suggest disparate growth rates that potentially arise as a consequence of variation in environmental conditions during development or genotypic differences between the phenotypes. Here we examine these alternative scenarios in the green treefrog, Dryophytes cinereus, using skeletochronological analysis combined with body size measures. As with many other anuran amphibians, male green treefrogs conditionally adopt a noncalling satellite mating tactic and attempt to intercept females attracted to the vocalizations of calling “host” males. We show that males adopting satellite behavior in natural choruses are smaller than calling males but do not represent a class of younger individuals, indicating that satellite males have lower growth rates than calling males. We also show that satellite males are in poorer condition than larger calling males, implicating energetic constraints in size‐related variation in mating tactic expression. Our work suggests that environmental conditions during development, genetic differences between phenotypes, or both, give rise to size discrepancies in behavioral phenotypes, neither of which have been previously explored in anurans. We discuss body size and condition differences between behavioral phenotypes in the context of energetic constraints and endocrine mediation of tactic expression in this species.

Barking up the wrong frog: global prevalence of misdirected amplexus in anuran amphibians

Abstract Reproduction is an energy-expensive life process in many organisms, and accurate conspecific recognition is crucial to successful reproduction. Nonetheless, misdirected attempts at amplexus towards heterospecifics appear to be common in many anuran amphibians. Such reproductive interference can have significant ecological and evolutionary consequences, but its prevalence remains unknown. Here, we compile a global dataset of anuran misdirected amplexus and test how phylogenetic relatedness, ecological niche, breeding phenology, and geography influence the prevalence of anuran misdirected amplexus. We find misdirected amplexus to be significantly higher among more closely related heterospecific pairs than between random pairs, but still occurred between species of different families. Misdirected amplexus was also significantly more common in arboreal and terrestrial anurans, and among species pairs with similar body sizes or with similar microhabitat use. We also show that misdirected amplexus is significantly more common among explosive breeders compared with prolonged breeders and is more prevalent in temperate regions compared with the tropics. Overall, we show that misdirected amplexus among anuran amphibians is not a rare phenomenon and that its prevalence is influenced by evolutionary relatedness, microhabitat use, ecological similarity, and breeding phenology. These interactions have the potential to cause species decline, hence understanding them is crucial.

State of populations of anuran amphibians (Anura, Amphibia) in the north of the Caspian lowland

State of populations of anuran amphibians (Anura, Amphibia) in the north of the Caspian lowland

Investigation of the presence of Brucella spp. in amphibians collected from some regions in Türkiye

Brucellosis is a zoonotic disease that causes economic losses in many countries worldwide, especially in livestock. With the development of molecular techniques, the diversity of Brucella species has been increasing in recent years. Recently, atypical Brucella spp. have been isolated mainly from cold-blooded animals. Firstly, the African bullfrog and then B. inopinata and B. microti-like strains have been identified in various frog species worldwide. This study aimed to determine the presence of Brucella in amphibian frogs for the first time in Türkiye by bacteriological and molecular methods. Internal organ samples (spleen, liver, lung, kidney, etc.) of 150 frogs from different regions of Türkiye (Edirne/Ipsala (53 pieces), Adıyaman/Kâhta (97 pieces)) were used for the isolation of Brucella spp. Simultaneously, DNA extraction was performed using a commercial isolation kit from tissue homogenates and samples cultured in media and left to incubation. As a result of Brucella genus-specific PCR (Polymerase Chain Reaction) and Multiplex PCR (Bruce-Ladder) methods performed with these extracts, no positivity was detected in the frog samples taken from Edirne province, while in 4 of the frog samples taken from Adıyaman province, bands of approximately 250, 600, 700, 1000, 1500 and 3000 bp were observed in Multiplex PCR. Sphingomonas paucimobilis (S. paucimobilis) was identified by analysing the culture obtained from these samples with VITEK®2:Healtcare. As a result, the presence of Brucella spp. could not be detected both bacteriologically and molecularly in the study samples. However, observing similar multiple bands in multiplex PCR suggested that this bacterium and Brucella species are phylogenetically close. At the same time, it was determined that this opportunistic pathogen isolated from various human infections can colonise amphibians. Since S. paucimobilis, which is found together with Brucella species under the class Alphaproteobacteria, causes opportunistic infections, especially in immunocompromised humans, it was concluded that this bacterium may pose a risk for those working in farms where frogs are raised for human consumption, and it is thought that it may be essential to take the necessary preventive measures.

Water Availability and Temperature as Modifiers of Evaporative Water Loss in Tropical Frogs.

Water plays a notable role in the ecology of most terrestrial organisms due to the risks associated with water loss. Specifically, water loss in terrestrial animals happens through evaporation across respiratory tissues or the epidermis. Amphibians are ideal systems for studying how abiotic factors impact water loss since their bodies often respond quickly to environmental changes. While the effect of temperature on water loss is well known across many taxa, we are still learning how temperature in combination with humidity or water availability affects water loss. Here, we tested how standing water sources (availability) and temperature (26 and 36°C) together affect water loss in anuran amphibians using a Bayesian framework. We also present a conceptual model for considering how water availability and temperature may interact, resulting in body mass changes. After accounting for phylogenetic and time autocorrelation, we determined how different variables (water loss and uptake rates, temperature, and body size) affect body mass in three species of tropical frogs (Rhinella marina, Phyllobates terribilis, and Xenopus tropicalis). We found that all variables impacted body mass changes, with greater similarities between P. terribilis and X. tropicalis, but temperature only showed a notable effect in P. terribilis. Furthermore, we describe how the behavior of P. terribilis might affect its water budget. This study shows how organisms might manage water budgets across different environments and is important for developing models of evaporative water loss and species distributions.

Natural disturbance allows multiple anuran taxa to persist in a dynamic wetland complex

AbstractThe maintenance of biological diversity is frequently enhanced in a heterogenous landscape by some level of disturbance. Thus, when a landscape becomes stabilized and homogenized through the spread of an invasive plant species, there may be consequences for native biodiversity, particularly for those biotas that depend on the pre‐existing, natural disturbance regime of that landscape. At Long Point, Ontario, Canada, a sandspit in Lake Erie, the community of anuran amphibians experienced the co‐incidence of 2 major disturbance events, 1 anthropogenic and 1 natural: an intervention to remove the invasive form of the common reed (Phragmites australis australis) and a spate of extensive dune washouts caused by high water levels and storms. As a result of the unequal distribution of disturbance in the landscape, different areas were affected by only the dune washouts, only the common reed treatment, both disturbances, or neither disturbance. From May to August 2021, we explored how the disturbances affected the resident frog and toad species habitat associations in the 4 different disturbance conditions in the landscape. By means of minnow traps, acoustic surveys, and visual surveys, we determined that the dune washouts had a greater influence on resident anurans than the common reed treatment. Ranid frogs (Ranidae) tended to inhabit non‐washout sites, whereas Fowler's toads (Anaxyrus fowleri) congregated in the newly formed, sand flats and shallow, de‐vegetated pools resulting from the washouts. Neither ranid frogs nor Fowler's toads demonstrated avoidance of the sites affected by the herbicide treatment and mechanical rollover of the common reed. This evidence of species sorting, which enables multiple species to persist in a dynamic and heterogeneous landscape, suggests that wildlife management in aid of threatened species recovery may find success by encouraging natural disturbance regimes in dynamic landscapes. Future management endeavors should consider refraining from complete dune stabilization in these landscapes to allow the natural washouts to occur at a higher frequency, while ensuring the continued effectiveness of the invasive common reed eradication.

Subcutaneous occurrence of encysted Acanthocephala in an anuran amphibian from Brazil.

Acanthocephalans, in their adult stage, are obligatory parasites of many types of vertebrates, including anuran amphibians. Their complex life cycle always involves an arthropod intermediate host but may include non-obligatory strategies that could improve transmission success, such as paratenic infections. In paratenic hosts, these parasites are normally found loose in the body cavity or encysted in internal organs. Here, we present the first report of acanthocephalans found encysted under the skin of an amphibian (i.e., external to its body cavity). The specimen, a clay robber frog [Haddadus binotatus (Spix, 1824)], had been collected in an Atlantic Forest area in southeastern Brazil. Upon examination of the frog, we recovered two specimens of acanthocephalan (Order Echinorhynchida) encysted under the skin of its venter. Considering the host's relatively small size and its thin ventral musculature, we believe that the acanthocephalans may have accidentally trespassed the muscular tissue while attempting to encyst in the frog's internal body wall.