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FIGURE 6 in A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola

FIGURE 6. Schismaderma branchi sp. nov. holotype (ZMB 91630). A. Dorsal surface, showing adult coloration, particularly the absence of obvious dorsal paired sacral dark blotches and presence of lateral dark stripe. B. Ventral surface showing characteristic white ground colour and heavily semi-reticulate, dark blotches on ventrum, throat and limbs. C. Lateral shot of head. D. Left hand. E. Left foot. Photographs by N.L. Baptista.

FIGURE 5 in A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola

FIGURE 5. Scatterplots of the first two principal components axes of 22 measurements of adult Schismaderma. Black dots represent S. carens, grey dots represent S. branchi sp. nov., triangles represent females, circles represent males. For loadings on axes see Table 7.

FIGURE 10 in A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola

FIGURE 10. Oscillogram and sonogram of advertisement calls of: A. Schismaderma carens. B. Schismaderma branchi sp. nov.

FIGURE 9 in A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola

FIGURE 9. Preserved tadpole of Schismaderma branchi sp. nov. (PEM A14307). A–C. Lateral, dorsal, and ventral view. D. Oral disc with LRTF of 2/3 (posterior 3rd low above 2nd row, not captured in photograph). Photographs by N.L. Baptista (A–C), W. Conradie (D).

FIGURE 1 in A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola

FIGURE 1. Map of sub-Saharan Africa with the known distribution of Schismaderma carens, and localities of S. branchi sp. nov. (pink circles) and S. carens specimens analysed morphologically (blue triangles) and genetically (red circles). Map adapted from IUCN (2020) and compiled by L. Veríssimo.

opencc-zeroJan 2022View details →

Annotated transcriptome data from: Transcriptome annotation reveals minimal immunogenetic diversity among Wyoming toads, Anaxyrus baxteri

Briefly considered extinct in the wild, the future of the wild population of the Wyoming toad (Anaxyrus baxteri) continues to rely on captive breeding to supplement the wild population. Given its small natural geographic range and history of rapid population decline at least partly due to fungal disease, investigation of the diversity of key receptor families involved in the host immune response represents an important conservation need. Population decline may have reduced immunogenetic diversity sufficiently to increase the vulnerability of the species to infectious diseases. Here we use comparative transcriptomics to examine the diversity of toll-like receptors and major histocompatibility complex (MHC) sequences across three individual Wyoming toads. We find reduced diversity at MHC genes compared to bufonid species with a similar history of bottleneck events. Our data provide a foundation for future studies that seek to evaluate the genetic diversity of Wyoming toads, identify biomarkers for infectious disease outcomes, and guide breeding strategies to increase genomic variability and wild release successes.

opencc-by-4.0Jan 2022View details →

Data from: Evolutionary analyses of visual opsin genes in frogs and toads: diversity, duplication, and positive selection

Data from: Evolutionary analyses of visual opsin genes in frogs and toads: diversity, duplication, and positive selection

opencc-zeroFeb 2022View details →

Maintenance of phenotypic plasticity is linked to oxidative stress in spadefoot toad larvae

Phenotypic plasticity allows organisms to improve the match between their phenotype and heterogeneous environments. Theoretical models have argued that costs of maintaining the sensory and response machinery necessary for adaptive phenotypic plasticity are important determinants to the evolution of plasticity. Despite recurrent arguments invoking putative metabolic costs associated with maintenance of cellular machinery, no studies have yet attempted to quantify it from a molecular standpoint. Here we experimentally examine physiological differences across genotypes (sibships) of spadefoot toad larvae with different degrees of plasticity in response to predator cues. We observed marked differences across sibships in developmental, growth and morphological responses to predators, and tested whether increased plasticity was associated with oxidative stress or immune suppression. We observed that more plastic sibships experienced higher antioxidant enzymatic activity when reared in the absence of predator cues, i.e. not expressing their plastic responses. The degree of plasticity was also associated with higher lipid peroxidation and slightly greater granulocyte-to-lymphocyte ratio. Higher antioxidant activity in highly plastic sibships suggests that maintenance of phenotypic plasticity may be linked to energy demanding metabolic processes. Our findings suggest that having the potential to produce plastic responses may incur oxidative and immunological costs. In the long term, such maintenance costs may erode individual fitness and even constrain the evolution of plasticity. To our knowledge, this is the first empirical evidence indicating the existence of a physiological cost to the maintenance of phenotypic plasticity.

opencc-zeroJan 2023View details →

Toxin cues affect cannibalism responses of cane toad tadpoles

In many species cannibalism is uncommon and involves non-selective consumption of conspecifics as well as heterospecifics. However, within their invasive Australian range cane toad larvae (Rhinella marina) specifically target and voraciously consume the eggs and hatchlings of conspecifics, often extirpating entire clutches. In contrast, toad larvae rarely consume the eggs and hatchlings of native frogs. Here, we use laboratory studies to demonstrate that this selective consumption is triggered by species-specific chemical cues: maternally-invested bufadienolide toxins that otherwise defend cane toad eggs and hatchlings against predators. We find that these cues stimulate feeding behaviors in toad tadpoles, such that the addition of bufadienolide toxins to the water column increases predation on eggs, not only of conspecifics, but also of native anuran species that are otherwise usually ignored. In contrast, we find that cannibalism rates on conspecific hatchlings are high and unaffected by the addition of bufadienolide cues. The maternally-invested toxins present in conspecific eggs may therefore be more easily detected post-hatching, at which point tadpole feeding behaviors are induced whether or not additional toxin cues are present. As bufadienolide cues have previously been found to attract toad tadpoles to vulnerable hatchlings, our present findings demonstrate that the same toxin cues that attract cannibalistic tadpoles also induce them to feed, thereby facilitating cannibalism through multiple behavioral effects. Because native fauna do not produce bufadienolide toxins, the species-specificity of these chemical cues in the Australian landscape may have facilitated the evolution of targeted (species-specific) cannibalism in invasive cane toad populations. Thus, producing bufadienalide toxins confers a cost (increased vulnerability to cannibalism in early life-stages) as well as a benefit (reduced vulnerability to predation by other taxa).

opencc-zeroApr 2022View details →

Drymarchon corais (Colubridae) and Caiman crocodilus (Alligatoridae) use different feeding behaviors to consume poisonous toads

Drymarchon corais and Caiman crocodilus are reported here using different feeding behaviors for consuming poisonous toads of the genus Rhinella (Bufonidae). Drymarchon corais was observed feeding on specimens of Rhinella diptycha without avoiding contact with the parotoid macroglands, suggesting that this snake species is immune to toad toxins. Caiman crocodilus was recorded avoiding contact with the parotoid macroglands of specimens of Rhinella marina by consuming only the front and rear legs, suggesting that this caiman may be sensitive to toad toxins. Further experimental and field studies are needed to better understand the feeding behavior of D. corais and C. crocodilus, and the effects of Rhinella toxins on these predators.

opencc-zeroApr 2022View details →

Transcriptomic analysis reveals potential candidate pathways and genes involved in toxin biosynthesis in true toads

Synthesized chemical defenses have broadly evolved across countless taxa and are important in 30 shaping evolutionary and ecological interactions within ecosystems. However, the underlying 31 genomic mechanisms by which these organisms synthesize and utilize their toxins are relatively 32 unknown. Herein, we use comparative transcriptomics to uncover potential toxin synthesizing 33 genes and pathways, as well as interspecific patterns of toxin synthesizing genes across ten 34 species of North American true toads (Bufonidae). Upon assembly and annotation of the ten 35 transcriptomes, we explored patterns of relative gene expression and possible protein-protein 36 interactions across the species to determine what genes and/or pathways may be responsible for 37 toxin synthesis. We also tested our transcriptome dataset for signatures of positive selection to 38 reveal how selection may be acting upon potential toxin producing genes. We assembled high 39 quality transcriptomes of the bufonid parotoid gland, a tissue not often investigated in other 40 bufonid related RNAseq studies. We found several genes involved in metabolic and biosynthetic 41 pathways (e.g. steroid biosynthesis, terpenoid backbone biosynthesis, isoquinoline biosynthesis, 42 glucosinolate biosynthesis) that were functionally enriched and/or relatively expressed across the 43 ten focal species that may be involved in the synthesis of alkaloid and steroid toxins, as well as 44 other small metabolic compounds that cause distastefulness in bufonids. We hope that our study 45 lays a foundation for future studies to explore the genomic underpinnings and specific pathways 46 of toxin synthesis in toads, as well as at the macroevolutionary scale across numerous taxa that 47 produce their own defensive toxins.

opennotspecifiedApr 2022View details →

FIGURE 1 in The tadpole of the red-bellied toad, Melanophryniscus dorsalis (Mertens, 1933) (Anura: Bufonidae)

FIGURE 1. Tadpole of Melanophryniscus dorsalis, MCN 14349, Stage 31. (A) coloration in life, (B) lateral view, (C) dorsal view with detail of the position of pineal end–organ (arrow), (D) oral disc (ventral view), (E) labial teeth observed with scanning electron microscope.

opencc-zeroMay 2022View details →

Rates of dispersal of cane toads during their global invasion

Invasions often accelerate through time, as dispersal-enhancing traits accumulate at the expanding range edge. How does the dispersal behaviour of individual organisms shift to increase rates of population spread? We collate data from 44 radio-tracking studies (in total, of 650 animals) of cane toads (Rhinella marina) to quantify distances moved per day, and the frequency of displacement in their native range (French Guiana) and two invaded areas (Hawai'i and Australia). Here we show that toads in their native-range, Hawai'i and eastern Australia are relatively sedentary, while toads dispersing across tropical Australia increased their daily distances travelled from 20 to 200 m per day. That increase reflects an increasing propensity to change diurnal retreat sites every day, as well as to move further during each nocturnal displacement. Daily changes in retreat site evolved earlier than did changes in distances moved per night, indicating a breakdown in philopatry before other movement behaviours were optimised to maximise dispersal.

FIGURE 10. A in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 10. A= Habitat of Rhinella unapensis sp. nov. B–C= R. unapensis sp. nov. resting in leaves and stems of low shrubs (~1.20 m).

FIGURE 9 in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 9. Morphological variation of living specimens of Rhinella unapensis sp. nov. A–D= Puerto Almendra locality; E–H= Allpahuayo Mishana Natural Reserve.

FIGURE 7 in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 7. Holotype of Rhinella unapensis sp. nov. (CRBIIAP-2125); A) dorsal view; B) ventral view; C) lateral view of head; D) dorsal view of head; E) ventral view of right hand; F) ventral view of right foot.

FIGURE 8 in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 8. Type series and morphological variation in preserved specimens of Rhinella unapensis sp. nov. A–C= CRBIIAP-2114 (adult female); D–F=MZUNAP-AN 540 (adult male); G–I= CRBIIAP-2115 (adult female); J–L= CRBIIAP-2123 (adult male).

FIGURE 5 in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 5. Distribution map of the two new species described herein. Rhinella angeli sp. nov. Yellow color: 1) Nueva Esperanza; 2) Panguana; 3) Mircillo; 4) Sacacaca; 5) Cauchuyo; 6) Corrientes; 7) Taguado; 8) Sierra del Divisor National Reserve; 9) Matsés National Reserve. R. unapensis sp. nov. Red color: 1) Puerto Almendra; 2) Fundo UNAP; 3) Iquitos-Nauta Highway 70 km. Stars indicate the type locality.

FIGURE 6. A–B in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 6. A–B= Camouflage behavior of Rhinella angeli sp. nov. during field work. C= coloration of the secretion of the parotoid glands.

FIGURE 4 in Two new surprising species of leaf-litter toad of the Rhinella margaritifera species group (Anura: Bufonidae) from the Peruvian Amazon, Loreto-Peru

FIGURE 4. Morphological variation of living specimens of Rhinella angeli sp. nov. A–D= Quebrada Blanco river basin; E–H= Yavari-Mirin river basin.