A new lab collaboration led by German Chavez and colleagues at the Instituto Peruano de Herpetologia described three new species of terrestrial-breeding frogs of the genus Pristimantis from the highlands of the Cordillera de Huancabamba, northwestern Peru. The three new species, Pristimantis chinguelas, P. nunezcortezi, and P. yonke (in the photo by G. Chavez) were distinguished based on a combination of morphological characteristics and genetic differences. These newly described species inhabit the remote páramos and adjacent elfin forests of the Peruvian Andes, a region known for its rugged topography and challenging weather. Each species has unique physical traits that differentiate it from similar frogs, such as variations in snout shape, skin texture, and color patterns. The discovery highlights the Cordillera de Huancabamba as a key biodiversity hotspot, with nearly 50% of the amphibian species previously recorded there being endemic. The paper emphasizes the importance of using an integrative approach, combining genetic and morphological studies, to accurately classify these complex and diverse frogs. Despite the evident habitat loss in the area, especially of cloud forests as the type locality of P. yonke (inset photo, G. Chavez), the researchers suggest that all three species should be placed in the Data Deficient category of the IUCN Red List due to a lack of sufficient data to assess their conservation status. This discovery reinforces the idea that much of this mountainous region remains unexplored, holding the potential for many more unique amphibian species to be found. Citation: Chávez, G., W. Aznaran, I. Wong, K. Victoriano-Cigüeñas, L. A. García-Ayachi, J. D. Valencia-Málaga, J. Ormeño, M. Gulman, R. Sumiano-Mejía, M. E. Thompson, and A. Catenazzi. 2025. Over the top: Three new species of terrestrial breeding frogs (Anura, Terrarana, Pristimantis) from the highlands of the Cordillera de Huancabamba, northwestern Peru. 2025. Evolutionary Systematics 91: 145-166.
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A recent lab collaboration on pumpkin toadlets in Brazil's Atlantic Forest revealed a surprising and complex relationship between drought and a deadly waterborne fungus, Batrachochytrium dendrobatidis (Bd). While a short-term, experimental drought directly suppressed the fungus's overall load on the toadlets, it also intensified its transmission. This paradoxical effect occurred because the dry conditions caused the toadlets to congregate in and around remaining water sources, increasing the opportunity for the pathogen to spread from one host to another. Furthermore, the study led by PhD student Shannon Buttimer from the lab of Gui Becker, found that the drought negatively impacted the toadlets' skin microbiome, a crucial part of their defense against pathogens. The skin of the drought-affected toadlets had a lower proportion of bacteria known to inhibit the Bd fungus, which may have made them more susceptible to infection. These findings highlight a critical point: climate change can affect wildlife health not just through simple cause-and-effect, but through a complex chain of events that alters animal behavior and disrupts their natural defenses, ultimately increasing the risk of disease. Citation: Buttimer, S., D. Medina, R.A. Martins, A.G. Morais da Silva, W.J. Neely, C.F.B. Haddad, G.V. DiRenzo, A. Catenazzi, R.C. Bell, C.G. Becker. 2025. Experimental drought suppresses amphibian pathogen yet intensifies transmission and disrupts protective skin microbiome. Global Change Biology 31: e70275.
One of Rachel's dissertation chapters was published today in the journal Comparative Biochemistry and Physiology. Carotenoids, which are vibrant pigments acquired through diet, provide health benefits and are crucial for reproductive success in some animals. The fungal pathogen Batrachochytrium dendrobatidis (Bd) causes a disease called chytridiomycosis that infects the skin of amphibians, disrupts their regulatory processes, and can lead to death. Rachel hypothesized that the energy needed to fight a Bd infection would lead to a depletion of skin carotenoids in strawberry poison frogs (Oophaga pumilio). She predicted that an energetic or immunological trade-off would force the frogs to prioritize fighting the infection over sequestering these colorful pigments. However, the study's findings challenged this prediction, showing that the frogs were able to maintain their skin carotenoids even while infected. To investigate this, Rachel infected a group of adult male and female strawberry poison frogs with Bd and compared their skin carotenoid concentrations to a mock-infected control group. All frogs were given a consistent, carotenoid-rich diet for six months before the experiment to ensure they had high levels of these pigments. Using high-performance liquid chromatography (HPLC), they measured the types and concentrations of 17 different skin carotenoids. The infected frogs developed a range of infection loads, from around 1.0×101 to over 1.0×107 zoospore equivalents. However, statistical analysis showed no difference in skin carotenoid concentrations between the infected and control frogs, regardless of the sex of the animal. The results suggest that in captive O. pumilio with abundant dietary carotenoids, Bd infection is not a sufficient stressor to alter their ability to sequester skin carotenoids. This might be due to the availability of sufficient energy to combat the infection while also maintaining skin carotenoids. The importance of skin carotenoids for ecological processes, such as mate choice, may outweigh the pressure from the Bd infection, leading the frogs to prioritize maintaining these pigments. Citation: Prokopius, R., K. McGraw, and A. Catenazzi. 2025. Fungal disease does not affect skin carotenoid concentration in dietary-supplemented strawberry poison frogs. Comparative Biochemistry and Physiology, Part B 279: 111113
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