AmphibiaWeb News of the Week
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Amphibian News!

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Every week, AmphibiaWeb offers the News of the Week to highlight breakthrough, significant, or impactful amphibian research and/or conservation actions. If you know of other current amphibian-related news or papers that would be of interest here, please let us know. We would love to hear from you!

For AmphibiaWeb's list of current papers related to amphibian declines and amphibian discovery, please see Recent Scientific Publications.


Tomopterna cryptotis by Alberto Sanchez-Vialas
February 26, 2024: Those trying to understand global amphibian declines in the context of the fossil record are probably out of luck. It’s not that the fossils aren’t there; rather, it’s that the fossils couldn’t be there. That’s the conclusion Krone et al. (2023) draw from a novel analysis of fossilization potential that includes nearly all modern tetrapods. To reach this rather jarring conclusion, the authors measured the area of overlap between the geographic ranges of modern tetrapods and areas of current sediment deposition. If no sediments are being deposited somewhere, no sedimentary rocks from our time period will exist there, which means that the animals living there won't have the opportunity to leave behind fossils. Among major tetrapod groups, amphibians have, by far, the poorest preservation potential, with only 40% of amphibian species having more than 1 km^2 of their geographic range in a sedimentary basin. Amphibians with a large amount of sedimentary basin overlap are even rarer. Additionally, more phylogenetically unique lineages of amphibians tend to be excluded from the fossil record. The authors link all of this to the particular affinity of amphibians for mountainous environments, which are areas of net erosion, rather than sedimentation. If this regime of under-preservation has affected amphibians throughout deep time, fluctuations in their diversity may be in principle impossible to recover. For instance, they show that, were the 40% of currently endangered amphibian species to go extinct, the fossil record would record, at best, a 13.6% drop in amphibian diversity, and more realistically, a drop of less than 5%. While these results suggest that the vast majority of amphibian history has gone unfossilized, their model can help point amphibian paleontologists away from hopeless dead-ends and remind us how precious and ephemeral modern amphibian species are. (Isaac Krone)
Siren intermedia by Jake Hutton
February 19, 2024: Nine of the 10 modern families of salamanders occur today in North America. But often overlooked are several other families of salamanders that occurred during the Mesozoic and Cenozoic of North America. One of those, the Batrachosauroididae, occurred along the coastal plain of the Western Interior Seaway during the Late Cretaceous and then persisted along the Southern coastal plain into the Miocene. Bourque and colleagues (2023) describe newly discovered fossils of Batrachosauroides from the Late Miocene of Florida. This reveals that this now extinct family persisted in the Florida peninsula until 9 or 10 million years ago, a time of global cooling. Although Batrachosauroides is now extinct, it co-occurred with other salamanders that still live today in Florida (Ambystoma, Siren), which adds new insight into the timing of turnover of the North American salamander fauna. (DCBlackburn)
Typhlonectes natans by Andrés Acosta
February 12, 2024: The caecilian fossil record is remarkably scarce. Although time-calibrated molecular phylogenies suggest that caecilians have existed for more than 200 million years, there has been named fossil referred to any of the lineages alive today (i.e., part of the crown group). Otávio Santos and colleagues (2024) have described a new extinct caecilian, Ymboirana acrux, from the Oligocene (approximately 25 million years ago) of Brazil and that they refer to the living family Typhlonectidae. This extinct caecilian was likely aquatic and was fossilized in what was then a lake. The remarkable preservation of both its vertebral column and much of its skull promises that this fossil will be an important resource for understanding the evolution of caecilians in South America. (DCBlackburn)
Atympanophrys gigantica by Benjamin Tapley
February 5, 2024: A whopping 59% of frogs and toads lack data on larval stages. Vera Candioti et al. (2024) quantify these gaps in knowledge of amphibian larvae. Of note is Brachycephaloidea (also known as the Terrarana) with larval stages described in only 3% of 1,228 species and a general lack of information regarding fossorial versus lentic/lotic tadpoles. In general, very few endotrophic species are known (226 species), but they are broadly distributed across the amphibian tree of life and are likely much more widespread than currently described. The Tropical Andes and New Guinea were identified as regions with particularly large knowledge gaps; the Andes is also a hot spot of new species descriptions, suggesting that specific efforts to describe larval stages will be increasingly necessary (Womack et al. 2022). In contrast, the Brazilian Atlantic forest and Madagascar have relatively high proportions of known larval stages. The authors propose that more focus on larval stage descriptions could reveal novel and highly specialized life stages equally exciting for researchers and local communities in addition to more general knowledge that is critical for successful conservation initiatives. (RTarvin)
Spea hammondii by Rob Schell
January 29, 2024: Animals that live underground have to deal with long periods with low oxygen and sometimes high carbon dioxide within burrows. Burrowing mammals often handle this challenge by having lower metabolisms than species that stay above ground. Many amphibians spend lots of time in burrows but it was not clear whether they had lower metabolisms like burrowing mammals. Giacometti and Tattersall (2023) compared metabolic rates among 185 amphibian species with different lifestyles including burrowing, but found that burrowing amphibians did not have lower metabolic rates than non-burrowing amphibians. Instead, they found that species living at higher latitudes generally had higher metabolic rates than species at lower latitudes, regardless of lifestyle. It is possible that having relatively low energy requirements, small body sizes, and multiple respiratory surfaces (skin and lungs) helps amphibians avoid negative respiratory effects of life underground. (MWomack)
Bufo praetextatus by Dr. Peter Janzen
January 22, 2024: When toads invade an environment, they arrive armed with a chemical weapon: bufadienolides (BDs). Toads synthesize these potent cardiotoxins and store them in their lumpy skin as a defense against predators. Sawada et al. (2023) demonstrate for the first time that invasive toads can serve as a toxin source for a sequestering predator. The Tiger Keelback, Rhabdophis tigrinus, is a poisonous snake that eats toads and concentrates the consumed BDs in specialized glands that run along its back. R. tigrinus living on Sado island in Japan have been isolated from toad prey for 120,000 to 800,000 years, until the introduction of the Eastern Japanese Common Toad, Bufo formosus (formerly Bufo japonicus formosus) in 1966. The researchers detected bufadienolides in the gland extracts of more than half of the snakes sampled from toad-infested areas of Sado, but found no poison in the snakes sampled from parts of the island not yet invaded by toads. Intriguingly, the BD composition largely matched that of keelbacks which predate native Japanese Common Toad in other regions of Japan, and differed from keelbacks which eat a different toad species, Bufo praetextatus (formerly Bufo japonicus japonicus). This strengthens the case that B. formosus is indeed the source of BDs in Sado island keelbacks. The Tiger Keelback snakes from historically nontoxic populations exhibit different antipredator behaviors than historically poisonous ones, thus the re-toxicification of Sado island keelbacks may have interesting effects on fitness and the microevolution of behavior. While its frequency of occurrence is yet unclear, the phenomenon of invasive species as toxin sources is a novel paradigm for the study of chemical ecology and evolution in a changing world. (Kannon Pearson)
Dendrobates truncatus by Victor Fabio Luna-Mora
January 15, 2024: Many frog enthusiasts have noticed that some frogs tap their toes on the ground fairly regularly. However we still do not know why most frogs exhibit this "toe tapping" behavior. To better characterize this toe tapping behavior, Vergara-Herrera et al. (2023) created a vibration-sensitive arena and examined toe tapping patterns during feeding in both males and females of the Yellow-striped Poison Frog, Dendrobates truncatus. The researchers found no differences between tapping behavior in males and females but they did find that tapping often increased before frogs attacked prey. And interestingly, frogs with longer third toes were more likely to increase their taps before attack. The patterns of toe tapping provided in this study provide an excellent starting point for asking more questions about the evolution and purpose (if any) of frog toe tapping. (Molly Womack)
Xenopus laevis by William Flaxington
January 8, 2024: Microplastics are becoming ubiquitous in waterways used by amphibians, and consequently tadpoles are ingesting those microplastics. There is growing concern of the effects of this environmental pollutant, however, few studies have quantified their effects. Ruthsatz et al. (2023) examined the effects of microplastics and climate change in lab experiments on the development of Xenopus laevis, African Clawed Frog. They found that microplastics increased larval metabolic and developmental rate as well as increased their corticosterone levels. The result of these changes led to juveniles that had wider bodies and longer limbs. Some of these changes were counteracted by the temperature treatments, but the authors noted that in other organisms the degree of temperature change can have opposing effects. Although the biological implications for these changes, particularly in amphibian species with more traditional life histories, is still murky, the illustration of this study that microplastics can cause sublethal and permanent changes to amphibian physiology and morphology is worth further investigation. (AChang)
Lyciasalamandra fazilae by Daniel Kane, 2023
January 1, 2024: Happy New Year’s! The AmphibiaWeb Team wishes you all a safe and happy year in 2024. We are grateful for the wonderful year we had in 2023 thanks to the enthusiasm and work of our users, contributors, and volunteers. We successfully launched our new initiative Species Account Live Training for AmphibiaWeb (SALTA) to expand our network of experts. So far we had two SALTA workshops and now have 39 new experts who will mentor students and other contributors to AmphibiaWeb. We also recorded 131 new species in 2023, over 680 new photos and 107 new species accounts. However, the main reason for launching AmphibiaWeb over 20 years ago, the alarming global decline of amphibians, has not abated but has since deepened. The recent news highlights have been a sober reminder that our mission to "connect people around the world by synthesizing and sharing information about amphibians to enable research, education, and conservation" is as important as ever.

News Archive by Year

Visit our News of the Week as they appeared below.