Three new toad species discovered in Nevada, USA


This video from the USA says about itself:

24 July 2017

Scientists have discovered three new species of toads living in Nevada’s Great Basin in the US, that have been isolated from other populations for 650,000 years and may already be at risk of extinction. Discoveries of new amphibians are extremely rare in the US with only three new frog species discovered since 1985 – and toad species are even more rare, with the last species discovered north of Mexico, the now extinct Wyoming toad, in 1968.

“We’ve found the toads in small, wet habitats surrounded by high-desert completely cut off from other populations,” said Dick Tracy, professor at University of Nevada in the US. “These are absolutely new, true species that have been separated from other populations for 650,000 years,” said Tracy. The three new species, the Dixie Valley toad, Railroad Valley toad and Hot Creek toad are not connected geographically.

They were found in Tracy’s 10-year long survey of the desert-dominated Great Basin. The toads are small in size, yet each have a suite of unique physical features that differ from each other, as well as other toads in the region. Each of the species have slightly different colours, and they are about two inches long when full grown.

“The Dixie Valley toad is a pretty toad, with flecks of gold on an olive background,” said Tracy. The Dixie Valley toad is only found in an isolated spring-fed marsh which make up less than four square miles surrounded by an arid region where aquatic resources are both rare and widely scattered. The habitat occupied by this newly described species is also adjacent to a proposed site for a geothermal power plant that could dry up the marsh and threaten the toad’s survival.

“If this power plant goes in and the habitat is dried up, this recently discovered species could go extinct,” Tracy said. “It’s a good candidate for an Endangered Species Act listing,” he said. The Dixie Valley species has the smallest body size among the region’s complex of related species in the western US, and can be further diagnosed from other toads in the complex by the large glands on its hind legs in addition to its distinctive colouration.

The Railroad Valley toad is in the Tonopah Basin in the central Nevada desert and the Hot Creek Toad is about 56 kilometres away but in Hot Creek Mountain Range, in a drainage isolated from the Railroad Valley toad. All three new species are natives of the Great Basin in Nevada, which was once covered by large marshes and giant inland lakes during the Pleistocene Epoch and is now among the most arid regions in the US with only one per cent of the landscape containing water. The findings were published in the journal Zootaxa.

From the University of Nevada, Reno in the USA:

Rare discovery of three new toad species in Nevada’s Great Basin

July 21, 2017

Summary: Three new species of toads have been discovered living in Nevada’s Great Basin in an expansive survey of the 190,000 square mile ancient lake bottom, report investigators.

Three new species of toads have been discovered living in Nevada’s Great Basin in an expansive survey of the 190,000 square mile ancient lake bottom. Discoveries of new amphibians are extremely rare in the United States with only three new frog species discovered since 1985 — and toad species are even more rare, with the last species discovered north of Mexico, the now extinct Wyoming toad, in 1968.

“We’ve found the toads in small, wet habitats surrounded by high-desert completely cut off from other populations,” Dick Tracy, a biology professor at the University of Nevada, Reno, and lead scientist on the project, said. “These are absolutely new, true species that have been separated from other populations for 650,000 years.”

The three new species, the Dixie Valley toad, Railroad Valley toad and Hot Creek toad are not connected geographically. They were found in Tracy’s 10-year long survey of the desert-dominated Great Basin. His team used 30 “shape” metrics and DNA studies to analyze these toads’ characteristics to determine if each were distinguishable from the closely related Western toad, found throughout the Western United States.

The evidence supports the recognition of three distinct new species. The toads are small in size, yet each have a suite of unique physical features that differ from each other, as well as other toads in the region. Each of the species have slightly different colors, and they are about two inches long when full grown.

“The Dixie Valley toad is a pretty toad, with flecks of gold on an olive background,” Tracy, a long-time professor in the biology department of the College of Science, said. “It’s not like the big, common green toads you might find in other marshes around the west or even in Rancho San Rafael Park in Reno.”

The Dixie Valley toad is in Churchill County about 100 miles east of Reno. The toad is only found in this isolated spring-fed marsh which make up less than four square miles, surrounded by an arid region where aquatic resources are both rare and widely scattered. Dixie Valley is the hottest and most geothermally active system in the Basin and Range Province. The habitat occupied by this newly described species is also adjacent to a proposed site for a geothermal power plant that could dry up the marsh and threaten the toad’s survival.

The power plant development is on hold while the Bureau of Land Management reviews the geothermal project and the possible impacts on the toad species. The Center for Biological Diversity, a national environmental group based in Tucson, Arizona, marshaled more than 1000 letters to the BLM asking them to reconsider permitting the power plant being built at the site of the newly discovered species.

Potential for Endangered Species Act listing

“If this power plant goes in and the habitat is dried up, this recently discovered species could go extinct,” Tracy said. “It’s a good candidate for an Endangered Species Act listing. The ESA was passed under Richard Nixon in 1973, and the second species listed under the new Act was the Houston Toad. This is a tough conflict between commerce and biological resources, and we need to seek compromises so if the project proceeds, it won’t hurt the toads.”

Tracy’s team includes his master’s student Michelle Gordon from the University’s Biology Graduate Program, who is the lead author of the scientific paper describing the new species, and his former doctoral student Eric Simandle from the University’s Ecology and Evolution and Conservation Biology Graduate Program. Simandle is now an associate professor at Paul Smiths College in New York and is a co-author on the study that discovered the toad in the thick underbrush of the spring-fed marsh.

The small isolated toad populations also have the smallest individuals compared to other western toads.

The Dixie Valley species has the smallest body size among the region’s complex of related species in the western United States, and can be further diagnosed from other toads in the complex by the large glands on its hind legs in addition to its distinctive coloration.

The overall population numbers of the Dixie Valley toad are unknown, and the current range is severely restricted, suggesting that this species’ population is likely very small and especially vulnerable to changes in environment.

“The toads are perfectly concealed in the dense vegetation of their habitat,” Gordon said. “You could easily miss seeing them during the day, making accurate counts difficult. But, during one trip at dusk, toads were everywhere, giving the impression that toads were locally abundant. And, without the water in this habitat, this toad species would completely disappear.”

Isolated by Desert

The Railroad Valley toad is in the Tonopah Basin in the central Nevada desert and the Hot Creek Toad is about 35 miles away but in Hot Creek Mountain Range, in a drainage isolated from the Railroad Valley toad. All three new species are natives of the Great Basin in Nevada, which was once covered by large marshes and giant inland lakes during the Pleistocene Epoch and is now among the most arid regions in the United States with only one percent of the landscape containing water.

“Our goal has been to understand the relationships among toad populations in the Great Basin,” Tracy said. “We’ve found that our knowledge of amphibian diversity in the western United States remains incomplete and that novel discoveries continue to occur, even in unlikely settings. This is really, really neat; an exciting thing, to find something not known to exist before.”

Tracy has been honored as a Guggenheim Fellow, as a Fellow in the American Association for the Advancement of Science, as a Distinguished Scholar at Pepperdine University, and as a Fellow of the Association of Western Universities. He is the recipient of an American Society of Zoologists’ Service Award, a Desert Tortoise Council Conservation Award and a Service Award from the U.S. Fish and Wildlife Service. Tracy has authored more than 200 scientific papers, and his work is known internationally.

“Dr. Tracy has long been recognized as one of the world’s leading ecologists,” Jack Hayes, chair of the Department of Biology said. “In recent years as he has turned his attention to conservation issues, he has been translating his basic knowledge into studies that make a difference for Nevada, the U.S., and the biodiversity of the world. The discovery of a new species of vertebrate in North America at this point in time is extremely rare, so the research by Dr. Tracy and his graduate students is a remarkable and exciting accomplishment.”

The discovery of the Dixie Valley toad was announced in the peer-reviewed science journal Zootaxa on July 6.

Glass frog protects eggs, video


This 3 July 2017 National Geographic video says about itself:

The Glass Frog: Ultimate Ninja Dad | Animal 24

3 July 2017

A male glass frog is the lone protector of his eggs 24/7 until they hatch. Sometimes this means protecting them from their worst enemy.

Dinosaurs extinct, frogs survived


This 2016 video is called Frogs: National Geographic Documentary HD.

From the University of California – Berkeley in the USA:

Dinosaurs’ loss was frogs’ gain: The upside of a mass extinction

88 percent of living frogs originated from an evolutionary radiation beginning at K-Pg boundary

July 3, 2017

Summary: Based on earlier studies, biologists believed that the vast majority of today’s frogs originated in a blossoming of new species 100 million years ago. New and more complete genetic data pinpoints this radiation much earlier: 66 million years ago at the Cretaceous-Paleogene boundary, precisely when much of life on Earth was wiped out by a comet or asteroid. Frogs took advantage of flourishing angiosperms to escape to the treetops into many more ecological niches.

Most of the frogs alive today owe a big thank you to the asteroid or comet that delivered the coup de grace to the dinosaurs.

A new study by Chinese and American biologists shows that if the calamity had not wiped the planet clean of most terrestrial life 66 million years ago, 88 percent of today’s frog species wouldn’t be here. Nearly nine out of 10 species of frog today have descended from just three lineages that survived the mass extinction.

The results, to be published this week in the journal Proceedings of the National Academy of Sciences, are a surprise, because previous studies of frog evolution pinpointed the blossoming of the main frog lineages today to about 35 million years earlier, in the middle of the Mesozoic era [rather: closer to the middle].

The new analysis of 95 genes from frogs within 44 of 55 living families shows that these three lineages started to take off precisely at the boundary between the Cretaceous and Paleogene periods — the K-Pg boundary, formerly called the KT boundary — when the last mass extinction occurred, and not 100 million years ago.

According to herpetologist and co-author David Wake, a University of California, Berkeley professor of the graduate school and a curator of the Museum of Vertebrate Zoology, new frog species likely radiated rapidly throughout the world because so many environmental niches were available after the animals occupying them disappeared.

“We think the world was quite impoverished as a result of the KT event, and when the vegetation came back, angiosperms dominated. That’s when trees evolved to their full flowering,” Wake said. “Frogs started becoming arboreal. It was the arboreality that led to the great radiation in South America in particular.”

Trees are an ideal habitat for frogs not only because they allow them to escape from terrestrial predators, but also because their fallen leaves provide protection while the frogs are on the ground, breeding habitat and plenty of food, such as insects. Trees and other flowering plants took off in the late Cretaceous, and were ready for exploitation by frogs after they recovered from the extinction.

Another adaptation that became popular was direct development, that is, producing young without a tadpole stage, which is standard for about half of all frog species today.

“The majority of the frogs that thrive now are thriving because of direct development of eggs in terrestrial situations,” he said. “It is a combination of direct development and use of arboreal habitat that accounts for a great deal of the radiation.”

Previous genetic analyses of frog evolution focused on mitochondrial DNA and how long the molecular clock had been ticking for mitochrondrial genes. However, analysis of molecular evolution in mitochondrial DNA often produces dates for lineage divergence that are too old. In the case of frogs, such analysis pinpointed the radiation of most living frogs at about 100 million years ago, which was a puzzle, since Earth’s environment was stable at that time. A changing environment typically drives evolution.

The new analysis, based on data assembled primarily by graduate student Yan-Jie Feng at Sun Yat-Sen University in Guangzhou, China, focused on the sequences of 95 genes located on chromosomes in the nucleus and how they changed over time. He and his colleagues gathered genetic data from 156 frog species and combined this with earlier information about two genes from 145 different frogs, for a total of 301 distinct frog species from all 55 families of frogs. The data were calibrated using 20 dates derived from fossils and Earth historical events.

The team, which includes scientists from the Florida Museum of Natural History at the University of Florida and the University of Texas, Austin, concluded that perhaps 10 groups of frogs survived the extinction, but only three of them (Hyloidea, Microhylidae, and Natatanura) flourished and diversified to claim habitats and niches around the world.

Nothing other than luck distinguishes the survivors, Wake said. Remnants of the other surviving lineages are scattered in isolated spots around the world, but are just as diverse today in their habitats and breeding strategies as the 88 percent.

Two of the three surviving lineages that subsequently radiated widely came out of Africa, which remained intact as the continents shifted around over the ensuing eons, with the breakup of Pangea and then Gondwana to form the continents we see today. The African rift zone and mountain building in West Africa generated new habitats for the evolving frogs, Wake noted. The third, Hyloidea, radiated throughout what became South America.

Today’s frogs, comprising more than 6,700 known species, as well as many other animal and plant species are under severe stress around the world because of habitat destruction, human population explosion and climate change, possibly heralding a new period of mass extinction. The new study provides one clear message for future generations.

“These frogs made it through on luck, perhaps because they were either underground or could stay underground for long periods of time,” Wake said. “This certainly draws renewed attention to the positive aspects of mass extinctions: They provide ecological opportunity for new things. Just wait for the next grand extinction and life will take off again. In which direction it will take off, you don’t know.”

Tree frog on video


This June 26 video is about a tree frog basking in the sun in Meijendel nature reserve in the Netherlands.

Fish to amphibian evolution, new research


This video says about itself:

The Evolution of Amphibians

23 January 2016

The first major groups of amphibians developed in the Devonian period, around 370 million years ago, from lobe-finned fish which were similar to the modern coelacanth and lungfish.

These ancient lobe-finned fish had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom. Some fish had developed primitive lungs to help them breathe air when the stagnant pools of the Devonian swamps were low in oxygen. They could also use their strong fins to hoist themselves out of the water and onto dry land if circumstances so required.

Eventually, their bony fins would evolve into limbs and they would become the ancestors to all tetrapods, including modern amphibians, reptiles, birds, and mammals. Despite being able to crawl on land, many of these prehistoric tetrapodomorph fish still spent most of their time in the water. They had started to develop lungs, but still breathed predominantly with gills.

From the University of Calgary in Canada:

Fossil holds new insights into how fish evolved onto land

‘It’s like a snake on the outside, but a fish on the inside’

June 21, 2017

The fossil of an early snake-like animal — called Lethiscus stocki — has kept its evolutionary secrets for the last 340 million years.

Now, an international team of researchers, led by the University of Calgary, has revealed new insights into the ancient Scottish fossil that dramatically challenge our understanding of the early evolution of tetrapods, or four-limbed animals with backbones.

Their findings have just been published in the research journal Nature. “It forces a radical rethink of what evolution was capable of among the first tetrapods,” said project lead Jason Anderson, a paleontologist and Professor at the University of Calgary Faculty of Veterinary Medicine (UCVM).

Before this study, ancient tetrapods — the ancestors of humans and other modern-day vertebrates — were thought to have evolved very slowly from fish to animals with limbs.

“We used to think that the fin-to-limb transition was a slow evolution to becoming gradually less fish like,” he said. “But Lethiscus shows immediate, and dramatic, evolutionary experimentation. The lineage shrunk in size, and lost limbs almost immediately after they first evolved. It’s like a snake on the outside but a fish on the inside.”

Lethicus’ secrets revealed with 3D medical imaging

Using micro-computer tomography (CT) scanners and advanced computing software, Anderson and study lead author Jason Pardo, a doctoral student supervised by Anderson, got a close look at the internal anatomy of the fossilized Lethiscus. After reconstructing CT scans its entire skull was revealed, with extraordinary results.

“The anatomy didn’t fit with our expectations,” explains Pardo. “Many body structures didn’t make sense in the context of amphibian or reptile anatomy.” But the anatomy did make sense when it was compared to early fish.

“We could see the entirety of the skull. We could see where the brain was, the inner ear cavities. It was all extremely fish-like,” explains Pardo, outlining anatomy that’s common in fish but unknown in tetrapods except in the very first. The anatomy of the paddlefish, a modern fish with many primitive features, became a model for certain aspects of Lethiscus’ anatomy.

Changing position on the tetrapod ‘family tree’

When they included this new anatomical information into an analysis of its relationship to other animals, Lethiscus moved its position on the ‘family tree’, dropping into the earliest stages of the fin-to-limb transition. “It’s a very satisfying result, having them among other animals that lived at the same time,” says Anderson.

The results match better with the sequence of evolution implied by the geologic record. “Lethiscus also has broad impacts on evolutionary biology and people doing molecular clock reproductions of modern animals,” says Anderson. “They use fossils to calibrate the molecular clock. By removing Lethiscus from the immediate ancestry of modern tetrapods, it changes the calibration date used in those analyses.”

Dinosaur age caecilian amphibian ancestor discovered?


This video says about itself:

19 June 2017

A new analysis of a pair of tiny fossils found in the 1990s has helped scientists to uncover the backstory of the most mysterious amphibian alive. Researchers used 3D X-rays to map out the remains of a now-extinct species that walked the Earth [220] million years ago. They found that the species is a long-missing amphibious link that expands the known history of frogs, toads and salamanders by at least 15 million years. Chinlestegophis jenkinsi (artist’s impression) was a tiny subterranean carnivore.

From Science News:

New fossils shake up history of amphibians with no legs

Tiny skulls and other bits hint at unexpected backstory for today’s snake-shaped caecilians

by Susan Milius

3:30pm, June 19, 2017

Newly named fossils suggest that a weird and varied chapter in amphibian deep history isn’t totally over.

Small fossils about 220 million years old found along steep red slopes in Colorado represent a near-relative of modern animals called caecilians, says vertebrate paleontologist Adam Huttenlocker of the University of Southern California in Los Angeles.

Caecilians today have long wormy bodies with either shrunken legs or none at all. Yet the nearly 200 modern species of these toothy, burrow-dwelling tropical oddballs are genuine amphibians. The fossil creatures, newly named Chinlestegophis jenkinsi, still had legs but could be the oldest known near-relatives of caecilians, Huttenlocker and colleagues suggest.

A popular view of the amphibian family tree has put caecilians on their own long, peculiar branch beside the ancient frogs and salamanders. But a close look at the new fossils suggests a much earlier split from ancestral frogs and salamanders, the researchers propose June 19 in Proceedings of the National Academy of Sciences. The move puts the caecilians into “a strange but incredibly diverse” group, the stereospondyls, Huttenlocker says. These species included elongated, short-legged beasts with heads shaped like toilet lids.

Among the many stereospondyls, Huttenlocker speculates that caecilians came from “an aberrant branch of miniaturized forms that went subterranean.” And today’s legless burrowers could be this once-flourishing group’s sole survivors.