How fish became amphibians, new research


This 2018 video says about itself:

385 million years ago, a group of fish would undertake one of the most important journeys in the history of life and become the first vertebrates to live on dry ground. But first, they had to acquire the ability to breathe air.

Thanks to Ceri Thomas for the Ichthyostega reconstruction.

From Uppsala University in Sweden:

Large tides may have driven evolution of fish towards life on land

October 27, 2020

Big tidal ranges some 400 million years ago may have initiated the evolution of bony fish and land vertebrates. This theory is now supported by researchers in the UK and at Uppsala University who, for the first time, have used established mathematical models to simulate tides on Earth during this period. The study has been published in Proceedings of the Royal Society A.

“During long periods of the Earth’s history, we’ve had small tidal ranges. But in the Late Silurian and Early Devonian, they seem to have been large in some parts of the world. These results appear highly robust, because even if we changed model variables such as ocean depth, we got the same patterns,” says Per Ahlberg, professor of evolutionary organismal biology at Uppsala University.

Between 420 and 380 million years ago (Ma) — that is, during the end of one geological period, the Silurian, and beginning of the next, the Devonian — Earth was a completely different world from now. Instead of today’s well-known continents there were other land masses, clustered in the Southern Hemisphere. Stretching across the South Pole was the huge continent of Gondwana. North of it was another big one known as Laurussia, and squeezed between the two were a few small continents. Other salient differences compared with now were that Earth’s day lasted only 21 hours, since our planet revolved faster on its own axis, and the Moon looked much larger because its orbit was closer to Earth.

Life on land had gradually begun to get established. But the vertebrates, then consisting only of various kinds of fish, were still to be found only in the oceans. Then, during the Devonian, immense diversification of fish took place. One group to emerge was the bony fish, which make up more than 95 per cent of all fish today but were also the ancestors of terrestrial vertebrates. The earliest bony fish were the first animals to evolve lungs. What set off the evolution of bony fish, and how some of them started to adapt to a life on land, has not been clarified. One theory is that it happened in tidal environments where, in some periods, fish had been isolated in pools as a result of particularly large tides. This challenging habitat may have driven the evolution of lungs and, later on, the transformation of fins into front and hind legs.

To test this tidal theory, researchers at Uppsala University, in collaboration with colleagues from the Universities of Oxford and (in Wales) Bangor, used an established mathematical model of the tidal system for the first time to simulate, in detail, the tides in the Late Silurian and Early Devonian. Data on the positions of the continents, the distance of the Moon, the duration of Earth’s day, our planet’s gravity and the physical properties of seawater were fed into the model. These simulations showed unequivocally that the period, just like that of the present day, was one when large tides occurred in some places. The small continent of South China on the Equator showed a difference of more than four metres in sea level between high and low tide. The existence of tides at the time has previously been verified through studies of geological strata, but determining the extent of the difference between low and high tide has not been feasible. To researchers this news has been interesting, since fossil finds indicate that it was specifically around South China that bony fish originated.

“Our results open the door to further and even more detailed tidal analyses of key episodes in Earth’s past. The method can be used to explore the possible role of tides in other evolutionary processes of vertebrate development. And perhaps, conversely, whether tides, with their influence on ocean dynamics, played a part in the big marine extinctions that have taken place again and again in Earth’s history,” Ahlberg says.

Lost frogs rediscovered in Brazil


Megaeloisa bocainensis. Photo Délio Baêta/Provided

From Cornell University in the USA:

Lost frogs rediscovered with environmental DNA

September 8, 2020

Scientists have detected signs of a frog listed extinct and not seen since 1968, using an innovative technique to locate declining and missing species in two regions of Brazil.

The frog, Megaelosia bocainensis, was among seven total species — including four other declining species, and two that had disappeared locally for many years — that were detected. The findings appeared in a paper, “Lost and Found: Frogs in a Biodiversity Hotspot Rediscovered with Environmental DNA,” published in August in Molecular Ecology.

Megaelosia bocainensis. A disappeared species from Parque Nacional da Serra da Bocaina, Brazil, known only from this museum specimen collected in 1968, and detected by eDNA surveys. In the study, the researchers collected and screened environmental DNA (eDNA) in the biodiverse Atlantic Coastal Forest and Cerrado grasslands of Brazil.

The eDNA technique offers a way to survey that can confirm the presence of species undetected by traditional methods, providing a tool for conservation scientists to evaluate the presence of threatened species, especially those with low population densities and those not seen in years.

After careful research to identify species at various levels of threat in these regions of Brazil, the researchers used the eDNA method to search for 30 target amphibian species in six localities where the frogs were known to previously live.

“Little bits of DNA in the environment don’t tell us about how many individuals there are or whether those individuals are healthy, but it does tell us that the species is still present,” said senior author Kelly Zamudio, the Goldwin Smith Professor of Ecology and Evolutionary Biology in the College of Arts and Sciences.

“This is one more kind of survey data, and for species that are declining or locally disappeared, it not only means they are there, but there’s now the potential to study them in more detail,” she said, noting that for many species, very little is known.

Around the world, conservationists have been challenged to keep pace with declining and disappearing amphibians. At the same time, living organisms leave DNA traces in the soil, water and air. Now, scientists are increasingly using highly sensitive sampling techniques to detect eDNA for conservation purposes.

In the study, the researchers targeted 13 frog species that have totally disappeared and are presumed extinct; 12 frogs that have disappeared locally but are still found in other parts of their range; and five species that were once very abundant and are still there but hard to find.

The researchers hiked into the sampling sites carrying battery packs, a shoebox-sized peristaltic pump and backpacks of sterile tubing. They used the pump and tubing to draw up to 60 liters of stream or pond water through a capsule fitted with a filter for capturing DNA. A buffer was then applied to stabilize and preserve the DNA on the filter.

Back in the lab, the researchers extracted the DNA, genetically sequenced it, weeded out genetic material from humans, pigs, chickens and other organisms until they could isolate all the frog DNA.

“Now you’ve got a subset of genetic sequences that we know only belong to frogs, and then it’s step by step, going finer and finer, until you get to the genus and species you are looking for,” Zamudio said.

Identifying M. bocainensis required clever detective work: The species disappeared long ago, and there were no tissues from which to extract DNA for comparison with the eDNA. But the researchers did have the sequences for all the sister species in the genus Megaelosia and they knew the ranges of the sister species and M. bocainensis.

“We know there’s a Megaelosia there,” Zamudio said, “we just don’t know which one it is, but the only one that has ever been reported there historically is the one that went missing. Do we believe it? That’s how far the analysis can take us.”

Zamudio added that samples from nearby areas may be worth collecting for more signs of M. bocainensis.

Carla Martins Lopes, a researcher at São Paulo State University in Brazil, is the paper’s first author.

The Brazilian National Council for Scientific and Technological Development and the São Paulo Research Foundation funded the study.

Ancient Indian Triassic amphibians, new research


This 2016 video says about itself:

INDIAN METOPOSAURID AMPHIBIANS: MORPHOMETRY, TAXONOMY AND DISPERSAL

by Sanjukta Chakravorti

Recorded at XIV Annual Meeting of the European Association of Vertebrate Palaeontologists, Teylers Museum, Haarlem, Netherlands.

From the University of Bonn in Germany:

Fossil growth reveals insights into the climate

Researchers examined bones of the puzzling Panthasaurus maleriensis

September 8, 2020

Panthasaurus maleriensis lived about 225 million years ago in what is now India. It is an ancestor of today’s amphibians and has been considered the most puzzling representative of the Metoposauridae. Paleontologists from the universities of Bonn (Germany) and Opole (Poland) examined the fossil’s bone tissue and compared it with other representatives of the family also dating from the Triassic. They discovered phases of slower and faster growth in the bone, which apparently depended on the climate. The results have now been published in the journal PeerJ.

Temnospondyli belong to the ancestors of today’s amphibians. This group of animals became extinct about 120 million years ago in the Early Cretaceous. The Temnospondyli also include the Metoposauridae, a fossil group that lived exclusively in the Late Triassic about 225 million years ago. Remains of these ancestors are present on almost every continent. In Europe, they are found mainly in Poland, Portugal and also in southern Germany.

Panthasaurus maleriensis, the most puzzling representative of the Metoposauridae to date, lived in what is now India, near the town of Boyapally. “Until now, there were hardly any investigation opportunities because the fossils were very difficult to access,” explains Elzbieta Teschner from the University of Opole, who is working on her doctorate in paleontology in the research group of Prof. Dr. Martin Sander at the University of Bonn. Researchers from the Universities of Bonn and Opole, together with colleagues from the Indian Statistical Institute in Kolkata (India), have now examined the tissue of fossil bones of a metoposaur from the Southern Hemisphere for the first time. The amphibian, which resembled a crocodile, could grow up to three meters in length.

Valuable insight into the bone interior

“The investigated taxon is called Panthasaurus maleriensis and was found in the Maleri Formation in Central India,” notes Teschner with regard to the name. So far, the fossil has only been examined morphologically on the basis of its external shape. “Histology as the study of tissues, on the other hand, provides us with a valuable insight into the bone interior,” says Dr. Dorota Konietzko-Meier from the Institute for Geosciences at the University of Bonn. The histological findings can be used to draw conclusions about age, habitat and even climate during the animal’s lifetime.

The histological examinations revealed that the young animals had very rapid bone growth and that this growth decreased with age. The Indian site where the bones were found provides evidence of both young and adult animals, in contrast to Krasiejów (south-western Poland), where only young animals were found. Geological and geochemical data show that the Late Triassic consisted of alternating dry and rainy periods, as in the present monsoon climate of India. “This sequence is also reflected in the material examined,” says Teschner. “There are phases of rapid growth, known as zones, and a slowdown, known as annulus.” Normally, one can still observe stagnation lines in the bones, which develop during unfavorable phases of life, for example during very hot or very cold seasons.

In Panthasaurus maleriensis, however, growth never comes to a complete cessation. In comparison: the Polish Metoposaurus krasiejowensis shows the same alternation of zones and annuli in one life cycle and no stagnation lines, whereas the Moroccan representative of the metoposaurs Dutuitosaurus ouazzoui shows stagnation lines — that is, a complete stop in growth — in each life cycle.

The different growth phases in the bones allow for a comparison of climatic conditions. This means that the climate in the Late Triassic would have been milder in Central India than in Morocco, but not as mild as in the area that today belongs to Poland. Sander: “Fossil bones therefore offer a window into the prehistoric past.”

Burrowing frogs, new research


This 2019 video from India says about itself

Why a Burrowing Frog is called a burrowing frog? See this video. Indian Burrowing Frog (Sphaerotheca breviceps).

Burrowing frogs have digging implements on the side of their back feet. In the dry season, they dig down backwards into the sand in search of a moist spot where they can sleep until heavy rain awakens them from their slumber. A short burst of activity then follows. They climb up to the surface, feed and reproduce in monsoon before the dry season starts.

Taken at At BNHS Nature Reserve, BNHS Conservation Education (Cec Bnhs), Goregaon, Mumbai.

From the Florida Museum of Natural History in the USA:

How to get the upper body of a burrowing frog

September 1, 2020

You might think the buffest frogs would be high jumpers, but if you want shredded pecs, you should train like a burrowing frog. Though famously round, these diggers are the unsung bodybuilders of the frog world. We bring you tips from frog expert Rachel Keeffe, a doctoral student at the University of Florida, and physical therapist Penny Goldberg to help you get the burrowing body of your dreams.

But first, a caveat: According to Keeffe, no workout regimen can help you train your way into a highly specialized frog physique honed by 200 million years of evolution. To better understand burrowing frog anatomy, Keeffe and her adviser David Blackburn, Florida Museum of Natural History curator of herpetology, analyzed CT scans from all 54 frog families to show these frogs boast a robust and quirky skeleton that is more variable than previously thought.

“People think about frogs as being clean and smooth and slimy, or the classic ‘green frog on a lily pad,’ but a lot of them are dirty — they like to scoot around and be in the dirt,” Keeffe said. “Burrowing frogs are really diverse and can do a lot of cool things. And when you look at the skeletons of known burrowers, they’re very different from what you would call a ‘normal frog.'”

Burrowing frogs are found all over the world from deserts to swamps, but their underground lifestyle makes them difficult to study, Keeffe said. Most tunnel hind end-first with their back legs. But a few species are forward burrowers, using pointed snouts and powerful forelimbs bolstered by strong pectoral muscles to scrabble into the earth.

Keeffe’s sample of 89 frog species revealed radical differences in burrowing bone structure, from clavicles the size of eyelashes to other bones that are unusually thick.

“They’re so diverse that it’s challenging to think about even comparing them. It’s almost a black hole of work that we can do with forward burrowers because we tend to focus on the legs,” she said.

Some burrow to seek refuge, whether from arid temperatures or predators, and underground habitats can be hunting grounds or secluded hiding places. Other burrowing frogs can spend months at a time as deep as 3 feet belowground, surviving on a high-protein diet of termites and ants. The takeaway: If you want to compete for resources with the pros, don’t be afraid to put in the work.

Get the burly burrowing body

To train like a burrowing frog, Goldberg, assistant director of ReQuest Physical Therapy in Gainesville, recommended dedicating time to strengthening your upper back.

“In humans, the most important muscle group to focus on if you were to train like one of these frogs would be the scapular stabilizers,” she said. “These include 17 muscles, such as the lats and rotator cuff, with attachments all the way down to the pelvis that allow the upper back to generate power. To burrow like a forward burrower, you need to strengthen this entire region.”

One strengthening move Goldberg recommended is the “Prone W.” Lie facedown with elbows bent and palms on the floor. Squeeze your shoulder blades down and toward your spine as you lift your arms to the ceiling for a couple seconds at a time.

Like any elite athlete, burrowing frogs also maintain an optimal form. They’re often orb-shaped to improve their ability to hold water.

“Personally, if I were a sphere, I think it would be hard for me to dig, but it doesn’t seem to affect these frogs at all,” Keeffe said. “However, frogs with stumpy legs are definitely worse at jumping, and they tend to stagger when they walk.”

For these frogs, time away from the tunnels might be spent swimming instead, Keeffe said. To compete here, Goldberg recommends the breaststroke, adding that her top training tips for getting the upper back and pecs of a forward burrower would include pullups and pushups to develop the shoulder blade area.

“In my world, we would use resistance bands and pushing or pulling motions to train this area,” Goldberg said. “Anything focusing predominantly on building strength in the upper back region.”

If resistance bands are part of your workout routine, try grasping one with both hands and extending your arms while keeping your elbows straight. For best results, Goldberg recommended starting with three sets of 10.

Burrowing frogs might also hold key answers to gaps in scientists’ understanding of amphibian evolution at large. Keeffe’s analysis also found that forward-burrowing behavior evolved independently at least eight times in about one-fifth of frog families, and the trait’s persistence in the frog family tree suggests it’s a beneficial adaptation. Keeffe also found that forward burrowers tended to have a highly contoured humerus, the bone that connects the shoulder to the elbow in humans.

Understanding how bone shape relates to musculature can help scientists identify which frogs, both modern and extinct, are forward burrowers, a helpful tool given their covert behavior.

“Even though it can be frustrating, I like them because they’re secretive,” Keeffe said. “But the whole thing underlying this study is that frogs can do a lot of cool things — they don’t just jump and they’re not just green.”

CT scans were generated from the National Science Foundation-funded oVert project.

Triassic fossil amphibian and reptile, video


This 20 August 2020 video says about itself:

The Oddest Couple in the Fossil Record

To figure out how Thrinaxodon and Broomistega became entombed together, scientists looked at the burrow itself, along with their fossilized bones. And it looks like their luck ran out, when a behavior that usually would’ve helped them survive just didn’t work.

Thrinaxodon was a mammal-like reptile. Broomistega was an amphibian. They lived during the Triassic in South Africa.

Prehistoric amphibians, four or five fingers?


This 2016 video says about itself:

OSTEOHISTOLOGICAL AND COMPUTED FEA OF METOPOSAURUS KRASIEJOWENSIS SKULL BIOMECHANICS

By Kamil Gruntmejer

Recorded at XIV Annual Meeting of the European Association of Vertebrate Palaeontologists, Teylers Museum, Haarlem, Netherlands.

From the University of Bonn in Germany:

Fossil tracks: Wrong number of fingers leads down wrong track

July 24, 2020

Have you ever wondered why our hands have five fingers? And what about amphibians? They usually only have four. Until now it was assumed that this was already the case with the early ancestors of today’s frogs and salamanders, the Temnospondyli. However, a new find of the crocodile-like Temnospondyl Metoposaurus krasiejowensis from the late Triassic (about 225 million years old) in Poland shows five metacarpal bones and thus five fingers. As the researchers from the Universities of Bonn and Opole (Poland) note, this finding is very important, because until now, fossil animal tracks may have been wrongly assigned. The results have now been published in the Journal of Anatomy.

Modern amphibians usually have four fingers on the forelimb (and never more), which is called a “four-rayed hand,” as opposed to our five-rayed hand. Of all groups of terrestrial vertebrates, amphibians show the greatest variation in the number of frontfingers. Reptiles are the most conservative and usually have five. In birds, the finger bones in the wing have been lost completely. In mammals, the number of toes in the forelimb also varies greatly: Primates and raccoons have five, in horses only the third has survived, while in cattle and other even-toed ungulates fingers three and four remain. What they all have in common, however, is that this loss of toes or fingers originates from a five-ray pattern, which is why amphibians cannot be the ancestors of all these terrestrial vertebrate groups.

Exact number of toes is controversial

It has been known for some time that the earliest quadrupeds had significantly more fingers than five, such as Acanthostega, which had eight in the forelimb, or Ichthyostega with seven in the hind foot. As early as 300 million years ago, all but the five-fingered forms became extinct. The five-ray pattern was then retained in the real land animals, but was reduced again and again (see horses). The ancestors of today’s amphibians, the Temnospondyli, presented contradictory evidence of skeletons with four fingers, but also tracks that had five.

Temnospondyli is an important group of the early, very diverse quadrupeds. Some temnospondyls became as big as crocodiles, others were rather small. However, like all amphibians, they were dependent on water during their larval stage. Their most famous representatives include Eryops or Mastodonsaurus. “It’s also important to understand the evolution of modern amphibians, as this group probably evolved from the Temnospondyli,” says Dr. Dorota Konietzko-Meier from the Institute for Geosciences at the University of Bonn, who discovered and prepared the left forelimb of a Metoposaurus krasiejowensis in Krasiejów (southwest Poland).

However, despite the long history of research, the exact number of fingers in Metoposaurus and other temnospondyls is still controversial. “It’s remarkable that even in the case of the very well-researched Eryops, the skeletal reconstruction exhibited at the Muséum National d’Histoire Naturelle in Paris has five fingers, while only four fingers can be seen at the National Museum of Natural History in Washington,” says Ella Teschner, a doctoral student from Bonn and Opole. Lately, science has assumed that, similar to most modern amphibians, all Temnospondyli have only four toes in their forelimbs. This resulted in the five-toed footprints common in the Permian and Triassic periods being almost automatically assumed to not belong to Temnospondyli.

“The find from the famous Upper Triassic site Krasiejów in Poland therefore offers a new opportunity to study the architecture and development of the hand of the early quadrupeds,” says paleontologist Prof. Dr. Martin Sander from the University of Bonn. A considerably broader view of the entire group of Temnospondyli did not show a clear trend with regard to the five-ray pattern and suggested that the number of digits was not as limited in the phylogenetic context as was assumed. “Evidently, the temnospondyls were already experimenting with the four-ray pattern, and the five-ray pattern died out before the emergence of modern amphibians,” adds Sander.

Five fingers on each hand?

“Even if the ossification of five metacarpal bones described here was only a pathology, it still shows that a five-ray pattern was possible in Temnospondyli,” says Konietzko-Meier. However, it could not be assumed with certainty that the reduction in the number of fingers/digits from five to four always affected the fifth place on the hand in these fossil taxa. The possibility that some of the four-fingered taxa were caused by the loss of the first ray cannot be excluded. Sander: “The new finding of a five-fingered hand is particularly important for the interpretation of tracks, as it shows that a five-fingered forefoot print could also belong to the Temnospondyli and thus indicate a considerably wider distribution area of these animals.”

These results are also of general importance, since limb development plays an important role in evolutionary biology and medicine, and fossils may therefore provide important information for the evaluation of theories of hand development.

Beelzebufo, big dinosaur age Madagascar frog


This 22 July 2020 video says about itself:

Untangling the origins of Beelzebufo — the giant frog that lived alongside the dinosaurs — turns out to be one of the most bedeviling problems in the history of amphibians.

Triassic era catastrophes and wildlife


This 18 June 2020 video from the USA says about itself:

Big Amphibians of the Chinle Formation!

Dinosaur Journey Re-Opens today! And to celebrate we wanted to share a video of Dr. Julia McHugh talking amphibians. Ever noticed the large red rock base of Independence Monument?! Well, that’s the Triassic age rock these amazing creatures were discovered. WATCH now to learn more!

From the University of Texas at Austin in the USA:

Arizona rock core sheds light on Triassic dark ages

July 20, 2020

A rock core from Petrified Forest National Park, Arizona, has given scientists a powerful new tool to understand how catastrophic events shaped Earth’s ecosystems before the rise of the dinosaurs.

The quarter-mile core is from an important part of the Triassic Period when life on Earth endured a series of cataclysmic events: Our planet was struck at least three times by mountain-sized asteroids, chains of volcanoes erupted to choke the sky with greenhouse gases, and tectonic movement tore apart Earth’s single supercontinent, Pangea.

Among the chaos, many plants and animals, including some of the long-snouted and armored reptiles that ruled Pangea throughout the Triassic, vanished in a possible shake-up of life on Earth that scientists have yet to explain.

The study, published July 20 in GSA Bulletin, offers scientists a foundation to explain the changes in the fossil record and determine how these events may have shaped life on Earth.

By determining the age of the rock core, researchers were able to piece together a continuous, unbroken stretch of Earth’s history from 225 million to 209 million years ago. The timeline offers insight into what has been a geologic dark age and will help scientists investigate abrupt environmental changes from the peak of the Late Triassic and how they affected the plants and animals of the time.

“The core lets us wind the clock back 225 million years when Petrified Forest National Park was a tropical hothouse populated by crocodile-like reptiles and turkey-size early dinosaurs,” said Cornelia Rasmussen, a postdoctoral researcher at the University of Texas Institute for Geophysics (UTIG), who led the analysis that determined the age of the core.

“We can now begin to interpret changes in the fossil record, such as whether changes in the plant and animal world at the time were caused by an asteroid impact or rather by slow geographic changes of the supercontinent drifting apart,” she said.

Petrified Forest National Park’s paleontologist Adam Marsh said that despite a rich collection of fossils from the period in North America, until now there was little information on the Late Triassic’s timeline because most of what scientists knew came from studying outcrops of exposed rock pushed to the surface by tectonic movements.

“Outcrops are like broken pieces of a puzzle,” said Marsh, who earned his Ph.D. from The University of Texas at Austin’s Jackson School of Geosciences. “It is incredibly difficult to piece together a continuous timeline from their exposed and weathered faces.”

Marsh was not an author of the study but is part of the larger scientific coring project. UTIG is a unit of the Jackson School.

The Petrified Forest National Park core overcomes the broken puzzle problem by recovering every layer in the order it was deposited. Like tree rings, scientists can then match those layers with the fossil and climate record.

To find the age of each layer, the researchers searched the rock core for tiny crystals of the mineral zircon, which are spewed into the sky during volcanic eruptions. Zircons are a date stamp for the sediments with which they are buried. Researchers then compared the age of the crystals with traces of ancient magnetism stored in the rocks to help develop a precise geologic timeline.

Geoscience is rarely so simple, however, and according to Rasmussen, the analysis of the core gave them two slightly different stories. One shows evidence that a shake-up in the species might not be connected to any single catastrophic event and could simply be part of the ordinary course of gradual evolution. The other shows a possible correlation between the change in the fossil record and a powerful asteroid impact, which left behind a crater in Canada over 62 miles wide.

For Marsh, the different findings are just part of the process to reach the truth.

“The two age models are not problematic and will help guide future studies,” he said.

The research is the latest outcome of the Colorado Plateau Coring Project. The research and the coring project were funded by the National Science Foundation and International Continental Drilling Program.

Crested newts DNA research


This 30 June 2020 video from the Netherlands says about itself:

Some newts have a genetic malfunction that causes half of the eggs to cease. How is that possible? Manon de Visser is investigating this at Naturalis and the University of Leiden (Wielstra lab) and tells you everything about it in her first DNA talk!

Caecilian amphibians’ snake-like venom, new discovery


This 2017 video says about itself:

On this episode of Breaking Trail, Coyote discovers the most bizarre creature he’s ever found, a Caecilian!

Wait a what?! A Caecilian, while at first glance looks exactly like a giant earthworm, is actually an amphibian more closely related to salamanders. It’s definitely NOT a worm.

These subterranean crawlies live in the loose soils and substrates all over the world. They are very elusive and almost never seen by humans, so even though the rain forced the camera crew to take shelter Coyote just had to share this amazing encounter with the Coyote Pack!

Get ready to see one of the rarest creatures we will ever show you!

From ScienceDaily:

First evidence of snake-like venom glands found in amphibians

July 3, 2020

Caecilians are limbless amphibians that, to the untrained eye, can be easily mistaken for snakes. Though caecilians are only distantly related to their reptilian cousins, researchers in a study appearing July 3 in the journal iScience describe specialized glands found along the teeth of the ringed caecilian (Siphonops annulatus), which have the same biological origin and possibly similar function to the venom glands of snakes. If further research can confirm that the glands contain venom, caecilians may represent the oldest land-dwelling vertebrate animal with oral venom glands.

Caecilians are peculiar creatures, being nearly blind and using a combination of facial tentacles and slime to navigate their underground tunnels. “These animals produce two types of secretions — one is found mostly in the tail that is poisonous, while the head produces a mucus to help with crawling through the earth,” says senior author Carlos Jared, a biologist and Director of the Structural Biology Lab at the Butantan Institute in São Paulo. “Because caecilians are one of the least-studied vertebrates, their biology is a black box full of surprises.”

“It is while examining the mucous glands of the ringed caecilian that I stumbled upon a never before described set of glands closer to the teeth,” says first author Pedro Luiz Mailho-Fontana, a post-doctoral student in the Structural Biology Lab at the Butantan Institute.

What Mailho-Fontana found were a series of small fluid-filled glands in the upper and lower jaw, with long ducts that opened at the base of each tooth. Using embryonic analysis, he found that these oral glands originated from a different tissue than the slime and poison glands found in the caecilian’s skin. “The poisonous skin glands of the ringed caecilian form from the epidermis, but these oral glands develop from the dental tissue, and this is the same developmental origin we find in the venom glands of reptiles,” says Mailho-Fontana. This marks the first time glands of this kind have been found in an amphibian.

Researchers suspect that the ringed caecilian may use the secretions from these snake-like oral glands to incapacitate its prey. “Since caecilians have no arms or legs, the mouth is the only tool they have to hunt,” says co-author Marta Maria Antoniazzi, an evolutionary biologist at the Butantan Institute. “We believe they activate their oral glands the moment they bite down, and specialized biomolecules are incorporated into their secretions.

A preliminary chemical analysis of the oral gland secretions of the ringed caecilian found high activity of phospholipase A2, a common protein found in the toxins of venomous animals. “The phospholipase A2 protein is uncommon in non-venomous species, but we do find it in the venom of bees, wasps, and many kinds of reptiles,” says Mailho-Fontana. In fact, the biological activity of phospholipase A2 found in the ringed caecilian was higher than what is found in some rattlesnakes. Still, more biochemical analysis is needed to confirm whether the glandular secretions are toxic.

If future work can verify the secretions are toxic, caecilian oral glands could indicate an early evolutionary design of oral venom organs. “Unlike snakes which have few glands with a large bank of venom, the ringed caecilian has many small glands with minor amounts of fluid. Perhaps caecilians represent a more primitive form of venom gland evolution. Snakes appeared in the Cretaceous probably 100 million years ago, but caecilians are far older, being roughly 250 million years old,” Jared says.

Very few groups of land-dwelling vertebrates have serpent-like bodies, and this research suggests there might be a connection between a limbless body plan and the evolution of a venomous bite. “For snakes and caecilians, the head is the sole unit to explore the environment, to fight, to eat, and to kill,” says Antoniazzi. “One theory is that perhaps these necessities encourage the evolution of venom in limbless animals.”