Dinosaur age snake discovery


This 22 November 2019 video says about itself:

On very rare occasions, an exceptional fossil is unearthed that provides an extraordinary glimpse into the evolution of a group of organisms.

This time, it is the beautifully preserved skull of an ancient snake with rear limbs, Najash rionegrina. Our study of this fossil has been published in the journal Science Advances.

This and other new fossils help answer longstanding questions on the origins of snakes, such as how they lost their limbs and evolved their highly specialized skulls.

Fossil history

Najash rionegrina is named after the legged biblical snake Nahash (Hebrew for snake), and the Río Negro Province in Argentina, where the fossils were discovered. Fossils of Najash are about 95 million years old, and were first described in Nature from a fragmentary skull and partial body skeleton that preserved robust rear limbs.

This rear-limbed fossil snake garnered a great deal of media interest as it followed earlier reports of fossil marine snakes with rear limbs. What made Najash unique was that it was a terrestrial snake living in a desert, not an aquatic snake living in the ocean. In addition, the fossils were not compressed flat by the weight of overlying sediments, and so they were preserved in three dimensions, unlike the fossil marine snakes.

Unfortunately, that first description of Najash relied on a very fragmentary skull. Scholars of snake evolution were left to guess at what the head of these ancient animals might have looked like.

We know from their shared anatomy that snakes evolved from lizards. We also know that the skulls of snakes have been key to their successful and highly specialized feeding adaptations. New Najash fossil skulls would be highly informative on the pattern of snake skull evolution.

The new discovery

It was a hot day in February of 2013 when Fernando Garberoglio, then an undergraduate palaeontology student from the Universidad de Buenos Aires, went on his first field trip to the La Buitrera Paleontological Area in northern Patagonia, Argentina. With him were two palaeontologists: Sebastián Apesteguía, from the Universidad Maimónides, and Guillermo Rougier, from the University of Louisville.

Looking for fossil vertebrates is an act of patient, painstaking discovery. It requires you to be close to the ground, scanning the grit, pebbles, rocks and sediments for a sign of bone. You must pick up each piece, inspect it closely, put it down and then repeat, hour after hour. At La Buitrera, you are scorched by the hot sun, pelted by driving rain and frozen by chilly Andean winds.

But it’s all worth it. Particularly when, as happened to Garberoglio, he finally picked up a pebble, only a few centimetres long, to find a small, ancient, bony face staring back at him.

From the University of Alberta in Canada:

An ancient snake’s cheekbone sheds light on evolution of modern snake skulls

100-million-year old legged snake fossil provides critical insight into how the heads of modern snakes evolved

November 20, 2019

New research from a collaboration between Argentinian and University of Alberta palaeontologists adds a new piece to the puzzle of snake evolution.

The researchers examined a strikingly well-preserved fossil of the rear-limbed snake Najash rionegrina, found in Argentina. The study shows that nearly 100 million years ago, these legged snakes still had a cheekbone — also known as a jugal bone — that has all but disappeared in their modern descendants.

“Our findings support the idea that the ancestors of modern snakes were big-bodied and big-mouthed — instead of small burrowing forms as previously thought,” explained Fernando Garberoglio, from the Fundación Azara at Universidad Maimónides, in Buenos Aires, Argentina and lead author on the study. “The study also reveals that early snakes retained their hindlimbs for an extended period of time before the origin of modern snakes which are for the most part, completely limbless.”

For decades, paleontologists’ understanding of snake evolution was hampered by the limited fossil record. The new fossils presented in this study are crucial for reconstructing the early steps in the evolutionary history of modern snakes.

“This research revolutionizes our understanding of the jugal bone in snake and non-snake lizards,” said Michael Caldwell, professor in the Department of Biological Sciences and Earth and Atmospheric Sciences, and a co-author on the study. “After 160 years of getting it wrong, this paper corrects this very important feature based not on guesswork, but on empirical evidence.”

The nearly 100 million-year-old fossil snakes described in this study, found in Northern Patagonia, are closely related to an ancient lineage of snakes that populated the southern hemisphere continents of Gondwana, and appear to be related to only a small number of obscure, modern snakes. The researchers used micro-computed tomography (micro-CT) scanning to visualize the skull structures within the specimen, examining the pathways of nerves and blood vessels as well as the skeletal structure that would be otherwise impossible to see without damaging the fossil.

“This research is critical to understanding the evolution of the skulls of modern and ancient snakes,” added Caldwell.

New Caledonian snorkeling grandmothers discover sea snakes


This sea snake video says about itself:

Filmed 1991 on various places of the Great Barrier Reef, Australia.

Adults of most species grow to between 120-150 cm (4-5 ft) in length with the largest, Hydrophis spiralis, reaching a maximum of 3 m. The lung has become very large and extends almost the entire length of the body. They can remain submerged for as much as a few hours. Most sea snake species prey on fish, especially eels. The majority of sea snakes are highly venomous. If bitten cardiac arrest can occur after 6-12 hours. All music by Smartsound royalty-free music.

From Macquarie University in Australia:

Underwater grandmothers reveal big population of lethal sea snakes

A novel citizen science project in New Caledonia finds an ‘astonishing’ number of venomous reptiles in a popular swimming spot.

October 23, 2019

A group of snorkelling grandmothers is helping scientists better understand marine ecology by photographing venomous sea snakes in waters off the city of Noumea, New Caledonia.

Two years ago the seven women, all in their 60s and 70s, who call themselves “the fantastic grandmothers”, offered to help scientists Dr Claire Goiran from the University of New Caledonia and Professor Rick Shine from Australia’s Macquarie University in their quest to document the sea snake population in a popular swimming spot known as Baie des citrons.

For 15 years Dr Goiran and Professor Shine had been documenting the presence of a small harmless species, known as the turtle-headed sea snake (Emydocephalus annulatus). In the first eight years of the project, they also glimpsed — just six times — another species, the 1.5 metre-long, venomous greater sea snake (Hydrophis major).

From 2013 the pair decided to look more closely for this much larger and much more robust snake, but over the ensuing 36 months saw just 10 every year.

Enter the Fantastic Grandmothers, who were fond of snorkelling recreationally in the Baie des citrons and proposed a citizen science project. Armed with cameras, for the past couple of years the women have been venturing underwater and getting up close and personal with the potentially lethal reptiles.

“The results have been astonishing,” says Dr Goiran.

“As soon as the grandmothers set to work, we realised that we had massively underestimated the abundance of greater sea snakes in the bay.”

Greater sea snakes have distinctive markings, allowing individuals to be easily identified from photographs. In a paper just published in the journal Ecosphere the scientists reveal that thanks to the diving grannies they now know that there are more than 249 of the snakes in the single bay.

The photography project has also revealed crucial new information about the snakes’ breeding patterns, and numbers of young — more information, says Dr Goiran, than for any other related species, worldwide.

“Remarkably,” says Professor Shine, “they found a large number of lethally toxic sea snakes in a small bay that is occupied every day by hordes of local residents and cruise-ship passengers — yet no bites by the species have ever been recorded at Baie des citrons, testifying to their benevolent disposition.”

Dr Goiran is full of praise for the elderly women who happily volunteered to take part in what became a very notable citizen science project.

“I have been studying sea snakes in the Baie des Citrons for 20 years, and thought I understood them very well — but the Fantastic Grandmothers have shown me just how wrong I was,” she says.

“The incredible energy of the Grandmothers, and their intimate familiarity with ‘my’ study area, have transformed our understanding of the abundance and ecology of marine snakes in this system. It’s a great pleasure and privilege to work with them.”

African toad pretends to be a snake


This 21 October 2019 video says about itself:

It is well known that some harmless animals mimic dangerous animals to ward off predators.

Eg, the Brazilian galliwasp lizard poses like a toxic millipede. And the zebra shark can mimic a highly poisonous banded sea snake.

Such posing is called Batesian mimicry. But the Congolese giant toad takes Batesian mimicry to a new level. According to a paper in the Journal of Natural History, the toad not only transform into a very good copy of a Gaboon Viper. It also tries to mimic the hiss the deadly snake make before an attack. The toad also postures so that its front limbs aren’t visible — making it look more snake-like. The Congolese giant toad are found in locations inhabited by the Gaboon viper. The Gaboon viper has the longest fangs and carries the most venom.

From ScienceDaily:

Toad disguises itself as deadly viper to avoid attack

Decades of fieldwork uncover hissing and strike-warning impersonations by toad

October 21, 2019

The first study of a toad mimicking a venomous snake reveals that it likely imitates one of Africa’s largest vipers in both appearance and behaviour, according to results published in the Journal of Natural History.

The Congolese giant toad, a triple cheeseburger-sized prize for any predator, may use its ability to mimic the highly venomous Gaboon viper to escape being eaten. The viper has the longest snake fangs in the world and produces more venom than any other snake.

“Our study is based on ten years of fieldwork and on direct observation by researchers lucky enough to see the toad’s behaviour first-hand. We’re convinced that this is an example of Batesian mimicry, where a harmless species avoids predators by pretending to be a dangerous or toxic one,” says Dr Eli Greenbaum from the University of Texas at El Paso. “To fully test our hypothesis, we’d have to demonstrate that predators are successfully duped, but this would be very difficult in the wild, where the toads are only encountered rarely. However, based on multiple sources of evidence provided in our study, we are confident that our mimicry hypothesis is well-supported.”

The researchers made comparisons between the appearance of the toad, found in central African rainforests, and the viper, which is more widespread in central, eastern and southern Africa. Using live wild-caught and captive specimens, as well as preserved museum ones, they found that the colour pattern and shape of the toad’s body is similar to that of the viper’s head. Most striking are two dark brown spots and a dark brown stripe that extends down the toad’s back, the triangular shape of the body, a sharp demarcation between the tan back and dark brown flanks, and the species’ extraordinarily smooth skin for a toad. Because the Gaboon viper is capable of causing deadly bites, would-be predators likely avoid the similar-looking toads to ensure they don’t make a lethal mistake.

Some mimics are exclusively visual, but for the Congolese giant toad, getting the look right is only part of the impersonation. If a Gaboon viper feels threatened, it will often incline its head and emit a long, loud warning hiss before it actually makes a strike. Similarly, Congolese herpetologist Chifundera Kusamba observed the toad emitting a hissing noise resembling the sound of air being slowly released from a balloon. Over a century ago, American biologist James Chapin observed a bow display by the toad, where the front limbs no longer prop up the viperine-shaped body, which looks similar to the cocked head of a snake threatening to strike.

The final part of the impersonation is getting the location right. Even the best impression will only work if predators of the harmless species are familiar with the venomous one. The researchers compared the geographical range of the toad and viper in the Democratic Republic of Congo (DRC) and found that the Congolese giant toad does not seem to occur in areas where the Gaboon viper is absent. The researchers identified 11 locations in the eastern rainforests where the range of both species overlaps.

Based on speciation dating estimates from genetic data, the Congolese giant toad and Gaboon viper first evolved at about the same time in the early Pliocene about 4-5 million years ago. Considered with their similar appearance, behaviour, and overlapping geographic distribution, the toads and vipers likely coevolved together, further supporting the mimicry hypothesis.

“Given the relatively large size and therefore calorific value of this toad compared to other species, it would make tempting prey to a large variety of generalist predators, including primates and other mammals, lizards, snakes and birds,” says Kusamba, from the Centre de Recherche en Sciences Naturelles, DRC. “Many of these predators use vision to find their prey, and because the viper is deadly venomous, they probably recognise the distinctive, contrasting markings from a considerable distance and avoid the toad because of them, receiving a threatening hiss if the appearance doesn’t put them off.”

Perhaps the best-known examples of Batesian mimicry are in butterflies, where around a quarter of over 200 Papilio swallowtail butterfly species are non-toxic impersonators of toxic ones. Other examples from the animal kingdom include comet fish that fool predators into thinking their tail is a moray eel‘s head, the Brazilian galliwasp lizard that mimics a toxic millipede, and zebra sharks that take on the coloration and undulating movements of venomous sea snakes. Many harmless snakes mimic venomous ones, and some caterpillars, legless lizards, and even birds are able to do so. However, the current study is the first to identify an amphibian mimicking a venomous snake.

Snakes in Uganda, video


This 2019 video says about itself:

In a new documentary by Living Zoology film studio, you will see fascinating footage of venomous snakes and know more about the export of snakes from Africa. Matej Dolinay and his wife Zuzana Dolinay visited Uganda in the quest to find some of the most beautiful venomous snakes in the world – Gaboon vipers, rhinoceros vipers, bush vipers (Atheris squamigera and Atheris hispida), Jameson’s mambas and forest cobras. They also found the hybrid between Gaboon and rhinoceros viper – gabino viper.

Top Ten of most beautiful snakes


This 2017 video says about itself:

10 Most Beautiful Snakes In The World

When it comes to snakes, most people would actually think of scary venomous animals. While some snakes are venomous, some are actually quite harmless to humans.

Despite their venomous / non-venomous properties, some snakes are actually really beautiful. In this video, we are going to look at 10 most beautiful / pretty / prettiest / gorgeous / wonderful looking snake species in the world.

These snake species include Asian vine snake, blue racer, eastern coral snake, green tree python, iridescent shieldtail, red-headed krait, Formosan odd-scaled snake, Honduran milk snake, Brazilian rainbow boa and San Francisco garter snake.

New snake species discovery in Eurasia


An individual of the new rat sake species, Elaphe urartica, from Armenia. Credit: Boris Tuniyev

From PeerJ:

New snake species in Europe named after a long-forgotten Iron Age kingdom

May 28, 2019

An international team of scientists identified the snake and its range, which includes Turkey, Azerbaijan, Armenia, Georgia, Iraq, Iran, and Russia including a small region extending into the corner of Europe. Based on the genetic and morphological data, the researchers were able to say that the Blotched Rat Snake (Elaphe sauromates) actually comprises two different species and includes a cryptic species — dubbed Elaphe urartica — that has been named after the old kingdom of Urartu.

The kingdom, forgotten for over a thousand years, flourished between the 9th and 6th centuries BCE in the region of today’s Armenian Highlands, centered around Lake Van in Turkey, where this new snake species occurs. The name was chosen out of respect for the original scientific name of the Blotched Rat Snake proposed by the famous Prussian natural historian of the 19th century, Peter Simon Pallas.

The name Elaphe sauromates refers to Sarmatians, a confederation of nomadic peoples who inhabited vast areas of the recent range of the Blotched Rat Snake between the 5th century BCE and 4th century CE. According to Daniel Jablonski and David Jandzik, lead scientists of the project from the Comenius University in Bratislava, Slovakia, these snakes are very rarely observed in the field and are mostly distributed in geopolitically complicated regions. As a result, the material for their study was collected for over 17 years and required a broad international collaboration.

The new snake species is a member of large-bodied snakes of an iconic genus Elaphe, which is very popular with snake hobbyists. The discovery and analysis of the biogeographical history of this new snake fills in an important piece of the Eurasian biota evolutionary puzzle.