This 30 January 2020 video says about itself:
“Dino-mite” invention: Lily Wilder, 4, finds 215-million-year-old ‘two-footed’ dinosaur footprint
Read more here.
This 30 January 2020 video says about itself:
“Dino-mite” invention: Lily Wilder, 4, finds 215-million-year-old ‘two-footed’ dinosaur footprint
Read more here.
This 22 December 2020 video says about itself
The Triassic Reptile With “Two Faces”
Figuring out what this creature’s face actually looked like would take paleontologists years. But understanding this weird animal can help us shine a light on at least one way for ecosystems to bounce back from even the worst mass extinction.
From Virginia Tech university in the USA:
New species of ancient cynodont, 220 million years old, discovered
November 4, 2020
Fossilized jaw bone fragments of a rat-like creature found at the Petrified Forest National Park in Arizona last year by a Virginia Tech College of Science Ph.D. candidate are in fact a newly discovered 220-million-year-old species of cynodont or stem-mammal, a precursor of modern-day mammals.
“This discovery sheds light on the geography and environment during the early evolution of mammals,” Kligman said. “It also adds to evidence that humid climates played an important role in the early evolution of mammals and their closest relatives. Kataigidodon was living alongside dinosauromorphs and possibly early dinosaurs related to Coelophysis — a small bipedal predator — and Kataigidodon was possibly prey of these early dinosaurs and other predators like crocodylomorphs, small coyote-like quadrupedal predators related to living crocodiles.”
Kligman added that finding a fossil that is part of Cynodontia, which includes close cousins of mammals, such as Kataigidodon, as well as true mammals, from Triassic rocks is an extremely rare event in North America. Prior to Kligman’s discovery, the only other unambiguous cynodont fossil from the Late Triassic of western North America was the 1990 discovery of a braincase of Adelobasileus cromptoni in Texas. Note that 220 million years ago, modern-day Arizona and Texas were located close to the equator, near the center of the supercontinent Pangaea. Kataigidodon would have been living in a lush tropical forest ecosystem.
Kligman made the discovery while working as a seasonal paleontologist at Petrified Forest National Park in 2019. The two fossil lower jaws of Kataigidodon were found in the Upper Triassic Chinle Formation. Because only the lower jaws were discovered and are quite small — half an inch, the size of a medium grain of rice — Kligman only has a semi-picture of how the creature looked, roughly 3.5 inches in total body size, minus the tail.
Along with the jawbone fossils, Kligman found incisor, canine, and complex-postcanine teeth, similar to modern day mammals. Given the pointed shape of its teeth and small body size, it likely fed on a diet of insects, Kligman added. (Why are jaw fossils commonly found, even among small specimens? According to Kligman, the fossil record is “biased” toward only preserving the largest and most robust bones in a skeleton. The other smaller or more fragile bones — ribs, arms, feet — disappear.)
Kligman carried out fieldwork, specimen preparation, CT scanning, conception, and design of the study and drafting of the manuscript. He added that he and his collaborators only discovered the fossils were of a new species after reviewing the CT scan dataset of the jaws and comparing it to other related species.
“It likely would have looked like a small rat or mouse. If you were to see it in person you would think it is a mammal,” Kligman added. Does it have fur? Kligman and the researchers he worked with to identify and name the creature actually don’t know. “Triassic cynodonts have not been found from geological settings which could preserve fur if it was there, but later nonmammalian cynodonts from the Jurassic had fur, so scientists assume that Triassic ones did also.”
The name Kataigidodon venetus derives from the Greek words for thunderstorm, “kataigidos,” and tooth, “odon,” and the Latin word for blue, “venetus,” all referring to the discovery location of Thunderstorm Ridge, and the blue color of the rocks at this site. Kligman didn’t name the creature, though. That task fell to Hans Dieter-Sues, coauthor and curator of vertebrate paleontology at the Smithsonian National Museum.
Additional collaborators include Adam Marsh, park paleontologist at Petrified Forest National Park, who found the jaw fossils with Kligman, and Christian Sidor, an associate professor at the University of Washington’s Department of Biology. The research was funded by the Petrified Forest Museum Association, the Friends of Petrified Forest National Park, and the Virginia Tech Department of Geosciences.
“This study exemplifies the idea that what we collect determines what we can say,” said Michelle Stocker, an assistant professor of geosciences and Kligman’s doctoral advisor. “Our hypotheses and interpretations of past life on Earth depend on the actual fossil materials that we have, and if our search images for finding fossils only focuses on large-bodied animals, we will miss those important small specimens that are key for understanding the diversification of many groups.”
With Kataigidodon being only the second other unambiguous cynodont fossil from the Late Triassic found in western North America, could there be more new species out there waiting to be found?
Kligman said most likely. “We have preliminary evidence that more species of cynodonts are present in the same site as Kataigidodon, but we are hoping to find better fossils of them,” he added.
This video is called Newly discovered Triassic lizard could float underwater to pick off prey 2020 10 28.
Ancient marine predator had a built-in float
New 240 million-year-old species uncovered in China
October 28, 2020
About 240 million years ago, when reptiles ruled the ocean, a small lizard-like predator floated near the bottom of the edges in shallow water, picking off prey with fang-like teeth. A short and flat tail, used for balance, helps identify it as a new species, according to research published in the Journal of Vertebrate Paleontology.
Paleontologists at the Chinese Academy of Scientists and Canadian Museum of Nature have analysed two skeletons from a thin layer of limestone in two quarries in southwest China. They identified the skeletons as nothosaurs, Triassic marine reptiles with a small head, fangs, flipper-like limbs, a long neck, and normally an even longer tail, probably used for propulsion. However, in the new species, the tail is short and flat.
“Our analysis of two well-preserved skeletons reveals a reptile with a broad, pachyostotic body (denser boned) and a very short, flattened tail. A long tail can be used to flick through the water, generating thrust, but the new species we’ve identified was probably better suited to hanging out near the bottom in shallow sea, using its short, flattened tail for balance, like an underwater float, allowing it to preserve energy while searching for prey,” says Dr Qing-Hua Shang from the Chinese Academy of Sciences, in Beijing.
The scientists have named the new species Brevicaudosaurus jiyangshanensis, from the Latin ‘brevi’ for ‘short,’ ‘caudo’ for ‘tail,’ and the Greek ‘sauros’ for ‘lizard.’ The most complete skeleton of the two was found in Jiyangshan quarry, giving the specimen its species name. It’s just under 60cm long.
The skeleton gives further clues to its lifestyle. The forelimbs are more strongly developed than the hind limbs, suggesting they played a role in helping the reptile to swim. However, the bones in the front feet are short compared to other species, limiting the power with which it could pull through the water. Most of its bones, including the vertebrae and ribs, are thick and dense, further contributing to the stocky, stout appearance of the reptile, and limiting its ability to swim quickly but increasing stability underwater.
However, thick, high-mass bones act as ballast. What the reptile lost in speed, it gained in stability. Dense bones, known as pachyostosis, may have made it neutrally buoyant in shallow water. Together with the flat tail, this would have helped the predator to float motionless underwater, requiring little energy to stay horizontal. Neutral buoyancy should also have enabled it to walk on the seabed searching for slow-moving prey.
Highly dense ribs may also suggest the reptile had large lungs. As suggested by the lack of firm support of the body weight, nothosaurs were oceanic nut they needed to come to the water surface for oxygen. They have nostrils on the snout through which they breathed. Large lungs would have increased the time the species could spend underwater.
The new species features a bar-shaped bone in the middle ear called the stapes, used for sound transmission. The stapes was generally lost in other nothosaurs or marine reptiles during preservation. Scientists had predicted that if a stapes was found in a nothosaur, it would be thin and slender like in other species of this branch of the reptilian family tree. However, in B. jiyangshanensis it is thick and elongate, suggesting it had good hearing underwater.
“Perhaps this small, slow-swimming marine reptile had to be vigilant for large predators as it floated in the shallows, as well as being a predator itself,” says co-author Dr. Xiao-Chun Wu from the Canadian Museum of Nature.
From Uppsala University in Sweden:
A tiny jaw from Greenland sheds light on the origin of complex teeth
October 13, 2020
A team of scientists led from Uppsala University have described the earliest known example of dentary bone with two rows of cusps on molars and double-rooted teeth. The new findings offer insight into mammal tooth evolution, particularly the development of double-rooted teeth. The results are published in the scientific journal PNAS.
The first mammals originated in the latest Triassic period, around 205 million years ago. An ancestor to mammals were the therapsids, “mammal-like reptiles” referred to as stem mammals or proto-mammals, which originated about 320-300 million years ago. One unique characteristic of the lineage that included mammals and animals related to mammals (synapsids) was that they developed complex occlusion. Close ancestors to mammals, called mammaliaforms, developed rows of cusps on molar-like teeth adapted for more omnivorous feeding. The origin of this multicusped pattern and double-rooted tooth has thus far remained unclear.
A team of scientists led by Grzegorz Niedzwiedzki from Uppsala University have investigated the jaw anatomy and tooth structure of a recently described new mammaliaform species named Kalaallitkigun jenkinsi. It was discovered on the eastern coast of Greenland and was a very small, shrew-like animal, probably covered with fur. It would have been the size of a large mouse and lived during the Late Triassic, around 215 million years ago.
“I knew it was important from the moment I took this 20 mm specimen off the ground,” says Niedzwiedzki, researcher at Uppsala University and the corresponding author of the publication.
Kalaallitkigun jenkinsi exhibits the earliest known dentary with two rows of cusps on molars and double-rooted teeth. The anatomical features place Kalaallitkigun jenkinsi as an intermediate between the mammals and the insectivorous morganucodontans, another type of mammaliaform.
The researchers believe that the structural changes in the teeth are related to changed feeding habits. In this case study, the animals were switching to a more omnivorous/herbivorous diet and the tooth crown was expanding laterally. Broader teeth with “basins” on the top surface are better for grinding food. This development also forced changes in the structure of the base of the tooth.
The biomechanical analysis that was carried out within the study found that multi-rooted teeth are better able to withstand mechanical stresses, including those of upper and lower tooth contact during biting, compared to single-rooted teeth. Human teeth, for instance, have this characteristic. The results suggest that the development of molar-like teeth with complex crowns may have developed together with biomechanically optimised dual roots.
“The early evolution of mammals is a particularly interesting topic in evolutionary studies. This tiny jaw from Greenland shows us how complex mammalian teeth arose and why they appeared,” says Niedzwiedzki.
“Our discovery of the oldest mammalian ancestor with double-rooted molars shows how important the role of teeth was in the origin of mammals. I had this idea to look at the biomechanics and the collaboration with the engineers turned out great,” says Tomasz Sulej, researcher at the Polish Academy of Sciences, first author of the publication.
“It seems that the fossils of close mammalian ancestors must be looked for in even older rocks,” says Sulej.
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.”
This BBC video is called Walking with Monsters – “Lystrosaurus“.
From the University of Washington in the USA:
Fossil evidence of ‘hibernation-like’ state in 250-million-year-old Antarctic animal
August 27, 2020
Summary: Scientists report evidence of a hibernation-like state in Lystrosaurus, an animal that lived in Antarctica during the Early Triassic, some 250 million years ago. The fossils are the oldest evidence of a hibernation-like state in a vertebrate, and indicate that torpor — a general term for hibernation and similar states in which animals temporarily lower their metabolic rate to get through a tough season — arose in vertebrates even before mammals and dinosaurs evolved.
Hibernation is a familiar feature on Earth today. Many animals — especially those that live close to or within polar regions — hibernate to get through the tough winter months when food is scarce, temperatures drop and days are dark.
According to new research, this type of adaptation has a long history. In a paper published Aug. 27 in the journal Communications Biology, scientists at the University of Washington and its Burke Museum of Natural History and Culture report evidence of a hibernation-like state in an animal that lived in Antarctica during the Early Triassic, some 250 million years ago.
The creature, a member of the genus Lystrosaurus, was a distant relative of mammals. Antarctica during Lystrosaurus’ time lay largely within the Antarctic Circle, like today, and experienced extended periods without sunlight each winter.
The fossils are the oldest evidence of a hibernation-like state in a vertebrate animal, and indicates that torpor — a general term for hibernation and similar states in which animals temporarily lower their metabolic rate to get through a tough season — arose in vertebrates even before mammals and dinosaurs evolved.
“Animals that live at or near the poles have always had to cope with the more extreme environments present there,” said lead author Megan Whitney, a postdoctoral researcher at Harvard University who conducted this study as a UW doctoral student in biology. “These preliminary findings indicate that entering into a hibernation-like state is not a relatively new type of adaptation. It is an ancient one.”
Lystrosaurus lived during a dynamic period of our planet’s history, arising just before Earth’s largest mass extinction at the end of the Permian Period — which wiped out about 70% of vertebrate species on land — and somehow surviving it. The stout, four-legged foragers lived another 5 million years into the subsequent Triassic Period and spread across swathes of Earth’s then-single continent, Pangea, which included what is now Antarctica.
“The fact that Lystrosaurus survived the end-Permian mass extinction and had such a wide range in the early Triassic has made them a very well-studied group of animals for understanding survival and adaptation,” said co-author Christian Sidor, a UW professor of biology and curator of vertebrate paleontology at the Burke Museum.
Paleontologists today find Lystrosaurus fossils in India, China, Russia, parts of Africa and Antarctica. These squat, stubby, creatures — most were roughly pig-sized, but some grew 6 to 8 feet long — had no teeth but bore a pair of tusks in the upper jaw, which they likely employed to forage among ground vegetation and dig for roots and tubers, according to Whitney.
Those tusks made Whitney and Sidor’s study possible. Like elephants, Lystrosaurus tusks grew continuously throughout their lives. The cross-sections of fossilized tusks can harbor life-history information about metabolism, growth and stress or strain. Whitney and Sidor compared cross-sections of tusks from six Antarctic Lystrosaurus to cross-sections of four Lystrosaurus from South Africa.
Back in the Triassic, the collection sites in Antarctica were at about 72 degrees south latitude — well within the Antarctic Circle, at 66.3 degrees south. The collection sites in South Africa were more than 550 miles north during the Triassic at 58-61 degrees south latitude, far outside the Antarctic Circle.
The tusks from the two regions showed similar growth patterns, with layers of dentine deposited in concentric circles like tree rings. But the Antarctic fossils harbored an additional feature that was rare or absent in tusks farther north: closely-spaced, thick rings, which likely indicate periods of less deposition due to prolonged stress, according to the researchers.
“The closest analog we can find to the ‘stress marks’ that we observed in Antarctic Lystrosaurus tusks are stress marks in teeth associated with hibernation in certain modern animals,” said Whitney.
The researchers cannot definitively conclude that Lystrosaurus underwent true hibernation — which is a specific, weeks-long reduction in metabolism, body temperature and activity. The stress could have been caused by another hibernation-like form of torpor, such as a more short-term reduction in metabolism, according to Sidor.
Lystrosaurus in Antarctica likely needed some form of hibernation-like adaptation to cope with life near the South Pole, said Whitney. Though Earth was much warmer during the Triassic than today — and parts of Antarctica may have been forested — plants and animals below the Antarctic Circle would still experience extreme annual variations in the amount of daylight, with the sun absent for long periods in winter.
Many other ancient vertebrates at high latitudes may also have used torpor, including hibernation, to cope with the strains of winter, Whitney said. But many famous extinct animals, including the dinosaurs that evolved and spread after Lystrosaurus died out, don’t have teeth that grow continuously.
“To see the specific signs of stress and strain brought on by hibernation, you need to look at something that can fossilize and was growing continuously during the animal’s life,” said Sidor. “Many animals don’t have that, but luckily Lystrosaurus did.”
If analysis of additional Antarctic and South African Lystrosaurus fossils confirms this discovery, it may also settle another debate about these ancient, hearty animals.
“Cold-blooded animals often shut down their metabolism entirely during a tough season, but many endothermic or ‘warm-blooded’ animals that hibernate frequently reactivate their metabolism during the hibernation period,” said Whitney. “What we observed in the Antarctic Lystrosaurus tusks fits a pattern of small metabolic ‘reactivation events’ during a period of stress, which is most similar to what we see in warm-blooded hibernators today.”
If so, this distant cousin of mammals isn’t just an example of a hearty creature. It is also a reminder that many features of life today may have been around for hundreds of millions of years before humans evolved to observe them.
The research was funded by the National Science Foundation.
Evidence Supporting Predation of 4-m Marine Reptile by Triassic Megapredator
A new fossil of a 5-m ichthyosaur contains remains of a 4-m thalattosaur
It likely represents the oldest record of megafaunal predation by a marine reptile
More Mesozoic marine reptiles than previously conceived likely fed on megafauna
Megafaunal predation simultaneously started in a few lineages of marine reptiles
Air-breathing marine predators have been essential components of the marine ecosystem since the Triassic. Many of them are considered the apex predators but without direct evidence—dietary inferences are usually based on circumstantial evidence, such as tooth shape.
Here we report a fossil that likely represents the oldest evidence for predation on megafauna, i.e., animals equal to or larger than humans, by marine tetrapods—a thalattosaur (∼4 m in total length) in the stomach of a Middle Triassic ichthyosaur (∼5 m). The predator has grasping teeth yet swallowed the body trunk of the prey in one to several pieces. There were many more Mesozoic marine reptiles with similar grasping teeth, so megafaunal predation was likely more widespread than presently conceived. Megafaunal predation probably started nearly simultaneously in multiple lineages of marine reptiles in the Illyrian (about 242–243 million years ago).
This 20 August 2020 video says about itself:
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.
This 7 August 2020 video says about itself:
For more than a hundred years, the fossil of the Tanystropheus has puzzled scientists. The strange reptile — resembling a real-life Loch Ness Monster or a prehistoric crocodile crossed with a giraffe — was first described in 1852 and first reconstructed in 1973.
Paleontologists have long known that the species once lived in Switzerland’s Monte San Giorgio basin during the Middle Triassic period (about 242 million years ago). They also knew the bizarre-looking 20-foot creature had a remarkably long neck, which at 10 feet long was half of its entire length. But the remaining details surrounding the remained fuzzy and have been much debated. Did these #animals live on land or in the water? What did their young look like? And how did they interact with the other species in their environment? No one knew — until now.
Scientists used computed tomography (CT) scan technology to digitally reconstruct the crushed skulls of the fossils, which revealed evidence that these reptiles were water-dwelling, according to new research published in Current Biology.
From the Field Museum in the USA:
Fossil mystery solved: Super-long-necked reptiles lived in the ocean, not on land
Twenty-foot-long specimens described as separate species from their cousins, named after mythology’s Hydra
August 6, 2020
A fossil called Tanystropheus was first described in 1852, and it’s been puzzling scientists ever since. At one point, paleontologists thought it was a flying pterosaur, like a pterodactyl, and that its long, hollow bones were phalanges in the finger that supported the wing. Later on, they figured out that those were elongated neck bones, and that it was a twenty-foot-long reptile with a ten-foot neck: three times as long as its torso. Scientists still weren’t sure if it lived on land or in the water, and they didn’t know if smaller specimens were juveniles or a completely different species — until now. By CT-scanning the fossils’ crushed skulls and digitally reassembling them, researchers found evidence that the animals were water-dwelling, and by examining the growth rings in bones, determined that the big and little Tanystropheus were separate species that could live alongside each other without competing because they hunted different prey.
“I’ve been studying Tanystropheus for over thirty years, so it’s extremely satisfying to see these creatures demystified,” says Olivier Rieppel, a paleontologist at the Field Museum in Chicago and one of the authors of a new paper in Current Biology detailing the discovery.
Tanystropheus lived 242 million years ago, during the middle Triassic. On land, dinosaurs were just starting to emerge, and the sea was ruled by giant reptiles. For a long time, though, scientists weren’t sure whether Tanystropheus lived on land or in the water. Its bizarre body didn’t make things clear one way or the other.
“Tanystropheus looked like a stubby crocodile with a very, very long neck,” says Rieppel. The larger specimens were twenty feet long, with their necks making up ten feet of that length. Oddly for animals with such long necks, they only had thirteen neck vertebrae, just really elongated. (We see the same thing with giraffes, which have only seven neck bones, just like humans.) And their necks were rather inflexible, reinforced with extra bones called cervical ribs.
In the same region where many of the big Tanystropheus fossils were found, in what’s now Switzerland, there were also fossils from similar-looking animals that were only about four feet long. So not only were scientists unsure if these were land-dwellers or marine animals, but they also didn’t know if the smaller specimens were juveniles, or a separate species from the twenty-footers.
To solve these two long-standing mysteries, the researchers used newer technologies to see details of the animals’ bones. The large Tanystropheus fossils’ skulls had been crushed, but Stephan Spiekman, the paper’s lead author and a researcher at the University of Zurich, was able to take CT scans of the fossil slabs and generate 3D images of the bone fragments inside.
“The power of CT scanning allows us to see details that are otherwise impossible to observe in fossils,” says Spiekman. “From a strongly crushed skull we have been able to reconstruct an almost complete 3D skull, revealing crucial morphological details.”
The skulls had key features, including nostrils on top of the snout like a crocodile’s, that suggested Tanystropheus lived in the water. It probably lay in wait, waiting for fish and squid-like animals to swim by, and then snagged them with its long, curved teeth. It may have come to land to lay eggs, but overall, it stayed in the ocean.
Rieppel wasn’t surprised that evidence pointed to a water-dwelling Tanystropheus. “That neck doesn’t make sense in a terrestrial environment,” he says. “It’s just an awkward structure to carry around.”
So that answered one question, about where Tanystropheus lived. To learn whether the small specimens were juveniles or a separate species, the researchers examined the bones for signs of growth and aging.
“We looked at cross sections of bones from the small type and were very excited to find many growth rings. This tells us that these animals were mature,” says Torsten Scheyer, the study’s senior author and a researcher at University of Zurich.
“The small form is an adult, which basically sealed the case,” says Rieppel. “It’s proven now that these are two species.” The researchers named the larger one Tanystropheus hydroides, after the long-necked hydras in Greek mythology. The small form bears the original name Tanystropheus longobardicus.
“For many years now we have had our suspicions that there were two species of Tanystropheus, but until we were able to CT scan the larger specimens we had no definitive evidence. Now we do,” says Nick Fraser, Keeper of Natural Sciences at National Museums Scotland and a co-author of the paper. “It is hugely significant to discover that there were two quite separate species of this bizarrely long-necked reptile who swam and lived alongside each other in the coastal waters of the great sea of Tethys approximately 240 million years ago.”
The animals’ different sizes, along with cone-shaped teeth in the big species and crown-shaped teeth in the little species, meant they probably weren’t competing for the same prey.
“These two closely related species had evolved to use different food sources in the same environment,” says Spiekman. “The small species likely fed on small shelled animals, like shrimp, in contrast to the fish and squid the large species ate. This is really remarkable, because we expected the bizarre neck of Tanystropheus to be specialized for a single task, like the neck of a giraffe. But actually, it allowed for several lifestyles. This completely changes the way we look at this animal.”
This “splitting up” of a habitat to accommodate two similar species is called niche partitioning. “Darwin focused a lot on competition between species, and how competing over resources can even result in one of the species going extinct,” says Rieppel. “But this kind of radical competition happens in restricted environments like islands. The marine basins that Tanystropheus lived in could apparently support niche partitioning. It’s an important ecological phenomenon.”
“Tanystropheus is an iconic fossil and has always been,” adds Rieppel. “To clarify its taxonomy is an important first step to understanding that group and its evolution.”