Millions of years ago, several species of crocodiles of different genera and characteristics inhabited Europe and sometimes even coexisted. But among all these species, it was thought unlikely that crocodiles of the genus Crocodylus, of African origin, had ever lived in the Mediterranean basin. The remains found in the Italian regions of Gargano, Tuscany and Scontrone over the last few decades confirm that they did.

Now, a study published in the Journal of Paleontology corroborates this with the fossils of two crocodiles measuring about three meters in length that were discovered in the Valencian Venta del Moro site -excavated by researchers from the University of Valencia between 1995 and 2006-, and which were ascribed at the time to the Crocodylus checchiai species . This new work describes the remains more than 14 years after they were found for the first time.

“Our comparisons indicate that this material clearly does not belong to the Diplocynodon genera -an extinct genus of alligatoroid, similar to today’s caimans- or Tomistoma -similar to gavials-, the only other two crocodilians described so far for the late European Miocene,” as Ángel Hernández Luján, a palaeontologist at the Miquel Crusafont Catalan Institute of Palaeontology (ICP) and co-author of the work, has explained to Sinc.

However, as the remains are too fragmented, an analysis of the cranial bones, isolated teeth and osteoderms (bone plaque on the skin) suggests that they could belong to the C. checchiai species, as assigned at the time of their discovery, but their taxonomy is still not completely clear and hinders a more precise specific identification. In any case, “the morphology of the Venta del Moro crocodile remains is congruent with the Crocodylus genus,” the researcher states.

Swimming from Africa to Europe

The fossil remains of this Valencian site, which are the first Crocodylus in the Iberian Peninsula, “unequivocally” support the non-occasional dispersion of this genus from Africa to Europe during the late Miocene, according to palaeontologists. The discovery of two partial individuals, instead of just one, could indicate that a whole population was present in this area.

During their ‘colonization,’ these reptiles spread more significantly in the southern areas of Mediterranean Europe, as suggested by the Italian and Spanish areas where the fossils have been found. “All European localities with late Miocene crocodilians, including Venta del Moro, were at that time close to the northern Mediterranean coast and therefore easily accessible thanks to specimens that became scattered in the seawater,” the authors stress in the study.

“What is most certain is that it would have also inhabited the coasts of Murcia and Andalusia, although we cannot rule out that it would also have become dispersed along the coast of Catalonia and the Balearic Islands,” Hernández Luján has pointed out to SINC. But how could they have got there from the African coasts?

The researchers’ hypothesis is that these crocodiles swam from one continent to another in the sea before a land connection was established between Africa and Europe. This idea would be supported by the behavior of modern crocodiles, which are good swimmers and can even reach 32 km/h in the water.

An example of this is the current saltwater crocodile (Crocodylus porosus), which can make significant forays into the open sea to colonize other islands or other continents between Oceania and South-East Asia. “You only have to look at how easily it moves in the open sea to be seen in the waters of the Solomon Islands or even in French Polynesia,” says the palaeontologist.

But there are more examples that reinforce this hypothesis. Because of its anatomical similarity to American crocodiles, the extinct species Crocodylus checchiai, which originated in Libya and Kenya, could well be its ancestor. This suggests that crocodiles were able to cross the Atlantic Ocean during the Miocene, which would explain the appearance of the genus in America.

Therefore, in the case of the specimens found in Venta del Moro, swimming from the African to the European continent “must not have meant a great effort for them before they reached the Peninsula,” the researcher concludes.

Reference:
Massimo Delfino et al, Late Miocene remains from Venta del Moro (Iberian Peninsula) provide further insights on the dispersal of crocodiles across the late Miocene Tethys, Journal of Paleontology (2020). DOI: 10.1017/jpa.2020.62

Note: The above post is reprinted from materials provided by Spanish Foundation for Science and Technology (FECYT).

Pioneering analysis of 200 million-year-old teeth belonging to the earliest mammals suggests they functioned like their cold-blooded counterparts — reptiles, leading less active but much longer lives.

The research, led by the University of Bristol, UK and University of Helsinki, Finland, published today in Nature Communications, is the first time palaeontologists have been able to study the physiologies of early fossil mammals directly, and turns on its head what was previously believed about our earliest ancestors.

Fossils of teeth, the size of a pinhead, from two of the earliest mammals, Morganucodon and Kuehneotherium, were scanned for the first time using powerful X-rays, shedding new light on the lifespan and evolution of these small mammals, which roamed the earth alongside early dinosaurs and were believed to be warm-blooded by many scientists. This allowed the team to study growth rings in their tooth sockets, deposited every year like tree rings, which could be counted to tell us how long these animals lived. The results indicated a maximum lifespan of up to 14 years — much older than their similarly sized furry successors such as mice and shrews, which tend to only survive a year or two in the wild.

“We made some amazing and very surprising discoveries. It was thought the key characteristics of mammals, including their warm-bloodedness, evolved at around the same time,” said lead author Dr Elis Newham, Research Associate at the University of Bristol, and previously PhD student at the University of Southampton during the time when this study was conducted.

“By contrast, our findings clearly show that, although they had bigger brains and more advanced behaviour, they didn’t live fast and die young but led a slower-paced, longer life akin to those of small reptiles, like lizards.”

Using advanced imaging technology in this way was the brainchild of Dr Newham’s supervisor Dr Pam Gill, Senior Research Associate at the University of Bristol and Scientific Associate at the Natural History Museum London, who was determined to get to the root of its potential.

“A colleague, one of the co-authors, had a tooth removed and told me they wanted to get it X-rayed, because it can tell all sorts of things about your life history. That got me wondering whether we could do the same to learn more about ancient mammals,” Dr Gill said.

By scanning the fossilised cementum, the material which locks the tooth roots into their socket in the gum and continues growing throughout life, Dr Gill hoped the preservation would be clear enough to determine the mammal’s lifespan.

To test the theory, an ancient tooth specimen belonging to Morganucodon was sent to Dr Ian Corfe, from the University of Helsinki and the Geological Survey of Finland, who scanned it using high-powered Synchrotron X-ray radiation.

“To our delight, although the cementum is only a fraction of a millimetre thick, the image from the scan was so clear the rings could literally be counted,” Dr Corfe said.

It marked the start of a six-year international study, which focused on these first mammals, Morganucodon and Kuehneotherium, known from Jurassic rocks in South Wales, UK, dating back nearly 200 million years.

“The little mammals fell into caves and holes in the rock, where their skeletons, including their teeth, fossilised. Thanks to the incredible preservation of these tiny fragments, we were able to examine hundreds of individuals of a species, giving greater confidence in the results than might be expected from fossils so old,” Dr Corfe added.

The journey saw the researchers take some 200 teeth specimens, provided by the Natural History Museum London and University Museum of Zoology Cambridge, to be scanned at the European Synchrotron Radiation Facility and the Swiss Light Source, among the world’s brightest X-ray light sources, in France and Switzerland, respectively.

In search of an exciting project, Dr Newham took this up for the MSc in Palaeobiology at the University of Bristol, and then a PhD at the University of Southampton.

“I was looking for something big to get my teeth into and this more than fitted the bill. The scanning alone took over a week and we ran 24-hour shifts to get it all done. It was an extraordinary experience, and when the images started coming through, we knew we were onto something,” Dr Newham said.

Dr Newham was the first to analyse the cementum layers and pick up on their huge significance.

“We digitally reconstructed the tooth roots in 3-D and these showed that Morganucodon lived for up to 14 years, and Kuehneotherium for up to nine years. I was dumbfounded as these lifespans were much longer than the one to three years we anticipated for tiny mammals of the same size,” Dr Newham said.

“They were otherwise quite mammal-like in their skeletons, skulls and teeth. They had specialised chewing teeth, relatively large brains and probably had hair, but their long lifespan shows they were living life at more of a reptilian pace than a mammalian one. There is good evidence that the ancestors of mammals began to become increasingly warm-blooded from the Late Permian, more than 270 million years ago, but, even 70 million years later, our ancestors were still functioning more like modern reptiles than mammals”

While their pace-of-life remained reptilian, evidence for an intermediate ability for sustained exercise was found in the bone tissue of these early mammals. As a living tissue, bone contains fat and blood vessels. The diameter of these blood vessels can reveal the maximum possible blood flow available to an animal, critical for activities such as foraging and hunting.

Dr Newham said: “We found that in the thigh bones of Morganucodon, the blood vessels had flow rates a little higher than in lizards of the same size, but much lower than in modern mammals. This suggests these early mammals were active for longer than small reptiles but could not live the energetic lifestyles of living mammals.”

Reference:
Elis Newham, Pamela G. Gill, Philippa Brewer, Michael J. Benton, Vincent Fernandez, Neil J. Gostling, David Haberthür, Jukka Jernvall, Tuomas Kankaanpää, Aki Kallonen, Charles Navarro, Alexandra Pacureanu, Kelly Richards, Kate Robson Brown, Philipp Schneider, Heikki Suhonen, Paul Tafforeau, Katherine A. Williams, Berit Zeller-Plumhoff, Ian J. Corfe. Reptile-like physiology in Early Jurassic stem-mammals. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-18898-4

Note: The above post is reprinted from materials provided by University of Bristol.

Researchers have discovered fossils of a tiny burrowing reptile among a vast expanse of petrified wood in eastern Arizona.

The new species has been named Skybalonyx skapter, a part of a group known as drepanosaurs from the Triassic Period, about 220 million years ago.

Petrified Forest National Park outside Holbrook is considered one of the premier places to study plants and animals from that period, sometimes known as the dawning age of dinosaurs.

The researchers say the ancient reptiles are strange because of morphologies that include enlarged second claws, bird-like beaks and tails with claws. They likely looked like a cross between an anteater and a chameleon.

They say the new species could be even stranger because it has claws that allow it to burrow, rather than climb into and live in trees, more like a mole or mole-rat.

The fossils were discovered by a team of researchers from the park, Virginia Tech, the University of Washington, Arizona State University, Idaho State University and the Virginia Museum of Natural History. They published their findings earlier this month in the Journal of Vertebrate Paleontology.

They found the fossils in the summers of 2018 and 2019 using a screen-washing technique.

Note: The above post is reprinted from materials provided by The Associated Press. All rights reserved.

A new species of an ancient marine reptile evolved to strike terror into the hearts of the normally safe, fast-swimming fish has been identified by a team of University of Alberta researchers, shedding light on what it took to survive in highly competitive ecosystems.

Gavialimimus almaghribensis, a new type of mosasaur, was catalogued and named by an international research team led by master’s student Catie Strong, who performed the research a year ago as part of an undergrad honours thesis guided by vertebrate paleontologist Michael Caldwell, professor in the Faculty of Science, along with collaborators from the University of Cincinnati and Flinders University.

More than a dozen types of mosasaur — which can reach 17 metres in length and resemble an overgrown komodo dragon — ruled over the marine environment in what is now Morocco at the tail end of the Late Cretaceous period between 72 and 66 million years ago.

What differentiates Strong’s version, however, is that it features a long, narrow snout and interlocking teeth — similar to the crocodilian gharials, a relative of crocodiles and alligators.

Strong said this discovery adds a layer of clarity to a diverse picture seemingly overcrowded with mega-predators all competing for food, space and resources.

“Its long snout reflects that this mosasaur was likely adapted to a specific form of predation, or niche partitioning, within this larger ecosystem.”

Strong explained there is evidence that each species of the giant marine lizard shows adaptations for different prey items or styles of predation.

“For some species, these adaptations can be very prominent, such as the extremely long snout and the interlocking teeth in Gavialimimus, which we hypothesized as helping it to catch rapidly moving prey,” she said.

She added another distinctive species would be Globidens simplex — described last year by the Caldwell lab — which has stout, globular teeth adapted for crushing hard prey like shelled animals.

“Not all of the adaptations in these dozen or so species are this dramatic, and in some cases there may have been some overlap in prey items, but overall there is evidence that there’s been diversification of these species into different niches,” Strong noted.

Alternatively, the main contrasting hypothesis would be a scenario of more direct competition among species. Strong said given the anatomical differences among these mosasaurs, though, the idea of niche partitioning seems more consistent with the anatomy of these various species.

“This does help give another dimension to that diversity and shows how all of these animals living at the same time in the same place were able to branch off and take their own paths through evolution to be able to coexist like that,” she said.

The remains of the G. almaghribensis included a metre-long skull and some isolated bones. There was nothing to explain the cause of death of the specimen, which was uncovered in a phosphate mine in Morocco that is rich in fossils.

“Morocco is an incredibly good place to find fossils, especially in these phosphate mines,” Strong said. “Those phosphates themselves reflect sediments that would have been deposited in marine environments, so there are a lot of mosasaurs there.”

Reference:
Catherine R. C. Strong, Michael W. Caldwell, Takuya Konishi, Alessandro Palci. A new species of longirostrine plioplatecarpine mosasaur (Squamata: Mosasauridae) from the Late Cretaceous of Morocco, with a re-evaluation of the problematic taxon ‘Platecarpus’ ptychodon. Journal of Systematic Palaeontology, 2020; 1 DOI: 10.1080/14772019.2020.1818322

Note: The above post is reprinted from materials provided by University of Alberta. Original written by Michael Brown.

About a year ago, researchers found fossil specimens of beetles in an amber deposit in Myanmar, thereby describing a new beetle family that lived about 99 million years ago. However, the scientists had not been able to fully describe the morphology of the insects in the amber sample, which is why the beetles were subsequently given the mysterious name Mysteriomorphidae. An international research team led by the University of Bonn (Germany) and Palacky University (Czech Republic) has now examined four newly found specimens of the Mysteriomorphidae using computer tomography and has been able to reconstruct them. The results allow to draw conclusions about the evolution of the species during the Cretaceous period. The study has been published in the journal Scientific Reports.

Small creatures enclosed in amber can provide scientists with important information about past times, some of which date back many millions of years. In January 2019, the Spanish paleontologist Dr. David Peris, one of the two main authors of the study, collected several amber samples from the northern state of Kachin in Myanmar during a scientific trip to China and found beetle specimens from the same group as the Mysteriomorphidae.

Some of the newly found specimens showed a very good state of preservation – a good prerequisite for David Peris and his colleagues to carry out a virtual reconstruction of one of the beetles using computer tomography (CT scan). The technique used in paleontology allows researchers to study many small features of the fossils – even internal structures such as genitalia, if preserved.

While David Peris and his colleagues started to study and describe the morphology, i.e. the outer shape of the beetles, another research group also described the new family of Mysteriomorphidae by means of further specimens, that also came from the amber deposit in Myanmar. “However, the first study left some open questions about the classification of these fossils which had to be answered. We used the opportunity to pursue these questions with new technologies,” explains David Peris, researcher now at the Institute for Geosciences and Meteorology at the University of Bonn.

“We used the morphology to better define the placement of the beetles and discovered that they were very closely related to Elateridae, a current family,” explains Dr. Robin Kundrata from Palacky University, the second main author of the study and also an expert on this group of beetles. The scientists discovered important diagnostic characters that these beetle lineages share on mouthparts, thorax and abdomen.

Analysis of the evolution of beetles

Apart from the morphology, the researchers also analyzed the evolutionary history of the beetles. Earlier models had suggested that the beetles had a low extinction rate throughout their long evolutionary history, even during the Cretaceous period. However, the researchers provided a list of fossil groups of beetles described from the Cretaceous amber findings that, as Mysteriomorphidae, are only known as fossils from that time and had not survived the end of the Cretaceous period.

Background: During the Cretaceous period, flowering plants spread all over the world, replacing the old plants in the changing environment. This distribution of plants was connected with new possibilities for many associated animals and also with the development of new living beings, for example pollinators of flowers. However, most previous theories had not described that the animal species that were previously well adapted to the old plants were under pressure to adapt to the new resources and possibly became extinct. “Our results support the hypothesis that beetles, but perhaps some other groups of insects, suffered a decrease in their diversity during the time of plant revolution,” states David Peris.

Reference:
David Peris, Robin Kundrata, Xavier Delclòs, Bastian Mähler, Michael A. Ivie, Jes Rust, Conrad C. Labandeira. Unlocking the mystery of the mid-Cretaceous Mysteriomorphidae (Coleoptera: Elateroidea) and modalities in transiting from gymnosperms to angiosperms. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-73724-7

Note: The above post is reprinted from materials provided by University of Bonn.

Paleontologists have discovered remarkable evidence of the sensory capabilities in the fossilized skin of a 155-million-year-old carnivorous dinosaur.

The juvenile dinosaur, named Juravenator, comes from the Jurassic of Germany and is perfectly preserved from nose to tail, including remains of its scaly skin and other soft tissues.

Dr. Phil Bell, from the Palaeoscience Research Center at the University of New England in Armidale, Australia, is a leading researcher in the study of dinosaur skin. “Few people pay much attention to dinosaur skin, because it is assumed that they are just big, scaly reptiles,” he said. “But when I looked closely at the scales on the side of the tail, I kept finding these little ring-like features that didn’t make sense; they were certainly unlike other dinosaur scales.”

The researchers found that the ring-like features were very similar to special sensory nodes found on the scales of modern crocodiles. These nodes, called integumentary sense organs (ISOs), are responsive to touch, chemistry, and temperature information, providing crocodiles with important sensory from their surroundings.

Dinosaur specialist Dr. Christophe Hendrickx, from the Unidad Ejecutora Lillo in San Miguel de Tucumán, Argentina, who co-authored the study points out, “very little in known about dinosaur sensory organs. Sensory scales were recently assumed to be present on the snout of tyrannosaurs like T. rex based on the texture of their facial bones, but this is the first direct evidence of their presence in a dinosaur.”

Because crocodiles are aquatic predators, the researchers also speculated that Juravenator too might have hunted fish and other aquatic animals. Whereas alligators only have ISOs on the face, crocodiles have ISOs all over the body, including the tail. Although the skin on other parts of the body of Juravenator is unknown, it may have submerged its tail to detect the movement of prey underwater.

The study was published in the journal Current Biology.

Reference:
Bell, P.R. and Hendrickx, C. 2020. Crocodile-like sensory scales in a Late Jurassic theropod dinosaur. Current Biology 30: doi.org/10.1016/j.cub.2020.08.066

Note: The above post is reprinted from materials provided by University of New England.

Challenging a 75-year-old notion about how and when reptiles evolved during the past 300 million-plus years involves a lot of camerawork, loads of CT scanning, and, most of all, thousands of miles of travel. Just check the stamps in Tiago R. Simões ‘ passport.

Simões is the Alexander Agassiz Postdoctoral Fellow in the lab of Harvard paleontologist Stephanie Pierce. From 2013 to 2018, he traveled to more than 20 countries and more than 50 different museums to take CT scans and photos of nearly 1,000 reptilian fossils, some hundreds of millions of years old. It amounted to about 400 days of active collection, helping form what is believed to be the largest available timeline on the evolution of major living and extinct reptile groups.

Now, a statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts. The findings are described in a recently published paper in Nature Communications.

In it, researchers show that the evolution of extinct lineages of reptiles from more than 250 million years ago took place through many small bursts of morphological changes, such as developing armored body plans or wings for gliding, over a period of 50 million years instead of during a single major evolutionary event, as previously thought. They also show that the early evolution of most lizard lineages was a continuously slower and more incremental process than previously understood.

“It wasn’t a sudden jump that kind of established the wide diversity that we see today in reptiles,” Simões said. “There was an initial jump, but relatively small, and then a sustained increase over time of those rates [of evolution] and different diversity values.”

Evidence of this has been seen in other types of animals, but this is the first time it’s been seen in reptiles — one of the most diverse animals on the planet, with more than 10,000 different species and a dizzying variety of abilities and traits. Consider how some lizard species can freeze solid overnight then thaw the next morning, or how turtles grow protective armor.

The findings run contrary to the evolutionary theory of adaptive radiation that Harvard paleontologist George G. Simpson popularized in the 1940s, which sought to explain the origins of the planet’s biological diversity. Adaptive radiation has been the focus of intense investigation for decades, but wasn’t until recent years that the technology, methods, and data have existed to precisely measure rapid rates of evolution in the fossil record in terms of different animal species, morphologies, and at the molecular level using DNA.

Researchers of this study also included Pierce, the Thomas D. Cabot Associate Professor of Organismic and Evolutionary Biology and curator of vertebrate paleontology in the Museum of Comparative Zoology; Oksana Vernygora, a graduate student from the University of Alberta in Canada; and Professor Michael Wayne Caldwell at Alberta.

Simões traveled to almost all of the world’s major natural history museums to collect the data for the study, including the national natural history museums in London, Paris, Berlin, Ottawa, Beijing, and Tokyo. In the U.S., he visited the Smithsonian National Museum of Natural History, the Carnegie Museum of Natural History, and Harvard’s Museum of Comparative Zoology.

The scientists believe that by understanding how animals evolve over longer periods of time, they can glean a number of lessons on ecology and how organisms are affected by environmental changes. Using the database, researchers can determine when major reptile lineages or morphologies originated, see how those changes affected reptile DNA, and learn important lessons about how species were impacted by historical events.

Reptiles, for instance, have survived three major mass extinction events. The biggest was the Permian–Triassic mass extinction about 250 million years ago that killed about 90 percent of the planet’s species, earning it the moniker the Great Dying. It’s believed to have been caused by a buildup of natural greenhouse gases.

The timeline researchers created found that the rates at which reptiles were evolving and the anatomical differences among them before the Great Dying were nearly as high as after the event. However, it was only much after the Great Dying that reptiles became dominant in many ecosystems and extremely diverse in terms of the number of different species.

That finding cemented that fast rates of anatomical change don’t need to coincide with genetic diversity or an abundance of species (called taxonomic diversity), and further rebutted adaptive radiation as the only explanation for the origin of new animal groups and body plans. The researchers also note that it took reptiles almost 10 million years to recover to previous levels of anatomical diversity.

“That kind of tells you on the broad scheme of things and on a global scale how much impact, throughout the history of life, sudden environmental changes may have,” Simões said.

Further evidence that contradicted adaptive radiation included similar but surprising findings on the origins of snakes, which achieved the major aspects of their skinny, elongated body plans early in their evolution about 170 million years ago (but didn’t fully lose their limbs for another 105 million years). They also underwent rapid changes to their skulls about 170 to 165 million years ago that led to such powerful and flexible mouths that today they can swallow whole prey many times their size. But while snakes experienced the fastest rates of anatomical change in the history of reptile evolution, these changes did not coincide with increases in taxonomic diversity or high rates of molecular evolution as predicted by adaptive radiations, the researchers said.

The scientists weren’t able to pinpoint why this mismatch happens, and suggested more research is needed. In particular they want to understand how body plans evolve and how changes in DNA relate to it.

“We can see better now what are the big changes in the history of life and especially in the history of reptile life on Earth,” Simões said. “We will keep digging.”

Reference:
Tiago R. Simões, Oksana Vernygora, Michael W. Caldwell, Stephanie E. Pierce. Megaevolutionary dynamics and the timing of evolutionary innovation in reptiles. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-17190-9

Note: The above post is reprinted from materials provided by Harvard University. Original written by Juan Siliezar.