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Teenage T. Rex Was Already Chomping on Prey

Tuesday, March 12, 2019

Joseph Peterson, a vertebrate paleontologist at the University of Wisconsin Oshkosh, demonstrates how a T. rex takes a bite. Credit: Patrick Flood, UW Oshkosh

New research from the University of Wisconsin Oshkosh indicates that even as a teenager the Tyrannosaurus rex showed signs that it would grow up to be a ferocious predator.

In a study published last week in the peer-reviewed journal Peerj -- the Journal of Life and Environmental Sciences, UWO scientists reported evidence that a juvenile T. rex fed on a large plant-eating dinosaur, even though it lacked the bone-crushing abilities it would develop as an adult.

While studying fossils from an Edmontosaurus -- a plant-eating Hadrosaurid or duck-billed dinosaur, UWO vertebrate paleontologist Joseph Peterson noticed three large, v-shaped, bite marks on a tail bone and wondered, "Who made these?"

Peterson knew that T. rex -- a member of the meat-eating dinosaur suborder known as Theropoda -- was "a likely culprit."

"We suspected that T. rex was responsible for the bit marks, because in the upper Cretaceous rock formation, where the hadrosaur was discovered, there are only a few carnivorous dinosaurs and other reptiles in the fossil record. Crocodile fossils are found there, but such a crocodile would have left tooth marks that are round rather than the elliptical punctures we found on the vertebra," Peterson explained.

"There also were small Velociraptor-like dinosaurs, but their teeth are too small to have made the marks. Finally, an adult T. rex would have made punctures that would have been too large! That's when we started considering a juvenile tyrannosaur."

To test the hypothesis, Peterson and geology student Karsen Daus, of Suamico, coated the fossil with a silicon rubber to make a silicone peel of the puncture marks.

They found that the dimensions of the "teeth" better matched a late-stage juvenile T. rex (11 to 12 years) than an adult (approximately 30 years).

"Although this T. rex was young, it really packed a punch," Peterson said.

"This is significant to paleontology because it demonstrates how T. rex -- the most popular dinosaur of all time -- may have developed changes in diet and feeding abilities while growing," he said. "This is part of a larger, ongoing research initiative by many paleontologists to better understand how T. rex grew and functioned as a living creature over 65 million years ago."

Most theropod feeding traces and bite marks are attributed to adults; juvenile tooth marks rarely have been reported in the literature, he added.

"We really are in the 'Golden Age' of paleontology," Peterson said. "We are learning more now than we ever thought we would know about dinosaurs. And, we're learn more about how they grew up."


Story Source:

Materials provided by University of Wisconsin OshkoshNote: Content may be edited for style and length.


Journal Reference:

  1. Joseph E. Peterson, Karsen N. Daus. Feeding traces attributable to juvenile Tyrannosaurus rex offer insight into ontogenetic dietary trendsPeerJ, 2019; 7: e6573 DOI: 10.7717/peerj.6573

Source: www.sciencedaily.com

Galleonosaurus dorisae: New Species of Plant-Eating Dinosaur Discovered in Australia

Tuesday, March 12, 2019

Galleonosaurus dorisae. Image credit: James Kuether.

Paleontologists in Australia have found fossil fragments from a new genus and species of ornithopod dinosaur that walked the Earth during the Early Cretaceous Period.

The new dinosaur belongs to Ornithopoda (ornithopods), a major group of herbivorous bird-hipped dinosaurs.

Dubbed Galleonosaurus dorisae, it inhabited the rift between Australia and Antarctica approximately 125 million years ago (Cretaceous Period).

Five fossilized upper jaws of the ancient beast were found at the Flat Rocks locality of the Wonthaggi Formation in a region of Gippsland, Victoria, Australia.

Galleonosaurus is the fifth small ornithopod genus named from Victoria,” said Dr. Matthew Herne, a postdoctoral researcher at the University of New England.

“The discovery confirms that on a global scale, the diversity of these small-bodied dinosaurs had been unusually high in the ancient rift valley that once extended between the spreading continents of Australia and Antarctica.”

“Small ornithopods appear to have thrived on the vast forested floodplain within the ancient rift valley.”

Specimens of Galleonosaurus dorisae from the Flat Rocks Sandstone in the upper Barremian, Wonthaggi Formation, Gippsland Basin, southeastern Australia. Scale bars – 10 mm (1-6); 1 mm (7). Image credit: Herne et al, doi: 10.1017/jpa.2018.95.

Galleonosaurus dorisae is a close relative of Diluvicursor pickeringi, another small ornithopod named by Dr. Herne and co-authors in 2018, from excavations along the Otway coast to the west of the Gippsland region.

“Interestingly, the jaws of the new species and the partial skeleton of Diluvicursor pickeringi were similarly buried in volcanic sediments on the floor of deep powerful rivers,” Dr. Herne said.

“However, Galleonosaurus dorisae is about 12 million years older than Diluvicursor pickeringi, showing that the evolutionary history of dinosaurs in the Australian-Antarctic rift had been lengthy.”

Prior to discovery of Galleonosaurus dorisae, the only other ornithopod known from the Gippsland region was Qantassaurus intrepidus, named in 1999.

“However, Qantassaurus intrepidus had a shorter more robust snout than that of Galleonosaurus dorisae,” Dr. Herne said.

“We consider that these two, similarly-sized dinosaurs fed on different plant types, which would have allowed them to coexist.”

The researchers also found that the ornithopods from Victoria are closely related to those from Patagonia in Argentina.

“We are steadily building a picture of terrestrial dinosaur interchange between the shifting Gondwanan continents of Australia, South America and Antarctica during the Cretaceous period,” Dr. Herne noted.

The study was published in the Journal of Paleontology.

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Matthew C. Herne et al. New small-bodied ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic rift system, with revision of Qantassaurus intrepidus Rich and Vickers-Rich, 1999. Journal of Paleontology, published online March 11, 2019; doi: 10.1017/jpa.2018.95

Source: www.sci-news.com

China Makes Major Progress in Paleontological Research in 2018

Monday, March 11, 2019

Liu Cun Yu, the director of the Beipiao Pterosaur Museum, poses in front of a full-scale model of a Moganopterus zhuiana, a species named after his wife. (Stefen Chow)

The Paleontological Society of China published ten major achievements made in the field in 2018. Here they are:

-- The 1st turtle with a beak from China

A fossilized skeleton of a turtle, dating back about 228 million years to the dawn of the dinosaur era, filled a missing link in turtles' evolutionary history.

Found in the late Triassic deposits in Guanling County in Guizhou Province, the turtle was named Eorhynchochelys sinensis, meaning "the first turtle with a beak from China." The turtle, more than two meters long, had a short trunk and no shell on its back and abdomen.

The turtle is between the evolutionary positions Odontochelys and Pappochelys, which was discovered in Germany, dating back about 240 million years.

-- New mammal ancestor

Scientists from Center for Vertebrate Evolutionary Biology of Yunnan University and Linyi University identified a new mammal ancestor and their research indicates that marsupials may not have originated in Asia.

Well-preserved skeletons of Ambolestes zhoui from 126 million years ago were found in Yixian County in north China's Inner Mongolia Autonomous Region.

Ambolestes zhoui is an early member of the placental lineage. It also carries mixed features both placentals and marsupials, which led researchers to believe that Asia may not be the place of origin for marsupials. The oldest known marsupials are from 110 million years ago from western North America.

-- Qinghai-Tibet Plateau first occupied by humans at least 30,000 years ago

Thousands of stone artifacts recovered from a paleolithic site in southwest China's Tibet Autonomous Region indicate that humans might have conquered one of the highest and most ecologically-challenging places on the globe at least 30,000 years ago.

The Nwya Devu site, located 4,600 meters above sea level in central Tibet, is the earliest archaeological site ever identified on the plateau.

-- Paleobiology Course Book

Evolution of Life and Environment, a book on paleobiology, is a course book for undergraduate and graduate students from all disciplines to grasp the general idea of evolution and environmental change, to consider the Earth as a system and to make contributions to reveal the evolutionary mechanisms of the current global environment and human future.

-- Understanding evolution of modern birds through fossilized tissues

Paleontology has traditionally focused on skeletal remains. Though rarely preserved, soft tissues have the potential to teach us far more about the biology of extinct organisms. Fossils from the Early Cretaceous Jehol Biota are rich with such traces, examples of which were described in the lung tissue and medullary bone of two birds.

The results of both studies indicate that soft tissue specializations evolved before many skeletal changes during the evolution of the highly modified modern bird. This fundamentally changes how paleontologists should interpret skeletal data when trying to reconstruct the biology o extinct animals.

-- Earliest asymmetrical flight feathers in the world

A bird-like dinosaur named Caihong juji from the Jurassic strata about 160 million years ago found in Qinglong of Hebei possesses not only symmetrical flight feathers on its forelimbs but also asymmetrical flight feathers on its tail, representing an important junction point in the evolution of flight feathers from symmetry to asymmetry.

-- Response of marine ecosystems during the end-Permian mass extinction

Professor Song Haijun's team, from China University of Geosciences (Wuhan), published their new findings concerning the evolution of marine ecosystems near the Permian-Triassic mass extinction in Sciences Advances and GSA Bulletin in 2018. Their results show that the end-Permian mass extinction resulted in an abnormal marine ecosystem. Additionally, biodiversity shows a rapid rebound after the mass extinction and reach the pre-extinction level around five million years later. But the recovery of the ecosystem is much more delayed, taking 50 million years, until the end of Triassic.

-- Earliest animal footprints found in China

Researchers from the Nanjing Institute of Geology and Palaeontology under the Chinese Academy of Sciences and Virginia Tech in the United States studied trackways and burrows in the Ediacaran Shibantan Member of the Dengying Formation (551 to 541 million years ago) in the Yangtze Gorges area of southern China.

They found trace fossils that represent some of the earliest known evidence for animal appendages, or legs.

-- The Snowball Earth triggered animal evolution

Professor Shen Bing from Peking University and his colleagues published research in Nature Communications on August 1, 2018, reporting the widespread pyrite concretions near the top of Nantuo Formation in South China. This study indicates that the termination of Marinoan global glaciation might have triggered the Ediacaran diversification of eukaryotes and the subsequent evolution of animals.

-- One more golden spike in China

A proposal that the Cambrian third series - 'Miaolingian series' and the fifth stage - 'Wuliuan stage' in Guizhou of China was passed by the International Union of Geological Sciences in 2018. Therefore, this is the 11th golden spike, or Global Standard Stratotype-Section and Point in China (GSSP).

Source: www.xinhuanet.com

27,000-Year-Old Tooth of Giant Ground Sloth Sheds Light on Animal’s Diet and Climatic Exposure

Saturday, March 9, 2019

The Pan-American sloth (Eremotherium laurillardi). Image credit: Sergio de la Rosa / CONABIO / CC BY-SA 4.0.

By analyzing a tooth from the first fossil remains of the extinct Pan-American sloth (Eremotherium laurillardi) found in Belize, a team of paleontologists has uncovered insights into the creature’s dietary adaptations, as informed by local climate.

The Pan-American sloth had a distribution from southern Brazil to the Gulf and Atlantic coast regions of North America.

This animal could reach a length of 20 feet (6 m), which, in an upright position, would have permitted it to feed at higher levels in trees.

In 2014, divers found the fossil remains of a 27,000-year-old Pan-American sloth — parts of a tooth, humerus and femur — while searching for ancient Maya artifacts in a water-filled sinkhole in Cara Blanca, Belize.

Though partially fossilized, the tooth still held enough unaltered tissue for stable carbon and oxygen isotope analysis, which provided clues to what the sloth ate in the last year of its life. This, in turn, revealed much about the local climate and environment of the region at the time.

“Our findings add to the evidence that many factors, in addition to a changing climate, contributed to the extinction of megafauna in the Americas,” said co-lead author Professor Lisa Lucero, from the Department of Anthropology at the University of Illinois at Urbana-Champaign.

“One of those potential factors is the arrival of humans on the scene 12,000 to 13,000 years ago.”

“The teeth of giant sloths like the one found in Belize, Eremotherium laurillardi, differ from those of other large mammals, like mammoths, that went extinct between 14,000 and 10,000 years ago,” said first author Jean Larmon, a graduate student at the University of Illinois at Urbana-Champaign.

“Giant sloth teeth have no enamel, the hard, outer layer of human and some animal teeth that can be analyzed to learn about their diet.”

Left: teeth of the Pan-American sloth (Eremotherium laurillardi) are composed of two cusps (i.e., bilophodont), are ever-growing (i.e., hypselodont) and self-sharpening, and are made of mineralized dental tissue types that are softer than enamel; numbers indicate the cementum (1), outer orthodentin (2), inner orthodentin (3), vasodentin (4), and carbonate concretion (5). Right: the location of isotope samples along the growth access of the tooth. Image credit: Jean T. Larmon & Stanley Ambrose, University of Illinois at Urbana-Champaign.

By using cathodoluminescence microscopy, a technique that causes minerals to glow and can detect the extent of mineralization in fossils, the researchers discovered that one type of tooth tissue, the dense orthodentin, was largely intact.

They drilled 20 samples of orthodentin for isotopic analysis along the 3.9-inch (10 cm) long tooth fragment, spanning more than a year of tooth growth.

“This allowed us to trace monthly and seasonal changes in the sloth’s diet and climate for the first time, and also to select the best part of the tooth for reliable radiocarbon dating,” said Professor Stanley Ambrose, also from the Department of Anthropology at the University of Illinois at Urbana-Champaign.

The isotopic analysis revealed that the giant sloth lived through a long dry season, which lasted about seven months, sandwiched between two short rainy seasons.

It also revealed that the creature lived in a savanna, rather than a forest, and consumed a variety of plants that differed between wet and dry seasons.

“We were able to see that this huge, social creature was able to adapt rather readily to the dry climate, shifting its subsistence to relying upon what was more available or palatable,” Larmon said.

“This supports the idea that the sloths had a diverse diet. That helps explain why they were so widespread and why they lasted so long. It’s likely because they were highly adaptable,” Professor Lucero said.

The findings were published in the journal Science Advances.

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Jean T. Larmon et al. 2019. A year in the life of a giant ground sloth during the Last Glacial Maximum in Belize. Science Advances 5 (2); doi: 10.1126/sciadv.aau1200

Source: www.sci-news.com

Reverse-Engineering Conservation: Revealing the Secrets of the First Scientifically Described Dinosaur

Saturday, March 9, 2019

Megalosaurus by Raul Martin

The right dentary of Megalosaurus bucklandii – the first scientifically described dinosaur – has been part of the collection of the Oxford University Museum of Natural History since 1797. Yet surprisingly little is known about the specimen’s history after it was acquired by the museum. A new analysis published in Heritage Science tried to reverse engineer that conservation history and in doing so discovered new findings.

The lectotype dentary of Megalosaurus bucklandii. Image copywright Oxford University Museum of Natural History (OUMNH).

Today’s museums are home to an overwhelming number of objects from the depths of history, ranging from relics of cultures and societies long past to the remains of ancient leviathans that defy modern understanding. Among these myriad objects are a smaller proportion with great cultural or scientific significance. Their importance to human understanding of the past means they remain sequestered away in museum collections, safely kept in the knowledge that their significance is fully understood.

The right dentary of Megalosaurus bucklandii, part of the lectotype of the specimen (one part of a collection of specimens that is the quintessential example of a species), is one such artefact at the Oxford University Museum of Natural History (OUMNH). This jawbone represents the first scientifically described dinosaur, the first fossil specimen to be recognized as belonging to a then as-yet unknown group of animals. Described by the Reverend Williams Buckland in 1824 and then included among the first description of the ‘Dinosauria’ by Richard Owen in 1842, Megalosaurus and its cousins went on to kickstart the first dinosaur craze in Victorian England. This legacy arguably persists to this day.

Reverse-engineering a conservation history

CT Scan Data of the dentary of Megalosaurus bucklandii. Red is P1 and Green is P2. Wilson et al. 2018. A) Medial; B) Lateral.

In spite of this, surprisingly little is known about the specimen itself. Museum records for the specimen are scant. It is known that it was purchased in 1797 but little information appears to have been recorded on what actually happened in the interim between then, its description and today. This is especially concerning as the specimen shows considerable evidence of restoration in plaster, as noted by Benson et al. (2008). The process of conservation, the treatment and stabilization of damage and degradation to museum objects mandates knowledge of what has previously been done to an object. An absence of this information makes future conservation efforts challenging and risky.

In order to overcome this conservational concern, we attempted to reverse engineer the conservational history of the specimen, utilizing cutting-edge imaging techniques. Previous research (Wilson et al. 2017) exploring the specimen using X-Ray Computed Tomography (XCT) – the use of X-rays to reconstruct the internal and external structure of an object based on its relative density – revealed the presence of two separate plasters used to repair the specimen. However, this was insufficient to properly determine the nature of the plasters.

To better characterise these plasters, two elemental mapping methods were used: Energy-Dispersive X-ray Spectroscopy (EDS) and X-Ray Fluorescence (XRF). Both of these methods rely on the principle of bombarding a material with high-energy x-rays and detecting the emission of characteristic secondary x-rays, which determine what elements are present in the sample.

A conservative conservation approach

Map of Elemental Composition of P1 in the dentary of Megalosaurus bucklandii. Wilson et al. 2018.

Analysis of the two plasters revealed that the more common plaster, P1, was composed of impure gypsum plaster (Plaster of Paris), filled with sand grains, grains of the original specimen, and small particles of the mineral Minium, a reddish lead oxide. The plaster was also coated in shellac. The second plaster, P2, was also a gypsum plaster, lacking these Minium and sand grains but being coated in barium hydroxide instead of shellac, a moisture sealant. The identification of these plasters has helped to better elucidate previous conservational efforts and how to treat the specimen in the future.

This overall represents an extremely conservative approach to conservation by the conservator. The integration of reddish Minium particles represents a conscious effort to colour the plaster to better match the weight and colour of the original specimen and to prioritise verisimilitude of the plaster restoration. The plaster restoration was also extremely conservative of the geometry of the specimen, with small fragments of the original damaged specimen being suspended in plaster.

Dinosaur teeth and evolutionary significant dentary canals

New Structures in the dentary of Megalosaurus bucklandii. A) Medial; B) Lateral.

Also revealed from the analysis are a number of new findings. Hidden teeth, in the process of growing and being replaced were elucidated by the XCT analysis, shedding some insight on the tooth replacement of Megalosaurus. Additionally, a complex series of dentary canals within the jawbone were revealed. These structures are poorly explored but recent research has begun to show that they could be of evolutionary significance. Thus, even an old specimen has some new tricks to show.

Overall, Megalosaurus presents a powerful case study for conservation professionals and shows how cutting edge technologies can reverse-engineer the chequered history of objects that are poorly understood. It showcases new opportunities to get new life out of old objects, and demonstrates that even objects that are thought to be understood can still surprise.

Source: http://blogs.springeropen.com

A Small Plesiosaur Lived in Spain 125 Million Years Ago

Saturday, March 2, 2019

The leptocleididae, whose remains have been found for the first time on the Iberian Peninsula, were smaller plesiosaurs with shorter necks living in shallow waters. Credit: José Antonio Peñas

Plesiosaurs, erroneously viewed as dinosaurs, inhabited all Earth's oceans between 200 million and 65 million years ago. In the Peninsula, only scarce remains of these long-necked reptiles had been found. Now, a group of palaeontologists has found the most abundant collection of fossils in Morella, Castellón. Among them, there is one vertebra that belonged to a type of plesiosaur never before discovered in the country, the leptocleidus.

During the Lower Cretaceous, some 125 million years ago, the Iberian Peninsula was very different from how we know it today. So much so that in what is now the village of Morella in Castellón, for example, a large delta had developed along the coast.

These shallow waters were home to a group of marine reptiles known as plesiosaurs, with small heads, long necks, short tails and wide, cylindrical bodies with large fins. Although they co-existed with the dinosaurs and became extinct at the same time, these reptiles, which may have exceeded 15 metres in length, were not closely related to the dinosaurs.

On the Peninsula, fossil findings of these animals have been rather scarce, limited and fragmentary. Evidence of this is a partial pelvis recently found in the town of Algora, in Guadalajara, which belonged to an elasmosaurus, a type of plesiosaur with such a long neck that a century and a half ago, when the species was discovered in the USA, it was thought to be the tail.

In a new study, published in Cretaceous Research, a group of UNED (National Distance Education University) palaeontologists has discovered an abundant and exclusive collection of remains of several plesiosaur specimens in the quarry of Mas de la Parreta, in Morella, that coexisted with the dinosaurs.

"The plesiosaur material identified in Morella is exceptional for the record of the Iberian Cretaceous," said Adán Pérez-García, a scientist in the Evolutionary Biology Group and co-author of the work.

The score of teeth and the large number of vertebrae (cervical, pectoral, dorsal and sacral) cannot be assigned to a particular group of plesiosaurs. Notably, however, an almost complete cervical vertebra can be attributed to a leptocleidus, a smaller type of plesiosaur, which until now was believed to have inhabited only England, Australia and South Africa.

The unknown leptocleidus

"It is the first reference of these animals in the Iberian Peninsula," the palaeontologist says. Leptocleidus corresponds to a group of very peculiar plesiosaurs, no more than three metres long, and which, unlike other plesiosaurs, had a relatively shorter neck.

"Their bodies were robust and their heads relatively large and triangular, and they were able to adapt from life in the open sea to that in coastal environments, such as the large delta located in Morella during that part of the Lower Cretaceous," explains Pérez-García.

Unlike other plesiosaur species, the leptocleididae lived in generally shallow waters, and it is believed that they were even able to adapt to brackish water environments, such as the mouths of large rivers very close to the coast.

Over the years, scientists have discovered a great diversity of vertebrates at the quarry site, including some that may have inhabited the Morella delta, as well as others whose corpses were washed away and accumulated in the current mining operation.

Along with the plesiosaurs, sharks have also surfaced, as have amphibians, other reptiles, including pterosaurs, land, freshwater and sea turtles, freshwater and marine crocodiles, and dinosaurs.

"The vertebrate fauna of the Lower Cretaceous of Morella is very well known. This is where some of the first dinosaur remains identified in the Spanish register in the second half of the 19th century come from," Pérez-García says, adding that paleontological activity in Morella has considerably increased in recent years.

More information: Juan M. Quesada et al. Plesiosauria remains from the Barremian of Morella (Castellón, Spain) and first identification of Leptocleididae in the Iberian record, Cretaceous Research (2018). DOI: 10.1016/j.cretres.2018.10.010

Source: https://phys.org

Ancient Tusked Sea Cow Unearthed in Panama

Saturday, March 2, 2019

The skull of Culebratherium alemani. Image credit: Aaron Wood.

The remarkably complete fossil skeleton of a sea cow with large incisor tusks that lived approximately 20 million years ago (Miocene Epoch) has been discovered in Panama.

The newly-discovered sea cow, named Culebratherium alemani, is a tusked seagrass-grazing relative of modern dugongs.

“While only one species of dugong is alive today — a second, Steller’s sea cow, was hunted to extinction within 27 years of its discovery — about 30 species have been recovered in the fossil record,” said Dr. Jorge Velez-Juarbe, a paleontologist in the Department of Mammalogy at the Natural History Museum of Los Angeles County and the Department of Paleobiology at the National Museum of Natural History, Smithsonian Institution.

“The group originated in the West Atlantic and Caribbean and dispersed westward through Panama, whose seaway did not close until a few million years ago, and south to Brazil.”

The fossil skull, vertebrae, ribs and other bones of Culebratherium alemani were recovered from marine deposits of the Culebra Cut of the Panama Canal.

“About 15 feet (4.6 m) long, this individual was not done growing,” Dr. Velez-Juarbe said.

“Its tusks had only begun to protrude and its newest molars showed little wear, indicating it was not yet an adult. But it was a powerful eater.”

Culebratherium alemani. Image credit: Jorge Velez-Juarbe & Aaron Wood.

Dr. Velez-Juarbe and his colleague, Dr. Aaron Wood from Iowa State University and the Florida Museum of Natural History, propose that Culebratherium alemani’s thick neck muscles, tusks and downward-pointing snout were adaptations for digging pits in the ocean floor to get to the underground stems of seagrass, the plants’ most nutritional parts.

“Finding Culebratherium alemani is pretty good evidence that there was seagrass in this region 20 million years ago,” Dr. Velez-Juarbe said.

“This particular group of sirenians are seagrass specialists.”

The discovery is described in a paper in the Journal of Vertebrate Paleontology.

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Jorge Velez-Juarbe & Aaron R. Wood. An early Miocene dugongine (Sirenia: Dugongidae) from Panama. Journal of Vertebrate Paleontology, published online February 15, 2019; doi: 10.1080/02724634.2018.1511799

Source: www.sci-news.com

Paleontology: Diversification After Mass Extinction

Saturday, March 2, 2019

Cartilaginous fishes were very diverse during the Permian period. However, after severe losses among cartilaginous fishes during the Middle Permian extinction, bony fishes experienced a massive diversification in the subsequent Trias period. Credit: UZH

A team led by Ludwig-Maximilians-Universitaet (LMU) in Munich paleontologist Adriana López-Arbarello has identified three hitherto unknown fossil fish species in the Swiss Alps, which provide new insights into the diversification of the genus Eosemionotus.

Monte San Giorgio in the Swiss canton of Ticino is one of the most important known sources of marine fossils from the Middle Triassic Period (around 240 million years ago). The new and exquisitely preserved fossil fish specimens, which Dr. Adriana López-Arbarello (a member of the Institute of Paleontology and Geobiology and of the Geobiocenter at LMU) has been studying in collaboration with colleagues based in Switzerland were also discovered in these dolomites and limestones. As the researchers now report in the online journal Palaeontologia Electronica, the specimens represent three previously unknown species of Eosemionotus, a genus of ray-finned fishes. "The largest episode of mass extinction in the history of the Earth took place about 250 million years ago," as López-Arbarello explains. "Our finds now provide further evidence that after this catastrophic event, the biosphere recovered relatively fast and went through a period of rapid diversification and the emergence of numerous new species during the Middle Triassic."

The first member of the genus Eosemionotus was discovered in the vicinity of Berlin in 1906, and was named E. vogeli. Almost a century later, in 2004, a second species was described from Monte San Giorgio as E. ceresiensis. Detailed anatomical studies of new material from this locality, carried out by López-Arbarello, have now enabled the recognition of three further species that can be assigned to same genus - E. diskosomusE. sceltrichensis and E. minutus. All five species are small in size, but they can be clearly distinguished from each other on the basis of the relative proportions of their bodies, the position of the fins, the morphology of the skull, and the disposition of teeth and scales. "These differences indicate that each species was adapted to different ecological niches," López-Arbarello concludes.

These findings provide new insights into the evolution of the genus. "Our phylogenetic analyses demonstrate that Eosemionotus is the oldest known member of an extinct family within the Order Semionotiformes. Although the Semionotiformes were a species-rich and highly diversified clade during the Mesozoic Era, the order died out in the Cretaceous. Only a few members of its sister group have survived down to the present day, and this ancient lineage is now represented by a single family, the gars," says López-Arbarello.

###

Palaeontologia Electronica 2019

Source: www.eurekalert.org

216-Million-Year-Old Microfossils Represent North America’s Earliest Frog

Friday, March 1, 2019

A Chinle frog, inside the jaw of a phitosaur. Image credit: Andrey Atuchin.

Paleontologists in Arizona have identified microfossils of what are thought to be the oldest known frog relative in North America.

The newly-discovered microfossils represent the first known and earliest equatorial remains of a salientian — the group containing living frogs and their most-closely related fossil relatives — from the Late Triassic, roughly 216 million years ago.

They came from the Chinle Formation of Arizona and are composed of several small pieces of hip bone, called an ilium.

“This new find highlights just how much there is still to learn about the Late Triassic ecosystem, and how much we find when we just look a little closer,” said Dr. Michelle Stocker, a researcher in the Department of Geosciences at Virginia Tech.

“We’re familiar with the charismatic archosaurs from the Chinle Formation, but we know that based on other ecosystems, they should make up a small percentage of the animals that lived together.”

“With this new focus we’re able to fill in a lot of those missing smaller components with new discoveries.”

Coming from multiple individuals, the hip bones are long and hollow, with a hip socket offset rather than centered.

“The bones of the frogs show how tiny they were: just a bit over half-an-inch long. The Chinle frog could fit on the end of your finger,” Dr. Stocker said.

Even though the fossils are part of the Chinle frog family, they are not yet naming the specific fossils.

“We refrain from naming this Chinle frog because we are continuing to process microvertebrate matrix that will likely yield additional skull and postcranial material that has the potential to be even more informative,” Dr. Stocker said.

The Chinle frog shares more features with living frogs and Prosalirus, an Early Jurassic frog found in sediments from the present-day Navajo Nation, than to Triadobatrachus, an Early Triassic frog found in modern day Madagascar in Africa.

“These are the oldest frogs from near the equator,” Dr. Stocker said.

“The oldest frogs overall are roughly 250 million years old from Madagascar and Poland, but those specimens are from higher latitudes and not equatorial.”

“Now we know that tiny frogs were present approximately 215 million years ago from North America, we may be able to find other members of the modern vertebrate communities in the Triassic period,” said team member Dr. Sterling Nesbitt, also from the Department of Geosciences at Virginia Tech.

The discovery is reported in a paper in the journal Biology Letters.

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Michelle R. Stocker et al. The earliest equatorial record of frogs from the Late Triassic of Arizona. Biology Letters, published online February 27, 2019; doi: 10.1098/rsbl.2018.0922

Source: www.sci-news.com

10 Birds That Look Eerily Similar To Their Dinosaur Ancestors

Thursday, February 28, 2019

Cassowaries are native to New Guinea and Australia. Shutterstock

  • All birds can be traced back to prehistoric creatures.

  • Many modern birds have retained traits of the dinosaurs they evolved from.

  • Chickens share genetic makeup with the Tyrannosaurus rex.

While what we think of as dinosaurs existed between 245 million and 66 million years ago, all you need to do to catch a glimpse of their descendants is take a look in your backyard. From lanky cranes to common chickens, all birds can be traced back to prehistoric creatures.

Some birds have retained ancient traits like extra claws and pouched beaks, while others have evolved into small, domesticated animals, but all are strong reminders that dinosaurs existed.

A fossil from 2 million to 5 million years ago has nearly the same structure as modern sandhill cranes.

Sandhill cranes feeding in Kentucky. David Stephenson/AP

The sandhill crane can be found across North America and can reach nearly 4 feet in height with a 6-foot wingspan. Between their deliberate walk, exuberant mating dance, and rattling trills, it's easy to imagine one of these birds walking among the dinosaurs.

Sandhill cranes' ancient relatives have nearly the same structure. According to the International Crane Foundation, a fossil from 2 million to 5 million years ago was discovered in Nebraska that appeared almost identical to modern sandhill cranes.

With 4-inch claws and a tall casque on its head, the cassowary shares physical traits with prehistoric creatures.

A cassowary in Australia. cuatrok77/Flickr

Cassowaries are native to New Guinea and Australia. They have 4-inch claws, a hard casque on their heads, and can jump 5 feet in the air.

National Geographic reported in July 2017 that a dinosaur called the Corythoraptor jacobsi was unearthed in China and shares many physical similarities to the cassowary, including its casque.

Chickens share genetic makeup with the Tyrannosaurus rex.

Chickens walk on a farm in Maryland. Joshua Roberts/Reuters

The domesticated chicken is one of the most common bird species on the planet. According to Statista, in 2011, there were about 20.88 billion in the world. And while they may not seem especially intimidating, they share genetic makeup with the Tyrannosaurus rex.

In a study published in 2008, researchers compared tissue found in a 68-million-year-old T. rex bone to 21 modern creatures, including alligators and chimpanzees. The study found that the T. rex's tissue was more similar to chickens and ostriches than to any other animals, including reptiles.

Shoebills are known to eat baby crocodiles.

A shoebill in the San Diego Zoo Safari Park. Lenny Ignelzi/AP

The menacing shoebill stands as tall as 5 feet and can be found in the swamps of East Africa. These huge birds gobble up smaller prey, including catfish, monitor lizards, and baby crocodiles.

Shoebills communicate by clattering their giant bill together, creating a call that has been compared to the sound of a machine gun. According to Australia's Special Broadcasting Service, the hook at the end of the shoebill's bill is similar to the bone structure of a velociraptor.

Baby hoatzins have extra claws growing from their wings for climbing.

Hoatzins at the Manu National Park in Peru. Enrique Castro-Mendivil/Reuters

The hoatzin is a common South American bird with tall plumage on its head, a bright-blue face, and piercing red eyes. Baby hoatzins grow an extra set of claws on their wings so that they can hide in water if threatened by predators and then climb back up to their nest.

According to research published in 2015 cited by the National Audubon Society, hoatzins are a unique species that separated from other birds approximately 65 million years ago, and their closest relatives are cranes and plovers.

Pelicans' pouches are reminiscent of pterosaurs that lived 120 million years ago.

Pelicans catching fish. B. Mathur/Reuters

Over six different species of pelicans live around the world. They're known for the giant pouch attached to their beaks, which they use to scoop up fish.

The Ikrandraco avatar, a pterosaur found in China and thought to have lived 120 million years ago, had a large, toothed beak with a pouch. According to researchers, the pouch indicates the creature may have scooped up its food, similar to a pelican.

The helmeted hornbill has a unique and vibrant beak.

The helmeted hornbill has a unique and vibrant beak.

The helmeted hornbill, with its striking appearance and maniacal-laughter-like call, is nothing short of a living, breathing dinosaur.

However, helmeted hornbills are critically endangered. They're found only in Borneo, Sumatra, and southern Thailand. They have a prominent red casque and are often hunted for their solid beaks and sold on the black market.

Creatures just like the modern ostrich have been found fossilized in Canada.

Ostriches crossing a road at the Nairobi National Park in Kenya. Thomas Mukoya/Reuters

The ostrich is an intimidating flightless bird that can reach 9 feet tall, 350 pounds, and run up to 43 miles an hour. Using its strong legs, an ostrich can kill a human, lion, or other threat with a couple of swift kicks.

The Ornithomimus, a Mesozoic Era dinosaur discovered fossilized in Canada, has similar traits to an ostrich. The Smithsonian, citing the journal Cretaceous Research, reported that both creatures have dense feathers covering their bodies, long necks, and bare legs, which help to regulate body heat.

The vicious red-legged seriema shakes its prey to death.

A red-legged seriema. Wagner Machado Carlos Lemes Follow/Flickr

The 1-meter-high red-legged seriema is a vicious bird commonly found in eastern regions of South America. The carnivore's diet includes venomous snakes and whole quail eggs.

When they catch their prey, red-legged seriemas shake it in their beak, beat it on the ground, and ultimately tear it to pieces. According to the Cornell Lab of Ornithology, red-legged seriemas are relatives with Phorusrhacids, which are extinct creatures known as "terror birds."

The large Canada goose makes honking noises like its prehistoric ancestors.

Two Canada geese feeding. Toby Talbot/AP

Canada geese can grow larger than 3 feet tall and can be found near bodies of water in North America. They make distinct honking noises to interact with one another.

In 2016, researchers discovered that the Vegavis iaai, which was found fossilized in the Antarctic Peninsula, likely made honking noises similar to a goose. Researchers found that the Vegavis iaai had a syrinx, which creates the squawking noises.

Source: www.thisisinsider.com

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