All about dinosaurs, fossils and prehistoric animals by Everything Dinosaur team members.
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20 06, 2020

Fossil “Stick” Proves to be New Species of Ancient Plant

By | June 20th, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Keraphyton mawsoniae – Late Devonian Fern-like Plant

A fossil found more than fifty years ago and described as a “fossilised stick” has proved to be a new species of Late Devonian plant and it is helping scientists to better understand the flora of the landmass of Gondwana.  The specimen measures a little over 9 cm in length, with a width across its ribbed surface of around 2 cm.  It was found by amateur geologist John Irving whilst exploring the banks of the Manilla River in Barraba (New South Wales, Australia), after a period of extensive flooding.  It remained unstudied in the fossil collection of the geological survey of New South Wales for five decades until it was despatched to France as part of a wider study to map plant evolution.

The Fossil and Cross-sectional Slices (K. mawsoniae)

Keraphyton mawsoniae fossil.

The newly described Keraphyton mawsoniae a fern-like land plant from the Late Devonian of Australia.  Scale bar in (B) equals 2 mm and scale bars in C-H equal 500 μm.

Picture Credit: Champreux et al (PeerJ)

The picture (above), shows (A) the fossil specimen before preparation, (B) a general view of the stem system shown in cross-section, with (C-H) highly magnified areas showing the internal structure of the plant.  The fossil is from the Mandowa Mudstone Formation (Upper Devonian) and it is believed to represent a plant stem.

A Very Rare Fossil Discovery

During the Middle to Late Devonian land plants were becoming larger, more complex and diverse.  Major groups of plants that were to dominate the flora of the Mesozoic evolved and the first widespread forests and land-based ecosystems became established.  Well-preserved plant fossils from this time in Earth’s history are exceptionally rare.  Plants related to ferns and other types that produce seeds (Euphyllophytina), became more specious during this time in Earth’s history, fossils of fern-like plants are known from the northern hemisphere but the Gondwanan record is extremely sparse.

The French laboratory of Botany and Modelling of Plant Architecture and Vegetation (AMAP) in Montpellier has been collating data on early plant species from the Devonian/Carboniferous of Australia and Antoine Champreux, studied the fossil specimen as part of his Master’s Degree before completing his research whilst a PhD student at Flinders University in South Australia.

Gondwana During the Late Devonian (Position of Australia)

Map showing the location of the Barraba fossil find in relation to Gondwana.

A map showing the location of Australia in relation to the rest of Gondwana during the Middle to Late Devonian.  The position of the fossil discovery is highlighted.

Picture Credit: University of Witwatersrand with additional annotation from Everything Dinosaur

Antoine commented:

“It’s nothing much to look at – just a fossilised stick – but it’s far more interesting once we cut it and had a look inside.  The anatomy is preserved, meaning that we can still observe the walls of million-year-old cells.  We compared the plant with other plants from the same period based on its anatomy only, which provide a lot of information.”

The research team found that this early land plant represents a new genus of plant, sharing some similarities with modern ferns and horsetails.

Antoine added:

“It is an extraordinary discovery, since such exquisitely-preserved fossils from this period are extremely rare.  We named the genus Keraphyton (like the horn plant in Greek), and the species Keraphyton mawsoniae, in honour of our partner Professor Ruth Mawson, a distinguished Australian palaeontologist who died in 2019.”

To read about a bizarre, giant predatory marine worm from the Devonian: Monster Worm of the Devonian.

The scientific paper: “Keraphyton gen. nov., a new Late Devonian fern-like plant from Australia” by Antoine Champreux​, Brigitte Meyer-Berthaud, and Anne-Laure Decombeix published in the open access journal PeerJ.

19 06, 2020

The First Dinosaur Eggs were Soft

By | June 19th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

The First Dinosaur Eggs were Soft like a Turtle’s

The scientific paper has a succinct title, but the repercussions for vertebrate palaeontologists are seismic.  This week has seen the publication in the journal Nature of a paper entitled “The first dinosaur egg was soft”.  Palaeontologists have inferred and implied a great deal about dinosaur reproduction, but the assumption had been that, just like living archosaurs today, the crocodiles and birds, dinosaurs laid hard-shelled eggs.  Dr Mark Norell (American Museum of Natural History) and his co-authors propose that calcified, hard eggshells were not the “default setting” for the Dinosauria, the first dinosaur eggs were soft-shelled like those of a turtle or a snake.  In addition, the researchers conclude that hard-shelled, calcified eggs evolved at least three times independently within the Dinosauria.

Protoceratops Protects a Nest from a Marauding Oviraptorosaur

Protoceratops defends its nest from Oviraptor.

Protoceratops confronts Oviraptor- the egg thief.  An inaccurate portrayal of both the Oviraptorosaur and Protoceratops, but until now, not many had questioned the accuracy of those hard-shelled eggs.

Picture Credit: Everything Dinosaur (from Zalinger)

Unscrambling Dinosaur Eggs

The research led by the American Museum of Natural History in collaboration with colleagues from Yale University, Universidad de Buenos Aires (Argentina), Montana State University, University of Calgary (Canada) and the Museo Paleontológico Egidio Feruglio, Trelew, (Argentina), applied a series of sophisticated geochemical techniques to analyse the eggs of two different non-avian dinosaurs.  They discovered that the eggs resembled those of extant turtles in their composition, microstructure and mechanical properties.

Commenting on the significance of this research, corresponding author Mark Norrell stated:

“The assumption has always been that the ancestral dinosaur egg was hard-shelled.  Over the last 20 years, we’ve found dinosaur eggs around the world.  But for the most part, they only represent three groups – theropod dinosaurs, which includes modern birds, advanced hadrosaurs like the duck-billed dinosaurs and advanced sauropods, the long-necked dinosaurs.  At the same time, we’ve found thousands of skeletal remains of ceratopsian dinosaurs, but almost none of their eggs.  So why weren’t their eggs preserved?  My guess – and what we ended up proving through this study, is that they were soft-shelled.”

Ceratopsian Eggs Were Probably Soft-shelled and This Explains their Rarity in the Fossil Record

The leathery, soft shells of turtle eggs.

The leathery, soft shell of the common snapping turtle (Chelydra serpentina). The eggs of the first dinosaurs were probably very similar.

Picture Credit: Jasmina Wiemann (Yale University)

Calcified Eggshells – An Evolutionary Hedge Against Environmental Stress

The amniotes, a group of tetrapods that includes the mammals, birds and the reptiles all produce eggs with an inner membrane, known as the amnion.  This inner membrane helps to prevent the embryo from drying out.  Some amniotes such as many turtles and squamates (lizards and snakes), lay soft-shelled, leathery eggs, whilst others such as birds and crocodilians produce eggs with a heavily calcified shell.  It is thought that these calcified eggs help to protect the developing embryos inside the eggs from environmental stresses, thus giving the calcified egg layers an evolutionary advantage.  The evolution of the hard-shelled egg is seen as a major step in the global dominance of the amniotes, it leading to greater reproductive success for those members of this group that developed this trait.

The Eggs from a Member of the Theropoda (Domestic Chicken)

Chicken eggs (theropod dinosaur eggs).

Calcified, hard-shelled eggs such as these from a theropod (domestic chicken) were thought to be representative of all Dinosauria eggs.

Picture Credit: Everything Dinosaur

The Fossil Record Shows Bias in Favour of Calcified Eggs

Soft-shelled eggs rarely preserve in the fossil record.  It is very likely that ancient turtles laid soft-shelled eggs, just like their modern counterparts, but such evidence is hard to find in the fossil record.  The same could be inferred for other amniotes, they too might have laid soft-shelled eggs but such evidence would be very difficult to find.  Therefore, studying the transition from soft-shelled eggs to biomineralised, calcified eggs is a substantial challenge for palaeontologists.  As birds and extant crocodilians lay hard-shelled eggs, this type of eggshell has been inferred for all the non-avian dinosaurs.

Protoceratops and Mussaurus

The research team undertook an intensive study of two fossil egg specimens appertaining to two very different dinosaurs – the neoceratopsian Protoceratops (P. andrewsi), known from the Upper Cretaceous Djadokhta Formation exposed in the Gobi Desert of Mongolia and Mussaurus (M. patagonicus) from the Upper Triassic-aged El Tranquilo Formation located in southern Argentina.   The beautifully preserved Protoceratops fossils include a clutch of at least a dozen eggs with embryos, half of which preserve nearly complete skeletons.  Most of the Protoceratops embryos are preserved in a posture in which their vertebrae and limbs are flexed, synonymous with a posture adopted by animals still inside their eggs.

The Protoceratops (P. andrewsi) Nest Fossil

Protoceratops Fossil Nest

The beautifully preserved nest with embryos of Protoceratops andrewsi.

Picture Credit: M. Ellison (American Museum of Natural History)

Some of the skeletal material is obscured by a black and white egg-shaped halo.  In contrast, two potentially recently hatched Protoceratops in the fossil specimen are largely free of this mineral halo.  The research team analysed tiny slices of this halo material using a petrographic microscope.  Further analysis was undertaken using Raman microspectroscopy, where light scattered by a high powered laser provides information on the molecular composition of a sample.  The scientists discovered chemically altered trace residues of the proteinaceous eggshell membrane that makes up the innermost layer of the eggshell of extant archosaurs.  Almost identical results were observed when the Mussaurus specimen was examined.

The Fossilised Remains of the Mussaurus Egg

Mussaurus fossil egg.

The fossilised remains of a Mussaurus.

Picture Credit: Diego Pol (Museo Paleontológico Egidio Feruglio, CONICET)

Comparing Biomineralisation Residue Signatures

The research team which included Diego Pol (Museo Paleontológico Egidio Feruglio CONICET), Darla Zelenitsky (University of Calgary) and Jasmina Wiemann (Yale University) then compared the data from the fossil material to eggshell data from other living amniotes such as turtles, birds, lizards and crocodiles.  They determined that the Mussaurus and the Protoceratops eggs were non-biomineralised and therefore they would have resembled the leathery, soft-shelled eggs of living turtles.

Graduate student Jasmina Wiemann explained:

“It’s an exceptional claim, so we need exceptional data.  We had to come up with a brand-new proxy to be sure that what we were seeing was how the eggs were in life and not just the result of some strange fossilisation effect.  We now have a new method that can be applied to all other sorts of questions, as well as unambiguous evidence that compliments the morphological and histological case for soft-shelled eggs in these animals.”

Creating a “Supertree” to Track Eggshell Evolution

In total, data from 112 extinct and living amniotes was analysed by the research team.  This enabled them to build a “supertree” to track the phylogeny of egg-shell evolution over geological time.  They concluded that the ancestors of the Dinosauria probably produced an egg that lacked a calcified layer, that these animals laid soft-shelled eggs and that the first, true dinosaurs had the same type of egg.  This element of the research suggests that calcified, hard-shelled eggs evolved independently at least three times throughout the Mesozoic era in the Dinosauria, explaining the bias towards eggshells of derived dinosaurs in the fossil record.  The calcified layer of eggshell evolved independently in ornithischian, sauropodomorph and theropod dinosaurs.

Co-author Matteo Fabbri (Yale University) added:

“From an evolutionary perspective this makes much more sense than previous hypotheses, since we’ve known for a while that the ancestral egg of all amniotes was soft.  From our study, we can also now say that the earliest archosaurs, the group that includes dinosaurs, crocodiles and pterosaurs had soft eggs.  Up to this point, people just got stuck using the extant archosaurs – crocodiles and birds to understand dinosaurs.”

Implications for the Pterosauria

This research has implications for the Pterosauria clade.  Pterosaur eggs are exceptionally rare, a fossil of the wukongopterid (Darwinopterus modularis), reveals the outline of a single egg inside the body cavity. The egg confirms that the pterosaur fossil represents a female that was gravid when she died.  More significantly, scientific papers detailing extensive fossil remains associated with the debris from a nesting colony of the pterosaur Hamipterus tianshanensis have been published and the three-dimensionally preserved eggs do resemble the leathery soft-shelled eggs now associated with members of the Dinosauria.

Fossilised Eggs of Hamipterus tianshanensis – Could They have the Same Biomineralisation Profile of Soft-shelled Dinosaur Eggs?

Egg fossils (Pterosaur).

Pterosaur egg fossils (Hamipterus tianshanensis).

Picture Credit: Xinhua/Wang Xiaolin

To read our 2017 blog post about the Hamipterus colony: Hamipterus Nesting Ground Discovery.

To read our recent article about the discovery of a giant soft-shelled egg associated with a marine reptile: It’s Not a Deflated Football, it’s Probably an Egg from a Mosasaur.

Everything Dinosaur acknowledges the assistance of a media release from the American Museum of Natural History in the compilation of this article.

The scientific paper: “The first dinosaur egg was soft” by Mark A. Norell, Jasmina Wiemann, Matteo Fabbri, Congyu Yu, Claudia A. Marsicano, Anita Moore-Nall, David J. Varricchio, Diego Pol and Darla K. Zelenitsky published in the journal Nature.

18 06, 2020

Tracking Down Australia’s Big Carnivorous Dinosaurs

By | June 18th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Tracking Down Australia’s Largest Ever Terrestrial Predator

Scientists from the University of Queensland have conducted a review of the data associated with a series of Jurassic-aged theropod dinosaur prints preserved on the ceilings of coal mine galleries deep underground.  They conclude that some of these prints represent predatory dinosaurs around ten metres in length, making these trace fossils evidence of the largest terrestrial carnivores ever to have lived in Australia.

A Life Reconstruction of a Large Carnosaur Compared to a Person and a Silhouette of Tyrannosaurus rex

Calculating the size of a theropod dinosaur from its tracks.

By measuring the length of a print the approximate hip height of the track-maker can be calculated.  In this case, the largest theropod tracks indicate a hip height of 3 metres.  This suggests an overall length of around 10 metres.

Picture Credit: Dr Anthony Romilio et al (University of Queensland)

Australia’s Big Carnivorous Dinosaurs

Dinosaur tracks from the coal-mines from Rosewood near Ipswich, and Oakey just north of Toowoomba in southern Queensland have been known about for decades.  The prints and trackways are located in sediments directly above coal seams and give the impression of dinosaurs defying gravity by walking on the ceiling.  The explanation for the trace fossils is rather more mundane but still quite remarkable when the age of these tracks (estimated at around 151 to 161 million years old) is considered.

Large Theropods (Carnosauria) Left the Prints When Walking Across Swampy Ground

T. gurneyi.

Trace fossils from theropod dinosaurs indicate that giant carnosaurs roamed southern Queensland during the Middle to Late Jurassic (Callovian to Tithonian).

Picture Credit:  Sergey Krasovskiy

How Were These Trace Fossils Formed?

Tridactyl prints made by theropod dinosaurs onto mats of compressed swamp-vegetation became covered with silt, mud and sand from flood-water.  Over millions of years the remains of the swamp vegetation became compressed and turned into coal, which was then excavated by Australian miners deep underground during the 19th and 20th centuries.  As the coal seams were removed, these left exposed on the ceiling of the mine galleries, the inlaid 160 million-year-old dinosaur tracks.  Many of the mines exploiting the Walloon Coal Measures from the Clarence-Morton Basin have been closed, with their access shafts filled in.  Access to many of these prints in the mines is no longer possible, so the researchers relied on previous research and unpublished archival photographs from which they were able to create three-dimensional images of some of the individual prints.

Photograph and False-Colour 3-D Map of a Tridactyl Print from the Oakey Coal Mine

Photograph and false-colour image of a theropod print.

One of the dinosaur footprints from the Oakey mine (photograph on the right and corresponding false-colour deep map on the left).

Picture Credit: Dr Anthony Romilio et al (University of Queensland)

The three-toed (tridactyl), prints with claw marks, typical of theropod dinosaurs, dominate the tracksites.  The size of the prints varies, most of the prints measure between 30 to 50 cm long.  However, a number of trace fossils from the eleven track-bearing sites analysed in this study, are much bigger.  The largest measures 79 cm in length, the biggest carnivorous dinosaur footprint discovered to date in Australia.

Footprint size can be used to calculate an approximate hip-height of the theropod dinosaur that made the track.  Once a hip-height has been estimated, then palaeontologists can quickly work out just how big that dinosaur actually was.

Lead author of the research, published in Historical Biology, Dr Dr Anthony Romilio explained:

“Most of these footprints are around 50 to 60 centimetres in length, with some of the really huge tracks measuring nearly 80 centimetres.  We estimate these tracks were made by large-bodied carnivorous dinosaurs, some of which were up to three metres high at the hips and probably around 10 metres long.  To put that into perspective, T. rex got to about 3.25 metres at the hips and attained lengths of 12 to 13 metres long, but it didn’t appear until 90 million years after our Queensland giants.”

Examining the Theropod Prints from the Walloon Coal Measures

False colour images and an assessment of theropod size

A variety of different sized theropod tracks were identified with the largest 79 cm long.

Picture Credit: Dr Anthony Romilio et al (University of Queensland)

Intriguingly, all the tracksites studied are dominated by the three-toed prints of theropods.  These theropod dominated trace fossil assemblages are unique among Australian dinosaur tracksites.  In the absence of any contemporaneous dinosaur body-fossils, these prints and tracks preserved on the ceilings of the coal mines provide palaeontologists with important data helping them to fill in gaps about the composition of Middle and Late Jurassic Australian dinosaur fauna.

What Type of Meat-eating Dinosaur Made the Tracks?

The strata in which the tracks are preserved span around ten million years or so (Callovian to Tithonian faunal stages of the Jurassic).  Palaeontologists are aware that during this time there was a change in the types of large, carnivorous dinosaurs that dominated terrestrial ecosystems.  The fossil record, although far from complete, suggests a decline in the Megalosauroidea during the Middle Jurassic and the rise to prominence of the Avetheropoda clade consisting of the Allosauroidea and the Coelurosauria.

A Faunal Turnover in Theropod Dinosaurs During the Jurassic

Theropod faunal turnover in the Jurassic.

Theropod faunal turnover (taxa estimated to be <250 kgs) the rise of the Allosauroidea.  It is likely that the type of dinosaur(s) that made the Queensland ceiling prints will never be known.

Picture Credit: Palaeontologica Electronica

However, the taxonomy of the Theropoda, even at the superfamily level is controversial and open to debate.  For example, the Carnosauria clade had been redefined, constraining it to the allosaurs and their closest relatives.  In 2019, a new basal allosauroid from the Middle Jurassic of Argentina was described Asfaltovenator (A. vialidadi).  Asfaltovenator had a combination of primitive and more derived anatomical features.  As a result, a new phylogenetic analysis extended the Carnosauria clade to once again include the Megalosauroidea.

A Life Reconstruction of Asfaltovenator from the Middle Jurassic of Argentina

Asfaltovenator illustration.

Asfaltovenator life reconstruction.  The scientific description of this carnivorous dinosaur led to a reassessment of the components of the Carnosauria clade.

Picture Credit: Gabriel Lio/Conicet

In short, the researchers are uncertain as to what types of meat-eating dinosaur left the prints.  In the absence of any other fossil evidence, we shall probably never know.

To read a related article examining three-toed tracks from the ceiling of the Australian Mount Morgan caves complex preserved in Lower Jurassic deposits: Mystery of Dinosaur Prints on Cave Ceiling Solved.

The scientific paper: “Footprints of large theropod dinosaurs in the Middle–Upper Jurassic (lower Callovian–lower Tithonian) Walloon Coal Measures of southern Queensland, Australia” by Anthony Romilio, Steven W. Salisbury and Andréas Jannel published in Historical Biology.

17 06, 2020

It’s Not a Deflated Football – It’s Probably an Egg from a Mosasaur

By | June 17th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Antarcticoolithus bradyi – An Egg from a Giant Mosasaur

A football-sized palaeontological mystery might have been solved.   A strange object found by a research team from Chile whilst exploring the López de Bertodano Formation on Seymour Island, in Antarctica back in 2011, is probably the fossilised remains of a mosasaur egg.  That is the conclusion of a scientific paper published this week in the journal Nature.  The strange object, described as looking like a deflated football was found in Upper Cretaceous (Maastrichtian) deposits and these strata yield the fossils of dinosaurs and early birds, but they are essentially near-shore marine deposits and mosasaur fossils are found in the vicinity.  The massive egg is the largest soft-shelled egg known to science and the second largest egg ever recorded.  Only the enormous, hard-shelled eggs of elephant birds (family Aepyornithidae), that once lived on the island of Madagascar, are larger.

A Scientist Holding the Strange “Deflated Football” – Probably the Egg of a Giant Mosasaur

The largest soft-shelled egg known to science.

The strange object identified as the giant egg from a mosasaur.  It was nicknamed “the Thing” in recognition of the 1982 American science fiction horror film directed by John Carpenter that told the story of an alien life form attacking a base in Antarctica.

Picture Credit: Legendre et al (Universidad de Chile)

One of the scientific paper’s co-authors, David Rubilar-Rogers from Chile’s National Museum of Natural History had been part of the field team that found the fossil.  It remained in the Museum’s fossil collection for years, unstudied and not classified.  Visiting scientists and academics were not able to identify what it was until Julia Clarke from the University of Texas at Austin visited in 2018 and proposed that the specimen represented a giant, soft-shelled egg.

A Thin Eggshell

Microscopy confirmed that the object was indeed an egg, one with a shell five times thinner than that associated with the hard-shelled eggs of elephant birds.  The structure of the fossil was similar to vestigial eggs laid by some snakes and lizards today (lepidosaurs).  These types of eggs are laid but hatch almost immediately, the babies are fully developed and entirely altricial.  Further analysis of the fossil discovered no evidence of an embryo to help confirm identification of the egg-layer, this was an eggshell, the baby having hatched.  However, mosasaurs are lepidosaurs, (Order Squamata) and the scientists propose that the egg was laid by a giant mosasaur.

Photographs, Illustrations and Microscopic Analysis of the Fossil Egg

Photographs, drawings and a microscopic analysis of the fossil egg.

Photographs and illustrations of the fossil egg with (bottom) a microscopic structure analysis of the eggshell layers.  In the illustrations (b, d and f) actual eggshell is shown in dark grey whilst the surrounding matrix is light grey.  Note the scale comparison with a person on the far right.

Picture Credit: Legendre et al

A Massive Egg Laid by a Massive Mosasaur

The scientists, which include lead author Lucas Legendre, of the Department of Geological Sciences (University of Texas at Austin), estimate that the egg would have weighed around 6.5 kilogrammes and it would have measured about 29 cm long when it was laid.  The actual fossil measures 28 cm by 18 cm.  The team compiled a data set comparing the body sizes of living and extinct amniotes to calculate the potential size of the animal that produced the massive egg.  They calculate that the egg was probably laid by a mosasaur that had a length of around 7 metres (excluding the tail).

A Mosasaur Hatching

A hatching mosasaur.

An artist’s impression of the hatching mosasaur emerging from the soft-shelled egg moments after the egg was laid.

Picture Credit: Legendre et al (Universidad de Chile)

A Scale Drawing Showing the Proposed Size of the Female Mosasaur that Laid the Egg

Scale drawing showing the size of the female mosasaur.

Scale drawing showing the female mosasaur, the egg and the size of the hatchling with the fossil specimen.  Scale bar = 1 metre

Picture Credit: Francisco Hueichaleo

The First Fossil Egg from Antarctica

The visibly collapsed and folded fossil specimen represents the first vertebrate egg of any kind to be discovered in Antarctica.  The researchers speculate that the near-shore, marine sediments of the López de Bertodano Formation represent an estuarine environment that linked onto a large, shallow bay.  Vertebrate fossils found on Seymour Island include dinosaur bones and poorly preserved footprints, shorebird and waterfowl fossils as well as the remains of marine reptiles such as elasmosaurs and mosasaurs.

Legendre, a Postdoctoral Fellow at the Department of Geological Sciences, commented:

“Many authors have hypothesised that this was sort of a nursery site with shallow protected water, a cove environment where the young ones would have had a quiet setting to grow up.”

Was the Egg Laid on Land or Was it Laid in the Sea?

Did mosasaur females struggle ashore to lay their eggs in nests like turtles or did they lay vestigial eggs that hatched almost immediately having been laid in the open sea.  The scientific paper does not specifically discuss how mosasaurs reproduced, but there are three competing hypotheses:

1).  Mosasaur females left the water and excavated nests on the beach in which their eggs were deposited.  When the eggs hatched, the young mosasaurs would scuttle down the beach and enter the water.

2). Mosasaurs were ovoviviparous – mosasaur embryos developed inside eggs that were retained inside the mother’s body until they were ready to hatch. This method of reproduction is similar to viviparity, but the embryos have no placental connection with the mother and they receive their nourishment from the yolk sac although some gaseous exchange between the egg and the mother takes place.

Ovoviviparity Reproduction in a Mosasaur

A hypothesis that mosasaurs were ovoviviparous

Ovoviviparity reproduction in mosasaurs.

Picture Credit: Legendre et al (Universidad de Chile)

3).  The female mosasaur remained mostly in the water, which helped to support its body weight, but manoeuvred its body so that it could reverse out of the water and deposits its eggs on the shore.

Although not convinced that mosasaurs laid their eggs on land, co-author of the scientific paper Julia Clarke explained:

“We can’t exclude the idea that they shoved their tail end up on shore because nothing like this has ever been discovered.”

An Artist’s Impression of an Ovoviviparous Marine Reptile

The Seymour Island fossil site could represent a mosasaur nursery.

An ovoviviparous mosasaur lays its egg in the bay and the young mosasaur quickly emerges.

Picture Credit: Legendre et al (Universidad de Chile)

This remarkable egg fossil has been given the oogenus Antarcticoolithus which translates as “late Antarctic stone egg”.

Everything Dinosaur acknowledges the assistance of a media release from the Universidad de Chile in the compilation of this article.

The scientific paper: “A giant soft-shelled egg from the Late Cretaceous of Antarctica” by Lucas J. Legendre, David Rubilar-Rogers, Grace M. Musser, Sarah N. Davis, Rodrigo A. Otero, Alexander O. Vargas and Julia A. Clarke published in the journal Nature.

16 06, 2020

Mojo Tyrannosaurus rex Deluxe “Turntable Tuesday”

By | June 16th, 2020|Adobe CS5, Dinosaur Fans, Everything Dinosaur Products, Everything Dinosaur videos, Main Page, Photos of Everything Dinosaur Products, Product Reviews|0 Comments

Mojo Tyrannosaurus rex Deluxe “Turntable Tuesday”

It is “Turntable Tuesday” on Everything Dinosaur’s YouTube channel once again and this time, it is the turn of the new for 2020 Mojo Fun Tyrannosaurus rex deluxe to go for a spin on our studio turntable.  The Mojo “Prehistoric and Extinct” range of figures is a little T. rex top heavy at the moment, Everything Dinosaur has seven Mojo tyrannosaur figures in stock at the moment, if the baby T. rex figure is included.  However, a number of the older models have been de-listed and are likely to be out of production very soon. All the more reason to focus on some of the sixteen new for 2020 dinosaurs introduced into this line, hence our decision to highlight the Mojo Tyrannosaurus rex deluxe dinosaur model.

Taking a Spin for “Turntable Tuesday” – The Mojo Fun Tyrannosaurus rex Deluxe

Video Credit: Everything Dinosaur

Mojo Tyrannosaurus rex Deluxe

This carefully crafted dinosaur figure shows plenty of detail, the bright yellow eye can be easily seen in the close up shots of the model when the articulated lower jaw is demonstrated.  The jaw opens quite well and the tongue has been skilfully painted.

A Close View of the Head and the Articulated Jaw of the T. rex Dinosaur Figure

The Mojo Fun Tyrannosaurus rex deluxe figure has an articulated jaw.

A close view of the head and articulated jaw of the Mojo T. rex dinosaur model.  Can you spot the yellow eye?

Picture Credit: Everything Dinosaur

The head sculpt has been designed to emphasis the stereoscopic vision of this apex predator.  The orbit in the skull of mature T. rex specimens suggest that the actual eye of this carnivorous dinosaur was about the size of a tennis ball.  Many palaeontologists believe, that just like its close relatives the birds, Tyrannosaurus rex had excellent colour vision.

A View of the Front of the Dinosaur Model (Anterior) Showing the Stereoscopic Vision

The Mojo Fun T. rex Deluxe dinosaur model approaches.

The Mojo Tyrannosaurus rex deluxe figure demonstrates stereoscopic vision.

Picture Credit: Everything Dinosaur

Everything Dinosaur’s Video Review

In our short “Turntable Tuesday” review, (the video lasts 1:45), we compare this new figure to the Papo brown running T. rex figure, that was originally introduced in 2013.  Although the figures are similar and both dinosaurs have articulated lower jaws, the Mojo model is slightly smaller and has a leaner look to it.  The Mojo Tyrannosaurus rex deluxe has a darker colour scheme providing emphasis on the countershading.

A Comparison Between Two Excellent Dinosaur Figures

Comparing T. rex dinosaur models.

A comparison between the Mojo T. rex deluxe and the Papo running T. rex dinosaur model.

Picture Credit: Everything Dinosaur

The Everything Dinosaur YouTube channel has over 170 dinosaur and prehistoric animal related videos and reviews: Subscribe to Everything Dinosaur on YouTube.

To view the Mojo Fun Tyrannosaurus rex deluxe model and the rest of the Mojo “Prehistoric and Extinct” model range: .Mojo Prehistoric Animal Models.

15 06, 2020

Overoraptor chimentoi On the Road to the Birds

By | June 15th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Overoraptor chimentoi – Closer to Birds than Most other “Raptors”

Time for Everything Dinosaur team members to catch up on their reading.  Whilst browsing through the various press releases, emails and news bulletins from around the world, our attention was drawn to the scientific description of a new, gracile “raptor” from the Upper Cretaceous of Argentina.  Named Overoraptor chimentoi, fossils of this 1.3 metre-long, theropod dinosaur were first discovered in 2013 during field work on 90 million-year-old strata associated with the Huincul Formation in the Patagonian province of Rio Negro.  Further fossils were found during excavations in the same area in 2018.  Although fragmentary, the bones of this small dinosaur suggest that it was more closely related to that lineage of dinosaurs that led to the birds than it is to the likes of Velociraptor and other dromaeosaurids.

A Life Reconstruction of a Pair of Overoraptor chimentoi

Overoraptor life reconstruction.

A life reconstruction of a pair Overoraptors.  Although no feather impressions were found in association with the fragmentary fossils, it is very likely that Overoraptor chimentoi had feathers.

Picture Credit: Gabriel Lio

A Very Bird-like Theropod

The fossil record of members of the Eumaniraptora group of dinosaurs known from the southern hemisphere is sparse.  Evidence of those “raptors” that were closely related to that branch of this group that led to the modern birds is even rarer.  At present, (2020), the fossil evidence is limited to the Unenlagiinae (mostly from the Late Cretaceous of Argentina such as Buitreraptor [B. gonzalezorum]) and the bizarre, bird-like Rahonavis (R. ostromi) from the Upper Cretaceous Maevarano Formation of north-western Madagascar.

Overoraptor exhibits a range of anatomical traits.  The feet and legs are very typical of a dromaeosaurid.  There is the second toe “killing claw” associated with the “raptors” and the lower limb bones indicate that this was a fast-running, cursorial predator.  However, the upper limb bones are very different.  The ulna for example, is very robust and long, reminiscent of the upper limb bones of modern birds.

The Fragmentary Fossils of Overoraptor chimentoi

Overoraptor fossil remains.

Tiny but very significant Overoraptor fossil material including unguals.

Picture Credit: Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”

The picture above shows the fragmentary fossils associated with the new species – Overoraptor chimentoi.  The genus name is from the Spanish “overo” which means piebald, a reference to the mixed colour of the fossil bones.  The trivial name honours Roberto Nicolás Chimento who found the first remains.

Close to the Bird Part of the Dinosaur Family Tree

A phylogenetic analysis conducted by the researchers revealed that Overoraptor was closely related to Rahonavis, that roamed Madagascar some twenty million years later.   The analysis suggests that these two dinosaurs are descended from a common ancestor (they form a monophyletic clade).  Together they are stem avialans within the Eumaniraptora, a line of theropods in which some flight-related adaptations of the forelimbs are present in non-flying taxa.

Commenting on the importance of Overoraptor, one of the co-authors of the paper, Fernando Novas (Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”) stated:

“Contrary to what we originally assumed, the Overoraptor is not part of the Unenlagia family, but from another group including a Madagascan species called Rahonavis.”

The discovery of Overoraptor sheds light on the acquisition of flight-related traits in non-avian dinosaurs and on the still poorly known paravian radiation in Gondwana.

The scientific paper: “New theropod dinosaur from the Upper Cretaceous of Patagonia sheds light on the paravian radiation in Gondwana” by Matías J. Motta, Federico L. Agnolín, Federico Brissón Egli and Fernando E. Novas published in The Science of Nature.

14 06, 2020

A Video Review of “Dinosaurs – how they lived and evolved”

By | June 14th, 2020|Adobe CS5, Book Reviews, Dinosaur Fans, Everything Dinosaur News and Updates, Everything Dinosaur videos, Main Page, Press Releases|0 Comments

“Dinosaurs – how they lived and evolved” Video Review

Everything Dinosaur Facebook fans and followers will know that recently we ran a special competition to win one of three signed copies of the new dinosaur book by Darren Naish and Professor Paul Barrett.  The contest may have drawn to a close but for those of you not lucky enough to win one of the “Dinosaurs – how they lived and evolved”, we have produced a short video, providing a brief overview of this excellent publication.

A Whizz Through “Dinosaurs – how they lived and evolved”

Video credit: Everything Dinosaur

Completely Revised and Updated

In our short video review, we highlight “Dinosaurs – how they lived and evolved”, a book originally published in 2016, but this edition has been updated and revised.  Conveniently split into six comprehensive chapters, starting with an introduction to the Dinosauria and concluding with the End-Cretaceous mass extinction event that saw the demise of the non-avian dinosaurs.  The final chapter also looks at those theropods that survived the extinction event – the birds.  This well-written book briefly highlights the diversity of the birds but also leaves the reader in no doubt that the Aves suffered extinctions at the end of the Mesozoic.

Beautifully Illustrated Dinosaur Book

Wonderful illustrations in the dinosaur book.

As well insightful writing, the book features the work of famous artists such as John Sibbick, Davide Bonadonna, Bob Nicholls and Mark Witton.

Picture Credit: Everything Dinosaur (from Dinosaurs – how they lived and evolved)

Fantastic Dinosaur Illustrations and Artwork

Aimed at the general reader with an interest in the Earth sciences and especially palaeontology, this new publication is eminently suitable for teenagers and above.  It is crammed full of fascinating information and provides a comprehensive overview of dinosaurs, with many detailed illustrations and cladograms provided by Darren Naish (University of Southampton).  Look out for amazing artwork produced by such luminaries as Bob Nicholls, Davide Bonadonna, Mark Witton, John Sibbick and Dr Julius Csotonyi (pronounced Chit-en-Knee).  It was Bob Nicholls who created the fascinating illustration of a ginkgo-chewing heterodontosaurid (Tianyulong confuciusi) that features on the front cover.

Tianyulong confuciusi Features on the Front Cover

The front cover of the dinosaur book.

Artwork by the very talented Bob Nicholls features on the front cover of “Dinosaurs – how they lived and evolved”.

Picture Credit: Everything Dinosaur

An illustration of Sinosauropteryx prima

An illustration of Sinosauropteryx prima.

An illustration of Sinosauropteryx with its countershading and “bandit mask” produced by Bob Nicholls, just one of large number of superb illustrations and examples of palaeoart included in the book.

Picture Credit: Everything Dinosaur

Everything Dinosaur Facebook Competition

Everything Dinosaur Facebook fans and followers will probably remember that we recently ran a special competition to win one of three signed copies of this brilliant dinosaur book.  Co-author Darren Naish had produced a personalised drawing on the inside front cover of each of the prizes that Everything Dinosaur gave away in their free to enter contest.

A Personalised and Signed Dinosaur Illustration on the Inside Front Cover

A sketch of Caudipteryx.

A sketch of the primitive oviraptorosaur Caudipteryx by Darren Naish.  Lucky Everything Dinosaur competition winners received a personalised and signed copy of this dinosaur book.

Picture Credit: Everything Dinosaur

The Everything Dinosaur YouTube channel, is packed with lots of amazing videos all about dinosaurs and prehistoric animals: Subscribe to Everything Dinosaur on YouTube.

13 06, 2020

Mojo Fun Brachiosaurus Deluxe Dinosaur Model

By | June 13th, 2020|Adobe CS5, Dinosaur Fans, Everything Dinosaur News and Updates, Everything Dinosaur Products, Main Page, Photos of Everything Dinosaur Products, Product Reviews|0 Comments

The Mojo Fun Brachiosaurus Deluxe Dinosaur Model

Brachiosaurus has been a mainstay of the Mojo Fun “Prehistoric and Extinct” prehistoric animal model range since this series was introduced.  Recently, new members of the Sauropodomorpha have been added, a colourful Diplodocus was included back in 2018 and this year, the long-necked dinosaur numbers have been swelled with the addition of a Mamenchisaurus, Brontosaurus and a new Brachiosaurus deluxe model.

The New for 2020 Mojo Fun Brachiosaurus Deluxe Dinosaur Model

The new Mojo Fun Brachiosaurus deluxe dinosaur model.

The new for 2020 Mojo Fun Brachiosaurus deluxe dinosaur model.

Picture Credit: Everything Dinosaur

A Subdued Colouration

The new Brachiosaurus figure has a more subdued colouration than the Mojo Fun Diplodocus.  There is certainly much to be admired in this new replica of “arm lizard” and at around eighteen centimetres tall, this is quite a sizeable dinosaur model too.  Prior to the model’s arrival we took the opportunity to take some photographs of the Brachiosaurus and other sauropods in the Mojo Fun “Prehistoric and Extinct” model range.

Getting to Grips with a Brachiosaurus

Mojo Fun Brachiosaurus dinosaur model.

The new for 2020 Mojo Fun Brachiosaurus dinosaur model measures around 25 cm long and that detailed head stands nearly 18 cm high.

Picture Credit: Everything Dinosaur

The 2018 Mojo Fun Diplodocus Dinosaur Model

Mojo Fun Diplodocus model (2018).

Mojo Fun Diplodocus dinosaur model.  This 2018 replica had a more colourful paint scheme than the other long-necked dinosaurs within the “Prehistoric and Extinct” model range.

Picture Credit: Everything Dinosaur

A spokesperson from Everything Dinosaur commented:

“Very little if anything is known about the colouration of the Sauropodomorpha.  Many of these dinosaurs were giants and although their colouration is speculative, the largest terrestrial vertebrates today, animals such as elephants and rhinos, tend to have subdued, grey colouration.  Whilst scientists cannot be certain what colour these dinosaurs were, a number of model making companies including Mojo have tended to depict these animals with more subtle colour schemes with greys and browns predominating.”

The New for 2020 Mojo Fun Brachiosaurus Deluxe Dinosaur Replica

Mojo Fun Brachiosaurus deluxe.

Photographing the Mojo Fun Brachiosaurus deluxe model in the Everything Dinosaur studio.

Picture Credit: Everything Dinosaur

Many of the recently introduced models in this range are larger than their predecessors.  For example, the new for 2020 Brachiosaurus is around 4 centimetres longer than the Mojo Fun “large” Brachiosaurus model.  In order to help collectors to distinguish the bigger models, many of these are termed “deluxe”.  As a further assistance, on the Everything Dinosaur website, actual model measurements are provided by clicking the “additional information” link on each product page.

To view the range of Mojo Fun “Prehistoric and Extinct” figures: Mojo Fun Prehistoric Animal Models and Figures.

12 06, 2020

Were Some Ancient Crocodiles Bipeds?

By | June 12th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Fossil Tracks Attributed to Crocodiles Show Bipedal Stance

Fossilised narrow-gauge tracks from the Lower Cretaceous Jinju Formation of South Korea suggest that some types of ancient crocodylomorphs were bipedal.  Writing in the academic journal “Scientific Reports”, the researchers which include palaeontologist Martin Lockley, an emeritus professor at the University of Colorado, describe a series of trackways discovered near Sacheon City, (south-eastern, South Korea).  Only prints made by the hind limbs are preserved and there are no manus (handprints) identified.  The quality of the trace fossils, the presence of well-preserved foot pads with skin traces and the absence of any foot-on-hand overprinting suggest that these ancient reptiles walked on their hind legs.

The tracks have been assigned to the ichnogenus Batrachopus and the largest tracks are believed to have been made by animals around three metres long.

A Life Reconstruction of the Ichnogenus Batrachopus (B. grandis)

Fossilised footprints suggest bipedal Cretaceous crocodylomorphs.

A life reconstruction of the crocodylomorph ichnogenus Batrachopus (B. grandis).

Picture Credit: A. Romilio (University of Queensland)

Batrachopus grandis

The tracksite covers approximately 800 square metres and has yielded four track-bearing levels from a series of strata the represent about 5 metres of the Jinju Formation.  The deposits consist of mudstones, shales and fine-grained sandstones that represent the margins of a large freshwater lake.  Based on the size of the prints, some of which measure up to 24 cm in length, the researchers have erected the ichnospecies Batrachopus grandis.  One track shows well-defined scale impressions on the heel that resemble those of modern crocodilians.

Tracks of the Ichnospecies Batrachopus grandis with Skin Impression Preserved (Photograph B).

Crocodylomorph tracks - Batrachopus grandis.

Photographs of well-preserved in situ Batrachopus grandis ichnosp. nov. track impressions from surface 2.  Left foot (A,B) and right foot tracks (C, D).  Scale bar = 20 cm.

Picture Credit: Kim et al

An Upright Bipedal Posture

The absence of any tail drag marks and the depth of the heel impressions support the idea that these reptiles were moving in a similar way to most theropod dinosaurs.  Team leader, Professor Kyung Soo Kim (Chinju National University of Education, South Korea), also stated that the width of the tracks indicate that these crocodiles were walking upright in a terrestrial environment.

The Professor remarked:

“Our trackways are very narrow-looking, more like a crocodile balancing on a tight-rope.  When combined with the lack of any tail-drag marks, it became clear that these creatures were moving bipedally.  They were moving in the same way as many dinosaurs, but the footprints were not made by dinosaurs.  Dinosaurs and their bird descendants walk on their toes.”

Plantigrade Prints

The Dinosauria generally, non-avian and avian forms, walk on their toes (digitigrade), whilst crocodiles walk on the soles of their feet, just like humans and bears (plantigrade).  The plantigrade nature of the tracks rules out them having been made by a member of the Dinosauria clade.

Photographs and Line Drawings of Trackways (Batrachopus grandis)

Batrachopus grandis - photographs and line drawings.

Photos and outline drawings of trackways and trackway segments of Batrachopus grandis.

Picture Credit: Kim et al

The picture above shows photographs and line drawings of trackways and trackway segments associated with the ichnospecies B. grandis.  The holotype track (T16), is enlarged and shown as a line drawing on the right.

These Tracks Shed Light on Pterosaur Locomotion

These tracks may also help to determine the track-maker from another tracksite from South Korea that was described back in 2012.  Professor Lockley was part of a research team that uncovered a set of less-well defined prints that were thought to have been made by a huge pterosaur.  It had been suggested that these tracks represented a flying reptile wading through shallow water with just its hind feet in contact with the sediment.  Although these tracks are geologically younger than the trackways discovered near Sacheon City, Professor Lockley discounts the wading pterosaur theory and suggests that these tracks too, were probably made by a bipedal crocodylomorph.

The Scientists Compared the Tracks to Other Tracks from the Fossil Record and with Those Made by American Crocodiles

Comparing fossil trackways.

Fossil crocodylomorph tracks compared to an American crocodile (Crocodylus acutus), the prehistoric crocodile Mehliella jeffersonensis and the pterosaur trackway Haenamichnus uhangriensis.

Picture Credit: Kim et al

The picture above, shows (far left) the trackway created by an extant crocodile species, the American crocodile (C. acutus).  A line drawing of a track associated with B. grandis is adjacent.  Note that the B. grandis tracks are narrower.  The third track represents a crocodilian known from trace fossils from Colorado (Mehliella jeffersonensis).  These tracks indicate quadruped locomotion and a clear tail drag mark is preserved in the centre of the trackway.  The line drawing (far right), represents tracks that had been thought to represent a pterosaur trackway (Haenamichnus uhangriensis).

Haenamichnus uhangriensis

The flying reptile tracks come from the Lower Cretaceous Haman Formation located in South Korea.  The large, bipedal plantigrade prints were assigned the ichnospecies Haenamichnus uhangriensis and it had been proposed that the tracks represented a pterosaur wading through shallow water, trying to avoid its wings becoming mired in the substrate.  The researchers confidently conclude that these tracks do not represent a large flying reptile and that they are actually poorly preserved bipedal crocodylomorph trace fossils.

To read a related article about the discovery of tiny dinosaur tracks: Smallest Dinosaur Tracks Known to Science.

The scientific paper: “Trackway evidence for large bipedal crocodylomorphs from the Cretaceous of Korea” by Kyung Soo Kim, Martin G. Lockley, Jong Deock Lim, Seul Mi Bae & Anthony Romilio published in Scientific Reports.

11 06, 2020

Still Time to Enter Everything Dinosaur Book Competition

By | June 11th, 2020|Adobe CS5, Dinosaur Fans, Everything Dinosaur News and Updates, Main Page, Photos/Pictures of Fossils|0 Comments

Everything Dinosaur Book Competition Closes Midnight 14th June (2020)

There is still time to enter Everything Dinosaur’s fabulous competition to win one of three signed dinosaur books!  However, time is running out as our competition closes at midnight on Sunday 14th June.  Everything Dinosaur is offering to give away three very special signed copies of “Dinosaurs – how they lived and evolved” by Darren Naish and Paul M. Barrett, a fantastic book published by the Natural History Museum of London in our free to enter competition.

PLEASE NOTE THIS COMPETITION IS NOW CLOSED

Win a Fantastic Book – “Dinosaurs – How they Lived and Evolved”

A free to enter competition organised by Everything Dinosaur.

Win a signed copy of the brilliant new book “Dinosaurs how they lived and evolved” by Darren Naish and Paul M. Barrett courtesy of Everything Dinosaur.

Picture Credit: Everything Dinosaur

Competition Time at Everything Dinosaur!

To enter our competition, all you have to do is “Like” Everything Dinosaur’s Facebook page, then comment on the “Dinosaurs – how they lived and evolved” picture, providing a suggested name for the Tianyulong dinosaur featured on the front cover.

Everything Dinosaur on Facebook: Visit Everything Dinosaur on Facebook.  Then “Like” our Facebook page, provide a name for the dinosaur in the comments suggestion and you have entered the competition!

We will draw the lucky winners at random and the “Dinosaurs – how they lived and evolved” competition closes at midnight Sunday 14th June.  Good luck to all those that enter, we hope you win one of these unique dinosaur books.  Each one of our prizes has been signed by Darren Naish one of the authors.  He has also included a little drawing on the inside front cover, making these prizes truly unique.

Comprehensive History of the Dinosauria – Great Photographs of Famous Fossils Too!

Coelophysis features in the dinosaur book.

The book contains lots of amazing colour photographs of famous dinosaur fossils.

Picture Credit: Everything Dinosaur

“Dinosaurs – How they Lived and Evolved” Features the Work of Famous Artists

Wonderful illustrations in the dinosaur book.

As well insightful writing, the book features the work of famous artists such as John Sibbick and Mark Witton.

Picture Credit: Everything Dinosaur

We wish everyone the very best of luck in our free to enter, dinosaur book contest.  For details of the competition including terms and conditions, hit this link here: Dinosaur Book Competition – Terms and Conditions.

PLEASE NOTE THIS COMPETITION IS NOW CLOSED

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