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/Palaeontological articles

Articles, features and information which have slightly more scientific content with an emphasis on palaeontology, such as updates on academic papers, published papers etc.

20 04, 2021

New Species of Titanosaur Described

By | April 20th, 2021|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A new species of titanosaur has been named and described this week based on a partial skeleton unearthed in the Atacama Desert of northern Chile. The dinosaur has been named Arackar licanantay which translates as “Atacama bones” in the indigenous Kunza language.

Life Reconstruction Arackar licanantay
A life reconstruction of the newly described Late Cretaceous titanosaur Arackar licanantay from the Atacama Desert of northern Chile. Picture Credit: Museo Nacional de Historia Naturala Santiago (Chile).

The Second Titanosaur from Chile to be Named

As far as Everything Dinosaur team members are aware, this is the second titanosaur to be named and described from fossil remains found in Chile. The first was Atacamatitan chilensis, fossils of which were discovered at the beginning of this century. Although Atacamatitan is only known from fragmentary remains, the alignment, shape and skeletal position of the femur in relation to the hips are very similar to that of Arackar, so, Atacamatitan was probably closely related to Arackar licanantay, although its fossilised remains were found many hundreds of miles to the north.

Three Chilean Dinosaurs to Date

In total, three non-avian dinosaurs have been described from fossil remains discovered in Chile. The other dinosaur making up this trio is the peculiar Chilesaurus (Chilesaurus diegosuarezi), which is know from Jurassic deposits in the Aysén region of southern Chile. To read about the discovery of Chilesaurus: Chilesaurus – Shaking the Dinosaur Family Tree.

Chilesaurus scale drawing.
A scale drawing of the bizarre Late Jurassic dinosaur Chilesaurus. Chilesaurus is one of just three non-avian dinosaurs known from Chile (April 2021). Picture Credit: Everything Dinosaur.

Arackar licanantay – “Atacameño Bones”

Writing in the journal “Cretaceous Research”, scientists from the National Museum of Natural History (Chile), the Palaeontological Network of the University of Chile and the Dinosaur Laboratory of the National University of Cuyo describe a partial skeleton from the Upper Cretaceous (Campanian–Maastrichtian) beds of the Hornitos Formation, Atacama Region, of northern Chile. The holotype material consists of cervical and dorsal vertebrae along with limb bones and the ischium. The dinosaur’s name translates as “Atacameño bones” in the language of the indigenous Kunza people.

Arackar licanantay fossil material being excavated
Identifying a limb bone from the new species of titanosaur (Arackar licanantay). Picture credit: Universidad de Chile.

A Sub-adult Specimen

The fossils were found in the 1990s by national geologist Carlos Arévalo (National Geology and Mining Service), at a site around 45 miles south of the city of Copiapó, (Atacama Region). The bones represent a sub-adult individual estimated to have been around 6.3 metres in length. Although the adult size of Arackar is not known, it has been suggested that when fully grown, this herbivorous dinosaur would have been around 8-9 metres long, relatively small for a titanosaur.

Arackar was certainly no giant unlike other titanosaurs such as Dreadnoughtus, Notocolossus or Argentinosaurus which lived millions of years earlier. The discovery of this dinosaur helps to support the idea that towards the end of the Cretaceous (Campanian to Maastrichtian stages), these types of dinosaurs got smaller, perhaps in response to climate change.

Bone Dry

The fossil site might be located in one of the driest parts of the world, but when Arackar roamed (sometime between 80 and 66 million years ago, the age of the Hornitos Formation is uncertain), the climate was much more humid with the lush vegetation consisting of many types of flowering plant (angiosperms), conifers such as araucarias and podocarpaceae as well as ferns and cycads.

Chile may have only three non-avian dinosaurs described to date, but the scientists are confident that many more genera will be named. For example, close to the Arackar fossils, the remains of a second, as yet undescribed titanosaur were discovered.

Titanosaur fossil material (Arackar licanantay)
Fossil remains at the dig site, the preserved remains of limb bone. Another titanosaur specimen that has yet to be described was found close by. Picture Credit: Universidad de Chile.

Commenting on the significance of this discovery, Consuelo Valdés, the Minister of Culture, Arts and Heritage stated:

“This finding is a relevant opportunity to learn about and disseminate the value of our country’s palaeontological heritage, which is unique in the world. But, at the same time, we hope to motivate curiosity and interest in research in children and young people. Chile in the extreme north and south has palaeontological treasures still hidden in layers many millions of years old. These bones can tell the story of the animals and plants that have lived in our country long before the first human groups arrived here.”

South America – Home to the Titanosaurs

The scientific description of Arackar licanantay may have important implications for the taxonomy and phylogeny of the clade of derived and advanced titanosaurs known as the Lithostrotia. Of the eighty or so genera of titanosaurs named and described so far, fifty-five come from South America but most have been found to the east of the Andes in Brazil and Argentina.

Unique autapomorphies (traits) in the skeleton such as the shape of the dorsal vertebrae that would have given this dinosaur a very straight withers and back indicate that A. licanantay is not only closely related to Chile’s other titanosaur – Atacamatitan chilensis, but also to Rapetosaurus from the Late Cretaceous of Madagascar and Isisaurus (from India).

Titanosaur Taxonomic Relationships
The taxonomy of South American titanosaurs over time and geographical distribution. The red star represents the approximate placement of Arackar licanantay. Picture credit: Hechenleitner et al (Communications Biology) with additional annotation by Everything Dinosaur.

Co-author of the paper, Alexander Vargas (Palaeontological Network of the University of Chile), commented that it would be helpful if palaeontologists could understand the biogeographical distribution that allowed related titanosaurs to be so widespread.

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

The scientific paper: “Arackar licanantay gen. et sp. nov. a new lithostrotian (Dinosauria, Sauropoda) from the Upper Cretaceous of the Atacama Region, northern Chile” by David Rubilar-Rogers, Alexander O. Vargas, Bernardo González Riga, Sergio Soto-Acuña, Jhonatan Alarcón-Muñoz, José Iriarte-Díaz, Carlos Arévalo and Carolina S. Gutstein published in Cretaceous Research.

12 04, 2021

New Jurassic Pterosaur Reveals the Oldest Opposed Thumb

By | April 12th, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|1 Comment

An opposable thumb gives us apes a huge advantage, just ask a dog to hold a spoon for you, however, opposable thumbs are not just limited to gorillas, chimps, orangutans and our own genus Homo. Other apes have them too, as do some marsupials and tree frogs. In reality, opposed thumbs are rare in the Kingdom Animalia, but an international team of scientists including researchers from the University of Birmingham, have just described a new species of flying reptile and it’s the earliest example known to science of a vertebrate with an opposed thumb.

Kunpengopterus life reconstruction
Life reconstruction of K. antipollicatus. The opposed pollex could have been used for grasping food items, as well as clinging and hanging to trees. Picture credit: Zhao Chuang.

Kunpengopterus antipollicatus

The new Jurassic pterosaur has been named Kunpengopterus antipollicatus, it was discovered in the Tiaojishan Formation of Liaoning, China.

It is a small-bodied darwinopteran pterosaur, with an estimated wingspan of 85 cm. Most importantly, the specimen was preserved with an opposed pollex (“thumb”) on both hands. The species name “antipollicatus” means “opposite thumbed” in ancient Greek, in light of the opposed thumb of the new species. This is the first discovery of a pterosaur with an opposed thumb. It also represents the earliest record of a true opposed thumb in the fossil record.

Kunpengopterus antipollicatus fossil and line drawing
Fossil of Kunpengopterus antipollicatus, discovered in the Tiaojishan Formation of China. It is housed in the Beipiao Pterosaur Museum of China. Image credit: Zhou et al., 2021.

“Monkeydactyl”

Kunpengopterus lived in a forested environment approximately 160 million years ago. It was nicknamed “monkeydactyl” as a true opposed thumb (pollex) is extremely rare amongst extant reptiles, only chameleons possess opposed thumbs. They use their thumbs to help them climb, the researchers writing in the academic publication “Current Biology”, also suggest that Kunpengopterus evolved such dexterity to help it to climb.

In order to test the arboreal interpretation, the team analysed K. antipollicatus and other pterosaurs using a set of anatomical characters related to arboreal adaptation. The results support K. antipollicatus as an arboreal species, but not the other pterosaurs from the same ecosystem. This suggests niche-partitioning among these pterosaurs and provides the first quantitative evidence supporting the theory that at least some darwinopteran pterosaurs were arboreal.

Minimising Competition Amongst Pterosaurs

Lead author Xuanyu Zhou (China University of Geosciences) commented:

“Tiaojishan palaeoforest is home to many organisms, including three genera of darwinopteran pterosaurs. Our results show that K. antipollicatus has occupied a different niche from Darwinopterus and Wukongopterus, which has likely minimised competition among these pterosaurs.”

Photo and digital model of the left hand of K. antipollicatus, showing the opposed thumb.
Photo and digital model of the left hand of K. antipollicatus, showing the opposed thumb. Image credit: Zhou et al., 2021.

Micro-CT Imaging Assists in Discovery

Fion Waisum Ma, co-author of the study and PhD researcher (University of Birmingham) explained:

“The fingers of “Monkeydactyl” are tiny and partly embedded in the slab. Thanks to micro-CT scanning, we could see through the rocks, create digital models and tell how the opposed thumb articulates with the other finger bones. This is an interesting discovery. It provides the earliest evidence of a true opposed thumb, and it is from a pterosaur – which wasn’t known for having an opposed thumb”.

Everything Dinosaur acknowledges the assistance of a press release from the University of Birmingham in the compilation of this article.

The scientific paper: “A new darwinopteran pterosaur reveals arborealism and an opposed thumb” by Xuanyu Zhou, Rodrigo V. Pêgas, Waisum Ma, Xuefang Wei, Caizhi Shen and Shu’an Ji published in Current Biology.

9 04, 2021

A New Species of Ancient Mammal from Southern Chile

By | April 9th, 2021|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A new species of Late Cretaceous South American mammal has been named and described. The omnivorous Orretherium tzen is only the second mammal from the Mesozoic known from Chile. The newly described O. tzen joins Magallanodon baikashkenke which was named in 2020. Orretherium has been described from a partial lower jawbone, which had 5 teeth in situ and a single isolated tooth found just a few metres away from the jaw fragment. It is thought to have been about the size of a modern skunk, although it was only distantly related to modern mammals.

Orretherium Life Reconstruction
Orretherium lived some 74-72 million years ago in South America. It shared its habitat with numerous dinosaurs including titanosaurs (seen in the background).

The Mammal Quarry

The fossils were found in exposures of the Dorotea Formation (late Campanian to early Maastrichtian faunal stages of the Late Cretaceous), on a small hill nicknamed “the mammal quarry”, reflecting the significance of the site in terms of Late Cretaceous mammalian fossil finds. Although the isolated tooth that helped describe this species was found close to the jaw fragment, the researchers cannot unambiguously refer this tooth to the same individual animal although it is highly probable taking in account their compatible size, wear and close proximity.

Orretherium fossil study.
Map (inset) showing the fossil find location, a reconstruction of the head of Orretherium along with a photograph of the jawbone and a computer enhanced image of the fossil.

Classified as a member of the Meridiolestida

Orretherium has been classified as a member of the Meridiolestida, an extinct group of mammals known from South America and Antarctica.

Co-author of the research paper published in the journal Scientific Reports, Sergio Soto-Acuña (University of Chile), commented:

“This mammal is a primitive lineage of the group of meridiolestids, very successful at the end of the Age of dinosaurs in South America. The jaw found has five teeth in place that indicate omnivorous habits, it probably fed on plants and insects”.

Looking for Late Cretaceous Mammals
Field work being carried out at “the mammal quarry” as scientists from the University of Chile in collaboration with researchers from Universidade Federal do Rio Grande do Sul (Brazil), Museo de La Plata (Argentina) and other South American academic institutions collaborated to produce the scientific paper describing Orretherium.

The scientific paper: “New cladotherian mammal from southern Chile and the evolution of mesungulatid meridiolestidans at the dusk of the Mesozoic era” by Agustín G. Martinelli, Sergio Soto-Acuña, Francisco J. Goin, Jonatan Kaluza, J. Enrique Bostelmann, Pedro H. M. Fonseca, Marcelo A. Reguero, Marcelo Leppe and Alexander O. Vargas published in Scientific Reports.

6 04, 2021

Trilobites had Gills on their Legs

By | April 6th, 2021|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Newly published research has provided palaeontologists with remarkable new evidence shedding light on the evolution of gill structures in the Arthropoda. Writing in the academic journal “Science Advances”, researchers from the University of California Riverside in conjunction with colleagues from the Indian Statistical Institute (Kolkata) and the American Museum of Natural History (New York), have demonstrated that some species of trilobite had gills on their upper limbs.

Trilobite Gill Fossil
One of the exceptionally rare trilobite specimens preserved in iron pyrite (fool’s gold) that led to the gill discovery. Picture Credit: Jin-bo Hou/University of California Riverside. The fossil is a specimen of Triarthrus eatoni from the famous Beecher’s trilobite bed from Oneida County, New York.

Exquisitely Preserved Fossils

Many thousands of species of trilobite have been named and described. However, very few fossils of these enigmatic, extinct members of the Arthropoda preserve soft parts of the animal’s bodies.

Trilobite fossils - the Selenopeltis slab.
Trilobites galore – the Selenopeltis slab from the Oxford University Museum of Natural History. The hard, exoskeletons of trilobites are extremely common fossils.

Fossils Preserved as Fool’s Gold Reveal New Information

The segmented limbs of trilobites were biramous, that is the limb was spilt into two branches. The function of the upper element of this limb has long been debated. It had been thought by some scientists that is served a respiratory function, but the evidence to support this hypothesis was lacking.

Remarkably detailed fossil specimens preserved in iron pyrite were subjected to scans using computerised tomography (CT scans). The computer generated images revealed dumbbell-shaped filaments in the upper limb branch that are morphologically comparable with gill structures in crustaceans.

A detailed view of a trilobite leg
A detailed view of a biramous (branched) trilobite leg showing the structures which have been interpreted as gill structures. Scale bar = 500 μm. Picture credit: Jin-bo Hou/University of California Riverside.

The Beecher’s Trilobite Bed

The beautifully preserved specimens with their soft parts replaced by pyrite come from the famous Beecher’s trilobite bed which is a Late Ordovician Lagerstätte with over 85% of the fossils found at the site representing the trilobite Triarthrus eatoni.

Lead author of the paper PhD student Jin-bo Hou (University of California Riverside) commented:

“Up until now, scientists have compared the upper branch of the trilobite leg to the non-respiratory upper branch in crustaceans, but our paper shows, for the first time, that the upper branch functioned as a gill”.

The research team mapped how blood would have filtered through chambers in these delicate structures, absorbing oxygen as it progressed through the tiny structures which measure around 30 microns across, that’s three times smaller than the diameter of a human hair.

These structures appear much the same as gills in modern marine arthropods like lobsters and crabs, but crucial anatomical differences were identified, helping scientists to better understand the phylogeny of the Trilobita within the arthropod phylum. Comparing the specimens in pyrite to another trilobite species (Olenoides serratus), gave the team additional information about how the filaments were arranged relative to one another and to the legs.

The researchers concluded that the upper limb’s partial articulation to the body via an extended membrane is morphologically comparable to the junction of the respiratory book gills of extant horseshoe crabs (Limulus). Furthermore, this morphology differentiates it from the typically robust junctions associated with crustaceans and the extinct sea scorpions.

The scientific paper: “The trilobite upper limb branch is a well-developed gill” by Jin-bo Hou, Nigel C. Hughes and Melanie J. Hopkins published in Science Advances.

3 04, 2021

Extra-terrestrial End-Cretaceous Impact Gave Rise to the Amazon Rainforest

By | April 3rd, 2021|Adobe CS5, Animal News Stories, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Key Stage 3/4, Main Page, Palaeontological articles|0 Comments

The Amazon rainforest is an extremely important low latitude habitat with a huge diversity of animals, fungi and plant species. Described as the “lungs of the planet”, this tropical rainforest is at the very centre of many global conservation efforts. New research suggests that it was the extra-terrestrial impact event some 66 million years ago that led to the rise of this angiosperm dominated ecosystem.

Earth impact event.
Cataclysmic impact event that led to the extinction of the dinosaurs and lots of other animal life. New research suggests that the dinosaur-killing bolide also gave rise to the Amazon rainforest ecosystem. Picture credit: Don Davis (commissioned by NASA).

K/Pg Extinction Event

Approximately 66 million years ago a rock from space smashed into our planet. This triggered a sudden mass extinction event devastating around 75% of all the animal and plant terrestrial species, many of which subsequently became extinct. At this time the dinosaurs, their cousins the pterosaurs and the majority of marine reptiles died out.

The end of the non-avian dinosaurs.
An artist’s impression of the bolide about to impact with the Gulf of Mexico 66 million years ago. This devastating event wiped out a large number of animals and plants, very probably contributing to the extinction of many different families including all the non-avian dinosaurs. Picture credit: Chase Stone.

Analysis of Fossil Pollen and Study of Fossil Leaves

Writing in the journal “Science”, researchers from the Southern Methodist University (Texas) and the University of Wyoming report on the study of tens of thousands of fossil pollen specimens along with thousands of leaf fossils from Cretaceous-aged strata and deposits laid down after the K/Pg extinction event. The scientists, which include co-author Dr Ellen Currano (Department of Botany, University of Wyoming), found that the types of plant creating tropical forests were very different pre and post the extra-terrestrial impact. In the Late Cretaceous tropical forests were dominated by conifers and they were much more open than the dense, angiosperm forests that came about during the Palaeocene.

Cretaceous maniraptora.
Study suggests the floral composition of tropical rainforests changed dramatically after the extra-terrestrial impact event. During the Late Cretaceous tropical forests were dominated by conifers and forest canopies were less dense. Picture Credit: Danielle Dufault.

A Thick Forest Canopy Denying Access to Light

The scientists discovered that the fossil pollen and leaves show a marked transition in tropical forest flora. After the extra-terrestrial impact forests developed a thick canopy blocking much of the light from reaching the ground and angiosperms became more dominant.

A view of a modern tropical rainforest canopy.
An aerial view of the dense angiosperm dominated canopy of a modern rainforest. Picture credit: BBC.

How Did These Changes Come About?

As well as the documenting the turnover in flora and the transition from one tropical forest environment to a different type of rainforest in the Palaeocene, the researchers propose three possible explanations for this change:

  1. The absence of large megaherbivores, specifically dinosaurs allowed plant densities in forests to increase. The extinction of giant plant-eating dinosaurs such as the Ceratopsia, hadrosaurs, armoured dinosaurs and the titanosaurs allowed plants to grow at lower levels as they were not being trampled or consumed by herbivorous dinosaurs.
  2. Several types of fern and conifer became extinct during the K/Pg transition permitting new types of angiosperm (flowering plants) to evolve and exploit the vacated niches.
  3. Falling ash from the impact enriched soils throughout the tropics, provided an advantage to faster-growing angiosperms.
The floral composition of rainforests radically altered after the K/Pg extinction event.
The floral composition of rainforests radically altered after the K/Pg extinction event. Picture Credit: BBC.

The scientists conclude that the three hypotheses are not mutually exclusive and that a combination of factors could have led to the change in the flora as recorded in the fossil record.

A Significant Lesson for Today

Today, a rapidly changing climate, largely caused by the actions of our own species is having a dramatic effect on the world’s forests. The researchers note that the fossil record demonstrates that rainforests do not simply “bounce back”, after a catastrophe. They can take millions of years to recover and a very different type of ecosystem is likely to emerge.

The scientific paper: “The impactful origin of neotropical rainforests” by Bonnie F. Jacobs and Ellen D. Currano published in the journal Science.

1 04, 2021

Llukalkan aliocranianus – New Abelisaurid from Argentina

By | April 1st, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A team of international researchers have named and described a new species of fearsome, meat-eating dinosaur based on a partial skull found in 2015 in Neuquén Province (northern Patagonia). The dinosaur is a member of the Abelisauridae family and it has been named Llukalkan aliocranianus. The genus name is from the local Mapuche dialect and translates as “one who causes fear”. Not only was Llukalkan a likely apex predator, its discovery helps to confirm that the abelisaurs were one of the most important and significant predators in South America during the Late Cretaceous.

A Life Reconstruction of the Abelisaurid Dinosaur Llukalkan aliocranianus
A life reconstruction of the newly described abelisaurid from Argentina Llukalkan aliocranianus. Picture credit: Jorge Blanco and the Journal of Vertebrate Paleontology.

Found in Close Proximity to Viavenator exxoni

The well-preserved skull was found in outcrops of the Bajo De La Carpa Formation at the La Invernada fossil site. The strata at this location were laid down approximately 85 million years ago (Santonian faunal stage of the Late Cretaceous) and the bones were found close to the location of an earlier abelisaurid discovery (Viavenator exxoni), which had been found by some of the scientists that also participated in the Llukalkan study.

Assessment of the lacrimal bone suggest that this skull material represents a sub-adult animal and comparison with other abelisaurids such as Carnotaurus indicates that Llukalkan may have been around five metres in length, making it slightly smaller than Viavenator which is estimated to have been around six metres long.

Skull Bones associated with Llukalkan aliocranius
A view of the cranial material of the holotype (Llukalkan aliocranianus) – view in left lateral view with line drawing showing where the bones fit with the rest of the skull. Unique rugose and roughened patches on the skull bones confirmed that the scientists were dealing with a new species.

Writing in the peer reviewed academic publication the “Journal of Vertebrate Paleontology”, the researchers which included Federico A. Gianechini, Leonardo S. Filippi and Ariana Paulina-Carabajal identified a number of autapomorphies within the skull material that led them to confidently assign a new species. The trivial name is derived from the Latin for “different skull”.

Abelisaurids “Top Dogs”

Something like ten different genera of abelisaurid dinosaur have been discovered in Patagonia to date. The scientists state that Llukalkan and Viavenator were probably contemporaneous and they help to demonstrate the dominance of this type of theropod dinosaur in the Late Cretaceous of Argentina. Both Viavenator and the newly described Llukalkan were closely related, both have been assigned to the Abelisauridae clade – the Furileusauria which includes the geologically much younger and much larger Pycnonemosaurus (P. nevesi), fossils of which come from Brazil.

Megaraptors for Company

It is likely that these two furileusaurian abelisaurids probably shared their environment with another type of large theropod hypercarnivore. Fossils of the megaraptor Tratayenia rosalesi, which was described in 2018, are also associated with the Santonian-aged strata of the Bajo de la Carpa Formation, albeit the Tratayenia material was found at a different location.

Tratayenia stalking prey.
An illustration of the new Late Cretaceous megaraptoran dinosaur Tratayenia. Picture credit: Andrea McAfee (Carnegie Museum of Natural History).

At around eight metres in length (possibly even bigger), T. rosalesi was a formidable predator. Whether the abelisaurids were the “top dogs” when it came to the food chain remains uncertain. However, with the discovery of Llukalkan so close to the fossils of Viavenator, it does suggest that these types of theropods were extremely successful predators.

To read Everything Dinosaur’s earlier article on the discovery of Tratayenia rosalesi: A New Megaraptoran Theropod from Argentina.

The scientific paper: “A New Furileusaurian Abelisaurid from La Invernada (Upper Cretaceous, Santonian, Bajo De La Carpa Formation), Northern Patagonia, Argentina” by Federico A. Gianechini, Ariel H. Méndez, Leonardo S. Filippi, Ariana Paulina-Carabajal, Rubén D. Juárez-Valieri and Alberto C. Garrido published in the Journal of Vertebrate Paleontology.

31 03, 2021

Studying the Brains of Australia’s “Thunderbirds”

By | March 31st, 2021|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|2 Comments

Australia boasts a weird and wonderful flora and fauna. Millions of years of isolation has led to the land “down under” evolving a very unique biota, perhaps most marked by the abundance of marsupial mammals. Today’s fauna, remarkable as it might be, is overshadowed somewhat by the incredible megafauna that once existed on the continent. For example, giant, flightless birds thrived and evolved into a myriad of different sized forms as climates and habitats changed. Some of these birds, members of the extinct family the Dromornithidae, were giants and have been nicknamed “Thunderbirds” or even “Devil Ducks”. A newly published study examines the evolutionary development of “bird brains” in a bid to settle the phylogeny of these giant birds.

Dromornis stirtoni life reconstruction.
A life reconstruction of the giant Australian “Thunderbird” Dromornis stirtoni of the Late Miocene. At around 3 metres tall and weighing approximately 600 kilograms, D. stirtoni is one of the largest avian dinosaurs to have ever lived. Picture credit: Peter Trusler.

Mapping the Brains of “Mihirungs”

Scientists had puzzled over the phylogeny of these extinct birds for some time. Earlier studies suggested that they were related to waterfowl – hence one of their nicknames “Devil Ducks”. Researchers from Flinders University (Adelaide, South Australia), reconstructed the brains of a number of dromornithid genera in a bid to better understand the family’s origins and to learn more about their place in the Australian megafauna dominated prehistoric ecosystems.

One of the birds studied was the enormous Dromornis stirtoni, the largest of the “mihirungs” (the Aboriginal word for “giant bird”).

Dromornis "Thunderbird" fossils
Dr Warren Handley and Associate Professor Trevor Worthy – the authors of the scientific paper, hold a skull (left) and partial upper bill (right) of the mihirung Dromornis planei. Picture credit: Flinders University.

Plant-eater or Meat-eater?

Heavier than a polar bear (Ursus maritimus) Dromornis stirtoni is known from Upper Miocene deposits from Australia’s Northern Territory. It had a huge skull, more than half a metre long, but its brain was squeezed for space.

It possessed a big, powerful beak, but its diet along with the diets of other dromornithids remains a mystery. It could have fed on leaves, nuts and fruit, or perhaps it was a predator. The lack of a “hook” and the absence of talons in this and other species suggests that these flightless birds were probably not hypercarnivores.

Examining Bird Brains

Writing in the academic journal “Diversity”, the researchers examined the craniums of giant “Thunderbirds” looking at a variety of genera including the earliest Dromornis murrayi from the Late Oligocene to Dromornis planei and Ilbandornis woodburnei from the mid Miocene Epoch and Dromornis stirtoni, that roamed northern Australia around 7 million years ago (Messinian, the last stage of the Miocene).

Examining the brain structures of living and extinct Australian fowl
Fossil study reveals lost diversity in the brain structure of Australian fowl. Picture credit: Flinders University.

Related to Gamefowl (Galliformes)

The researchers conclude that these birds were probably more closely related to gamefowl (Galliformes) than they were to waterfowl (Anseriformes).

Commenting on the research, one of the authors Dr Warren Handley (Flinders University) stated:

“Together with their large, forward-facing eyes and very large bills, the shape of their brains and nerves suggested these birds likely had well-developed stereoscopic vision, or depth perception, and fed on a diet of soft leaves and fruit. The shape of their brains and nerves have told us a lot about their sensory capabilities, and something about their possible lifestyle which enabled these remarkable birds to live in the forests around river channels and lakes across Australia for an extremely long time.”

An Evolutionary Experiment

The researchers suggest that the Dromornithidae were the result of birds distantly related to chickens getting a free reign in evolutionary terms on the isolated continent. They took a very different evolutionary path when compared to their relatives the megapodes which still exist in Australasia.

The researchers postulate that the range in body sizes exhibited by dromornithids were due to climate change and the availability of food within the ecosystem. The Late Miocene was a period of dramatic climate change with the continent becoming more arid and cooler. Rainforests retreated and were replaced by more open woodlands, these changes may have played a role in the evolution of giant forms such as D. stirtoni.

Everything Dinosaur acknowledges the assistance of a media release from Flinders University in the compilation of this article.

The scientific paper: “Endocranial Anatomy of the Giant Extinct Australian Mihirung Birds (Aves, Dromornithidae)” by W. D. Handley and T. H. Worthy published in Diversity.

26 03, 2021

Study Shows Lots of Variation in Dinosaur Species

By | March 26th, 2021|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Researchers from the University of Bonn (Germany), in collaboration with colleagues from Liverpool John Moores University examined cranial material of the Plateosaurus species – P. trossingensis and discovered that the skulls of these dinosaurs demonstrated a high degree of variation. Just like people, this Plateosaurus species demonstrates a high degree of individual variation within a species.

Plateosaurus trossingensis fossil skeleton
Fossil of a Plateosaurus trossingensis, on loan from the Sauriermuseum Frick and on display at the Zoological Research Museum Alexander Koenig (ZFMK) in Bonn. Doctor Katja Waskow (left) from the Zoological Research Museum and on the right, Prof. Dr Martin Sander from the University of Bonn. Picture Credit: Volker Lannert/University of Bonn.

Not All Dinosaurs of the Same Species Looked Alike

Plateosaurus from the Late Triassic of Europe is one of the most extensively studied of all the dinosaurs, thanks mainly to the huge bonebeds containing thousands of fossilised bones that have been found. It is by studying the fossilised remains that palaeontologists can put forward evidence to suggest the erection of a new species. However, this new study published in Acta Palaeontologica Polonica, suggests that the anatomy of Plateosaurus was significantly more variable than previously thought.

A Plateosaurus dinosaur model.
A rearing Plateosaurus. A model of a Plateosaurus (CollectA Plateosaurus), this Late Triassic member of the Prosauropoda is one of the most extensively studied of all the Dinosauria.

Natural Variation

The researchers examined the complete skulls of fourteen individual Plateosaurus trossingensis specimens, eight of which had not been studied before, along with numerous other skull bones and discovered that there was considerable variation in the skulls. Such variation had been noted before and it had been suggested that the extensive bonebeds at Frick (northern Switzerland), Trossingen (south-western Germany) and Halberstadt (central Germany) might contain the fossilised remains of more than one species. However, the researchers which included PhD student Jens Lallensack (University of Bonn), could not group these variations according to specific anatomical traits, locality or their stratigraphy. The team concluded that there was no evidence to indicate the presence of more than one species, but these types of dinosaurs showed considerable variation within their species (intraspecific variability).

Plateosaurus trossingensis skull and drawing.
A Plateosaurus trossingensis skull in right lateral view with a colour coded diagram (below) showing individual fossil bones. Picture Credit: Jens Lallensack (University of Bonn).

Taking into Account Bone Deformation

The careful documentation of the skull variation will assist other palaeontologists when it comes to understanding the distinct individuality of dinosaurs within a given population. The team were able to distinguish these differences from those characteristics of the bones that are deformed and altered as a result of their fossilisation. Being able to attribute bone deformation due to taphonomy (the fossilisation process), is extremely useful in helping to determine unique anatomical traits that could lead to the identification of a new species.

Photograph (top) and a model of a deformed skull resulting from the fossilisation process (below)
Photograph (top) and a model of a deformed skull resulting from the fossilisation process (below). Picture Credit: Jens Lallensack (University of Bonn).

The scientific paper: “New skulls of the basal sauropodomorph Plateosaurus trossingensis from Frick, Switzerland: Is there more than one species?” by Jens N. Lallensack, Elżbieta M. Teschner, Ben Pabst and P. Martin Sander published in Acta Palaeontologica Polonica.

25 03, 2021

Cephalopods Evolved 30 Million Years Earlier Than Previously Thought

By | March 25th, 2021|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Cephalopods those advanced sophisticated molluscs such as octopi, squid and cuttlefish evolved some thirty million years earlier than previously thought according to some new research published this week.

Nautilus scale drawing.
A scale drawing of an extant nautilus (Nautilus pompilius). Newly published research suggests the ancestors of the modern Nautilus were around at least 522 million years ago.

Cephalopods belong to the phylum Mollusca. Animals such as the octopus are regarded as highly intelligent, capable of complex behaviours and are regarded by many scientists as being as sophisticated, if not more so, than many vertebrates. The ancestors of the extant cephalopods around today originally possessed a chambered shell, indeed, the pearly nautilus still retains this feature (see above for a nautilus illustration). Researchers from Heidelberg University in collaboration with colleagues from the Bavarian Natural History Collections examined a 522 million-year-old outcrop from the Lower Cambrian Bonavista Formation exposed at Bacon Cove (south-eastern Newfoundland, Canada). Slices of the red sandstone which represent a shallow, marine depositional environment revealed tantalising glimpses of ancient Cambrian animals.

Looking for evidence of the oldest cephalopods known to science.
Scientists documenting the evidence at Bacon Cove (Newfoundland). Picture Credit Anne Hildenbrand (Heidelberg University).

The Oldest Known Cephalopods

Tiny calcareous shells measuring no more than 14 mm high and around 3 mm wide discovered in cross-sections of the red sandstone rock are interpreted as representing phragmocones, part of the internal skeleton of a marine invertebrate. The researchers postulate that as similar structures are found in cephalopods, then these fossils represent the earliest evidence of the Cephalopoda.

Longitudinal and cross-sectional images of the fossils that could represent the oldest cephalopods known to science.
Longitudinal and cross-sectional images of the fossils that could represent the oldest cephalopods known to science. Picture credit Gregor Austermann, Heidelberg University / Communications Biology.

An Extraordinary Find

Co-author of the research, Dr Gregor Austermann (Institute for Earth Sciences at Heidelberg University), commented:

“This find is extraordinary. In scientific circles it was long suspected that the evolution of these highly developed organisms had begun much earlier than hitherto assumed. But there was a lack of fossil evidence to back up this theory.”

Documenting the fossil finds.
Carefully documenting the fossil finds at Bacon Cove. Picture credit Anne Hildenbrand (Heidelberg University).

Plectronoceras cambria

Although molecular studies had suggested that cephalopods evolved earlier than indicated by the fossil record, there was very little physical evidence to back this up. Many palaeontologists regard Plectronoceras cambria, fossils of which come from Texas limestones and date from the Middle/Late Cambrian as the earliest cephalopod. These Canadian fossils, if proved to represent the body fossils of cephalopods, push back the evolutionary origins of this important group by at least 30 million years.

The specimens described here may represent the earliest cephalopods capable of regulating the buoyancy of their shell through a siphuncle. This view supports the molecular studies that suggest that cephalopods originated in the Early Cambrian. These animals may have been the first to actively control their buoyancy and therefore to be capable of moving up and down the water column. It could be speculated that these fossils which are around 522 million years old, represent the remains of some of the first animals living above the sea floor (pelagic animals) and able to swim (nektonic).

The scientific paper: “A potential cephalopod from the early Cambrian of eastern Newfoundland, Canada” by Anne Hildenbrand, Gregor Austermann, Dirk Fuchs, Peter Bengtson and Wolfgang Stinnesbeck published in Communications Biology.

24 03, 2021

Dig Those Ankylosaurs

By | March 24th, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A study of the fossilised remains of an as yet unnamed species of ankylosaurid suggests that these dinosaurs were adapted for digging. Whilst it seems unlikely that these large herbivores could have lived in burrows, they may have been able to dig for roots and tubers, excavate wells in dried up rivers to reach subsurface water and dig into sediments to obtain supplementary minerals in a similar way that extant elephants do today.

The compact and low-slung Pinacosaurus could have been adapted for digging.
A compact and low-slung body shape with powerful limbs could be adaptations for digging. The low profile of the PNSO Pinacosaurus ankylosaurid model. A newly published scientific paper suggests that these types of dinosaurs may have dug shallow pits in which they could protect themselves from attack.

Digging Pits to Protect Their Undersides

Furthermore, many palaeontologists have postulated that these armoured herbivores might have been able to hunker down to defend their limbs and undersides from theropod predators. If these animals dug shallow pits they might have been able to protect themselves from attack and make it difficult for carnivorous dinosaurs to spot them when they were partially buried. Horned lizards (Phrynosoma) have a similar flat body and lateral fringe scales as seen in some types of ankylosaurid, these extant reptiles adopt these types of defensive strategies.

Discovered in the Early 1970s

Remains of an armoured dinosaur was first reported by a joint Soviet-Mongolian expedition to the southern Gobi Desert of Mongolia in the early 1970s. The skeleton consisting of dorsal vertebrae, elements from the limbs, ribs parts of the pelvis and the pectoral girdle along with several armoured scutes, was partially prepared for removal, but the excavation was not completed. The fossil specimen remained uncollected but crated up until 2008 when it was taken away for preparation by members of a Korean/Mongolian research team.

The crate containing (MPC-D 100/1359)
A close view of the crate containing the postcranial remains in a dorsal orientation. The fossil specimen was partially crated up but not removed from the site at Hermiin Tsav in the southern Gobi Desert (Mongolia). Abbreviations sc = scapula, dr = dorsal ribs, il = ilium.

Probably a New Species of Armoured Dinosaur

The sandstone sediments of the Upper Cretaceous (Middle to Late Campanian stage), Baruungoyot Formation have yielded the remains of three ankylosaurid taxa, namely Saichania chulsanensis, Tarchia kielanae and Zaraapelta nomadis. Writing in the journal “Scientific Reports” the researchers which include such luminaries as Phil Currie and Eva Koppelhus (University of Alberta), Michael Ryan (Canadian Museum of Nature) and corresponding author Yuong-Nam Lee (Seoul National University, South Korea), state the unnamed ankylosaurid has some similarities to S. chulsanensis, but there are anatomical differences. Unfortunately, very little postcranial fossils of Tarchia kielanae and Zaraapelta nomadis have been found making it impossible to undertake a direct comparison with this specimen (MPC-D 100/1359).

Photograph (a) and line drawing (b) of ankylosaurid fossil material.
The new ankylosaurid postcranial specimen (MPC-D 100/1359). Photograph (a) and line drawing (b) of the specimen in ventral view. Note scale bar equals 1 metre.

Adapted for Digging

The scientists speculate that several anatomical features identified in MPC-D 100/1359 could indicate that this ankylosaurid was adapted for digging. The bones in its front feet are arranged in a shallow arc, which could have enabled it to dig soft earth. The fused vertebrae and the reduced number of bones in its hind feet, compared to other dinosaurs, may have helped anchor the ankylosaurid when digging or moving its tail. The body shape of MPC-D 100/1359, which is wider in the middle and narrower at the front and rear, may have helped its body to remain straight when digging. These traits such as the narrow-wide-narrow body shape and the manus (hand) and pes (foot) bone configuration are also known in other ankylosaurids. Digging for resources out of reach from other animals and excavating shallow pits as part of a defensive strategy might have been prevalent amongst these armoured dinosaurs.

Ankylosaurid skeletal drawing.
Line drawing of the ankylosaurid skeleton, known elements in white (c) dorsal view, (d) left lateral view with armour shown, (e) left lateral view with armour removed. Note scale bar = 1 metre.

To read Everything Dinosaur’s article from 2014 about the discovery of Zaraapelta nomadis: New Species of ankylosaurid in Praise of Victoria Arbour.

The scientific paper: “A new ankylosaurid skeleton from the Upper Cretaceous Baruungoyot Formation of Mongolia: its implications for ankylosaurid postcranial evolution” by Jin-Young Park, Yuong-Nam Lee, Philip J. Currie, Michael J. Ryan, Phil Bell, Robin Sissons, Eva B. Koppelhus, Rinchen Barsbold, Sungjin Lee and Su-Hwan Kim published in Scientific Reports.

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