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/Dinosaur and Prehistoric Animal News Stories

Fossil finds, new dinosaur discoveries, news and views from the world of palaeontology and other Earth sciences.

14 05, 2021

Tlatolophus galorum new Lambeosaurine from Mexico

By | May 14th, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

A new species of lambeosaurine hadrosaurid has been named and described this week from fossil material excavated from a site close to the town of Presa de San Antonio in northern Mexico. The dinosaur has been named (Tlatolophus galorum) and it represents the most complete lambeosaurine known to date from Mexico. A phylogenetic assessment of the extensive fossil material suggests that this dinosaur was more closely related to Parasaurolophus which is known from roughly contemporaneous strata further north than it was to the lambeosaur Velafrons coahuilensis, the first duck-billed dinosaur from Mexico to be scientifically described.

Life Reconstruction of Tlatolophus galorum.
Tlatolophus galorum life reconstruction. Picture credit: Marco Pineda.

The Tail of a Hadrosaur’s Tail

In 2013, Everything Dinosaur reported on the discovery of an articulated dinosaur tail in upper Campanian deposits of the Cerro del Pueblo Formation that had been putatively assigned to a hadrosaur. Field team members from the National Institute of Anthropology and History (INAH), an institution of the Ministry of Culture and the National Autonomous University of Mexico (UNAM) were despatched to excavate the specimen. The fossils had been spotted weathering on the surface in 2005, but serious field work did not commence until 2013.

The Tlatolophus galorum dig site
Tlatolophus galorum – the quarry. Field team members at the dig site, elements of the tail and hips can be seen exposed on the surface. Picture credit: INAH

Exposing More of the Specimen

The first aim was to collect and stabilise the material exposed to the elements on the surface. Once this had been taken care of further excavation work revealed that almost the entire tail was present (just the most distal elements were missing). As more of the specimen was revealed the field team slowly began to realise that the anterior portion of the dinosaur might be present too.

Co-author of the scientific paper, published this week in Cretaceous Research Ramírez Velasco (UNAM) commented:

“Although we had given up hope of finding the upper part of the specimen, once we recovered the tail, we continued excavating underneath where it was located. The surprise was that we began to find bones such as the femur, the scapula and other elements”.

The Excavation of Tlatolophus galorum
Field team members at an early stage of the excavation project, the tail of the hadrosaur has been exposed. Picture credit: INAH

An Elongated Drop-shaped Bone

As more of the front half of the dinosaur was exposed, a drop-shaped bone was found. At first, this was interpreted as part of the pelvis, but researcher José López Espinoza suggested that this was a bone from the skull. It was only after careful cleaning, preparation and analysis in the laboratory that the scientists realised that they had 34 bone fragments that formed a considerable portion of the skull and jaws.

Tlatolophus galorum - preparing fossil material
Air scribes being used to remove the matrix close to the bone (Tlatolophus galorum fossil preparation). Thirty-four bone fragments when pieced together formed the skull of the hadrosaur. Picture credit: INAH.

Identifying the Crest

The team were excited to discovery that about 80% of the skull had been recovered including the premaxillae that formed the top part of this duck-billed dinosaur’s head crest. The crest measures an impressive 1.32 metres in length, as well as being able to determine the shape of the crest the scientists could also reconstruct the neurocranium, that part of the skull that housed the brain.

The fossilised skull of Tlatolophus galorum.
The skull of Tlatolophus galorum. Picture credit: Juan Miguel Contreras Fotógrafo (técnico del Instituto de Geología).

Comparison with Velafrons coahuilensis

With so much of the skull material preserved, the research team was able to compare these fossils to other lambeosaurines, including the contemporaneous Velafrons coahuilensis which is also known from the Cerro del Pueblo Formation. Taxonomic and phylogenetic assessments consigned Tlatolophus to the Parasaurolophini tribe, suggesting that it was more closely related to hadrosaurs found further north than it was to Velafrons.

Tlatolophus galorum - Examining the Bones
Careful assessment of the fossil bones to establish a new genus and to place Tlatolophus within the Parasaurolophini tribe. This Mexican dinosaur was closely related to the famous Parasaurolophus crested dinosaur. Picture credit: INAH.

Tlatolophus – What’s in a Name?

The etymology of this dinosaur’s name reflects the shape of the distinctive head crest. The genus name derives from the local Náhuatl dialect for the word “tlahtolli” which translates as “word” as the crest shape resembles a symbol used by native people to demonstrate communication. The Latin “lophus” means “crest” and therefore the genus name translates as “word crest”. The species or trivial name honours the philanthropist Jesús Garza Arocha and recognises the assistance of the López family, who helped the palaeontologists by providing accommodation, food and other facilities during the field seasons.

Cleaning and preparing Tlatolophus galorum fossils
Many hours of work in the preparation laboratory were required in order to clean and preserve the fossil material. The trivial name of this new dinosaur honours the philanthropist Jesús Garza Arocha without whose support much of the extensive preparation work would not have been undertaken. Picture credit: INAH

Tail Bones on Display

The articulated tail of Tlatolophus galorum is on display in the municipal capital of General Cepeda, where, with the support of the city council, a special area was set aside to highlight the dinosaur fossils that have been found in this region of northern Mexico.

Tlatolophus galorum life reconstruction
A life reconstruction of the newly described hadrosaur Tlatolophus galorum (assigned to the Parasaurolophini tribe). Picture credit: Luis Rey.

Everything Dinosaur acknowledges the assistance of a media release and scientific notes provided by the INAH in the compilation of this article.

To read Everything Dinosaur’s 2013 blog post about the excavation work to uncover and remove the articulated tail of the specimen: The Tail of a Hadrosaur’s Tail.

To read about the discovery of Mexico’s first duck-billed dinosaur: Viva Mexico – New Duck Billed Dinosaur Discovered “South of the Border”

The scientific paper: “Tlatolophus galorum, gen. et sp. nov., a parasaurolophini dinosaur from the upper Campanian of the Cerro del Pueblo Formation, Coahuila, northern Mexico” by Ángel A. Ramírez-Velasco, Felisa J. Aguilar, René Hernández-Rivera, José Luis Gudiño Maussán, Marisol Lara Rodríguez and Jesús Alvarado-Ortega published in Cretaceous Research.

12 05, 2021

Menefeeceratops – The Oldest Centrosaurine?

By | May 12th, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Fossilised dinosaur remains found over twenty years ago have been re-examined and determined to represent a new species of horned dinosaur. Menefeeceratops (M. sealeyi) from the early Campanian of New Mexico, might just be the oldest centrosaurine described to date.

Menefeeceratops sealeyi life reconstruction.
Menefeeceratops sealeyi life reconstruction. Picture Credit: Sergey Krasovskiy. This horned dinosaur was contemporaneous with the tyrannosaur Dynamoterror (D. dynastes). This theropod can be seen in the background (right). Recent fossil discoveries are helping scientists to better understand the dinosaur dominated biota of southern Laramidia during the Campanian. The picture (above) also depicts a hadrosaur in the background (left), team members at Everything Dinosaur consider this to be a depiction of the saurolophine hadrosaur Ornatops (O. incantatus)

From the Menefee Formation of New Mexico

Researchers from the University of Pennsylvania, the New Mexico Museum of Natural History and Science in collaboration with a colleague from the State Museum of Pennsylvania, writing in the academic journal Paläontologische Zeitschrift, report on the reassessment of ceratopsian bones originally collected at a site near to Cuba, in New Mexico. The fossils, representing a partial skeleton of a single dinosaur were found by Paul Sealey, a research associate at the New Mexico Museum of Natural History and Science, whilst exploring the Allison Member of the Menefee Formation in 1996 and discussed in academic literature a year later but no genus name was proposed or other research conducted.

The fossils which consist of cranial and postcranial material remained within the collection of the New Mexico Museum of Natural History and Science, however, with dinosaurs being named and described from the Menefee Formation such as the tyrannosaur Dynamoterror dynastes and the nodosaurid Invictarx zephyri, both of which were named and described in 2018, interest in this specimen was reawakened. Further preparation revealed unique traits associated with the skull material that permitted the establishment of a new genus.

A skeletal reconstruction of Menefeeceratops showing known bones in blue.
Skeletal reconstruction of Menefeeceratops showing known bones in blue. Picture credit: Dalman et al.

Menefeeceratops sealeyi

Classified as a basal member of the Centrosaurinae, Menefeeceratops sealeyi helps palaeontologists to piece together the evolutionary history of the Ceratopsia. Estimated to have lived around 82 million years ago (Early Campanian), the authors of the scientific paper Sebastian Dalman, Spencer G. Lucas and Asher Lichtig (New Mexico Museum of Natural History and Science), Steven Jasinski (State Museum of Pennsylvania) and Peter Dodson (University of Pennsylvania) postulate that Menefeeceratops represents the earliest member of the centrosaurine subfamily of horned dinosaurs known to science.

The distinctive shape of the squamosal (skull bone that formed part of the neck frill), permitted the scientists to erect a new genus. The name honours the Menefee Formation, whilst the trivial name recognises the work of Paul Sealey, not only for the original discovery but for his contribution to the study of the dinosaurs of New Mexico.

Views of the left squamosal bone of Menefeeceratops,
Views of the left squamosal bone of Menefeeceratops sealeyi (left lateral and right lateral views). Picture credit: Dalman et al. The squamosal, whilst less ornate than other ceratopsids has a distinctive shape which helped permit the erection of a new genus.

How Big was Menefeeceratops?

By comparing the bones of Menefeeceratops to more complete centrosaurine specimens, the research team were able to estimate the size of this dinosaur. They conclude that it was relatively small, when compared to later members of the Centrosaurinae such as Pachyrhinosaurus and Styracosaurus, at around 3.9 to 4.4 metres in length.

Commenting on the significance of the reassessment of the fossil material that led to the naming of Menefeeceratops, co-author of the scientific paper Spencer G. Lucas stated:

“Menefeeceratops shows us just how much we still have to learn about the horned dinosaurs of western North America. The oldest centrosaur, Menefeeceratops indicates that the southwest region of the United States was an important place in the evolution of the centrosaurs. The recognition of this new centrosaur adds to a growing diversity of centrosaurs, and thus provides impetus to further efforts to discover fossils of these kinds of dinosaurs.”

Authors involved in this study, also named and described the related but geologically much younger centrosaurine Crittendenceratops. To read about Crittendenceratops krzyzanowskii: A New Horned Dinosaur from Arizona.

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

The scientific paper: “The oldest centrosaurine: a new ceratopsid dinosaur (Dinosauria: Ceratopsidae) from the Allison Member of the Menefee Formation (Upper Cretaceous, early Campanian), north-western New Mexico, USA” by Sebastian G. Dalman, Spencer G. Lucas, Steven E. Jasinski, Asher J. Lichtig & Peter Dodson published in Paläontologische Zeitschrift.

7 05, 2021

Nocturnal Dinosaurs Hunting in the Dark

By | May 7th, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Key Stage 3/4, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Scientists have proposed that the bizarre, chicken-sized alvarezsaurid Shuvuuia (S. deserti) had amazing eyesight and owl-like hearing, adaptations for a nocturnal hunter in its Late Cretaceous desert environment.

The Mongolian alvarezsaurid hunting at night
Shuvuuia deserti artist’s life reconstruction. Picture credit: Viktor Radermacher.

A Very Bizarre, Tiny Theropod

Named and described in 1998 from fossil material associated with the famous Djadochta Formation (Campanian faunal stage), Shuvuuia has been assigned to the Alvarezsauridae family of theropods. It may have been small (around 60 cm in length), but its skeleton shows a range of bizarre anatomical adaptations. It had long legs, a long tail, short but powerful forelimbs that ended in hands with greatly reduced, vestigial digits except for the thumb which was massive and had a large claw. The skull was very bird-like with disproportionately large orbits.

Photograph of fossilised Shuvuuia deserti skeleton.
Photograph of fossilised Shuvuuia deserti skeleton. Picture credit: Mick Ellison (American Museum of Natural History).

Writing in the academic journal “Science” a team of scientists led by Professor Jonah Choiniere (University of Witwatersrand, Johannesburg, South Africa), used sophisticated computerised tomography to examine the skull of Shuvuuia and to map this dinosaur’s sensory abilities, as part of a wider study into non-avian dinosaur sensory abilities.

Shuvuuia deserti fossil skull
Photograph of fossilised Shuvuuia deserti skull. Picture credit: Mick Ellison (American Museum of Natural History).

The international team of researchers used CT scanning and detailed measurements to collect data on the relative size of the eyes and inner ears of nearly 100 living bird and extinct dinosaur species. There are more than 10,000 species of bird (avian dinosaurs) alive today, but only a few have evolved sensory abilities that enable them to track and hunt prey at night. Owls are probably the best known, but not all owls are nocturnal. Kiwis hunt at night using their long, sensitive beaks to probe in the leaf litter for worms, whilst another bird endemic to New Zealand, the large, flightless Kakapo (a member of the parrots – Order Psittaciformes), is also nocturnal. Other birds active at night include the globally widespread black-capped night heron and the Stone-curlew (Burhinus oedicnemus) which is an occasional visitor to East Anglia in the UK.

To measure hearing ability, the team measured the length of the lagena, the organ that processes incoming sound information (known as the cochlea in mammals). The barn owl, which can hunt in complete darkness using hearing alone, has the proportionally longest lagena of any bird.

Barn owl skull CT scan showing lagena
Barn owl skull CT scan showing lagena. Picture credit: Jonah Choiniere/Wits University.

Assessing Vision

To examine vision, the team looked at the scleral ring, a series of bones surrounding the pupil, of each species. Like a camera lens, the larger the pupil can open, the more light can get in, enabling better vision at night. By measuring the diameter of the ring, the scientists could estimate how much light the eye can gather.

The researchers found that many carnivorous theropods such as large tyrannosaurs and the much smaller Dromaeosaurus had vision optimised for the daytime, and better-than-average hearing presumably to help them hunt. However, Shuvuuia, had both extraordinary hearing and night vision. The extremely large lagena of this species is almost identical in relative size to today’s barn owl, suggesting that Shuvuuia could have been a nocturnal hunter. With many predators sharing its Late Cretaceous desert environment, a night-time existence may have proved to be an effective strategy to avoid the attentions of much larger theropods.

Side by side comparison of the lagena of a Barn owl and Shuvuuia deserti
Side by side comparison of the lagena of a Barn owl (left) and Shuvuuia deserti (right). Picture credit: Jonah Choiniere/Wits University.

Commenting on the significance of this discovery, joint first author of the scientific paper, Dr James Neenan exclaimed:

“As I was digitally reconstructing the Shuvuuia skull, I couldn’t believe the lagena size. I called Professor Choiniere to have a look. We both thought it might be a mistake, so I processed the other ear – only then did we realise what a cool discovery we had on our hands!”

Extremely Large Eyes

The eyes of Shuvuuia were also remarkable. Skull measurements suggest that this little dinosaur had some of the proportionally largest pupils yet measured in birds or dinosaurs, suggesting that they could likely see very well at night.

Professor Jonah Choiniere holding a 3D Print of a Shuvuuia lagena
Professor Jonah Choiniere holding a 3D printed model of the lagena of Shuvuuia deserti. Picture credit: Jonah Choiniere/Wits University.

The Alvarezsauridae remain one of the most unusual of all the types of non-avian dinosaur known to science. Their place within the ecosystems of the Late Cretaceous remains controversial. Geographically widespread, a recently described alvarezsaurid from China Qiupanykus zhangi may have been a specialised ovivore (egg-eater), whilst other palaeontologists have postulated that these theropods used their strong forelimbs and large thumb claws to break into termite mounds. Perhaps, these small (most probably feathered), dinosaurs occupied a number of niches within Late Cretaceous ecosystems – including that of a nocturnal hunter of small vertebrates and insects.

Shuvuuia deserti artist's reconstruction.
Shuvuuia deserti artist’s reconstruction. Picture credit: Viktor Radermacher.

To read Everything Dinosaur’s blog article about Qiupanykus zhangi and the evidence behind the egg-eating theory: Did Alvarezsaurids Eat Eggs?

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

The scientific paper: “Evolution of vision and hearing modalities in theropod dinosaurs” by Jonah N. Choiniere, James M. Neenan, Lars Schmitz, David P. Ford, Kimberley E. J. Chapelle, Amy M. Balanoff, Justin S. Sipla, Justin A. Georgi, Stig A. Walsh, Mark A. Norell, Xing Xu, James M. Clark and Roger B. J. Benson published in the journal Science.

30 04, 2021

Japan’s Second Hadrosaur

By | April 30th, 2021|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Scientists from the Hokkaido University Museum in collaboration with colleagues from the Okayama University of Science have named a second hadrosaurid from the Late Cretaceous of Japan. Described from a partial skeleton, Yamatosaurus izanagii lived at the same time as the first duck-billed dinosaur named from Japan (Kamuysaurus japonicus), but these two dinosaurs probably did not co-exist, instead Kamuysaurus may have been restricted to more northern coastal environments whilst the newly described Yamatosaurus may have been confined to more southerly habitats.

Yamatosaurus izanagii Life Reconstruction with more Advance Forms of Duck-billed Dinosaur in the Background
Yamatosaurus izanagii life reconstruction (centre), with a Lambeosaurinae representative (right) and a representative of the Saurolophinae (left), the dentition and shoulder bones suggest that Yamatosaurus is a basal member of the Hadrosauridae family and its discovery supports the idea that hadrosaurs evolved in Asia. Picture Credit: Masato Hattori.

Did the Hadrosauridae Originate in Asia or North America?

The researchers, who included Yoshitsugu Kobayashi, Ryuji Takasaki and Anthony R. Fiorillo (who wrote the scientific paper describing Kamuysaurus in 2019), plus Katsuhiro Kubota (Hokkaido University Museum), conducted a phylogenetic analysis suggesting that Yamatosaurus was a primitive member of the hadrosaur family. Intriguingly, the team also undertook a biogeographical analysis (plotting age of ornithopod fossil finds against geographical location). They conclude that basal hadrosaurids were widely distributed in both Asia and Appalachia (the landmass representing eastern North America). In addition, the scientists postulate that the discovery of Yamatosaurus supports the theory that the sub-families of more derived duck-billed dinosaurs the Lambeosaurinae and the Saurolophinae originated in Asia and that towards the end of the Cretaceous, basal hadrosaurids such as Plesiohadros djadokhtaensis (Mongolia), Tanius sinensis (C‌hina) and Yamatosaurus (Japan) continued to thrive in eastern Asia but were extinct elsewhere.

Data Suggests an Asian Origin for Hadrosaurs
A biogeographical analysis indicates that the Hadrosauridae may have originated in Asia. The discovery of Yamatosaurus izanagii in Japan supports the idea of an Asian original for that line of ornithopods that evolved into hadrosaurs.

Discovered in Marine Sediments

Amateur fossil collector Mr. Shingo Kishimoto discovered the fossilised remains in 2004, whilst exploring exposures of the Kita-ama Formation on the island of Awaji (Hyogo Prefecture). The fossil material consists of a dentary (lower jawbone), along with the surangular, neck bones, bones from the tail, cervical ribs and a coracoid plus some isolated teeth. Although hadrosaur fossils have been found in several locations in Japan (all four main islands – Hokkaido, Honshu, Shikoku, and Kyushu), they are, with the exception of the Kamuysaurus material, highly fragmentary consisting of teeth, portions of the limbs and vertebrae, this is only the second time that a new genus of duck-billed dinosaur has been erected from Japanese fossils.

The stratum from which the Yamatosaurus material was collected consists of marine mudstones of approximately the same age (early Maastrichtian), as the sediments in which Kamuysaurus was found.

Various views of the right dentary of Yamatosaurus
Right dentary of Yamatosaurus izanagii gen. et sp. nov. in lateral (a), medial (b), dorsal (c), ventral (d), and anterior (e) views.

Unique Traits and Basal Characteristics

Study of the nearly complete right dentary helped the researchers to erect a new, basal hadrosaur genus. Unlike other hadrosaurs Yamatosaurus had just one functional tooth in several battery positions and no branched ridges on the chewing surfaces. This suggests that Yamatosaurus evolved to feed differently compared to other duck-billed dinosaurs. Furthermore, the coracoid (that with the scapula would have formed the shoulder joint), shows traits linked to the movement away from a bipedal gait to becoming quadrupedal. This bone shows transitional characteristics that in later, more derived hadrosaurs, were more fully developed permitting these animals to become facultative bipeds (adopting a quadrupedal gait but able to run on their hind legs if required to do so).

To read Everything Dinosaur’s article from 2019 about the formal description of the first hadrosaur named from Japan (Kamuysaurus japonicus): Japan’s Greatest Fossil Dinosaur Gets a Name.

The scientific paper: “A new basal hadrosaurid (Dinosauria: Ornithischia) from the latest Cretaceous Kita-ama Formation in Japan implies the origin of hadrosaurids” by Yoshitsugu Kobayashi, Ryuji Takasaki, Katsuhiro Kubota and Anthony R. Fiorillo published in Scientific Reports.

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.

7 04, 2021

Sinomacrops – A New Anurognathid Pterosaur from China

By | April 7th, 2021|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Researchers have published a description of a new species of anurognathid pterosaur from the Tiaojishan Formation in Hebei Province China. The diminutive flying reptile has been named Sinomacrops bondei and is the third anurognathid species to have been described from Jurassic-aged rocks found in China. Although the specimen is badly crushed, it represents the near complete skeleton of a single individual and as such it has helped palaeontologists to better understand the phylogeny of these enigmatic, but poorly known, wide-mouthed pterosaurs.

Sinomacrops bondei life reconstruction.
Sinomacrops bondei life reconstruction. Picture credit: Zhao Chuang.

The Amazing Anurognathidae

Palaeontologists that focus on the Pterosauria have long speculated as to where in the flying reptile family tree the Anurognathidae fit. Very few fossils are known and those that have been made available to study demonstrate a mix of basal as well as more derived traits. All the anurognathids described to date are estimated to have had wingspans less than 90 cm. Their fossils are associated with terrestrial environments and it has been suggested that these little flying reptiles lived in forests and ate insects, perhaps capturing them on the wing.

Sinomacrops bondei

The genus name translates from the Greek for Chinese, large eyes/face. The specimen (number JZMP-2107500095) is the first record of an anurognathid pterosaur skull preserved in a mostly lateral view. The species epithet honours the Danish palaeontologist Niels Bonde in recognition of his many years contributing to vertebrate palaeontology.

Sinomacrops bondei fossil and line drawing
The fossilised remains of Sinomacrops bondei and an accompanying line drawing.

A Crushed Skeleton

Although the skeleton is badly crushed, the fossilised remains which herald from the Daohugou Beds of the Tiaojishan Formation and are therefore between 164 – 158 million years old (Callovian to the Oxfordian stage of the Middle to Late Jurassic), have provided a new insight into the variation of jaw shape in these wide-mouthed pterosaurs. In addition, the Sinomacrops discovery permitted the researchers to undertake a revision of anurognathid phylogeny and the researchers propose that these strange flying reptiles are a sister group of the Darwinoptera and basal members of the Monofenestrata.

The Monofenestrata

The Monofenestrata comprises a wide range of pterosaur families, broadly grouped together as they had long tails, a lengthy fifth toe and the possession of a single large opening on each side of the skull in front of the eyes. Hence the name Monofenestrata (Latin for “one window”), the merging of the nasal and antorbital openings into a single feature.

Sinomacrops skull and line drawing.
The crushed skull of Sinomacrops bondei and accompanying line drawing.

The scientific paper: “Sinomacrops bondei, a new anurognathid pterosaur from the Jurassic of China and comments on the group” by Xuefang Wei, Rodrigo Vargas Pêgas, Caizhi Shen, Yanfang Guo, Waisum Ma, Deyu Sun, Xuanyu Zhou​ published in PeerJ.

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.

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