Scientific Paper on Oculudentavis khaungraae Retracted

On March the 11th (2020), a scientific paper was published in the academic journal “Nature” highlighting another remarkable discovery found in an amber nodule from northern Myanmar.  The Cretaceous-aged amber had already provided some astonishing information on the forest biota close to a coastline from around 100 million years ago.

An ammonite shell entombed in the ancient tree resin for example, then there was the remains of a tiny baby snake (Xiaophis myanmarensis), fossilised frogs and a whole range of insects, plant and pollen fossils, not to mention preserved remains of enantiornithine birds and a partial feathered tail from a dinosaur.  Everything Dinosaur had covered these discoveries within this blog, but this new paper, written by Xing et al concerned something truly breath-taking… the title of the paper summed it up nicely – “Hummingbird-sized dinosaur from the Cretaceous period of Myanmar”.

A Tiny Fossilised Skull – The Skull of a Maniraptoran?

Picture credit: Lida Xing et al

Something Tiny But Very Big

The research team, comprised of scientists from the China University of Geosciences, the Natural History Museum of Los Angeles County (USA), the Royal Saskatchewan Museum (Canada) and the Chinese Academy of Sciences, described an amazingly well-preserved tiny fossil skull with very bird-like features but miniscule teeth present in its jaws.  The tiny specimen, less than 1.5 cm long was thought to represent the smallest dinosaur known to science.  The animal was named Oculudentavis khaungraae, the genus name means “eye tooth bird” in recognition of its enormous eyes and unusual characteristic of having some of the upper teeth located directly under the eye socket.

Computer Generated Image of the Bird-like Skull (O. khaungraae)

Picture credit: Xing et al (Nature)

Oculudentavis khaungraae was documented as representing the smallest dinosaur and compared to the smallest extant avian dinosaur Mellisuga helenae, the bee hummingbird.

However, in what we at Everything Dinosaur think is an unprecedented development, the scientific paper announcing this amazing discovery has, this week, been retracted.

A statement on the “Nature” website reads:

“We, the authors, are retracting this Article [the March 11th paper] to prevent inaccurate information from remaining in the literature.  Although the description of Oculudentavis khaungraae remains accurate, a new unpublished specimen casts doubts upon our hypothesis regarding the phylogenetic position of HPG-15-3.

The specimen number HPG-15-3, is the holotype cranial material currently in the collection of the Hupoge Amber Museum in China.

A Controversial Scientific Paper

Shortly after the scientific paper’s publication, a number of academics challenged the conclusions drawn and criticised the authors for their taxonomic assessment which relates to Oculudentavis khaungraae being classified as “bird-like” and placed within the Avialae, a clade that includes elements of the Maniraptora (some theropod dinosaurs and birds).

It was suggested that the phylogenetic assessment carried out was too biased towards resolving the placement of Oculudentavis as a bird or a very closely related dinosaur, rather than considering other data sets that might resolve its position elsewhere.  The “bird-like” skull is found in a number of lizards (examples of convergent evolution), several authors commented that the possibility of O. khaungraae being a lizard was discounted too quickly by the paper’s authors.

Everything Dinosaur reported these concerns and doubts in a follow up article to the original post about the scientific paper on March 15th (2020): Casting Doubt over Oculudentavis.

Can a Binomial Name be Obliterated?

It is rare for a scientific paper to be retracted, but occasionally this happens.  Papers can be retracted for any of a number of reasons, but normally a retraction occurs when serious questions surrounding its veracity are identified.  For example, a paper published in 1998 in the medical journal the “Lancet” by Wakefield et al reporting a link between the MMR vaccination and autism was retracted in 2012 following an extensive investigation.  The British Medical Journal (BMJ), put out a press release stating that following the investigation it had been concluded that the paper implying a link between the MMR jab and autism was an “an elaborate fraud.”

Dr Fiona Godlee, BMJ Editor in Chief stated at the time:

“The MMR scare was based not on bad science but on a deliberate fraud” and that such “clear evidence of falsification of data should now close the door on this damaging vaccine scare.”

The scientific binomial name Oculudentavis khaungraae is now in limbo.  It is a matter of record that the taxon name exists, but with the withdrawal of the paper, we at Everything Dinosaur are not sure what will happen.  It probably falls within the remit of the International Commission on Zoological Nomenclature (ICZN), to produce a ruling on how to treat this taxon.

This development does not undermine the astonishing fossil discoveries being made as researchers study amber from Myanmar, it might help to bring into focus some of the ethical issues associated with the commercial mining and use of funds, but scientific reporting is essentially built on trust.  Fossils have been frequently misidentified , as new evidence emerges so ideas, theories and hypotheses evolve and develop.  Normally, scientists correct their findings in subsequent papers, to have a scientific paper retracted is highly unusual.

Oculudentavis khaungraae – A Taxon in Limbo

Picture credit: Han Zhixin with additional annotation by Everything Dinosaur

We shall await developments…

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Schleitheimia schutzi – Oldest Known Transitional Sauropodomorph

The biggest dinosaurs of all were the sauropods.  Famous giants such as Diplodocus and Brachiosaurus, exhibits of which adorn numerous main galleries of natural history museums around the world.  However, how these giant quadrupeds evolved from their much smaller sauropodomorph ancestors is poorly understood.  A team of scientists from Munich, Utrecht and Zürich have been able to identify a new ancestor of the long-necked dinosaurs (true Sauropoda),  from strata in the Swiss Canton of Schaffhausen.  The dinosaur named Schleitheimia schutzi is the oldest transitional form between the Sauropodomorpha and the Sauropoda described to date.

A Life Reconstruction of Schleitheimia schutzi

Picture credit: Beat Scheffold (Naturforschende Gesellschaft Schaffhausen)

Hidden Amongst the Substantial Plateosaurus Remains

Although there are several substantial bonebeds in Switzerland that represent the Plateosaurus genus, (a sauropodomorph) and our knowledge regarding the global distribution of this group has certainly improved over the last five years or so, the diversity of the Sauropodomorpha and its composition remains controversial.

The researchers which include Professor Oliver Rauhut from the Bayerische Staatssammlung für Paläontologie und Geologie, (Munich), Femke Holwerda currently at the Royal Tyrrell Museum (Alberta, Canada) and Heinz Furrer from Zürich University re-examined a series of fragmentary fossils recovered from three different locations associated with Plateosaurus bonebeds.  They concluded that the material represents the remains of two different, very big and robust sauropodomorphs.  One of these is described as a new taxon – Schleitheimia schutzi.

A Partial Femur Assigned to Schleitheimia schutzi

Picture credit: Rauhut et al (Swiss Journal of Geosciences)

The fossils had been thought to represent large examples of Plateosaurus.  Some of the material had been collected decades ago and given the huge size of the bonebeds and their monodominant nature little further thought had been given to the over-sized bones associated with the sites.

Identifying Schleitheimia schutzi

Professor Rauhut explained:

“Although Schleitheimia schutzi probably looked quite similar to Plateosaurus, this dinosaur with an estimated 9 to 10 metres body length is already significantly larger than the latter.  The new species [S. schutzi] was apparently very robust and like its gigantic descendants, probably moved on all fours, while Plateosaurus mostly walked on its hind legs.”

The genus name honours the type locality at Schleitheim, Canton Schaffhausen, Switzerland, whilst the species name honours Emil Schutz (1916-1974) who collected the type material.

Special in Two Ways

Schleitheimia roamed central Europe around 210 million years ago (late Norian faunal stage of the Triassic).  This makes Schleitheimia a lot older than other known transitional types of dinosaur between sauropodomorphs and sauropods.  Secondly, it is the first transitional form known from the continent of Europe.  Phylogenetic assessment suggests that this dinosaur is a derived basal sauropodiform and possibly very close to the evolutionary line that led to the Sauropoda.  Its discovery highlights the diversity of sauropodomorphs in the Late Triassic and suggests that many types of sauropodomorph survived the end-Triassic extinction event and flourished in the early Jurassic.

Views of a Cervical Vertebra (Schleitheimia schutzi)

Picture credit: Rauhut et al (Swiss Journal of Geosciences)

The scientific paper: “A derived sauropodiform dinosaur and other sauropodomorph material from the Late Triassic of Canton Schaffhausen, Switzerland” by Oliver W. M. Rauhut, Femke M. Holwerda and Heinz Furrer published in the Swiss Journal of Geosciences.

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The “Hunter of Lusitania” – Lusovenator santosi

The fearsome carcharodontosaurids (family Carcharodontosauridae), comprise some of the largest terrestrial predators that ever lived.  Giant theropods such as Giganotosaurus, Carcharodontosaurus and Tyrannotitan rivalled the largest tyrannosaurs in terms of size and probably (in some cases), were even bigger.  It had been thought that these types of carnivorous dinosaur were confined to the Cretaceous, but there is a growing body of evidence to suggest that this group was well established and geographically widespread by the Late Jurassic.

Lusovenator santosi

A team of scientists writing in the “Journal of Vertebrate Paleontology” have described a new species of carcharodontosaurid based on fossils found in Portugal.  The dinosaur has been named Lusovenator santosi, the genus name translates as “hunter of Lusitania”, a reference to the Lusitanian Basin, the geological region where the fossils are from.  Their research supports the idea that these types of predators were present in the Northern Hemisphere some twenty million years earlier than previously thought.

A Life Reconstruction of the Late Jurassic Carcharodontosaurid Lusovenator santosi

Picture credit: Carlos de Miguel Chaves

A Reassessment of Allosaur Fossil Material

The researchers, based in Lisbon and Madrid, re-evaluated fragmentary fossil material collected over the last two decades at sites located on the Portuguese coast about 35 miles (60 kilometres), north of Lisbon.  Initial examination suggested that this material represented a member of the Allosauridae, but a more detailed analysis of the fossils led the researchers to conclude that this material represented a dinosaur from the Carcharodontosauridae, a family nested within the clade Allosauria, but distinct from famous Late Jurassic super-predators such as Allosaurus fragilis, which is known from the western United States.

Lead author of the scientific paper, Elisabete Malafaia (University of Lisbon), commented that this discovery demonstrates the importance of the Iberian Peninsula as a key region for understanding the dispersal of carcharodontosaurids as well as other types of dinosaur across the northern hemisphere during the Late Jurassic and Early Cretaceous.

Fossil Material Assigned to Lusovenator santosi

Picture credit: Malafaia et al (Journal of Vertebrate Palaeontology)

One of the Oldest Members of the Carcharodontosauridae

The oldest definitive carcharodontosaurid described to date is Veterupristisaurus (V. milneri) from the Middle Dinosaur Member of the famous Tendaguru Formation of Tanzania.  Veterupristisaurus (pronounced Vet-ter-roo-pris-tee-sore-us), is believed to have lived around 154 million years ago (Kimmeridgian faunal stage of the Late Jurassic).  Other fragmentary fossil remains from China and Germany have also been tentatively assigned to Late Jurassic carcharodontosaurids.  Lusovenator lived around 145 million years ago, as such, it is the oldest carcharodontosaurian allosauroid yet discovered from Laurasia.

The fossil material is believed to represent a relatively young animal, with a body length of approximately 3.5 metres.  Although, probably not fully grown, the vertebrae and the ilium show a number of anatomical traits that distinguish Lusovenator from the Allosauridae and nest it with the related, but distinct Carcharodontosauridae.

A Member of a Field Team Working on a Fossil Specimen

Picture credit: LUSA

Furthermore, the identification of this new species expands the diversity of theropod dinosaurs known from the Late Jurassic of Portugal and reinforces the theory that the Iberian Peninsula is a key region to help understand the dispersal of a number of different types of dinosaur across the Northern Hemisphere at the end of the Jurassic and into the Early Cretaceous.

The scientific paper: “A new carcharodontosaurian theropod from the Lusitanian Basin: evidence of allosauroid sympatry in the European Late Jurassic” by Elisabete Malafaia, Pedro Mocho, Fernando Escaso and Francisco Ortega published in the Journal of Vertebrate Paleontology.

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Aratasaurus museunacionali Newly Described Basal Coelurosaur

This month a new basal member of the Coelurosauria has been named and described from limb bones sourced from the Romualdo Formation in north-eastern Brazil.  The dinosaur has been named Aratasaurus museunacionali, the genus name translates as “lizard born of fire” a reference to the fact, the fossil had been in the National Museum of Brazil (Museu Nacional), when a fire ripped through the building.  Fortunately, the fossil material was not damaged and the research could be successfully concluded and a new genus of Early Cretaceous dinosaur described.

A New Theropod – Aratasaurus museunacionali

Aratasaurus museunacionali Life Reconstruction

Picture credit: Museu Nacional

The species name honours the Museu Nacional in recognition of the tragic fire that took place in September 2018.  To read more about the fire: Devastating Fire at Brazil’s National Museum.

Helping to Better Understand the Coelurosauria

Juliana Sayão, a palaeontologist from the Federal University of Pernambuco and lead author of the scientific paper, commented that this new theropod will help scientists to better understand the evolutionary history of the Coelurosauria, an extensive clade of dinosaurs that consists of the tyrannosaurids, compsognathids, the ornithomimosaurs and the Maniraptora which includes birds.

A phylogenetic assessment suggests that Aratasaurus is closely related to Zuolong (Z. salleei), from the Late Jurassic of China, although it lived much more recently, the sediments from which the limb elements were excavated have been dated to approximately 110-115 million years ago (Albian faunal stage of the Cretaceous).

The Right Pes of Aratasaurus museunacionali after Preparation

Picture credit: Museu Nacional

Evidence of Seasonal Fires

The genus name might reflect the ordeal of the fire at the Museu Nacional but tiny pieces of fossilised wood found in association with the dinosaur bones suggest that Aratasaurus had to contend with forest fires within its ecosystem when it roamed this part of Gondwana more than 100 million years ago.

Highlighting the significance of this fossil discovery Juliana Sayão commented:

“Every discovery of a fossil is important because we obtain records that help to reconstruct the history of the planet and remake the path of evolution of the organisms that lived here millions of years ago.  Many times the fossil is unique and provides all the information about that species or group of animals”.

Brazil’s Newest Carnivorous Dinosaur

A model of the Brazil’s newest carnivorous dinosaur from the Araripe Basin has been commissioned.  Careful examination of the bone structure (histology), suggests that the individual was approximately four years old when it died.  Based on the growth rates of other, better known coelurosaurs, the researchers propose that the fossils represent a sub-adult specimen.  As such, the size estimate of around three metres in length probably does not represent the maximum size for this dinosaur species.

The Model of Aratasaurus museunacionali

Picture credit: Museu Nacional

The fossils, consisting of a partial femur, a tibia and foot bones representing an incomplete right limb were discovered in 2008 and first taken to the Museum of Palaeontology Plácido Cidade Nuvens, in Santana do Cariri but transferred to the Laboratory of Paleobiology and Microstructures, at the Academic Centre of Vitória, (Federal University of Pernambuco), for further preparation and study.

As part of the research project, the fossil material was taken in 2016 to the Museu Nacional for further analysis.  Although caught up in the conflagration that destroyed much of the museum in 2018, the specimen survived and the analysis was able to be completed.

Photograph and Line Drawing Showing the Right Pes (Foot)

Picture credit: Manso Sayão et al (Scientific Reports)

Comments from Everything Dinosaur

A spokesperson from Everything Dinosaur commented:

“The specimen might be fragmentary, but it’s discovery underpins the significance of the Romualdo Formation and helps to extend our knowledge of the dinosaur biota inhabiting this part of Gondwana in the later stages of the Early Cretaceous.  As this genus has been classified as the sister taxon of the Chinese Zuolong, it suggests that basal coelurosaurs may have been more widely distributed and had a greater temporal range than previously thought.”

Everything Dinosaur acknowledges the assistance of a media release from the Museu Nacional in the compilation of this article.

The scientific paper: “The first theropod dinosaur (Coelurosauria, Theropoda) from the base of the Romualdo Formation (Albian), Araripe Basin, Northeast Brazil” by Juliana Manso Sayão, Antônio Álamo Feitosa Saraiva, Arthur Souza Brum, Renan Alfredo Machado Bantim, Rafael Cesar Lima Pedroso de Andrade, Xin Cheng, Flaviana Jorge de Lima, Helder de Paula Silva and Alexander W. A. Kellner published in Scientific Reports.

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