Macrocollum itaquii – Oldest Long-necked Sauropodomorph is Described

A team of scientists based in Brazil have described the fossilised remains of three Triassic dinosaurs that lived some 225 million years ago that shed light on the evolution of long-necks in plant-eating dinosaurs.  The new species, a member of the Sauropodomorpha, has been named Macrocollum itaquii, the genus name comes from the Greek for “long neck”, an appropriate moniker for a prehistoric animal that is helping to unravel the developmental history of the long-necked dinosaurs bauplan.

Macrocollum itaquii

Although Macrocollum is estimated to have measured about four metres in length and weighed approximately 100 kilograms, a lot smaller than later sauropods, some of which were the largest terrestrial animals to have ever lived, it is considerably bigger than older dinosaur fossil specimens found in South America, some of the earliest dinosaurs known, that lived around ten million years earlier and represent some of the very first dinosaurs to evolve.

A Life Reconstruction of Macrocollum itaquii

Picture credit: SWNS

The Rise of the Sauropodomorpha

Despite a number of recent fossil discoveries, palaeontologists have a relatively poor understanding of the rise of the sauropodomorphs, a group that includes some of the most famous of all the dinosaurs, giants such as Diplodocus and Brachiosaurus.

The fossil material, representing three individuals, was collected from the upper portion of the  Candelária Sequence of the Paraná Basin, from a site in Agudo, Rio Grande do Sul (southern Brazil).  Nearby strata have been dated to the Norian faunal stage of the Late Triassic.  Writing in the academic journal “Biology Letters”, the researchers, which included biologist Rodrigo Müller from the Federal University of Santa Maria (Brazil), conclude that these three animals died together and therefore provide the oldest evidence of herding behaviour in sauropodomorphs described to date.

The proposal that the three individuals died together and as such, indicate gregarious behaviour, has been challenged by a number of academics.  It is possible that these three herbivores died at different times and the carcases just happened to be transported and ended up in association.

Commenting upon this, Rodrigo Müller explained:

“There are three articulated skeletons in five tons of rock.  This is unique.  It suggests these animals probably died together, as they share the same degree of disarticulation.  So, if they died together, these dinosaurs probably lived together.”

Long Necks and Long Thigh Bones

Two of the specimens include skull material, the holotype (CAPPA/UFSM (Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia) 0001a), is virtually complete and articulated.  It is one of the best preserved Triassic dinosaur skeletons ever found.  With such exceptionally well-preserved specimens the scientists have been able to conduct an analysis looking at how the long-neck of these types of dinosaurs evolved and study the femur (thigh bone), length to give an indication in the change of body size since the first plant-eating dinosaurs evolved.  In addition, these fossils have shed light on how these animals adapted to a fully herbivorous diet.

Macrocollum Fossil Material Has Helped Shed Light on Important Evolutionary Developments within the Sauropodomorpha

Picture credit: R T Müller et al in Biology Letters

The table above shows the phylogenetic position attributed to the newly described M. itaquii.  Based on this assessment it has been assigned to the Unaysauridae family, basal members of the Sauropoda, that are known from Triassic-aged rocks from the Southern Hemisphere (India and South America).  The discovery of Macrocollum has helped palaeontologists to gain a better understanding of the evolution of the long-neck of sauropods.  The cervical vertebrae (neck bones) of M. itaquii are already much more elongated than seen in earlier representatives of the Sauropodomorpha known from around 233 million years ago.  The teeth are more spatulate in shape, indicating an adaptation to a plant-eating diet and over this 8 million year period (233-225 million years ago), femora measurements demonstrate that sauropodomorphs increased in size by 230%.

Views of Skull Material Associated with M. itaquii

Picture credit: R T Müller et al in Biology Letters

The typical long neck was also established,  becoming proportionally twice as long than those necks of basal taxa.  Indeed, the new dinosaur is the oldest-known sauropodomorph with such an elongated neck, suggesting that the ability to feed on high vegetation was a key trait achieved along the early Norian.

Skeletal Reconstruction and Significant Bones Including Elongated Cervical Vertebrae

Picture credit: R T Müller et al in Biology Letters

The species name honours Mr José Jerundino Machado Itaqui, one of the main drivers behind the creation of the Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia and the Federal University of Santa Maria.

To read about the recent discovery of an Early Jurassic sauropod from China (Yizhousaurus sunae), that is helping palaeontologists to learn more about how some types of dinosaur were able to evolve into giants: Helping to Give Sauropod Evolution a Head Start.

To read about a giant Late Triassic sauropodomorph (Ingentia prima): Triassic Dinosaur Just Got a Lot Bigger.

The scientific paper: “An Exceptionally Preserved Association of Complete Dinosaur Skeletons Reveals the Oldest Long-necked Sauropodomorphs” by Rodrigo Temp Müller, Max Cardoso Langer and Sérgio Dias-da-Silva published in Biology Letters.

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An Oregon Ornithopod

There may be many famous dinosaurs known from the United States of America, after all, when it comes to naming dinosaurs, Tyrannosaurus rex, Stegosaurus and Triceratops tend to trip off the tongue, but America’s dinosaur fossil heritage is not uniform across the whole country.  Several parts of the U.S. have no record of dinosaur discoveries, and numerous others have a very fragmentary record when it comes to the preserved remains of Dinosauria.  Oregon, the ninth largest State in terms of area, has a very poor dinosaur fossil record, however, a newly described fossil discovery made in the eastern part of the “Beaver State”, has got palaeontologists quite excited about the prospect of more dinosaur fossil finds being made.

The Toe Bone from a Dinosaur (Ornithopoda)

Writing in the “Journal of Vertebrate Palaeontology”, scientists from the University of Oregon in collaboration with the University of Calgary (Canada), have published a paper on the discovery of a single toe bone from a plant-eating dinosaur – an extremely rare find considering that this part of north-western North America was underwater throughout most of the Mesozoic Era.

Various Views of the Single Dinosaur Toe Bone (Pedal Phalanx)

Picture credit: University of Oregon

The fossil bone was found by University of Oregon Earth Sciences Professor Greg Retallack during field work in 2015, near the town of Mitchell (Wheeler County, eastern Oregon).  The single bone was spotted amongst mollusc fossils exposed on a slope consisting of marine shale.  The fossil dates from the Albian fauna stage of the Cretaceous and is the first ever Oregon dinosaur fossil to be the subject of a paper in a peer-reviewed scientific journal.  Furthermore, it represents the first dinosaur fossil find from Oregon from strata not regarded as Upper Cretaceous.

Oregon might be bigger than the whole of the United Kingdom, but the Mesozoic-aged exposures represent marine sediments, that harbour very few remains of ancient terrestrial animals.

Greg Retallack stated:

“Oregon landscapes are rich with Cretaceous rocks, but they rarely contain the kinds of dinosaur remains we see elsewhere in the United States.  The rocks here are the right age but are mostly from under the sea where dinosaurs did not live or from swamps where dinosaur bones are seldom preserved.”

Not Able to Assign a Genus

Although, identified as a dinosaur bone (pedal phalanx), it is not possible to assign it to a specific species or genus, although the research team are confident that it came from a plant-eating ornithopod dinosaur.

An Illustration of a Typical Ornithopod Dinosaur

Picture credit: Edyta Felcyn

Co-author of the paper, Edward Davis (University of Oregon), explained that the remains of a terrestrial animal ended up in the mollusc bed, after having been swept out to sea.

He explained:

“It’s a phenomenon we sometimes call “bloat and float”.  That is, the animal died on shore in its terrestrial habitat, then was washed out to sea, where it floated while bloated with decomposition gasses.  Eventually it burst, and only this toe bone was entombed and became a fossil.”

A Sizeable Plant-eating Dinosaur

Although very little taxonomic information can be gained from a single, isolated toe bone, a size comparison with much more complete and better known Cretaceous ornithopods such as Tenontosaurus, suggests that this dinosaur may have been about six to seven metres long and weighed around a tonne.

A spokesperson from Everything Dinosaur commented:

“Although such a fossil find in marine sediments is exceptionally rare, it just goes to show that dinosaurs fossils can be found and if there is one, then there may be more. Many of the Mesozoic-aged rocks in this part of Oregon represent near coastal marine deposits.  Given that dinosaurs would have roamed the land close to the sea for millions of years it is possible that more dinosaur remains might be found.”

To read an article published by Everything Dinosaur in 2015, which looks at which part of the United States are not associated with dinosaur fossils: Washington State the 37th U.S. State with a Dinosaur.

Visit the Everything Dinosaur website: Everything Dinosaur.

Lavocatisaurus agrioensis – A New Long-Necked Dinosaur from Argentina

A team of palaeontologists from Argentina and Spain have announced the discovery of a new species of long-necked dinosaur from the Early Cretaceous of Argentina.  The dinosaur, represented by a set of bones that indicate the remains of at least three individuals, has been named Lavocatisaurus agrioensis and it will help to shed more light on a rare and enigmatic group of sauropods known as the rebbachisaurids.

A Skeletal Reconstruction and Photographs of Key Fossils from L. agrioensis

Picture credit: AFP/Agencia CTYS

The picture above shows the skeletal drawing of the adult dinosaur with illustrations of key bones from the excavation.  Most of the neck and the skull has been recovered.  Cranial fossils associated with the Rebbachisauridae are rare, the discovery of these specimens from Agrio del Medio (Neuquén Province, Argentina) will help scientists to better understand taxonomic relationships amongst members of this sauropod family, largely associated with Gondwanaland fossil deposits.

Fossils of a Family Group?

Writing in the journal “Acta Palaeontologica Polonica”, the scientists report the discovery of one large, presumably adult animal with two smaller sub-adults found in association.  The fossil material come from terrestrial sandstone deposits laid down around 110 million years ago (Aptian to Albian faunal stage of the Early Cretaceous), in an arid environment with isolated oasis and other water sources (Rayoso Formation).

One of the authors of the scientific paper, José Luis Carballido, of the Egidio Feruglio Museum (Argentina), stated:

“We found most of the cranial bones: the snout, the jaws, a lot of teeth, also the bones that define the eye sockets for example and in that way, we were able to create an almost complete reconstruction.  Not only is this the discovery of a new species in an area where you wouldn’t expect to find fossils, but the skull is almost complete.”

Lavocatisaurus agrioensis

The fossils represent one large dinosaur estimated to be around twelve metres in length and two smaller animals around six to seven metres in length.  The research team postulate that this could represent a family group that lived together and perished together, perhaps unable to find a water source in a time of drought.

Preparing to Move Some of the Fossil Material (Lavocatisaurus)

Picture credit: AFP/Agencia CTYS

Lead author of the paper, José Ignacio Canudo (Zaragoza University, Spain) added:

“This discovery of an adult and two juveniles also signifies the first record of a group displacement among the Rebbachisaurus dinosaurs.”

The Rebbachisauridae Family

The Rebbachisauridae family of sauropods are a group of basal members of the Diplodocimorpha clade that includes more famous Late Jurassic dinosaurs such as Diplodocus, Apatosaurus and Brontosaurus.  The rebbachisaurids are known from both Lower Cretaceous and Upper Cretaceous strata and had a wide geographical distribution throughout Gondwana and southern Laurasia with fossils reported from north and central Africa as well as South America and Europe (Spain).

An Illustration of a Typical Rebbachisaurid Dinosaur (R. garasbae)

Picture credit: Everything Dinosaur

Visit the Everything Dinosaur website: Everything Dinosaur.

Mistralazhdarcho maggii – From the Upper Cretaceous of France

A team of scientists based in France and Belgium have announced the discovery of a new species of pterosaur from Upper Cretaceous rocks in south-eastern France (Bouches-du-Rhône).  The fragmentary bones have been assigned to the Azhdarchidae family of pterosaurs, one of the last groups of flying reptiles to exist and a family that contains giants such as Quetzalcoatlus and Hatzegopteryx.  With a wingspan estimated to be around 4.5 metres, the specimen, believed to be a juvenile, provides evidence of a third azhdarchid pterosaur size class from the cluster of islands that represented continental Europe towards the end of the Mesozoic.

The pterosaur has been named Mistralazhdarcho maggii pronounced (miss-tral-ads-dar-cho may-gee).

A Life Reconstruction of the Newly Described French Azhdarchid Pterosaur – Mistralazhdarcho maggii

Picture credit: Pierre Lavaud

One of the Most Complete Pterosaur Fossils Known from Late Cretaceous Europe

Writing in the academic publication the “Journal of Vertebrate Paleontology”, the researchers describe the finding of part of a lower jaw, a neck bone and several other postcranial bones in 2009.  The bones were found in association with each other and therefore, probably represent the fossilised remains of a single pterosaur.  The material comes from the excavation site of Velaux, near Aix-en-Provence and from strata that dates to the Campanian faunal stage of the Late Cretaceous.

Views of the Fossil Material Ascribed to the New Pterosaur Mistralazhdarcho maggii

Picture credit: Royal Belgian Institute of Natural Sciences

The photograph (above), shows a part mandible (a) with a distinctive ridge (mandibular symphysis).  A cervical vertebra (b), left humerus (c), left radius (d) and two bones from the hand – metacarpal IV (e) and a finger bone (f).

Although the fossil material is fragmentary, such is the poor fossil record of Late Cretaceous pterosaurs from Europe that these few bones make Mistralazhdarcho one of the most complete European azhdarchids described to date.  In addition, Mistralazhdarcho is the first partial skeleton of a flying reptile excavated from Upper Cretaceous deposits of western Europe.

Related to a North African Pterosaur?

The scientists, which included researchers from the University of Rennes, the Royal Belgian Institute for Natural Sciences and Poitiers University, conclude that Mistralazhdarcho was related to an earlier pterosaur called Alanqa (A. saharica), which lived in North Africa around 95 million years ago.  When Alanqa was first described, back in 2010, it was assigned to the Azhdarchidae, but more recent studies incorporating skull material discovered in 2015, have cast doubt on the taxonomic position of Alanqa.

To read about the discovery of Alanqa saharica: Dublin Team Announce the Discovery of a New Pterosaur.

An Adult Probably Had a Wingspan of Around 5-6 metres

Examination of the fossil bones suggest that they were not fully ossified and that this was a sub-adult.  The researchers speculate that a fully-grown Mistralazhdarcho would have had a wingspan of around 5 to 6 metres, possibly even bigger.  This size estimate is in between the size estimates given for the two azhdarchids from the Maastrichtian of Romania (Hateg Formation), which also represents the European Late Cretaceous archipelago environment.

A Size Comparison of European Azhdarchid Pterosaurs

Picture credit: Everything Dinosaur

Mistralazhdarcho is estimated to be intermediate in size between the medium-sized genus Eurazhdarcho (wingspan of 3 metres) and the enormous Hatzegopteryx (estimated wingspan of 10 metres or more), the two other azhdarchids associated with the island ecosystem of the latest Cretaceous European archipelago.  The different sized pterosaurs might reflect a form of niche partitioning, whereby, different sized animals did not directly compete with each other for resources.

The flying reptile’s genus name is from the “mistral”, a strong, north-westerly wind associated with southern France.  The species name honours the former mayor of Velaux, Jean-Pierre Maggi, without whom, the excavation of the fossil material would not have been possible.

Field Team Members Working at the Velaux Excavation Site

Picture credit: Royal Belgian Institute of Natural Sciences

The scientific paper: “Mistralazhdarcho maggii, gen. et sp. nov., a New Azhdarchid Pterosaur from the Upper Cretaceous of south-eastern France” by Romain Vullo, Géraldine Garcia, Pascal Godefroit, Aude Cincotta and Xavier Valentin published in the Journal of Vertebrate Paleontology.

Visit the Everything Dinosaur website: Everything Dinosaur.

Anhuilong diboensis – From the Middle Jurassic of Anhui Province

Chinese scientists have published details of a new species of long-necked dinosaur from eastern China.  The fossilised remains, although fragmentary, have permitted the researchers to confidently assign the specimen (AGB 5822), to the Mamenchisauridae family of sauropods.  The dinosaur has been named Anhuilong diboensis and it suggests that by the Middle Jurassic, mamenchisaurids were already a diverse family.  It is likely that the sandstones and mudstones that form the majority of the fossil bearing, Middle Jurassic-aged strata near Huangshan (Anhui Province), will yield more dinosaur fossils.

A Life Reconstruction of a Typical Mamenchisaurid Dinosaur

Picture credit: Julius Csotonyi/Natural History Museum of Los Angeles County

The Second Member of the Mamenchisauridae from Anhui Province

The fossil material, consisting of the remains of a single forelimb, representing one individual dinosaur (humerus, ulna and radius bones), was distinct enough to permit the scientists, which included researchers from the Chinese Academy of Sciences and the Anhui Geological Museum, to establish a new genus.

Anhuilong diboensis

Anhuilong diboensis is the second mamenchisaurid to be identified from the Middle Jurassic Hongqin Formation of Shexian, Huangshan (Anhui Province, eastern China).  The first mamenchisaurid from this locality, Huangshanlong anhuiensis, was named and described in 2014.  The authors of the scientific paper describing A. diboensis were also responsible for the earlier study of H. anhuiensis.  A phylogenetic analysis of the limb bones from these two specimens suggest that Anhuilong is the sister taxon of Huangshanlong and with Omeisaurus from Sichuan Province, they together form a sister clade to all other members of Mamenchisauridae.

Views of the Right Humerus of Huangshanlong anhuiensis

Picture credit: Vertebrata PalAsiatica/Jian-Dong Huang et al

The picture above shows various views of the right humerus (upper arm bone) of H. anhuiensis.  The morphology of limb bones and how they compare to each other (total length of the ulna to the humerus and the total length of the radius to the humerus), are distinct enough for palaeontologists to ascribe them to the Mamenchisauridae and to erect a new genus.

Key

A = humerus viewed from the front.

B = humerus viewed from one side (medial view).

C = humerus viewed from the back.

D = humerus viewed from the other side (lateral view).

E = viewed from the top down (cranial margin pointing upwards)

F = view of a cross section, near the narrowest part of the bone.

G = viewed from underneath (distal view).

The Spread of the Sauropoda

Until recently, palaeontologists had thought that although the Sauropoda were geographically widespread by the Middle Jurassic, sub-groups such as the Mamenchisauridae family and the Diplodocidae had restricted geographical ranges.  However, earlier this year, a diplodocid dinosaur was described from northern China, proving that these long-necked dinosaurs were present in Asia during the Middle Jurassic.  The fossil record for the Mamenchisauridae indicates that these types of Sauropods were restricted to China.

To read the article describing the diplodocid dinosaur (Lingwulong shenqi) from northern China: The First Diplodocid Dinosaur Described from China and the Earliest Known Member of the Diplodocidae.

Picture credit: Everything Dinosaur

The picture (above) shows Lingwulong dinosaur models arriving at Everything Dinosaur’s warehouse. These are PNSO figures.

To view the PNSO prehistoric animal model range: PNSO Age of Dinosaurs Models.