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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.

21 10, 2020

Remembering “Joe” the Baby Parasaurolophus

By | October 21st, 2020|Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Remembering “Joe” the Baby Parasaurolophus

This week, seven years ago, a remarkable paper was published in the academic journal PeerJ.  The research centred upon a beautifully-preserved fossil specimen of a baby Parasaurolophus that at around two and a half metres in length, represented the smallest and most complete specimen described to date for this genus.  Nicknamed “Joe” this dinosaur that roamed southern Utah some 75 million years ago, demonstrated the astonishing growth rates of duck-billed dinosaurs.  Although approximately a quarter of the size of a fully grown Parasaurolophus, bone histology suggested that “Joe” was less than a year old when it died.

Interpretive Drawing and Right Lateral View of the Fossilised Remains  -“Joe” the Parasaurolophus

"Joe" the baby Parasaurolophus.

The skeleton of “Joe” the Parasaurolophus (specimen number RAM 14000), in right lateral view (A) interpretive drawing and (B) photograph.   Note scale bar = 10 cm.

Picture Credit: Farke et al (PeerJ)

A Baby Dinosaur Found by Students

The fossilised remains of the young Parasaurolophus were found in 2009 by a group of students on a field trip to the Kaiparowits Formation (Campanian faunal stage), exposures at the famous Grand Staircase-Escalante National Monument, with Andrew Farke of the Raymond M. Alf Museum of Palaeontology. When first shown a fragment of fossil bone eroding out of the surrounding sediment, Dr Farke dismissed it as an inconsequential piece of fossil rib.  It was only when they explored the area a little more closely did they realise the potential significance of the discovery.

The scientific paper on this remarkable specimen was published in October 2013.  The skull, measuring 24.6 cm in length showed signs of the tubular crest beginning to form, although a cross-section of bone from the tibia (lower leg bone), showed no lines of arrested growth (LAGs), implying that the Parasaurolophus may have been less than twelve months old when it died.  Based on a comparison with other Lambeosaurine fossils, the research team concluded that Parasaurolophus initiated development of its head crest at less than 25% maximum skull size, contrasting with 50% of maximum skull size in hadrosaurs such as Corythosaurus.

Parasaurolophus formed its unusual headgear by expanding some of its skull bones earlier and for a longer period of time than other closely related duck-billed dinosaurs.

An Interpretative Drawing of the Skull with Fossil Shown in Left Lateral View

Interpretive drawing and photograph of baby Parasaurolophus skull.

Left half of the skull of Parasaurolophus sp., RAM 14000, in lateral view. Interpretive drawing (A) and (B) photograph of the skull.

Picture Credit: Everything Dinosaur

“Joe” was named after Joe Augustyn, a patron of the Raymond M. Alf Museum of Palaeontology, where the fossils can be seen on display.

To read Everything Dinosaur’s original article on “Joe” the baby Parasaurolophus: Fossilised Remains of a Baby Parasaurolophus from Southern Utah.

The scientific paper: “Ontogeny in the tube-crested dinosaur Parasaurolophus (Hadrosauridae) and heterochrony in hadrosaurids” by Andrew A. Farke, Derek J. Chok, Annisa Herrero, Brandon Scolieri and Sarah Werning published in PeerJ.

15 10, 2020

Catching Up with Ordosipterus planignathus

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

Ordosipterus planignathus – The First Pterosaur from the Ordos Region of Inner Mongolia

Time to catch up with developments in the world of the Pterosauria with a brief look at the recently described new dsungaripteroid pterosaur named Ordosipterus planignathus.  Researchers from the Chinese Academy of Geological Sciences have described a new species of flying reptile from a partial lower jawbone found in the Ordos region of Inner Mongolia.  This is the first confirmed pterosaur discovery from the Lower Cretaceous deposits associated with this region.  The Dsungaripteridae are both geographically and temporally widespread, with taxa known from South America, Asia, North America and Europe as well as China and Mongolia.  However, Ordosipterus enlarges the geographical distribution of this kind of pterosaur, from north-western China (with western Mongolia), to central northern China.

A Life Reconstruction of Ordosipterus planignathus

Life reconstruction - Ordosipterus planignathus.

A life reconstruction of Ordosipterus planignathus.

Picture Credit: Ji/China Geology

Probing in the Mud for Crustaceans or an Insect Eater

Palaeontologists are uncertain as the trophic habits of these pterosaurs.  That is, it is hard to say what these animals ate.  Dsungaripteroid skulls are characterised by their stoutness and their study bones.  The skulls seem to be reinforced and strengthened to cope with disproportionately large bite forces.  These reinforced skulls in combination with the robust teeth associated with this family suggest that these types of pterosaurs might have probed in soft-mud to find molluscs such as snails and bivalves.  They may also have fed on hard-shelled insects.  The jaws and teeth of dsungaripteroid pterosaurs seem particularly suited to a durophagus diet.

To read a recent Everything Dinosaur blog post that looked at the evidence for probe feeding amongst flying reptiles: The Sensitive Beaks of Pterosaurs.

Only one tooth crown was found in situ, it appears to be short and blunt, perhaps, further evidence of durophagy in this type of pterosaur.

The Holotype Material for O. planignathus with Accompanying Line Drawings

Ordosipterus planignathus (holotype IG V13-011) with line drawings.

The incomplete but articulated lower jaw bones of Ordosipterus planignathus (Holotype IG V13-011) with accompanying line drawings.  Note scale bar equals 2 cm.

Picture Credit: Ji/China Geology

The picture (above), shows the anterior portion of the lower jaws of the recently described flying reptile (a) dorsal view, (b) left lateral view and (c) ventral view.  The genus name honours the Ordos region, whilst the species or trivial name translates from the Greek and Latin as “flat-jawed”, in reference to the shape of the lower jaws.

Evidence of a Unique Biota in Northern China/Mongolia during the Early Cretaceous

The finding of a new species of Early Cretaceous (Aptian faunal stage), pterosaur unique to this area of Asia further strengthens the idea that two distinct terrestrial faunas existed.  It has been suggested that during the Early Cretaceous, two separate dinosaur/pterosaur dominated biotas could be identified in China and Mongolia.  The northern fauna was characterised by the presence of Psittacosaurus and a number of pterosaur genera (including Ordosipterus), whilst the southern fauna was distinguished by an absence of psittacosaurs.

The scientific paper: “First record of Early Cretaceous pterosaur from the Ordos Region, Inner Mongolia, China” by Shu-an Ji published in China Geology.

13 10, 2020

A New Basal Abelisaurid is Described “Ghost Hunter”

By | October 13th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A New Basal Abelisaurid – Spectrovenator ragei

Researchers from the Universidade de São Paulo (Brazil), in collaboration with colleagues from the Museo Paleontológico Egidio Feruglio (Argentina), have described a new species of basal abelisaurid from the Early Cretaceous of Brazil.  The theropod has been named Spectrovenator ragei, the genus name translates from the Latin as “Ghost Hunter” as the fossilised remains were found unexpectedly underneath the holotype of the titanosaur Tapuiasaurus macedoi when the fossils of this dinosaur were being partially prepared by the field team.

An Illustration of Spectrovenator ragei with Key Fossils Highlighted that Help to Define the Dinosaur’s Taxonomy

Spectrovenator key fossils.

Key fossil bones that helped to define Spectrovenator taxonomically.  Known fossil material shaded blue.

Picture Credit: Zaher et al

The species or trivial name honours the late Dr Jean-Claude Rage, an eminent French researcher who made a significant contribution to the study of South American Mesozoic vertebrates.

Described from a partially articulated skeleton including a virtually complete skull, the dinosaur is thought to have measured around 2.2 metres in length and it is the first Early Cretaceous abelisaurid known with an almost complete skull.  The cranial material has helped the researchers to demonstrate the evolution of abelisaurid skulls from the earliest, most basal Eoabelisaurus to the abelisaurids that existed in Gondwana during the later stages of the Cretaceous.

Views of the Skull with Accompanying Line Drawings

The Skull of Spectovenator (lateral view with line drawings).

The skull of Spectrovenator ragei (MZSP-PV 833) in (a) right lateral view with (b) line drawing and (c) left lateral view and accompanying line drawing (d).  Scale bar equals 5 cm.

Picture Credit: Zaher et al

With a beautifully preserved skull to study, the scientists have been able to compare the function of the skull and jaws of Spectrovenator with more derived members of the Abelisauridae.  The Early Cretaceous Spectrovenator (Barremian-Aptian), lacks the specialisations, such as a high occipital region and highly flexible jaw joints linked to a modified feeding strategy suggested for much later abelisaurids.  For example, some scientists, think that large-bodied abelisaurids such as Carnotaurus (C. sastrei) specialised in hunting titanosaurs (large prey).  The lack of these specialisations in the skull of Spectrovenator suggests this modified feeding strategy may be restricted to Late Cretaceous abelisaurids and linked to an increase in body size by this type of predatory dinosaur which occurred during the Cenomanian and through to the Maastrichtian.

Phylogenetic relationships of Spectrovenator within the Ceratosauria

Phylogenetic relationships of Spectrovenator within the Ceratosauria.

Phylogenetic relationships of Spectrovenator within the Ceratosauria with a geographical and temporal break down of fossil material.  Spectrovenator is regarded as a basal member of the Abelisauridae.

Picture Credit: Zaher et al

The discovery of Spectrovenator helps to fill a sizeable gap in the evolutionary history of the Abelisauridae.  The earliest member of the Abelisauridae described to date Eoabelisaurus (E. mefi), is known from the Middle Jurassic of Argentina (around 166 million years ago), whilst other abelisaurids such as Rugops and Skorpiovenator are known from Upper Cretaceous sediments (100 million years ago approximately).  Whereas Spectrovenator was found in strata that is approximately 120 million years old.

The scientific paper: “An Early Cretaceous theropod dinosaur from Brazil sheds light on the cranial evolution of the Abelisauridae” by Hussam Zaher, Diego Pol, Bruno Albert Navarro, Rafael Delcourt and Alberto Barbosa Carvalho published in Comptes Rendus Palevol.

9 10, 2020

The Sensitive Beaks of Pterosaurs

By | October 9th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Sensitive Probe Feeding Pterosaurs

Whilst it is not always sensible to compare the Pterosauria to birds, they do have a number of things in common.  As vertebrates they may not be very closely related but both birds and pterosaurs share some common anatomical characteristics that have helped them to conquer the sky.  Their skeletons show special adaptations to assist with powered flight and if we focus on modern birds for a moment, we can see that many forms have evolved to occupy different niches in ecosystems.  For example, some birds such as vultures and condors are primarily scavengers, whilst others are active predators (eagles, hawks and falcons).  Yet more are omnivores and some such as flamingos (filter feeders), swifts (aerial insect hunters) and hummingbirds (nectar feeders) occupy very specialist roles within food chains.

Although the known fossil record of the Pterosauria probably grossly under-represents these flying reptiles, palaeontologists are becoming increasingly aware of the diversity of this enigmatic clade.  Around 130 genera have been described, probably only a fraction of the total number of genera that evolved during their long history and recently a combination of fossil finds from Morocco in conjunction with a re-examination of fossils from a chalk pit near Maidstone in Kent (England), has led researchers to propose yet another environmental niche for pterosaurs.  Some pterosaurs evolved sensitive beaks that allowed them to probe sediments to help them find food just like many types of modern wading birds and members of the Aves such as the kiwi.

A Life Reconstruction of the Lonchodectid Lonchodraco giganteus Probing in the Mud to Find Food

Lonchodraco (pterosaur) probing mud for food.

A life reconstruction of a lonchodectid pterosaur using its sensitive beak to find food.

Picture Credit: Megan Jacobs (The University of Portsmouth)

Unusual Foramina in a Fossil Specimen

Researchers from the University of Portsmouth in collaboration with Dr Nicholas Longrich (University of Bath), took a close look at the fragmentary remains of the anterior of the rostrum (front of the jaws), of the pterosaur Lonchodraco giganteus (formerly referred to as Lonchodectes giganteus).  These fossils had been found in a chalk pit, close to the village of Burham, near Maidstone, Kent.  They were originally described as a species of Pterodactylus by the British naturalist James Scott Bowerbank in 1846.

Lonchodraco giganteus Holotype Jaws

Lonchodraco giganteus holotype rostrum and mandible.

Holotype rostrum and mandible of Lonchodraco giganteus (NHMUK 39412) in (a) left lateral and (b) right lateral views.  Scale bar = 1 cm.

Picture Credit: Martill et al (Cretaceous Research)

Like many pterosaur fossils from southern England, the fossilised remains are extremely scrappy, more recent studies have assigned these remains to the little-known lonchodectid pterosaurs (Lonchodectidae family).  These types of pterosaurs are united by having low profile jaws, raised teeth sockets and uniformly small teeth.  In a study of the holotype rostrum and mandible of L. giganteus, dozens of tiny holes (foramina) were discovered in the beak tip.  These are thought to represent sensory areas on the beak, where nerves pass through the bone and make contact with the beak’s surface.  Although foramina have been observed in the Pterosauria before, the pattern identified on the tip of the rostrum of Lonchodraco is unique.

Lonchodraco giganteus Holotype (Anterior View)

Lonchodraco giganteus holotype (anterior view).

Lonchodraco giganteus (NHMUK 39412).  Two views of anterior rostrum and mandible.  Photograph ( a) showing anterior margin of mandible with small, triangular symphysial process and (b), anterior view of rostrum showing the rounded termination of the beak and the fine perforations of the dental borders.  Black arrows indicate symphysial process/odontoid.  Scale bar = 1 cm.

Picture Credit: Martill et al (Cretaceous Research)

These types of nerve clusters are reminiscent to those found in living birds such as kiwis, sandpapers, spoonbills, geese, ducks and snipes.  These birds rely on their sense of touch when finding and catching food.  Typically, they either probe in water, mud, sand or soil to locate and catch prey.  This research, in combination with a second paper that also postulates on probe-feeding behaviour in the Pterosauria, suggests that just like modern birds, the pterosaurs were capable of evolving into a myriad of forms to exploit different food sources.

Concentration of Foramina at the Jaw Tips (Lonchodraco giganteus)

Lonchodraco line drawing showing concentration of foramina at the jaw tips

Hypothetical restoration of the jaw tips of Lonchodraco giganteus.  The black dots represent sensory areas (foramina).

Picture Credit: Martill et al (Cretaceous Research)

The scientific paper: “Evidence for tactile foraging in pterosaurs: a sensitive tip to the beak of Lonchodraco giganteus (Pterosauria, Lonchodectidae) from the Upper Cretaceous of southern England” by David M. Martill, Roy E. Smith, Nicholas Longrich and James Brown published in Cretaceous Research.

A Second Example of Probe Feeding

Recently, Professor David Martill, along with colleagues from Portsmouth University, pterosaur expert Samir Zouhri (Université Hassan II, Casablanca, Morocco) and Nicholas Longrich (University of Bath), published a paper in Cretaceous Research describing a new species of long-jawed pterosaur from Morocco that also could have been a probe feeder.  The flying reptile was described as having exceptionally long jaws for its body size, which terminated in a flattened beak with thickened bony walls.  The shape of these jaws superficially resembled the beaks of probing birds such as kiwis, ibises and curlews.  The research team hypothesised that like these living birds, this pterosaur probed in soft sediments in search of invertebrates.  The age of the fossils is not certain, although an Albian to Cenomanian age was postulated.  This pterosaur was tentatively assigned to the azhdarchoids, but if it is a member of the Azhdarchoidea, then it represents an extremely atypical form.

The scientists conclude that this Moroccan pterosaur adds to the remarkable diversity of the Pterosauria known from the Cretaceous.

Everything Dinosaur acknowledges the assistance of media releases from the University of Portsmouth and the University of Bath in compilation of this article.

The scientific paper: “A long-billed, possible probe-feeding pterosaur (Pterodactyloidea: ?Azhdarchoidea) from the mid-Cretaceous of Morocco, North Africa” by Roy E. Smith, David M. Martill, Alexander Kao, Samir Zouhri, and Nicholas Longrich published in Cretaceous Research.

8 10, 2020

Two-fingered Oviraptosaur Sheds Light on the Success of the “Egg Thiefs”

By | October 8th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Oksoko avarsan – New Species of Oviraptorosaur with Two Fingers

That inappropriately named clade of “Egg Thief Lizards”, the Oviraptorosauria has a new member.  Standing around one metre high at the hips, the newly described Oksoko avarsan (Oak-soak-oh), which had just two digits on each hand, instead of the default Oviraptor setting of three, is helping palaeontologists to understand the radiation and success of these feathered dinosaurs.

A Life Reconstruction of the Newly Described Oksoko avarsan

Oksoko avarsan life reconstruction.

A trio of oviraptors – a life reconstruction of Oksoko avarsan.

Picture Credit: Michael Skrepnick

The First Evidence of Digit Loss in the Oviraptorosaurs

Over the last forty years or so, lots of new oviraptorosaur theropods have been named and described, principally from fossil finds made in China and Mongolia.   These feathered dinosaurs were highly successful and although their origins are uncertain, this type of dinosaur probably evolved in the Early Cretaceous of northern China and by the Late Cretaceous they had spread across much of Asia and into North America.

Whilst most palaeontologists confronted with the wealth of fossil material would concede that these theropods were geographically widespread, little research has been undertaken to ascertain the reasons for their evolutionary success.  The discovery of Oksoko with its reduced forelimb with only two functional digits suggests that this group could alter their diets, behaviours and habits which enabled them to diversify and multiply.  In essence, variation in forelimb length and hand morphology provides another example of niche partitioning in oviraptorosaurs, which may have contributed to their incredible diversity in the latest Cretaceous of Asia.

The Holotype Block Containing Three Specimens of O. avarsan

The holotype block consisting of three individuals (Oksoko avarsan).

The holotype block of Oksoko avarsan MPC-D 102/110 with an explanatory line drawing.  The holotype fossil is individual A coloured blue.

Picture Credit: Funston et al (Royal Society Open Science)

Gregarious Behaviour in Oviraptorids

Oksoko is known from four specimens, a group of three (see picture above) and a fourth specimen found in the same crouched position that is believed to come from the same location.  All the fossil material was confiscated from poachers so the exact discovery site of these fossils remains unknown.  However, the researchers have confidently assigned them to the Nemegt Formation of the Gobi Desert and the material is estimated to be around 68 million years old.  It had long been suspected that oviraptorosaurs were gregarious social animals.  The finding of three individuals preserved together represents the first, definitive evidence that these animals probably lived in groups and that they were gregarious.  The fossil bones of all four individuals have provided the researchers with an almost complete skeleton of this two-metre-long dinosaur to study.

Key Fossils Representing the Anatomy of Oksoko avarsan

Key fossils associated with Oksoko avarsan.

Skeletal anatomy of Oksoko avarsan with key fossils including skull in lateral view (b) with line drawing (c).

Picture Credit: Funston et al (Royal Society Open Science)

A Three-headed Eagle

The scientists which included Dr Gregory Funston (Edinburgh University) and Phil Currie (University of Alberta), named this dinosaur after the three-headed eagle of Altaic mythology, a reference to the holotype block which contains the skulls of three individuals.  The species or trivial name is from a Mongolian word for “rescued”, it alludes to the fact that these fossils were recovered from poachers.

The remarkably well-preserved fossil material provides the first documented evidence of digit loss in the usually three-fingered Oviraptorosauria.  The holotype block material represents the remains of three dinosaurs that were approximately the same size and bone histology reveals that these animals died when they were around a year old.  The fourth specimen is believed to represent an older animal that died around the age of five.

Commenting on the discovery, Dr Funston remarked:

“Oksoko avarsan is interesting because the skeletons are very complete and the way they were preserved resting together shows that juveniles roamed together in groups.  But more importantly, its two-fingered hand prompted us to look at the way the hand and forelimb changed throughout the evolution of oviraptors — which hadn’t been studied before.  This revealed some unexpected trends that are a key piece in the puzzle of why oviraptors were so diverse before the extinction that killed the dinosaurs.”

Finger Loss in a Dinosaur Family

Oksoko is the sixth genus of the Oviraptoridae family to be named from fossils associated with the Nemegt Formation.  This demonstrates the diversity of these types of dinosaurs in the Late Cretaceous of China.

The other five oviraptorids known from the Nemegt Formation of Mongolia as stated by Everything Dinosaur team members are:

  • Rinchenia mongoliensis
  • Nomingia gobiensis
  • Nemegtomaia barsboldi
  • Gobiraptor minutus
  • Conchoraptor gracilis

In addition, a number of closely related dinosaurs are known from the Nemegt Formation including the caenagnathid Elmisaurus rarus

The scientists produced a phylogeny of the Oviraptorosauria based in a reduction in size and eventual loss of digit III as shown in the most derived form described to date (O. avarsan) and a corresponding increase in size and robustness of digit I.  They concluded that the arms and hands of these dinosaurs changed radically in conjunction with migrations into new geographical areas and presumably different habitats – specifically to what is now North America and the Gobi Desert.

Plotting the Change in Hand Morphology and the Radiation of the Oviraptorosauria

Phylogeny, biogeography and digit reduction in Oviraptorosauria.

Phylogeny, biogeography and digit reduction in Oviraptorosauria.  The map (top left) shows the distribution of oviraptorids during the Late Cretaceous of Asia.

Picture Credit: Funston et al (Royal Society Open Science)

To read a related article that considered the holotype block as evidence for communal roosting in oviraptorids: Three Theropods Preserved in a Resting Pose.

The scientific paper: “A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria” by Gregory F. Funston, Tsogtbaatar Chinzorig, Khishigjav Tsogtbaatar, Yoshitsugu Kobayashi, Corwin Sullivan and Philip J. Currie published in Royal Society Open Science.

7 10, 2020

Little Juravenator Had Sensory Scales on its Tail

By | October 7th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Juravenator and a “Tale” of Sensory Scales

Researchers writing in the academic journal “Current Biology”, have revealed how dinosaurs may have made sense of their surroundings using special sensory nodes embedded in the scales on their skin.  A new paper focusing on the small, theropod Juravenator starki from the Torleite Formation (upper Kimmeridgian), Solnhofen, Bavaria, (Germany), reports on the discovery of dermal structures along the side of the dinosaur’s tail resembling the integumentary sense organs found in extant crocodiles.

Getting a Sense of Dinosaur Senses

Identifying integumentary sense organs in the Juravenator holotype specimen.

Integumentary sense organs identified in the Juravenator starki holotype.  The black arrow points to the sensory organ, which are found on polygonal scales covering the lower part of the tail

Picture Credit: Bell et al Current Biology with additional annotation by Everything Dinosaur

Juravenator starki

Once thought to be a close relative of the contemporary Compsognathus longipes, Juravenator is known from a single, beautifully preserved fossil specimen (JME Sch 200), found in a limestone quarry in 1998.  Although squashed flat, the specimen is mostly articulated and complete with only some caudal vertebrae missing.  It is a juvenile and as such, placing it within the Theropoda has proved problematic.  The taxonomic position is uncertain, but it has been suggested that it could represent a basal member of the Coelurosauria or perhaps a primitive member of the Maniraptora.

The genus name is derived from the Bavarian Jura mountains and “venator” – Latin for “hunter”.  The species (trivial) name honours the Stark family who owned the quarry where the sixty-centimetre-long dinosaur fossil was discovered.

Soft tissue representing body scales have been identified associated with the lower leg bones and between the 8th and 22nd caudal vertebrae.  Other soft tissue structures have been found probably representing preserved tendons and ligaments.  It is these dermal structures that have been the centre of this new study.

A Life Reconstruction of the Late Jurassic Theropod Juravenator starki

Juravenator starki illustrated.

An illustration of the theropod Juravenator starki.

Picture Credit: Jake Baardse

Specialised Scales

Scientists are aware that early in the evolution of the first truly terrestrial tetrapods epidermal scales evolved to provide an effective barrier against ultraviolet radiation and to prevent excessive water loss.  This evolutionary development meant that stem reptiles were no longer constrained by having to stay close to freshwater like their amphibian ancestors.  Epidermal scales in extant reptiles are not simple, inert structures but can perform a suite of functions and assist in how the animal senses its environment.

Researchers Dr Phil Bell (University of New England) in Armidale, Australia along with his colleague Dr Christophe Hendrickx, from the Unidad Ejecutora Lillo in San Miguel de Tucumán, (Argentina), both specialists in dinosaur dermatology, identified a unique scale type with distinctive, prominent circular nodes on the preserved integumentary covering on the tail of Juravenator. They interpret these raised nodes as integumentary sense organs, analogous to those found today in living crocodilians.

Dr Bell commented:

“Few people pay much attention to dinosaur skin, because it is assumed that they are just big, scaly reptiles.  But when I looked closely at the scales on the side of the tail, I kept finding these little ring-like features that didn’t make sense; they were certainly unlike other dinosaur scales.”

Integumentary Sense Organs Identified in a Dinosaur

Crocodilian integumentary sense organs.

Crocodilian integumentary sense organs, circular objects visible on the dermal scales.

Picture Credit: Bell et al Current Biology

The surprising presence of such structures suggests the tail of Juravenator played a role in how this dinosaur sensed the world around it.  This is the first direct evidence of such structures being present on the skin of a dinosaur.

The shape and the orientation of the teeth, especially those in the upper jaw suggest Juravenator ate fish (piscivore).  During the Late Jurassic, this part of Europe was covered by a warm, tropical, shallow sea with numerous small islands.  This archipelago was home to a number of dinosaurs including the famous “urvogel” Archaeopteryx.  As crocodiles are aquatic predators, the research team speculate that Juravenator may have been an aquatic hunter too.  Alligators have integumentary sense organs on their snout, whereas crocodiles have these special scales all over their body including the tail.  These sensory nodes help these reptiles to detect temperature changes, chemical signals in the water as well as having tactile properties.  Although the entire integumentary covering of Juravenator is unknown, this lithe dinosaur could have submerged its tail to help it detect the movement of prey underwater.

To read an article about the sense of smell in the Dinosauria: Don’t Get Sniffy About Dinosaur Sense of Smell.

The scientific paper: “Crocodile-like sensory scales in a Late Jurassic theropod dinosaur” by Phil R. Bell and Christophe Hendrickx published in Current Biology.

3 10, 2020

Naked Pterosaurs – No Protofeathers on Pterosaurs

By | October 3rd, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

New Study Refutes the Idea of Protofeathers in the Pterosauria

A newly published study casts doubt on the idea that members of the Pterosauria had an integumentary covering of insulating protofeathers.  Professor David Martill (University of Portsmouth), in collaboration with fellow flying reptile expert Dr David Unwin (University of Leicester), have reviewed the evidence and they propose that these vertebrates essentially lacked a feathery covering or indeed pycnofibres.

This research contradicts and refutes an earlier study published in the academic journal “Nature Ecology and Evolution” in 2018.

To read our article about the 2018 paper: Are the Feathers About to Fly in the Pterosauria?

Pterosaurs Uncovered – Lacking an Integumentary Covering

No protofeathers in the Pterosauria.

Naked pterosaurs – British researchers refute the idea of protofeathers in the Pterosauria.

Picture Credit: Megan Jacobs (University of Portsmouth)

Feather-like Branching Filaments

Dr Unwin and Professor Martill have challenged the findings of a research paper that examined the fossilised remains of two anurognathid pterosaurs which concluded that some of the structures preserved in association with the fossil bones were pycnofibres with characteristic features of feathers including non-vaned grouped filaments and bilaterally branched filaments.  The 2018 paper implied that if pterosaurs as well as dinosaurs had feather-like body coverings, then this type of integumentary covering was deeply rooted in the Archosauria.  This would suggest that the common ancestor of both the Pterosauria and the Dinosauria evolved this type of body covering.

If this interpretation of the fossil evidence is correct, then the very first feather-like elements evolved at least eighty million years earlier than currently thought.  It would also suggest that all dinosaurs started out with feathers, or protofeathers but some groups, such as the Sauropoda, subsequently lost them again, the complete opposite of currently accepted theory.

Unwin and Martill challenge the interpretation of the material that featured in the 2018 paper.  The propose that tiny, hair-like filaments reported by Yang et al (2018), are not protofeathers at all but tough fibres which form part of the internal structure of the pterosaur’s wing membrane, and that the “branching” effect may simply be the result of these fibres decaying and unravelling.

Dr Unwin from the University of Leicester’s Centre for Palaeobiology Research commented:

“The idea of feathered pterosaurs goes back to the nineteenth century but the fossil evidence was then and still is, very weak.  Exceptional claims require exceptional evidence – we have the former, not the latter.”

Feather-like Filaments in Pterosaur Fossils

Different types of filaments associated with pterosaur fossils.

Close-up views of different types of feather-like filaments identified in pterosaur fossils.

Picture Credit: Yang, Jiang, McNamara et al

Highlighting the difficulties of interpretating filament-like structures, Professor Martill commented that either way, palaeontologists have to take care when considering theories related to the Pterosauria, they have no extant equivalents so the reliance of fossil material is perhaps greater when compared to the Dinosauria with their close relatives the birds still very much with us.

Professor Martill observed:

“If they really did have feathers, how did that make them look and did they exhibit the same fantastic variety of colours exhibited by birds.  And if they didn’t have feathers, then how did they keep warm at night, what limits did this have on their geographic range, did they stay away from colder northern climes as most reptiles do today.  And how did they thermoregulate?  The clues are so cryptic, that we are still a long way from working out just how these amazing animals worked”.

The scientific paper: “No protofeathers on pterosaurs” by David M. Unwin and David M. Martill published in Nature Ecology and Evolution.

2 10, 2020

That Famous Single Feather Fossil – Probably Archaeopteryx

By | October 2nd, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Famous Feather Fossil – Probably Represents a Feather from Archaeopteryx

The feathers are flying when it comes to an iconic fossil, arguably one of the most significant in any vertebrate palaeontology collection – a single, carbonised feather from the Solnhofen area of southern Germany.

Described in 1861, this isolated feather specimen is regarded as the first fossil feather known to science.  Having been scientifically studied just two years after the publication of Charles Darwin’s “Origin of Species”, the “Urfeder” – first feather in German, a modern-looking bird feather preserved in lagoonal sediments laid down around 150 million years ago, sent shock waves around the scientific community when it was first described.

The Iconic Feather Fossil – Is this from the “Urvogel” (Archaeopteryx lithographica)?

The Berlin feather - preserved as a carbonised film.

The slab from the Berlin museum showing the iconic feather, so long associated with Archaeopteryx and recently thought to have come from a dinosaur.  New research suggests this is a feather from Archaeopteryx.

Picture Credit: Everything Dinosaur

The Application of Laser-Stimulated Fluorescence

Ever since its discovery, scientists have debated what sort of creature this single feather came from.  In February 2019, Everything Dinosaur reported on research conducted by a team of international scientists that applied a sophisticated imaging method called Laser-Stimulated Fluorescence (LSF) to reveal previously unseen details in a forensic examination of both the slab and the counter slab of the fossil feather.  The team, which included Dr Michael Pittman (University of Hong Kong), proposed that the feather did not come from the famous “first bird”, but instead from an unknown species of dinosaur that co-existed with Archaeopteryx.

To read our blog post from February 2019, that disputed the claim that this specimen represented a feather from an Archaeopteryx: Iconic Feather Did Not Belong to Archaeopteryx.

New Study Re-affirms the Archaeopteryx Link

This new research utilised images generated from an electron microscope of the single feather specimen along with detailed examinations of known Archaeopteryx fossils that displayed feather impressions.  The study published in “Scientific Reports” was led by Ryan Carney, an assistant professor of integrative biology at the University of South Florida.  The researchers analysed nine characteristics of the feather, particularly the long quill, which runs up the centre of the specimen (centreline).  This centreline is composed of two parts:

  • Calamus – centreline below the skin (shown in red in the diagram below)
  • Rachis – tubular extension of the calamus above the skin (shown in blue in the diagram below)

The New Study Suggests The Single Feather Fossil is Congruent with Archaeopteryx Feathers

Correcting the centre line from the 2019 scientific paper.

The centre line of the feather has been recalculated to show that the 2019 paper was inaccurate in this regard. The placement of the centreline now falls within the range of selected modern Aves species.

Picture Credit: Carney et al (Scientific Reports)

The photograph (above), shows (a) centrelines of the isolated fossil feather modified from Hermann von Meyer’s original 1861 description and (b) Laser-stimulated fluorescence image modified from the 2019 scientific paper.  In (a) and (b), the centerline comprises the calamus (red) and rachis (blue).  An alignment error made in the earlier (2019) research led to the orientation of the centreline of the fossil feather to be out of the expected range found in extant birds (c).  The final figure (d) has been modified from (c) and shows a more representative range of centreline morphologies associated with modern birds (areas shaded yellow in (c) and (d).

Based on this new research, the scientists conclude that the single feather represents a feather from the left wing called a primary covert.  Primary coverts are small contour feathers that overlay the main wing feathers.  As similar feather characteristics were identified in other Archaeopteryx fossil feathers Carney et al conclude that the 1861 specimen probably does represent a feather lost by the famous “Urvogel” (Archaeopteryx lithographica).

Ryan Carney commented:

“There’s been debate for the past 159 years as to whether or not this feather belongs to the same species as the Archaeopteryx skeletons, as well as where on the body it came from and its original colour.  Through scientific detective work that combined new techniques with old fossils and literature, we were able to finally solve these centuries-old mysteries.”

The Location of the Fossil Finds

In addition, the research team looked at the provenance of the single feather, where it was found in relation to known discoveries of Archaeopteryx remains.  Four Archaeopteryx specimens, including the London specimen which is now the holotype for A. lithographica were found within 2.2 kilometres of the site where the single feather was discovered.  All of these specimens are coeval (having the same age and origin), from the same horizon in the limestone, all linked by biostratigraphy.  The Archaeopteryx material being associated with the same zonal ammonite fossils (Subplanites rueppellianus).

The Provenance of the Single Feather Fossil in Relation to Other Archaeopteryx Specimens

Supporting evidence for the single feather specimen coming from Archaeopteryx.

Map of the Solnhofen-Langenaltheim quarry district, illustrating locations of the isolated feather and the London (type), Maxberg, Munich, and Ottmann & Steil (9th) specimens of Archaeopteryx.

Picture Credit: Carney et al (Scientific Reports)

Detecting and Interpreting Melanosomes on the Feather

The electron microscopy employed permitted the scientists to identify melanosomes (microscopic pigment structures).  They determined that this primary covert feather was coloured matte black.  Other studies have also shown the Archaeopteryx may have been black in colour, with some feathers showing iridescence.

The scientific paper: “Evidence corroborates identity of isolated fossil feather as a wing covert of Archaeopteryx” by Ryan M. Carney, Helmut Tischlinger and Matthew D. Shawkey published in Scientific Reports.

21 09, 2020

Euparkeria Steps Out

By | September 21st, 2020|Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Euparkeria Study Provides Important Step in Evolution of Archosaur Posture

Fossils of the stem-archosaur Euparkeria (pronounced Yoo-park-air-ree-ah), have been studied by scientists from the University of Bristol and the Royal Veterinary College in a bid to better understand the evolution of different gaits and locomotion within archosaurs.  Three-dimensional modelling based on high resolution CT scans of the hindlimb of the small, agile Euparkeria (E. capensis), has revealed that it had a “mosaic” of functions associated with locomotion.

Euparkeria, which roamed southern Africa around 245 million years ago, is believed to be a close relative of the last common ancestor of both crocodilians and the dinosaur/bird branch of the Archosauria family tree, as such, a study of its fossil bones can provide important insights into the evolution of the archosaurs.

A Life Reconstruction of Euparkeria capensis

Euparkeria life reconstruction

A life reconstruction of the basal archosauriform Euparkeria (E. capensis).  As the hindlimbs are longer than the front legs, many researchers believe that Euparkeria was capable of adopting a bipedal stance when it wanted to (facultative biped).

Picture Credit: Everything Dinosaur

This little reptile, that was formerly named and described in 1913, has recently been at the centre of another study which examined skull fossil material originally reported upon in 1965, but with the advance of scanning technology, scientists were able to provide much more information about the structure of Euparkeria’s skull: Little Euparkeria Steps into the Spotlight.

Euparkeria Provides Insight

Birds have an upright, erect bipedal posture, whilst extant crocodilians are quadrupedal and have a sprawling gait.  The ancestor of the birds and crocodiles once shared a common mode of locomotion and Euparkeria can provide vital information helping scientists to work out how these differences came about.

Life Reconstruction of Euparkeria capensis

Euparkeria life reconstruction.

A life reconstruction of Euparkeria highlighting the hip and ankle that were the focus of the study.  Note in this illustration the archosaur has been given a more sprawling, quadrupedal posture when compared to the first illustration of Euparkeria on this post.

Picture Credit: Oliver Demuth

Writing in the academic journal “Scientific Reports”, the researchers which included John Hutchinson, Professor of Evolutionary Biomechanics at the Royal Veterinary College, explained how they reconstructed the hip structure of Euparkeria based on CT scans.  The complex and very detailed computer models these scans produced demonstrated that Euparkeria had a distinctive bony rim on the pelvis, called a supra-acetabular rim, covering the top of the hip joint.  This anatomical feature had only previously been found in later archosaurs on the crocodilian branch of the Archosauria.  As a result, a more erect posture had been inferred for these extinct crocodiles.  The supra-acetabular rim permitted the pelvis to cover the top of the femur (thigh bone) and support the body with the limbs in a more columnar arrangement – this type of joint is referred to as “pillar-erect”.

Identifying the Supra-acetabular Rim on the Hip Bone

Euparkeria hip bones.

The black arrow points to the supra-acetabular rim.  This projection of the hip bone above the hip joint permitted the tucking of the limbs under the body to support the body in a columnar arrangement.  This is so far the earliest occurrence of this structure in the archosaur family tree.

Picture Credit: Demuth et al (Scientific Reports)

Euparkeria is the oldest known reptile that possessed such a joint, this raises the intriguing question as to whether it had a more erect dinosaur/bird-like posture rather than the more sprawling posture as seen in modern crocodilians.

Testing How the Hindlimbs Could Move

Computer simulations were created to test the range of movement in the hindlimbs.  The team estimated how far the femur could have rotated until it collided with the hip bones.  The computer models also examined how the ankle joint functioned as well.  The simulations suggested that while the femur could have been held in an erect posture, the foot could not have been placed steadily on the ground due to the way the foot rotates around the ankle joint, implying a more sprawling posture.  However, the supra-acetabular rim covering the hip joint restricted the movement of the thigh bone in a way that is not seen in any living tetrapod with a sprawling gait, this indicates that Euparkeria had a more upright posture.

Examining Three-dimensional Models of the Euparkeria Ankle to Assess Function

Modelling the ankle structure of Euparkeria.

The oblique ankle joint did not allow Euparkeria to assume a fully upright posture as the foot also turns medially when the ankle joint is extended.  An ankle joint allowing a more upright posture evolved later independent from the hip structure.

Picture Credit: Demuth et al (Scientific Reports)

The researchers conclude that Euparkeria possessed a “mosaic” of locomotor functions.  It is the earliest reptile known with this peculiar hip anatomy and an ankle joint allowing a more erect posture did evolve in later Triassic archosaurs.

Professor Hutchinson stated:

“The mosaic of structures present in Euparkeria, then, can be seen as a central stepping-stone in the evolution of locomotion in archosaurs.”

The scientific paper: “3D hindlimb joint mobility of the stem-archosaur Euparkeria capensis with implications for the postural evolution within the Archosauria” by Oliver E. Demuth, Emily J. Rayfield and John R. Hutchinson published in Scientific Reports.

17 09, 2020

Carnian Pluvial Episode – Late Triassic Mass Extinction

By | September 17th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page, Palaeontological articles|0 Comments

Getting to Grips with a Mass Extinction Event – Carnian Pluvial Episode

The fossil record of the Phanerozoic (the Eon of visible life), indicates that there were five major mass extinction events.  The fossil record marks huge and very rapid (at least in geological terms anyway), reductions in the diversity of life on a world-wide scale.  Our planet might well be going through a mass extinction event at the moment, but for one team of scientists their attention has been on the Late Triassic (Carnian faunal stage), plotting a time of extensive terrestrial and marine faunal turnover.  The researchers, which include scientists from Bristol University, the University of Ferrara (Italy), the University of Vienna and the China University of Geosciences in Wuhan Province, conclude that around 233 million years ago about a third of all marine genera disappeared.

Terrestrial Fauna in the Late Triassic – Did a Major Extinction Event Help to Trigger the Rise of the Dinosaurs

Late Triassic terrestrial fauna.

Life in the Late Triassic, an explosion in dinosaur diversity.  Did the Crocodylomorpha and the Dinosauria benefit from the Late Triassic Carnian Pluvial Episode?

Picture Credit:  Davide Bonadonna

Many types of land-living animal did no better.  The herbivorous rhynchosaurs and dicynodonts were greatly reduced in diversity during the Carnian, but intriguingly crocodylomorphs and those other archosaurs, the Dinosauria seem to have benefitted from the extinction of other types of tetrapod, with both the Crocodylomorpha and dinosaurs diversifying towards the end of the Carnian.  The scientists postulate that the rise of the dinosaurs to dominance might have been a direct consequence of the Carnian Pluvial Episode (CPE).

To read an earlier blog article that links the CPE with dinosaur diversification: Out with a Bang! In with a Bang! The story of the Dinosauria.

 A Time of Immense Global Environmental Change

The Carnian Pluvial Episode took place from around 234 to 232 million years ago.  There was a marked rise in rainfall (at least four episodes of increased rainfall have been deduced from sedimentary and palaeontological data).  The Earth got warmer and more humid.  This led to extensive environmental changes and the subsequent demise and then collapse of many ecological systems.  Writing in the academic journal “Science Advances”, the scientists throw their collective weight behind the theory that enormous volcanic eruptions in the Wrangellia Province of western Canada, that resulted in the deposition of vast amounts of basalt, were probably the cause of the global environmental changes.

Co-author of the paper Jacopo Dal Corso (China University of Geosciences), explained:

“The eruptions peaked in the Carnian.  I was studying the geochemical signature of the eruptions a few years ago and identified some massive effects on the atmosphere worldwide.  The eruptions were so huge, they pumped vast amounts of greenhouse gases like carbon dioxide and there were spikes of global warming”.

This warming resulted in the increased humidity and higher levels of rainfall, a phenomenon first detected by geologists Mike Simms and Alastair Ruffell in the 1980s.  The climate change caused major biodiversity loss in the ocean and on land, but just after the extinction event new groups took over, forming more modern-like ecosystems.

Environmental and Geochemical Changes of the CPE

Environmental and geochemical changes associated with the Carnian Pluvial Event.

(A) Calculating the age of the CPE based on geochemical indicators and (B) Palaeogeography during the Carnian, the map showing where sedimentary and palaeontological data has been obtained documenting changes in environmental conditions.

Picture Credit: Jacopo Dal Corso et al/Science Advances

The environmental changes had a profound effect on life on our planet.  As well as a diversification of the dinosaurs, many other modern groups of animals and plants appeared at this time, including lizards and the first mammals.  When mapping the losses of marine fauna at the genus level, the team concluded that whilst the CPE was not as devastating as the either the end-Triassic or end-Cretaceous extinction events, some 33% of all marine genera died out.

A Comparison of Marine Faunal Turnover During Major Extinction Events

Plotting marine extinctions and faunal turnover over the Carnian Pluvial Event.

(A) Comparison of extinction rates of all marine genera during the CPE with those of major Phanerozoic mass extinction events.

Picture Credit: Jacopo Dal Corso et al/Science Advances

The Effect on Plant Life

The shifts in climate encouraged substantial changes in global flora too.  Many new types of plants emerged that were more suited to the humid climate.  Several modern fern families emerged and the Bennettitales (cycad-like plants), diversified.  Extensive coal deposits formed once again, the first substantial coal seams being produced since the Permian.  Conifers seem to have benefitted and the researchers, which include Professor Mike Benton (Bristol University), remark that the CPE provides the first major finds of amber in the fossil record.  As tree resin is usually produced when plants are under stress, this suggests that terrestrial ecosystems were in a state of flux during this period in Earth’s history.

Professor Benton stated:

“The new floras probably provided slim pickings for the surviving herbivorous reptiles.  I had noted a floral switch and ecological catastrophe among the herbivores back in 1983 when I completed my PhD.  We now know that dinosaurs originated some 20 million years before this event, but they remained quite rare and unimportant until the Carnian Pluvial Episode hit.  It was the sudden arid conditions after the humid episode that gave dinosaurs their chance.”

Terrestrial Extinctions and Originations During the Carnian (Late Triassic)

Mapping the major biological changes amongst plants, insects and vertebrates during the Carnian.

Plotting the major biological changes amongst plants, insects and vertebrates during the Carnian.  Trackmaker assemblages from the Southern Alps suggest a faunal turnover within the Archosauria with the dinosaurs replacing the crocodylomorphs as a significant component of terrestrial ecosystems.

Picture Credit: Jacopo Dal Corso et al/Science Advances

The researchers conclude that the CPE may not have been as significant as the big five Phanerozoic mass extinctions but it did have a dramatic impact on terrestrial and marine environments and helped to bring in a variety of new types of plants and animals, marking an important step towards the origins of the types of ecosystems we see around us today.

The scientific paper: “Extinction and dawn of the modern world in the Carnian (Late Triassic)” by Jacopo Dal Corso et al published in Science Advances.

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