It was the English engineer William Smith (1769-1839), who pioneered the idea that different strata located in different places could be correlated using the fossils that were contained therein. Although, his astonishing feat of compiling the world’s first geological map did not receive all the recognition it deserved, after all, it was only later in his life that his achievements gained prominence in scientific circles, William Smith is regarded by many as the “father of geology”.
As he examined different layers of rock he perceived that any succession of fossils could represent particular periods of geological time. Furthermore, the age of widely separated strata could be compared and correlated using the fossils that they contained. These fossils helped to indicate the relative age of various rock formations. Thus, Smith helped to lay the foundations for the science of biostratigraphy. ammonites and other invertebrate fossils are extremely important in the relative dating process.
Different Fossils of Ammonites Associated with Different Layers of Rock – Building a Biostratigraphical Column
Demonstrating a sequence of ammonite fossils identified from specific strata that helps to form a biostratigraphic column.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Ammonite Biozones
The above photograph was taken by an Everything Dinosaur team member on a recent visit to the Naturmuseum Senckenberg (Frankfurt, Germany), it demonstrates that different types of ammonite fossils are associated with different layers of rocks in a sequence of deposition. The stratigraphic column can therefore be divided into zones (biozones), that are characterised by one or more particular type of fossil. The sequence of these biozones in the correct order, creates a biostratigraphical column.
Ammonites are ideal zone fossil candidates. These cephalopods were ubiquitous in Mesozoic marine deposits, their shells formed abundant fossils and ammonites evolved rapidly into many distinctive types (species). We congratulate the Museum for such a beautifully created and instructive display.
A new species of large, toothless pterosaur has been described based on fossil specimens excavated from the “cemitério dos pterossauros” (pterosaur graveyard), in southern Brazil. This new flying reptile has been named Keresdrakon vilsoni. The researchers, writing in the academic journal “Anais da Academia Brasileira de Ciências” conclude that Keresdrakon co-existed with another, smaller and, based on the fossil evidence more numerous, pterosaur (Caiuajara dobruskii). In addition, the two distinct pterosaurs coexisted with a theropod dinosaur (Vespersaurus paranaensis) and together they provide an unique insight into an ancient desert ecosystem.
The Palaeoenvironment of the “Cemitério dos Pterossauros”
Keresdrakon life reconstruction, feeding on the carcase of a Vespersaurus.
Picture credit: Maurilio Oliveira
Interpreting the Palaeoenvironment
The age of the strata is disputed. Some authors favour a Turonian to Campanian age indicating Upper Cretaceous deposits, whilst other scientists have suggested that the rocks might be Lower Cretaceous in age (Aptian to Albian). The bonebeds associated with these sandstones indicate a congregation of vertebrates in what was probably an interdunal wetland in the middle of a desert. Caiuajara is interpreted as a likely frugivore, a feeding behaviour associated with other members of the Tapejaridae family. Although, the much larger, edentulous (toothless), Keresdrakon probably filled a different niche in the ecosystem. Its fossils are much rarer than those of Caiuajara, the researchers infer that Keresdrakon vilsoni might have behaved as an opportunistic predator or a scavenger.
Analysis of this pterosaur’s beak suggest that it did not have a strong bite, so overcoming larger prey such as the theropod Vespersaurus might have been difficult for Keresdrakon, but it could have fed on carrion, as depicted in the above illustration.
Keresdrakon vilsoni
The authors of the scientific paper, which include pterosaur expert Alexander Kellner of the Museu Nacional/Universidade Federal do Rio de Janeiro (Brazil), consider Keresdrakon to be the equivalent of a modern-day Marabou stork (Leptoptilos crumenifer), which scavenges but also eats any small animal that it can swallow.
The scientists speculate that K. vilsoni might have eaten juvenile Caiuajara or even hatchlings and eggs. Given the geological and fossil evidence, it is likely that these two pterosaurs along with Vespersaurus co-existed together and that the “cemitério dos pterossauros”, demonstrates evidence of sympatry in the Pterosauria, if this is the case, then these sandstone deposits of uncertain age in Paraná State represent an extremely significant discovery for vertebrate palaeontologists.
The Holotype Fossil Material of Keresdrakon vilsoni
Holotype of Keresdrakon vilsoni gen. et sp. nov. (CP.V 2069). Skull and lower jaw are presented in right lateral view. Note scale bar = 10 cm.
Picture credit: Kellner et al
What is Sympatry?
Sympatry is a term used in biology to describe the situation when two or more related species co-exist in the same environment at the same time. Caiuajara and Keresdrakon are contemporaneous, occupying the same space and time in the fossil record.
A phylogenetic analysis suggests that Keresdrakon sits outside the Tapejaridae family but is still quite closely related to these types of flying reptiles. It is described as part of a non-tapejarid lineage within the wider Tapejaromorpha.
A Sandstone Block Showing Keresdrakon vilsoni and Caiuajara dobruskii Fossils in Association
Sample (CP.V 5697) from bonebed C showing on the right (a) a partial skeleton of the Caiuajara dobruskii the left (b) elements of Keresdrakon vilsoni gen. et sp. nov. separated by the white line. Scale bar = 10 cm.
Picture credit: Kellner et al
The scientific paper: “A new toothless pterosaur (Pterodactyloidea) from Southern Brazil with insights into the paleoecology of a Cretaceous desert” by Kellner, Alexander W. A.; Weinschütz, Luiz C.; Holgado, Borja; Bantim, Renan A. M.; Sayão, Juliana M. and published in the Anais da Academia Brasileira de Ciências.
Our thanks to Thomas for sending into us the third and final article that he has compiled over the summer holidays. Thomas has chosen to feature the biota associated with the Lower Cretaceous deposits of the Purbeck Group of south-eastern England.
The Purbeck Group
The Purbeck Group consists of limestone, mudstones and evaporites representing a series of freshwater, brackish and marine environments laid down in the Upper Jurassic and into the Lower Cretaceous, approximately 145 to 139 million years ago. The fossils associated with these sedimentary rocks provide evidence of changing palaeoenvironments and also of faunal turnover, including a record of different types of dinosaur.
This world is not talked about often but is very interesting for at some point during the Late Jurassic allosauroids became extinct in the British Isles only to return sometime in the Early Cretaceous (around 140-139 million years ago). Falling sea levels are thought to have contributed to the reintroduction of these theropods to their former territory. During their absence, tyrannosauroids evolved to fill the niche left by the allosauroids, although in the Jurassic, they were not apex predators.
Let’s Meet the Dinosaur Fauna of this Lost Kingdom
Nuthetes destructor – known from extremely fragmentary fossil material, possibly a dromaeosaurid or perhaps a member of the Tyrannosauroidea (Proceratosauridae?). The size of this dinosaur is unknown, although based on measurements of the anterior portion of the partial dentary associated with this species, a length of approximately 1.6 metres has been speculated.
Echinodon becklesii – represented by isolated teeth, one fragmentary skull and a handful of isolated jaw bones, this dinosaur is thought to be a member of the Heterodontosauridae. It was a relatively small dinosaur with a body length of approximately 60 centimetres.
Owenodon hoggii – regarded as an ornithopod and known from a badly crushed right dentary found at Durleston Bay (Dorset) in 1860. Hind limb material from near Speeton, (Yorkshire), recovered from Berriasian-aged deposits and a single tooth from Spain have also been tentatively assigned to O. hoggii. The size of Owenodon remains unknown but it has been suggested that it could have been around 6 metres long. Its taxonomic position remains uncertain. When first described in the mid 1870s it was thought the fossils represented a type of Iguanodon.
A Life Reconstruction of the Ornithopod Owenodon hoggii
A reconstruction of Owenodon hoggii.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Undiagnostic Dinosaur Specimens
The Purbeck Limestone Group has also yielded a variety of other dinosaur fossils. For example, a single, beautifully preserved tooth and a partial tail bone (caudal vertebra), which represent an armoured dinosaur. These fossils lack any specific autapomorphies (distinct features or traits), they are regarded as indeterminate, although it could be speculated that these fragmentary fossils represent a member of the Nodosauridae family, possibly a member of the subfamily Polacanthinae. A single, partial metacarpal from a sauropod has also been found.
Numerous trace fossils consisting of dinosaur tracks have been identified. Footprint fossils suggest the presence of other types of dinosaurs such as small ornithopods within the Purbeck Group ecosystem, there is even a track-way which may have conceivably been left by the “Purbeck giant tyrannosauroid”.
The Purbeck Giant Tyrannosauroid
Dinosaur tracks (natural casts), along with a single metatarsal bone indicate the presence of large theropods. Classifying this material has proved difficult. It has been suggested that these trace fossils and the body fossil (single foot bone), could represent a member of the Tyrannosauroidea. This theropod superfamily is now known to have been both geographically and temporally wild spread during the Late Jurassic and the Early Cretaceous.
Evidence linking this fossil to the Maniraptora is limited. Based on comparative studies of other theropod toe bones, it has been estimated that the “Purbeck giant” could have been around 6.7 metres long with a hip height of approximately 1.9 metres. To put into perspective why the “Purbeck giant” can’t be a maniraptoran, comparative analysis based on the foot bones of members of the Maniraptora suggest that this toe bone represents a maniraptoran that would have measured in excess of 9 metres in length.
The fossil bone (metatarsal III), could have come from a tyrannosauroid. Until the arrival of the carcharodontosaurids in this part of western Europe, the “Purbeck giant” was most likely the apex predator. This specimen was collected from Durlston Bay on the Isle of Purbeck (Lulworth Formation subdivision of the Purbeck Group).
When allosauroids (carcharodontosaurids), recolonised what was to become the southern British Isles, there may have been a faunal turnover event with the carcharodontosaurids replacing members of the Tyrannosauroidea as apex and secondary predators. The youngest strata associated with the Purbeck Group (the Durlston Formation), partly overlaps with the Ashdown Formation of the Wealden Group (both Berriasian in age). The dinosaur fossils associated with the Ashdown Formation and the younger elements that between them form the Hastings Subgroup, represent a different dinosaur fauna than what is associated with the Purbeck Group.
Neovenator salerii – Known from the Isle of Wight (Barremian Stage)
“New Hunter” from the Isle of Wight – N. salerii. Did these types of theropod dinosaur replace the Tyrannosauridea in western Europe?
The picture (above) shows a model from the CollectA Deluxe range.
The climate at the time would have been like the Late Jurassic and it gradually became more temperate. The fossil forest ledges, preserved east of Lulworth Cove, represent an interesting and integral part of this ecosystem. Imagine a coastal conifer forest, now cover the floor of it in mosses and algae and dried up seaweed. The ingress of the tides permitted bacterial colonies to form large doughnut-shaped concretions around many tree stumps, these structures, termed thromobolites, can be observed today. Some of these circular structures are big enough for a person to sit in.
Fossils of Mammals Associated with the Purbeck Group
The sedimentary rocks associated with the Purbeck Group has also yielded fossils of many other types of vertebrate including fragmentary jaws and teeth of several types of Early Cretaceous mammal: Early Placental Mammals Identified. It is likely that pterosaurs were present, the fossil record of flying reptiles is particularly poor, but tracks preserved in sediments that represent intertidal flats have been ascribed to the ichnogenus Purbeckopus pentadactylus and these tracks suggest the presence of large pterosaurs.
The speed in which the carcharodontosaurids outcompeted tyrannosauroids, like the “Purbeck giant”, might lead to the conclusion that carcharodontosaurids were more successful, efficient and effective predators than either the Pantyrannosauria, a recently proposed clade consisting of all those theropods related to T. rex and Dilong paradoxus but not including Proceratosaurus bradleyi and the Proceratosauridae. Owenodon was a bit like a blend between Camptosaurus and Mantellisaurus – fast but still of decent size. Nuthetes would have mainly hunted the mammals, reptiles, baby dinosaurs and Echinodon.
Our thanks to Thomas for sending in the information which helped us to compile this article.
To read an article published in 2018, which provides information on the discovery of sauropod tracks on the Isle of Purbeck: Dorset Dinosaur Tracks Discovered.
“King of the Tyrant Lizards” on American Postage Stamps
The United States Postal Service saluted one of natural history’s superstars this week, with the introduction of a set of stamps depicting Tyrannosaurus rex, which has been known to science for over a hundred years. One of the apex predators of the tail-end of the Mesozoic is commemorated with new Forever stamps, reflecting current scientific thinking about T. rex which roamed North America around sixty-six million years ago.
The Four U.S. Postal Service Stamps (2019) that Feature Tyrannosaurus rex
Four new stamps issued by the U.S. Postal Service celebrate Tyrannosaurus rex.
Picture credit: U.S. Postal Service
Two of the four designs show movement when rotated. See the skeletal remains with and without flesh and watch as an approaching T. rex suddenly lunges forward. This printing method was first used by the Postal Service to produce the Rabbit and Hat stamp on the Art of Magic souvenir pane in 2018.
A Dinosaur that has Stirred the Public’s Imagination for over a Hundred Years
Speaking at the dedication ceremony for these stamps held at the prestigious Smithsonian National Museum of Natural History (Washington D.C.), Isaac Cronkhite, the U.S. Postal Service’s chief human resources officer and executive vice president stated:
“With the dedication of these dazzling new Forever stamps today, the Postal Service pays tribute to the king of dinosaurs. More than any other dinosaur, since its discovery more than a century ago, the T. rex has stirred the public imagination. We are proud to bring the powerful T. rex on stamps that will whiz through the mail stream on millions of birthday cards, letters and thank-you notes.”
Available in Panes of Sixteen Stamps with Four Designs
Available as a set of sixteen stamps.
Picture credit: U.S. Postal Service
The Digital Artwork of Julius T. Csotonyi (T. rex Stamps)
The artwork for these dinosaur-themed stamps was created by renowned palaeoartist Julius T. Csotonyi and these stamps are available in sets of sixteen with four different designs depicting this iconic dinosaur at different growth stages and reflecting inferred behaviours. Julius T. Csotonyi created photorealistic illustrations of T. rex with depictions based on the growing body of research on these dinosaurs. The artist painted digitally using a stylus on a computer screen, an approach he likens to acrylic painting. Art director Greg Breeding designed the pane.
The Newly Hatched T. rex – Artwork Created by Julius T. Csotonyi
A newly hatched T. rex features on one of the Tyrannosaurus rex stamps issued by the U.S. Postal Service.
Picture credit: U.S. Postal Service based on original artwork by Julius T. Csotonyi
The Nation’s T. rex
The young, sub-adult T. rex that is featured on two of the stamps, is specimen number MOR-555, discovered in 1988 on federal land in Montana. When first brought to the attention of the scientific community, this specimen was nick-named “the Wankel T. rex” in honour of the person who found these fossilised remains, which represent about 45% of the skeleton of a single T. rex. Painstaking excavation revealed what would become one of the most studied and important tyrannosaur specimens ever found, including the first T. rex arms ever recovered. The Nation’s T. rex is now exhibited at the Smithsonian Institution’s National Museum of Natural History.
Dinosaurs on Postage Stamps
This is not the first time that dinosaurs have featured on a set of postage stamps. Many stamps featuring prehistoric animals have been issued. For example, back in 2013, Everything Dinosaur team members were asked to help write the press releases for a set of prehistoric animal stamps produced by Royal Mail: Royal Mail Issues New Prehistoric Animal Stamps.
A spokesperson from Everything Dinosaur commented:
“It is great to see that such an iconic animal from North America’s natural history being honoured in this way. These stamps are ‘roarsome’!”
Everything Dinosaur acknowledges the assistance of a press release from the United States Postal Service in the compilation of this article.
Praising the CollectA Prehistoric Life Fukuiraptor
Japan might not be that famous for its dinosaurs, although several Japanese dinosaurs have been named and described and we are expecting a new hadrosaurid to be announced from a substantial fossil found on the island of Hokkaido shortly*. Fukuiraptor, from Fukui Prefecture on the largest island that makes up the country of Japan (Honshu), is known from fragmentary remains and its taxonomic affinity remains controversial. However, those clever and talented model makers at CollectA were undeterred and this year, saw the introduction of a Fukuiraptor dinosaur model into the company’s “Prehistoric Life” model range.
The CollectA New for 2019 Fukuiraptor Dinosaur Model
The vast majority of the fossil material ascribed to Fukuiraptor (F. kitadaniensis), comes from excavation sites located along the banks of the Sugiyama River. The strata are estimated to be around 120 million years of age (late Barremian to Aptian faunal stages of the Early Cretaceous). This dinosaur was scientifically described nineteen years ago (Phil Currie and Yoichi Azuma), in the Canadian Journal of Earth Sciences. It had been suggested that these fossils represented a large dromaeosaurid, however, more recent taxonomic assessment has suggested affinities with the Megaraptora.
A CollectA Fukuiraptor Dinosaur Model on Display
The new for 2019 CollectA Prehistoric Life Fukuiraptor dinosaur model.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Creating a Favourable Impression
A spokesperson from Everything Dinosaur commented:
“The CollectA Fukuiraptor dinosaur model has created a very favourable impression amongst dinosaur fans and model collectors. Models representing relatively obscure species are always appreciated and this finely detailed and well-painted figure has proved to be very popular.”
Everything Dinosaur has compiled several reviews of this recently introduced dinosaur figure, including one from a French customer who described it as a “beau modèle”. It is pleasing to note that this figure has such an international appeal.
*A new species of hadrosaurid, assigned to the Edmontosaurini subfamily has been announced. It has been named Kamuysaurus japonicus and it lived at least forty million years after Fukuiraptor became extinct. To read Everything Dinosaur’s article about this newly described (September 2019) hadrosaurid: Japan’s Greatest Dinosaur Discovery Gets a Name – Kamuysaurus japonicus.
Perhaps CollectA will make a model of Kamuysaurus in the future.
Update
CollectA did make a model of Kamuysaurus. To see this model and the rest of the items at the Everything Dinosaur website: Everything Dinosaur.
Occasionally, Everything Dinosaur features the artwork of the talented Chinese palaeoartist Zhao Chuang on this blog. Today, we feature one of his illustrations of a dubious species of sauropod named from fragmentary fossils found in Wiltshire.
An Illustration of the Sauropod Bothriospondylus (B. suffossus) by Zhao Chuang)
An illustration of the dubious (nomen dubium) sauropod Bothriospondylus by the Chinese artist Zhao Chuang.
Picture credit: Zhao Chuang (from the Science Art World by Zhao Chuang and Yang Yang)
Bothriospondylus
Named and described by Richard Owen in 1875, based on four dorsal vertebrae collected from Upper Jurassic strata (Kimmeridgian faunal stage), a number of species have subsequently been assigned to this genus including a species based on fossils from as far afield as Madagascar.
The four vertebrae (along with three unfused, fragmentary sacral vertebrae), referred to this species are now regarded as non-diagnostic. They lack distinctive characteristics to permit the establishment of a new genus, therefore Bothriospondylus is regarded by most palaeontologists as nomen dubium.
What Does Nomen dubium Mean?
Nomen dubium is a term that we have explained in previous articles on this blog. It simply means that the name given to the organism is doubted. Any organism whose validity is in doubt is regarded as nomen dubium.
The recently introduced Papo Gorgosaurus model has been very well received by dinosaur fans and model collectors. Everything Dinosaur team members have been sent lots of photographs from customers showing us how this tyrannosaurid figure has fitted into their prehistoric animal collections. We have also received some wonderful outdoor shots of this dinosaur model. Take for example, some photographs sent to us by Amy.
The Papo Gorgosaurus Goes for a Wander Around the Garden
A Gorgosaurus in the garden.
Picture credit: Amy
Our thanks to Amy for sending in such a splendid set of photos.
Papo Gorgosaurus in the Garden
Amy has skilfully used the available light and ensured that the model is the central focal point. The dinosaur is shown in stark contrast to the blurred background, permitting the fine details on this excellent dinosaur replica to be displayed.
The Papo Gorgosaurus Dinosaur Model Roars as the Sun Sets
Roaring at the sunset – the Papo Gorgosaurus.
Picture credit: Amy
Having a Stroll and Sniffing the Air – the Papo Gorgosaurus Figure
The Papo Gorgosaurus dinosaur model displayed in the garden.
Picture credit: Amy
Amy sent us a Facebook message, commenting:
“Hi, I recently made my first purchase with your company and bought the new Papo Gorgosaurus and was amazed by the quick and easy service I received. Here are some snaps I took of my new model, I will definitely be coming back to you guys again!”
A Dinosaur in the Water
Amy has produced some very clever shots, including a very well composed photograph of her Papo model in water. Water lilies were around when Gorgosaurus roamed the Late Cretaceous landscape of Laramidia. Gorgosaurus would have been familiar with these flowering plants. The model is waterproof and the spines along the back make this dinosaur look a little crocodilian.
A Gorgosaurus Goes for a Dip
A Papo Gorgosaurus takes a dip.
Picture credit: Amy
A spokesperson from Everything Dinosaur commented:
“We really appreciate the photographs sent into us by Amy. The Papo Gorgosaurus has been one of the most eagerly anticipated models this year and in these pictures, the details on this replica are superbly displayed. Our congratulations to Amy for her imaginative and creative pics.”
Recently Everything Dinosaur in collaboration with Eofauna Scientific Research announced the introduction of two new prehistoric animal models for the autumn of 2019. The first model to be announced was a replica of the amazing African sauropod Atlasaurus. A few days later, a second new Eofauna prehistoric animal figure was announced, this time, it was a prehistoric elephant, a beautiful scale model of Deinotherium.
To celebrate this news, Everything Dinosaur included pictures of these two new figures in their latest customer newsletter.
The Two New for Autumn 2019 Eofauna Scientific Research Models Feature in Everything Dinosaur’s Customer Newsletter
The Eofauna Deinotherium model (left) and the Atlasaurus model (right). Two new Eofauna scale models are scheduled for autumn 2019.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Two Eofauna Models Due out in October
The two models are due out in October and Everything Dinosaur has already opened a reservation list for these eagerly anticipated prehistoric animal figures.
To join our priority reserve list for the Eofauna Atlasaurus and the Eofauna Deinotherium, just email Everything Dinosaur: Email Everything Dinosaur and our team members will be happy to add you to our special, priority reserve list.
Reserving a model or models is easy with Everything Dinosaur, there is no deposit to pay, no need to hand over credit/debit card details and you will not be bombarded with emails. Our team members will contact you when the model is stock, ensuring that you have the opportunity to acquire a model. There is no obligation to purchase, it is just our way of helping collectors out, after all, we are dinosaur model collectors too.
Everything Dinosaur is proud to have featured the two new Eofauna models scheduled for release in 2019 (Deinotherium and Atlasaurus) in the company’s recent newsletter.
Oxfordian Britain – The Kingdom of Metriacanthosaurus parkeri
Our thanks once again to young Thomas who has spent part of his summer holiday compiling blog articles for Everything Dinosaur. In this, his second piece, he focuses on the theropod fauna of the Late Jurassic of the British Isles and in particular a dinosaur known as Metriacanthosaurus parkeri, fossils of which come from Dorset.
Metriacanthosaurus parkeri
The Oxfordian in the UK is a rather mysterious faunal stage of the Late Jurassic, especially when it comes to what was living on land at the time. There are four described dinosaurs from this time one of which lived later in the Oxfordian than the others. These three are the metriacanthosaurid Metriacanthosaurus parkeri at 7.5 metres long and just over 2 metres tall, the megalosaurid Eustreptospondylus oxoniensis which had a juvenile length of 5 metres and hypothesised adult length of 6 metres and the ankylosaurian Priodontognathus phillipsii which was probably, only a few metres long, maybe 2 to 3 metres long.
Indeterminate Dinosaur Fossil Remains
Strata associated with the Oxfordian faunal stage, (early Late Jurassic), yields fragmentary, indeterminate dinosaur remains including an indeterminate sauropod found nearby to Metriacanthosaurus, a femur of a juvenile stegosaur and a large tooth from North Yorkshire belonging to a theropod, possibly metriacanthosaurid in nature. In addition, footprints have been found indicating other types of dinosaur present and based on fossil discoveries associated with strata from geologically older and slightly younger rocks than those ascribed to the Oxfordian, it can be concluded that megalosaurine megalosaurids, tyrannosauroids and ornithopods would have lived in the Oxfordian too, we just haven’t found them yet.
A Scale Drawing of Metriacanthosaurus parkeri
A scale drawing of the theropod dinosaur Metriacanthosaurus.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
The British Isles During the Late Jurassic
The ecology of the time is also mysterious. We know for certain that the UK was separated into a series of islands, many of the islands were close enough to allow dinosaurs like Metriacanthosaurus and Eustreptospondylus to travel between them. However to reconstruct the flora and habitat we can look back to the Callovian stage as its likely the environment wasn’t too different from then which allows for the conclusion to be drawn that the islands were semi-tropical and lush in plant life with forests located in the middle of the islands spreading outwards and ending near or in some places at the coast.
Mixed in with the forests would have been rivers, streams, small lakes, swamps, floodplains, open woodland areas closer to the coast and at the coast, estuaries, marshes, ooid beaches, bars, lagoons, coves and other coastal structures.
A Seasonal Climate
The dry season on the islands would have been long and dry with humid areas and during the wet season, the islands would have had to endure harsh tropical storms with hurricane force winds. Plant life consisted of pollen and spore releasing plants, gymnosperms like ginkgoes, conifers and cycads, ferns, other pteridophytes along with other plants such as horsetails. The climate would have been warm and subtropical to tropical.
Ooid Beaches – An Explanation and Metricanthosaurus parkeri
For context, ooid beaches are where beaches are made of small, fine sand-like granules of calcium carbonate, the largest quarry in the UK (Ketton Quarry), has a portion of it that dates to just before the Oxfordian stage and might help unravel the mystery behind the Oxfordian of Britain.
Metriacanthosaurus was most likely the apex predator of the time, hunting anything from smaller theropods to perhaps the sauropod dinosaurs it coexisted with, it would have had powerful jaws with large sharp teeth and long powerful arms tipped with large hand claws for grasping prey. Metriacanthosaurus’s raised neural spinal ridge was probably used for extra back muscle attachment anchor points allowing the animal to be physically stronger than other similarly sized theropods of the time, although this assessment remains largely speculative.
Metriacanthosaurus means “moderately-spined lizard”.
The CollectA Prehistoric Life Metriacanthosaurus parkeri Dinosaur Model
“Parker’s moderately-spined lizard”. This dinosaur was named after its tall neural spines.
The image (above) shows a Metriacanthosaurus model from the CollectA Age of Dinosaurs model series.
Eustreptospondylus is a rather unique megalosaur, it may have been a lot like today’s Komodo dragon frequenting many islands combing beaches, hunting down smaller animals, perhaps raiding nests of larger dinosaurs and possibly even hunting fish. Despite Eustreptospondylus’s hypothesised adult size, it would have still been prey for the likes of Metriacanthosaurus. A specimen of another dinosaur found from this geological time is an ankylosaur called Priodontognathus. It was around 2 to 3 metres long and is known from Yorkshire.
Our thanks once again to Thomas for sending in his article to us.
Researchers from the Chinese Academy of Sciences, in collaboration with colleagues from Carleton University (Ottawa, Canada) and Bristol University, have produced a new study on the Early Cretaceous Asian dinosaur Psittacosaurus (P. lujiatunensis). This new research, published in PeerJ, provides the first detailed survey of Ceratopsian braincase changes as a dinosaur grows.
Three growth stages were studied – hatching, juvenile and adult and as Psittacosaurus got bigger, so its brain changed in shape. Furthermore, the study suggests that these little, herbivorous dinosaurs changed posture as the aged. When young they were facultative quadrupeds, but as they matured they favoured a bipedal stance.
Psittacosaurus Gets Its Head Examined
A typical psittacosaurid. A model of Psittacosaurus (CollectA Psittacosaurus).
Hundreds of Psittacosaurus Specimens Examined
Hundreds of Psittacosaurus fossil specimens were examined. These fossils herald from the Early Cretaceous (Barremian–Aptian) of China, specifically from the Yixian Formation. The lack of fossils representing dinosaurs at different growth stages limits ontogenetic studies, but Psittacosaurus is an exception, it is one of the better represented members of the Ornithischia. The cranial and endocranial morphology of Psittacosaurus has been well documented, but only cursory details have been published on the bones surrounding the brain.
Comparing Skulls Psittacosaurus “Parrot Lizard” Compared to a Parrot
Comparing skulls. The skull of an adult Psittacosaurus – P. gobiensis (left) is compared with an adult parrot (right).
Picture credit: Mike Hettwer
From Hamster-sized Hatchlings to Two-metre-long Adults
From hamster-sized babies these dinosaurs grew relatively quickly into two-metre-long adults. As they grew, their brain changed in shape from being crammed into the back of the head, behind the huge eyes in the hatchling, to being longer, and extending under the skull roof in the adult animals. The braincase provides evidence that supports the idea that these dinosaurs changed posture as they got older. The position and the orientation of the semi-circular canals, which helped these dinosaurs with their balance, changed as they grew.
Corresponding author of the paper, Claire Bullar (University of Bristol School of Earth Sciences), commented:
“I was excited to see that the orientation of the semi-circular canals changes to show this posture switch. The semi-circular canals are the structures inside our ears that help us keep balance, and the so-called horizontal semi-circular canal should be just that – horizontal – when the animal is standing in its normal posture. This is just what we see, with the head of Psittacosaurus pointing down and forwards when it was a baby – just right for moving on all-fours. Then, in the teen or adult, we see the head points exactly forwards, and not downwards, just right for a biped.”
Dinosaur Brains from Baby to Adult (left to right)
A study of the brain of Psittacosaurus (ontogenetic study). Head posture if the lateral (horizontal) semi-circular canal is parallel to the ground, in hatching (A), juvenile (B) and adult (C) Psittacosaurus lutjiatunensis. Images not to scale.
Picture credit: Claire Bullar/Institute of Vertebrate Palaeontology and Palaeoanthropology
Changing Postures
The change in posture is supported by postcranial fossil evidence. The relative limb lengths indicate that a juvenile Psittacosaurus would have moved around on four legs, but by the age of two or three, they switched to a bipedal posture, standing upright on their elongate hind legs. This would have freed up the arms and hands to help with gathering food. The team used reconstructions created from micro-computed tomography scans of well-preserved skulls to plot the ontogenetic changes.
Co-supervisor Dr Qi Zhao from the Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP) in Beijing, where the specimens are housed, added:
“It’s great to see our idea of posture shift confirmed, and in such a clear-cut way, from the orientation of the horizontal ear canal. It’s also amazing to see the results of high-quality CT scanning in Beijing and the technical work by Claire to get the best 3-D models from these scan data.”
Skulls of Psittacosaurus (P. lujiatunensis) Showing Different Growth Stages
Ontogenetic skull sequence from hatchling to adult (Psittacosaurus). Hatchling (IVPP V15451) – (A) in lateral view. (B) Hatchling in dorsal view. (C) Juvenile (IVPP V22647) in lateral view. (D) Juvenile in dorsal view. (E) Adult (IVPP V12617) in lateral view. (F) Adult in dorsal view. All shown to the same scale; scale bar represents 2 cm.
Picture credit: Claire Bullar/Institute of Vertebrate Palaeontology and Palaeoanthropology
Psittacosaurus and the Posture Shift
Co-author Professor Michael Ryan (Carleton University) contributed:
“This posture shift during growth from quadruped to biped is unusual for dinosaurs, or indeed any animal. Among dinosaurs, it’s more usual to go the other way, to start out as a bipedal baby, and then go down on all fours as you get really huge. Of course, adult Psittacosaurus were not so huge, and the shift maybe reflects different modes of life: the babies were small and vulnerable and so probably hid in the undergrowth, whereas bipedalism allowed the adults to run faster and escape their predators.”
Professor Michael Benton (Bristol University), another collaborator in this study commented:
“This is a great example of classic, thorough anatomical work, but also an excellent example of international collaboration.”
Everything Dinosaur acknowledges the assistance of a press release from Bristol University in the compilation of this article.
The scientific paper: “Ontogenetic braincase development in Psittacosaurus lujiatunensis (Dinosauria: Ceratopsia) using micro-computed tomography” by C. Bullar, Q. Zhao, M. Benton and M. Ryan in PeerJ — the Journal of Life and Environmental Sciences.
