The new for 2022 Rebor Saurophaganax models feature in an Everything Dinosaur customer newsletter. All three colour versions of the Rebor Saurophaganax “Notorious Big” 1:35 scale models are in stock (Badlands, Jungle and Volcanic Cavern).
The Rebor Saurophaganax maximus dinosaur model comes in three colour variants “Jungle” (left), “Badlands” (centre) and “Volcanic Cavern” (right). These new for 2022, 1:35 scale dinosaur figures feature in an Everything Dinosaur customer newsletter (March 2022).
Rebor Saurophaganax maximus Notorious Big!
The three Saurophaganax models are the first dinosaur models to be released by Rebor in 2022. Each model measures over 41 cm in length and has an articulated lower jaw, flexible tail and moveable arms. Some customers have reported difficulties fitting the tail to the model, Everything Dinosaur has passed on helpful information and provided advice.
To assist the tail to slot home, dip the white tail plug into a cup of boiling water for 2-3 seconds. The heat will make the plastic more malleable and allow the tail to be inserted. Please take care when handling hot water.
The Rebor Saurophaganax in the “Volcanic Cavern” colour variant is the first model featured in the Everything Dinosaur newsletter.
The new for 2022 Rebor Saurophaganax maximus in the “Volcanic Cavern” colour scheme is the featured product in a recently despatched Everything Dinosaur customer newsletter. This crimson- coloured predator has proved to be popular amongst model collectors and dinosaur fans.
Rebor Saurophaganax Models “Jungle” and “Badlands” Colour Variants
The newsletter also features the other two colour variants, the “Jungle” version and “Badlands”. All three figures have proved to be extremely popular amongst model collectors and dinosaur fans.
The Rebor Saurophaganax maximus “Jungle” on the left with the Rebor Saurophaganax maximus “Badlands” on the right. These two theropod models feature in an Everything Dinosaur newsletter (March 2022).
Originally named and described in 1941 as Saurophagus maximus by the American palaeontologist John Willis Stovall, the genus name was already occupied and in a review of the fossil material published as a short paper in 1995 Daniel J. Chure erected the genus Saurophaganax. This theropod is regarded as one of the largest carnivorous dinosaurs described to date from fossils associated with Jurassic strata.
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Palaeontologists have debated the validity of the Torosaurus genus for decades. Some scientists see this large chasmosaurine known from the Upper Cretaceous (Maastrichtian faunal stage) as a distinct taxon, whilst others consider the genus to be invalid, the fossil material representing old and mature examples of Triceratops.
Analysis of horned dinosaur fossil material from Canada lends support to the idea that Torosaurus is distinct from Triceratops and that it is a valid taxon. A microscopic study of bone composition indicates that the individual animal represented was still growing at the time of its death. This evidence challenges the idea that fossils attributed to Torosaurus are just the remains of very old, fully grown and very mature Triceratops.
An illustration of the Late Cretaceous chasmosaurine Torosaurus latus. Some palaeontologists have proposed that Torosaurus is simply a skeletally mature growth form of the contemporaneous Triceratops. New research studying partial ceratopsian frills and limb bones found in Canada suggests that Torosaurus is a valid taxon.
Canadian Fossils Indicate that Torosaurus is a Valid Taxon
Writing in the Zoological Journal of the Linnean Society, researchers from the Canadian Museum of Nature, the Royal Saskatchewan Museum and Fibics Incorporated (Ontario), analysed two partial cranial frills attributed to Torosaurus. The first, EM P16.1 comes from Frenchman Formation exposures in Saskatchewan which represent uppermost Maastrichtian deposits. This fossil material was collected in 1947 along with two fragmentary thigh bones that were later damaged by floodwater when in storage, the limb bones provided the material for the osteohistological analysis to determine the age of dinosaur. The second specimen UALVP 1646, was found along the Red Deer River valley (Alberta) in 1964. It comes from higher parts of the Lower Scollard Formation. Both frill specimens are estimated to between 66 and 67 million years of age.
In horned dinosaurs, taxonomy is complicated by the fact that the cranial ornamentation that is often used to distinguish species changes radically with age. The long head shield of Torosaurus with its fenestrae was thought to represent the head crest of very old and mature Triceratops. New research using Canadian fossils refutes this theory and postulates that Torosaurus is a valid genus and the Canadian specimens mark the northernmost distribution of this ceratopsid.
Identifying Torosaurus
Torosaurus has been distinguished from the contemporary Triceratops by the presence of two large holes (paired fenestrae) in the neck frill, which tends to be longer and wider, formed by the longer and tapering squamosal skull bones. In addition, Torosaurus is associated with an increased number of epiparietals (bony bumps and horns) on the margins of the neck shield.
Parietosquomosal frill of Torosaurus latus (EM P16.1). Dorsal surface (A) which has been reconstructed using plaster and clay with interpretative drawing (B). Schematic transverse cross-section of squamosal near caudal edge based on a sketch by H. Jones. Schematic of frill showing paired fossae and channels on ventral surface of squamosals, based on a sketch by H. Jones. Picture credit: Mallon et al.
Osteohistological Sampling
A fragment of limb bone representing a portion of the left femur found in association with EM P16.1 was subjected to osteohistological analysis to determine the age of the dinosaur when it died. Small cross-sections of bone were cut and mounted onto epoxy resin. These were then carefully ground down to produce the extremely thin bone slices. Light microscopy and scanning electron microscopy (SEM) were then employed to reveal the bone structure at the cellular level. Although the femur had been extensively repaired with plaster, enough of the bone structure remained for the research team to identify that this dinosaur was still growing when it died. They conclude that the fossil material comes from a late subadult or early adult individual and not an extremely old and mature animal. The scientists refute the hypothesis that Torosaurus represents very old examples of Triceratops.
T. latus limb bones found in association with EM P16.1. Photograph (A) shows the thin cross-section of prepared bone taken from a fragmentary femur, the red box area is shown in greater magnification (B). Haversian tissue (C), thin section of cortical bone of left femur, the red box is highly magnified (D). The bone analysis indicates that this individual was still growing at the time of death, leading the researchers to conclude that Torosaurus is a valid genus and not simply a very old specimen of a Triceratops. Picture credit: Mallon et al.
Torosaurus and Triceratops Present in the Late Cretaceous of Canada
Based on this study, the researchers conclude that Torosaurus was present in Canada during the Late Cretaceous. Triceratops is also known from fossils found in Canada, both the currently recognised species Triceratops horridus and the geologically younger T. prorsus have been reported. If the frill fossils and limb bone fragments do represent Torosaurus then they mark the northernmost range of this taxon.
Parietal of Torosaurus latus (UALVP 1646). Dorsal surface (A); with (B) interpretive reconstruction of dorsal surface. The ventral surface is shown (C) and (D) interpretive reconstruction ventral surface. Photograph (E), detail of left parietal fenestra. Arrows in B and D indicate epiparietal loci. Picture credit: Mallon et al
Different Species of Torosaurus?
Intriguingly, much of the fossil material that was used in the original description of Torosaurus (Marsh 1891) was not precisely recorded. As a result, the stratigraphic distribution of the early collected Torosaurus fossils is unknown. Most of the recently collected Torosaurus latus fossils from the Hell Creek Formation comes from the lower half of the formation. The majority of the Hell Creek Formation Torosaurus material was deposited earlier than the Torosaurus fossils from the geologically younger upper portion of the Scollard Formation and the Frenchman Formation of Canada which are approximately the same age as the uppermost parts of the Hell Creek Formation.
One Torosaurus specimen (MPM VP6841) is an exception it having been discovered in sediments associated with the upper part of the Hell Creek Formation. Specimen number MPM VP6841 compares closely to the Canadian specimen EM P16.1 and it has been proposed that these fossils may represent another Torosaurus species. The Hell Creek Formation was deposited over a period of at least 700,000 years (possibly as much as a million years). Palaeontologists are aware that the Triceratops material associated with different stratigraphy represent different Triceratops species – T. horridus and the geologically younger T. prorsus plus another, as yet unnamed transitional form between the two.
The distribution of Torosaurus latus fossil material suggests that as with Triceratops the Hell Creek strata may contain more than one species. Picture credit: Mallon et al with additional annotation by Everything Dinosaur.
The researchers conclude that different species of Torosaurus would turn over in a similar manner as Triceratops within these uppermost Maastrichtian strata. There may be more species of Torosaurus identified in the future.
The scientific paper: “The record of Torosaurus (Ornithischia: Ceratopsidae) in Canada and its taxonomic implications” by Jordan C. Mallon, Robert B. Holmes, Emily L. Bamforth and Dirk Schumann published in the Zoological Journal of the Linnean Society.
PNSO will be introducing a 1:35 scale replica of an adult Torosaurus and a juvenile. The PNSO Aubrey and Dabei Torosaurus dinosaur models will be in stock at Everything Dinosaur later in the spring (2022). After the success of the adult Stegosaurus and juvenile set (PNSO Biber and Rook) that was introduced last year, PNSO have decided to add a pair of ceratopsians to this series.
The new for 2022 PNSO adult Torosaurus and baby (Aubrey and Dabei) with a declared scale of 1:35.
PNSO Aubrey and Dabei
The models represent Torosaurus latus, a genus that was described in 1891 (Othniel Charles Marsh), after the discovery of two elongated ceratopsian frills in Niobrara County, Wyoming. The validity of the Torosaurus genus has been a subject of recent debate, with some arguing that Torosaurus is simply a skeletally mature growth form of the contemporaneous Triceratops. However, recent publications, for example Mallon et al (2022) support the idea that “Bull Lizard” is indeed a distinct taxon and that it is separate, but closely related to Triceratops and the similarly controversial Nedoceratops, also known from skull material discovered in Wyoming. The PNSO Torosaurus replicas are named Aubrey and Dabei.
Following on from the success of the adult and baby Stegosaurus models (Biber and Rook) PNSO will add a Torosaurus adult and baby to their 1:35 scale scientific art range.
The adult Torosaurus model measures 23 cm in length and that colourful neck frill gives this herbivorous dinosaur a height of 12.2 cm (measured to the top of neck frill). Everything Dinosaur team members estimate that the juvenile model measures around 5.5 cm in length.
The adult Torosaurus model measures 23 cm long and that impressive, large headshield stands 12.2 cm high. Everything Dinosaur team members estimate the baby Torosaurus to be around 5.5 cm long.
A spokesperson from Everything Dinosaur commented:
“We are expecting the recently announced Jennie the Centrosaurus and Anthony the Styracosaurus to be in stock at Everything Dinosaur by the end of this month [March 2022], it is great to see that a Torosaurus pair have been added to the PNSO Sci-Art range.
Posters and Illustrated Booklet Included
This amazing pair of horned dinosaurs comes with a full-colour, 48-page illustrated booklet and a set of posters inspired by the fossil material, featuring other ceratopsian discoveries and highlighting the artwork of Zhao Chuang. PNSO have also prepared a short video explaining how the figure was developed.
The Torosaurus pair will be supplied with posters and a full-colour booklet (48 pages). A video has been prepared that highlights how the figures were created.
The models will be supplied with a series of A3 and A4 posters highlighting the artwork of Zhao Chuang.
The PNSO Torosaurus models Aubrey and Dabei are expected in stock at Everything Dinosaur later this spring, to view the current range of PNSO models available: PNSO Age of Dinosaurs Models and Figures.
Team members at Everything Dinosaur review the Rebor Saurophaganax maximus “Notorious Big” dinosaur model in the “volcanic cavern” colour scheme. In total, three colour variants of this Late Jurassic apex predator have been introduced by Rebor in 2022, “Badlands” was highlighted in an earlier (March 2022), blog post: Rebor Saurophaganax “Badlands” . This week, we posted up more pictures of the “jungle” colour variant: Rebor Saurophaganax “Jungle” and today, we conclude by focusing on the stunning, crimson “volcanic cavern” Saurophaganax dinosaur model.
The crimson coloured Rebor Saurophaganax maximus “Notorious Big” in the “volcanic cavern” colour scheme.
Volcanic Ash and the Brushy Basin Member
The name of this brightly coloured, 1:35 scale dinosaur model has links with volcanism. Naming a Saurophaganax model “volcanic cavern” is highly appropriate and we congratulate Rebor for their choice of moniker. The holotype material collected by J. W. Stovall in 1931 and 1932 comes from a site in Cimarron County, Oklahoma (OMNH Quarry 1). The sediments represent the Brushy Basin Member of the Morrison Formation, one of the youngest geological units associated with the famous, highly fossiliferous Morrison Formation.
The upper portions of the Brushy Basin Member are dominated by layers of weathered volcanic ash. Altered volcanic ash is particularly abundant in the Brushy Basin Member of the upper part of the Morrison Formation. In one 110-metre-thick section in eastern Utah, 35 separate beds of volcanic ash were deposited over a period of 2.2 million years.
Rebor Saurophaganax in the “volcanic cavern” colour scheme shown in anterior view.
A “Popcorn” Texture
A characteristic of the Brushy Basin Member is the amount of bentonite present. This is a form of weathered ash that has become mixed with fine clay. It is extremely absorbent and tends to swell up as it absorbs moisture giving the ground a bubbly appearance resembling popcorn.
During the Late Jurassic, subduction of the North American tectonic plate led to the creation of a line of volcanoes along the western margins of North America. Periodically, these volcanoes would erupt and eject huge volumes of ash into the atmosphere. The ash clouds would drift eastwards and blanket the land further inland. Saurophaganax lived during this time of volcanic activity and these reptiles would have witnessed the volcanism and suffered the consequences as a result of the periodic eruptions that took place far to the west.
The impressive Rebor Saurophaganax maximus dinosaur model in the “volcanic cavern” colour scheme. Fossils of this large theropod have been recovered from the Brushy Basin Member of the Morrison Formation. The upper sections of the Brushy Basin Member contain extensive layers of volcanic ash which once weathered form the clay material bentonite. Naming a model of Saurophaganax after volcanism is highly appropriate.
Dating the Strata from Zircons
These volcanic ash deposits yield, extremely resistant zircon crystals which can be used to precisely date the time of deposition by measuring the radiometric decay of isotopes within the igneous material (usually uranium to lead decay). Radiometric dating permits scientists to make an estimate of the age of the bedding planes and infer the age of the fossils that they contain. The presence of the weathered volcanic ash has assisted palaeontologists in working out the age of Brushy Basin component layers.
Rebor Saurophaganax maximus in the “volcanic cavern” colour scheme shown in right lateral view.
Yesterday, March 16th (2022), a new batch of frogspawn was spotted in the office pond. This spawning has occurred a fortnight after the first frogspawn was observed. Team members at Everything Dinosaur think it is unusual for there to be such a protracted spawning season for the frogs in our area (Rana temporaria).
The newly laid frogspawn has been highlighted with a red circle. It is pleasing to note that such a large amount of frogspawn has been laid, indicating a healthy frog population.
2022 Spawning Season
The first frogspawn was observed on the morning of March 2nd, the following day much more frogspawn was laid and team members counted as many as seven frogs in the pond.
The exact amount of frogspawn is difficult to calculate as it tends to congeal into a single mass (making predation and consumption difficult). However, it was estimated on the 3rd March that perhaps seven or eight batches of spawn had been produced. The frog species is the Common frog (Rana temporaria). In 2021, frogs spawned around the 11th of March, in 2020, the spawning occurred around the 22nd of the month. Team members have kept a record of the time of spawning over the last decade or so, for example, in 2018 frogspawn was spotted on the 17th of March, whilst in 2017 spawning occurred six days earlier.
The frogspawn laid on the 16th was produced 14 days later than the first batch. We are not sure why spawning has taken place over two weeks, we have not recorded this protracted spawning previously.
A closer view of the newly laid frogspawn discovered on Wednesday 16th March. The first frogspawn was spotted on the morning of the 2nd of March, on the 3rd of March several more batches of eggs were laid.
It is pleasing to note that such a large amount of frogspawn has been laid. This indicates a healthy frog population in the local area.
The timing of events such as seasonal spawning can be used as an indicator of climate change, it is likely that as our planet continues to warm events such as frogs spawning will occur earlier in the spring.
Scientists including Professor Paul Barrett of the London Natural History Museum have described a new species of basal armoured dinosaur from fossils found in China. The dinosaur named Yuxisaurus kopchicki, represents the first valid and undisputed member of the Thyreophora (armoured dinosaurs) to be described from fossils found in Lower Jurassic Asian strata.
A life reconstruction of the newly described, Early Jurassic Chinese armoured dinosaur Yuxisaurus kopchicki. Picture credit: Yu Chen.
The Rapid Geographic Spread of Early Armoured Dinosaurs
With an estimated body length of around three metres, Yuxisaurus might be small compared to some of the later and much more famous members of the Thyreophora clade such as Ankylosaurus and Stegosaurus, but confirmation of the presence of early armoured dinosaurs in China underlines the rapid geographic dispersal of these ornithischians. The first armoured dinosaurs are thought to have evolved around 200 million years ago (Hettangian faunal stage of the Early Jurassic). Yuxisaurus fossils consisting of vertebrae, skull bones, elements from the limbs, shoulder blades (scapulae) and 120 osteoderms (bony armour), were excavated from the upper portion of Fengjiahe Formation exposures, near Jiaojiadian village, Yimen County, Yuxi Prefecture, Yunnan Province (southwestern China).
Although the dating of the strata has proved problematical, it is likely that the fossils are somewhere between 192 and 182 million years old (late Sinemurian to early Toarcian stage of the Early Jurassic).
Variety Amongst Early Members of the Thyreophora
Although relatively small compared to later armoured dinosaurs, the limb bones suggest a robust, stout animal indicating that Yuxisaurus had a different body shape compared to other known early thyreophorans such as Scutellosaurus and Emausaurus. This suggests that early armoured dinosaurs had a diverse morphology and ecology and they spread rapidly establishing a wide geographical distribution and filling a variety of niches in Early Jurassic ecosystems.
Skeletal reconstruction of Y. kopchicki showing main preserved elements from the holotype (highlighted in blue). Details of the skull bones (A), cervical vertebrae (B) and dorsal vertebrae (C). The left scapula is shown (D) and the right humerus (E) along with the distal portion of the left femur (F). Note scale bars equal 5 cm for A-C and 10 cm for D-F. Osteoderms have been omitted to show the skeleton. Picture credit: Xi Yao.
The First Unambiguous Armoured Dinosaur from the Early Jurassic of Asia
First author of the scientific paper, Professor Paul Barrett (Natural History Museum, London), commented:
“Although we’ve had tantalising fragments of early armoured dinosaurs from Asia, this is the first time we’ve had enough material to recognise a new species from the region and investigate its evolutionary history. I hope it’s the first of many new dinosaurs from the localities being discovered by my colleagues in Yunnan.”
Senior author of the paper, Dr Shundong Bi, a professor at Indiana University of Pennsylvania, explained that the dinosaur had been named Yuxisaurus kopchicki in honour of the Yuxi Prefecture, whilst the trivial or species name was in recognition of the work of molecular biologist Dr John J. Kopchick and for his support and funding of a new Indiana University of Pennsylvania science complex which is due to open in autumn 2023.
Dr Shundong Bi stated, that despite its robust body:
“Yuxisaurus was possibly a facultative quadrupedal. It was primarily adapted for walking on four legs, but also able to walk on two legs.”
Where Did Armoured Dinosaurs Originate?
Until recently all the unambiguous Early Jurassic Thyreophora taxa were described from fossils found in North America (Scutellosaurus) or Europe (Emausaurus and Scelidosaurus). This led palaeontologists to conclude that armoured dinosaurs originated in Laurasia, however, new phylogenetic analyses (Butler et al 2020, Boyd 2015, Raven and Maidment 2017, Maidment et al 2020 and Baron et al 2017a) have proposed that Lesothosaurus from southern Africa and Laquintasaura from Venezuela might also represent early members of the Thyreophora. If Lesothosaurus and Laquintasaura are early armoured dinosaurs, then this suggests that this clade could have originated in Gondwana.
Phylogenetic assessments plotting the relationship of Yuxisaurus within the Thyreophora. Analysis (A) modified from Norman (2021) dataset which places Yuxisaurus as a sister taxon to Emausaurus which is known from the Early Jurassic (Toarcian) of Germany. Analysis (B) modified from Maidment et al (2020) places Yuxisaurus within the Thyreophora as an early-diverging branch between Emausaurus and Scelidosaurus which is known from older sedimentary deposits from Charmouth on the Dorset coast. Picture credit: Xi Yao et al.
The phylogeny of early ornithischians remains disputed, it is hoped that further fossil finds will resolve this debate.
Everything Dinosaur acknowledges the assistance of a media release from the London Natural History Museum in the compilation of this article.
The scientific paper: “A new early-branching armoured dinosaur from the Lower Jurassic of southwestern China” by Xi Yao, Paul M. Barrett, Lei Yang, Xing Xu and Shundong Bi preprint via bioRxiv before publication in eLife.
Team members at Everything Dinosaur review the Rebor Saurophaganax maximus “Notorious Big” dinosaur model in the “jungle” colour scheme. Three colour variants of this Late Jurassic apex predator have been introduced. “Badlands” was highlighted in an earlier blog post: Rebor Saurophaganax “Badlands”, we intend to showcase the crimson-coloured “volcanic cavern” in the near future but today, we focus on the “jungle” colour variant.
The Rebor Saurophaganax maximus 1:35 scale dinosaur model in the “Notorious Big” series. This is the “jungle” colour variant.
An Articulated Dinosaur Model
The Saurophaganax figure measures 41.5 cm long and it is articulated, with a flexible tail, moveable forelimbs and an articulated lower jaw so the model can be posed either mouth open or mouth closed. Of the three figures introduced, the “jungle” colouration is perhaps the most realistic colour scheme, after all, Saurophaganax fossils are associated with the famous Morrison Formation of the United States and these strata represent deposits laid down in a lush, verdant floodplain environment.
The Rebor Saurophaganax maximus
The Rebor Saurophaganax maximus dinosaur model has a declared scale of 1:35.
Conifers dominated the riparian* environment along with cycads, horsetails, tree ferns and ginkgo trees. As these tend to be predominately shades of green, a green coloured theropod would have been well camouflaged amongst the vegetation.
The colouration of the Rebor Saurophaganax model is predominately green with yellow countershading. Prominent stripes can be seen on the broad, deep tail.
A riparian* environment is a terrestrial zone that lies between the land and a river or stream. It describes the ecosystem (plant habitats and animal communities) that inhabit river margins and the banks of streams. The Morrison Formation deposits were laid down in floodplains and riparian zones. Several theropod dinosaurs have been described from fossils found in these strata, Saurophaganax (S. maximus) is one of the largest described to date.
A view of the Rebor Saurophaganax maximus “jungle” colour variant (lateral view). This is a 1:35 scale dinosaur model.
The Rebor Saurophaganax maximus Museum Class replica in the “jungle” colour scheme. All three colour variants will be available from Everything Dinosaur. This is one of the Rebor images sent to Everything Dinosaur.
To view the Rebor Saurophaganax dinosaur models in stock at Everything Dinosaur including the “jungle” colour variant: Rebor Models and Figures.
Only two living species of dolphins (members of the Delphinidae family), are known to attack and feed upon large mammals. There is the killer whale, also referred to as the Orca, (Orcinus orca) and the false killer whale (Pseudorca crassidens). Orcas attack a wide variety of other marine mammals including seals, sealions, whales and other dolphins, whereas the false killer whale mainly eats fish but attacks on smaller dolphins, sperm whales and the young of baleen whales have been reported.
When did this feeding behaviour evolve? The fossilised remains of a newly described killer whale (Rododelphis stamatiadisi) which is believed to be the closest relative to both O. orca and P. crassidens may provide an answer. The fossils of R. stamatiadisi were found in Pleistocene strata aged between 1.5 and 1.3 million years old on the Greek island of Rhodes, traces of the last meal consumed were found, fish – blue whiting. This suggests that macropredation in members of the Delphinidae evolved relatively recently.
A life reconstruction of Rododelphis feeding on blue whiting. Picture credit: Rossella Faleni.
Comparing Two Ancient Whale Fossils Found Centuries Apart
Researchers from the University of Pisa (Italy) and the New York Institute of Technology (USA), analysed the fossil remains from Rhodes, discovered in 2020 and compared them to the fossils of Orcinus citoniensis, from Pliocene-aged deposits in Tuscany (Italy). The O. citoniensis fossils, consisting of partial postcranial material, skull and jaw bones were first described in 1883 by the famous Italian palaeontologist Giovanni Capellini.
Co-author of the Rododelphis paper, published in the academic journal “Current Biology”, Sara Citron (University of Pisa), had just finished her master’s thesis on Orcinus citoniensis. Microwear on the teeth was consistent with a diet of medium-sized fish, so although Orcinus citoniensis had a body length in excess of four metres, it probably did not specialise in hunting other marine mammals.
The Rododelphis material was discovered in the Bay of Pefkos on the south-eastern coast of the island by Polychronis Stamatiadis, an expert in the geology and palaeontology of Rhodes. Analysis of these fossils revealed five otoliths (calcium carbonate structures found in the inner ear of fish) from Micromesistius poutassou (blue whiting) which indicates that the last meal of this extinct cetacean was fish.
Cranial and postcranial Rododelphis fossil material. Analysis of tooth wear suggests that this 5-metre-long cetacean was primarily a piscivore. Picture credit: G. Bianucci (University of Pisa).
Although estimated to have been around five metres long, R. stamatiadisi, like Orcinus citoniensis, was probably not a hunter of other marine mammals.
Evolution of Macropredation not Linked to Gigantism in Baleen Whales
Anatomist and co-author Jonathan Geisler (New York Institute of Technology), carried out an phylogenetic assessment and identified that Rododelphis was a close relative to Pseudorca crassidens as well as the extinct Orcinus citoniensis, which in turn was closely related to the living killer whale.
Dr Geisler explained:
“Our study supports the hypothesis that the Rhodes dolphin [R.stamatiadisi] and the Italian Orca [Orcinus citoniensis] represent two similar, but separate, evolutionary stages. In these stages, true and false killer whales preferentially preyed on medium-sized fish, rather than on seals, dolphins, and baleen whales. Thus, feeding on marine mammals happened very recently, showing that the predation by these fossil killer whales was not a driving force in the evolution of gigantism in baleen whales”.
Orcinus citoniensis lived around three million years ago, Rododelphis stamatiadisi is more recent, having lived approximately 1.5 to 1.3 million years ago. As baleen whales had already evolved large forms by the Late Miocene, it seems that predation from other cetaceans was not a factor in the development of gigantism.
Prepared vertebrae and ribs of the recently described cetacean from the Pleistocene of Rhodes (Rododelphis stamatiadisi). Picture credit: G. Bianucci (University of Pisa).
Everything Dinosaur acknowledges the assistance of a media release from the University of Pisa in the compilation of this article.
The scientific paper: “The origins of the killer whale ecomorph” by Giovanni Bianucci, Jonathan H. Geisler, Sara Citron and Alberto Collareta published in Current Biology.
The trouble with being regarded as the biggest, longest, tallest or oldest when you are newly described species of dinosaur, is that sooner or later another fossil discovery will take this claim away from you. Back in 2019, team members wrote a blog post about the discovery of Adratiklit boulahfa from the Middle Jurassic of Morocco North Africa’s First Stegosaur. The fossils of this armoured dinosaur were estimated to be around 168 million years old (Bathonian faunal stage), making Adratiklit the oldest definitive stegosaur described.
Scientists including Dr Susannah Maidment a senior researcher at the London Natural History Museum, who co-authored the paper describing A. boulahfa, have announced the discovery of an even older stegosaur, this time from China. The new stegosaur named Bashanosaurus primitivus is at least one million years older than the Moroccan stegosaur.
The Fossils of Bashanosaurus
The fossils of Bashanosaurus herald from the Lower Member of the Shaximiao Formation and radiometric dating based on isotope decay analysis using zircon crystals (geochronological data), suggest that the deposits associated with the fossil bones are around 169 ± 0.68 million years of age.
A life reconstruction of the newly described Chinese stegosaur Bashanosaurus primitivus. Picture credit: Banana Art Studio.
Did the Stegosauria Evolve in Asia?
The fossil record of early stegosaurs is highly fragmentary and the evolution of this iconic branch of the Thyreophora is poorly understood. The Stegosauria represents a major clade within the Ornithischia (bird-hipped dinosaurs). Fourteen genera of stegosaur have been described to date and they are both geographically and temporally widespread, known from all the major landmasses except for Australia and Antarctica.
In 2016, a new dinosaur quarry was opened in Yunyang County, Chongqinq Municipality in southwestern China. Stegosaur fossil material was identified on the western side of the quarry. The disarticulated material preserved within the sandstone consisted of a dorsal vertebra, two tail bones (caudal vertebrae), a right scapula, a right coracoid and elements from the hind legs. Three pieces of dermal armour were also discovered at this location (one plate and two spines) along with fragments of rib bones. These fossils (CLGPR V00006-1) are regarded as the holotype of B. primitivus.
Potentially Three Bashanosaurus Specimens
More stegosaur fossils were found at the site approximately fifty metres away from the holotype material (CLGPR V00006-2). They consist of five dorsal vertebrae, a right tibia, a right fibula some ribs and a single piece of dermal armour (one plate). In addition, a single dorsal vertebra (CLGPR V00006-3) was found on the eastern part of the site some one hundred and twenty metres away from the holotype material.
Whilst the researchers have confidently assigned these fossils to the Stegosauria and specifically to Bashanosaurus primitivus, three individual stegosaurs are represented by the bones.
Photograph (A) with interpretative line drawing showing the position of the B. primitivus holotype fossil material (CLGPR V00006-1) on the western side of the wall of dinosaur fossils. Photograph (B) with interpretative line drawing showing the second location with B. primitivus fossil material (CLGPR V00006-2) towards the middle of the wall of dinosaur fossils. Picture credit: Hui et al.
It is not known whether the fossil bones represent a juvenile or a fully-grown animal. However, based on these bones, the researchers estimate that the largest stegosaur from the quarry was about 2.8 metres in length.
Unique Anatomical Traits
The scientists who include researchers from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development in China and London’s Natural History Museum identified several unique anatomical traits that led to the erection of a new genus. Bashanosaurus possesses anatomical characteristics associated with basal thyreophorans as well as more derived features associated with early stegosaurs. For example, it has a smaller and less developed shoulder blade, the bony projection of the thighbone (fourth trochanter) is positioned below the middle of the shaft and the bases of the armour plates curve outwards and are thicker than the plates on the backs of later stegosaurs.
The genus name is derived from “Bashan” in reference to the ancient name for the area of Chongqing in China where the dinosaur was found. The species moniker is derived from the Latin for “first” – primitivus.
Lead author of the research team, Dr Dai Hui from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development commented:
“All these features are clues to the stegosaurs’ place on the dinosaur family tree. Bashanosaurus can be distinguished from other Middle Jurassic stegosaurs, and clearly represents a new species.”
Phylogenetic Analysis
Phylogenetic analysis shows that Bashanosaurus primitivus is the earliest-diverging stegosaur, along with Chungkingosaurus (C. jiangbeiensis), which is thought to be closely related, although Chungkingosaurus lived much later than Bashanosaurus. Chungkingosaurus fossils are known from the Upper Member of the Shaximiao Formation.
The discovery of Bashanosaurus will help researchers to learn more about the evolution of stegosaurs and supports the theory that this type of armoured dinosaur first appeared in Asia. Although there have been some exciting fossil discoveries helping to improve understanding with regards to the evolution of armoured dinosaurs (Thyreophora), there are still numerous gaps in the fossil record which makes mapping the evolutionary development of these iconic dinosaurs extremely difficult.
For example, Everything Dinosaur recently wrote an article about the discovery of the basal thyreophoran Yuxisaurus kopchicki, whose fossils also come from China. Scientists from the London Natural History Museum also contributed to the scientific paper on Yuxisaurus: The Earliest Armoured Dinosaur Found to Date.
Everything Dinosaur has inserted Yuxisaurus kopchicki within the phylogenetic assessment of Bashanosaurus to help put these recent fossil discoveries into context (see below).
A phylogenetic analysis showing the placement of B. primitivus within the Stegosauria. It is believed to be around one million years older than the recently described Adratiklit boulahfa (Maidment et al) from the Middle Jurassic of Morocco. The earliest armoured dinosaur from Asia known to date (Yuxisaurus kopchicki) from Yunnan Province, China (Yao et al) has been incorporated into the image by Everything Dinosaur to show the approximate phylogenetic and temporal placement of Y. kopchicki when compared to B. primitivus. Picture credit: Hui et al with additional annotation by Everything Dinosaur.
The Stegosauria Clade Originated in Asia?
Commenting on the phylogenetic assessment Dr Hui stated:
“What’s more, our analysis of the family tree indicates that it [B. primitivus] is one of the earliest-diverging stegosaurs along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus. These were all unearthed from the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs might have originated in Asia”
An illustration of the Chinese stegosaur Chungkingosaurus. Chungkingosaurus fossils are known from the Upper Member of the Shaximiao Formation. It lived around 160 – 157 million years ago, several million years after Bashanosaurus, although the phylogenetic analysis suggests that Bashanosaurus and Chungkingosaurus are closely related.
The picture (above) shows a drawing of a model from the PNSO model range.
Co-author of the scientific paper published in the Journal of Vertebrate Paleontology, Dr Susannah Maidment of the London Natural History Museum and an expert in ornithischian dinosaurs added:
“The discovery of this stegosaur from the Middle Jurassic of China adds to an increasing body of evidence that the group evolved in the early Middle Jurassic, or perhaps even in the Early Jurassic, and as such represent some of the earliest known bird-hipped dinosaurs. China seems to have been a hotspot for stegosaur diversity, with numerous species now known from the Middle Jurassic right the way through until the end of the Early Cretaceous period.”
Everything Dinosaur acknowledges the assistance of a media release from the Taylor & Francis Group in the compilation of this article.
The scientific paper: “New Stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China” by Dai Hui, Li Ning, Susannah C. R. Maidment, Wei Guangbiao, Zhou Yuxuan, Hu Xufeng, Ma Qingyu, Wang Xunqian, Hu Haiqian and Peng Guangzhao published in the Journal of Vertebrate Paleontology.
Everything Dinosaur has another fantastic, prehistoric animal themed giveaway. We have a copy of the new book “Explorers of Deep Time” by the eminent palaeontologist Roy Plotnick of the University of Illinois, Chicago and we are giving you the chance to win it.
The front cover of “Explorers of Deep Time” by eminent American palaeontologist Roy Plotnick. Win a copy of this fabulous book that provides a behind the scenes look at the life and work of a palaeontologist. Picture credit: Columbia University Press.
“Explorers of Deep Time” Competition
In this beautifully crafted book, author Roy Plotnick provides a rare and very personal look at the trials and tribulations of working in the Earth sciences. If you have ever wondered about what it is like to be a palaeontologist, then this book is for you. Roy does not write about fossils, this book is dedicated to the scientists that study them.
All you have to do to enter the competition to win a free copy is visit Everything Dinosaur on Facebook “Like” our page, then leave a comment on the competition post naming the dinosaur whose skull fossil features on the front cover.
Win a copy of “Explorers of Deep Time” in Everything Dinosaur’s free to enter Facebook competition.
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To Enter the Competition
To enter Everything Dinosaur’s competition to win a free copy of “Explorers of Deep Time”, all you have to do is:
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Name the dinosaur whose skull is shown on the front cover of the book (hint – it is the skull of a famous horned dinosaur).
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Or, if you are not on Facebook, just leave a comment on this blog post to enter. Tell us the name of the horned dinosaur whose skull is shown on the bottom of the front cover of “Explorers of Deep Time” in the comments section of this blog post and we will automatically enter you into our free prize draw to win a copy of the book.
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