Back in January, Everything Dinosaur reported upon the scientific description of a new species of giant otter from the Late Miocene of south-west China. At around fifty kilogrammes in weight, the new species Siamogale melilutra, is a much more heavy-set and robust animal compared to extant otter species. At the time, the scientists responsible for studying the fossil material, which included an almost complete but crushed cranium, speculated on what this super-sized member of the weasel family would have fed on.
Siamogale melilutra Jaw Study
Writing in the journal “Scientific Reports”, some of the scientists involved in the original description have followed up this research by publishing a new paper on the feeding capabilities of such a powerful carnivore.
This wolf-sized, aquatic predator had a surprisingly strong bite that might have made S. melilutra an apex predator.
A Digitally Reconstructed View of the Skull and Jaws of Siamogale melilutra
A digitally reconstructed cranium of S. melilutra .
Picture credit: Scientific Reports
Comparing Otter Skulls and Jaws
The researchers digitally recreated jaw models of extinct otters as well as ten extant species (living species of otters) and then subjected these models to engineering stress tests. The researchers discovered that the jaw of Siamogale melilutra was six times stronger than expected.
Although, the teeth morphology and biting efficiency was found to be very similar to living otters, these very strong jaws open up the possibility that Siamogale melilutra fed on a range of animals that its modern-day contemporaries could not. Sea Otters (Enhydra lutris) and the African Cape Clawless Otter (Aonyx capensis), specialise in feeding upon shellfish and have a durophagous diet. Even accounting for the size difference between the Miocene giant Siamogale melilutra and these living otter species, the jaws of S. melilutra are much stronger.
Comparing the Stress on Jaws on Living and Extinct Species of Otter
Stress during biting (otter jaw comparison).
Picture credit: Scientific Reports
The picture above shows the results of computer modelling to indicate potential bite force stresses in a number of otter species. Warmer colours depict high levels of bite stress, whilst cooler colours depict areas of lower stress.
The research team conclude that S. melilutra has no living analog. Its huge size and powerful jaws could have enabled this otter to exploit an environmental niche not found in living otter species. It might even have been an apex predator.
The scientific paper: “Feeding Capability in the Extinct Giant Siamogale melilutra and Comparative Mandibular Biomechanics of Living Lutrinae” by Z. Jack Tseng, Denise F. Su, Xiaoming Wang, Stuart C. White and Xueping Ji published in the journal “Scientific Reports”.
Why Do Asteroids Always Land in Craters? A Lesson Plan
Team members at Everything Dinosaur have been busy preparing another lesson plan idea linked to the concept of “working scientifically” when it comes to delivering teaching outcomes related to the science elements of the national curriculum for England. The lesson is aimed at both Key Stage 1 and Key Stage 2 students and asks the question “Why do asteroids always land in craters”?
The Lesson Plan with Teaching Notes for Key Stage 1
PDF download of teaching notes/lesson plan is available from Everything Dinosaur.
Picture credit: Everything Dinosaur
Linking to the Dinosaur Extinction Event as well as Space Modules
The dinosaur extinction is linked to a large impact event, in this lesson plan our aim is to encourage the children to work scientifically, experience and observe phenomena, devise and complete simple comparative tests, communicate ideas, observe closely and to use simple equipment to find answers. This lesson plan relates to both the “dinosaurs” and the “space” term topic. It should also help young minds to explore everyday materials and describe the simple physical properties of those materials.
One of the factors involved in the extinction event at the end of the Age of Dinosaurs involved an extra-terrestrial object crashing into our planet, so teachers can tie in extinction and the causes of extinction to an extension activity involving the class having to work scientifically to explore what happens when objects fall to Earth.
Two types of lesson plans have been developed, the lesson plan with accompanying teaching notes aimed at Upper Key Stage 2 deals with issues such as animals and their habitats, natural selection, evolution and introduces the idea of the force of gravity.
Essentially, to test this idea of asteroids always landing in craters, the children would have to develop an experiment whereby they drop objects into a substrate and record what happens.
Suggested Resources to be Used to Test the Hypothesis
Resources suggested for the “why do asteroids always land in craters?” A lesson plan.
Picture credit: Everything Dinosaur
Suggested Resources for the Key Stage 1 Lesson Plan
Here is a list of typical resources suggested to test the idea of asteroids always landing in craters with a Key Stage 1 class. Essentially, the children need to consider a suitable substrate and to test what happens when objects are dropped into the substrate.
* Tray * Flour or sand (substrate) * Objects of various sizes, shapes and weight * Table covers/newspaper * Ruler for measuring (optional) * Paper for making notes (optional) * Camera to record experiment results (optional)
Whilst exploring with the class the idea that the non-avian dinosaurs no longer exist, seek an unprompted definition of the word “extinction”. Can the class demonstrate further pre-knowledge by explaining about how the dinosaurs died out? If needed, explain about the space rock impact idea and challenge the children to work out whether asteroids always land in craters or does the impact create the crater?
Can the Children Create Simple Comparative Tests?
Different objects landing in flour, modelling asteroid impacts.
What sort of craters do the different objects make? What makes the larger crater a big object or a small object? Which makes the deeper crater a heavy object or a light object? What sort of craters do different shaped objects make? Does it make a difference if you vary the height from which you drop the objects? Can the children make a prediction about the size/shape/depth of the crater depending on the object dropped?
In addition, the Key Stage 2 lesson plan and teaching notes asks the class to devise their own experiments to answer the asteroid/always in a crater question.
As a “wow” moment to conclude the lesson plan, try this idea. Working outside, what happens when a really big object such as a football is dropped into a bucket of flour? The spraying of flour should provide a suitable memorable moment to help the class remember the key learning points from this simple experiment.
For further advice and ideas about science teaching in school, simply email our team members at Everything Dinosaur: Email Everything Dinosaur.
The next batch of new for 2018 CollectA prehistoric animal figures include a stunning 1:40 scale deluxe replica of the famous ornithopod Iguanodon (I. bernissartensis). Here is another CollectA dinosaur figure honouring Gideon Mantell (Mantell named Iguanodon), after the news about the introduction of Mantellisaurus, it is great to see an updated version of the iconic Iguanodon too. Fossils of Mantellisaurus and I. bernissartensis have been found in the same horizon, namely the Wessex Formation (Early Cretaceous, Barremian faunal stage). It is likely that these two herbivores were contemporaneous and therefore, diorama fans can place both Mantellisaurus and Iguanodon into the same prehistoric scenes.
New CollectA Models
The New for 2018 1:40 Scale Deluxe Iguanodon Dinosaur Model
CollectA 1:40 scale Iguanodon model.
Designer Anthony Beeson commented:
“It seemed about the right time to produce a new Iguanodon which had been one of our earliest models. I had wanted to do a Mantellisaurus, so we decided to do a deluxe Iguanodon to bring the species up to date in our models. As Mantellisaurus seems to have herded with Iguanodons, the two can go together in play or dioramas notwithstanding the differences in size.”
Spectacular Estemmenosuchus
The dinocephalians (the name means “terrible heads”) are represented by this spectacular 1:20 scale replica of Estemmenosuchus and what a beautiful model of one of the most amazing therapsids to have ever lived. It is great to see Permian giants like Estemmenosuchus (pronounced Est-ter-men-oh-sook-us), included in the CollectA Deluxe model range. This wonderful replica has an articulated jaw and it is being produced in an approximate scale of 1:20, in line with other prehistoric animal models on the “mammalian line” of the tree of life, already represented in the CollectA model range.
The Estemmenosuchus 1:20 Scale Deluxe Model by CollectA
A Deluxe 1:20 scale Estemmenosuchus model from CollectA.
Estemmenosuchus uralensis
Best on our calculations, this model represents the type species Estemmenosuchus uralensis. We look forward to revealing our scale drawing of this amazing creature, that is distantly related to us. As for those strange, bony growths on the head, their purpose remains unknown. They could have used in intraspecific combat, perhaps over herd hierarchy or to win mates. The design team at CollectA are to be congratulated for creating such a fantastic prehistoric animal model. It is brilliant to see Permian reptiles represented in model ranges.
CollectA Deluxe 1:20 Scale Dunkleosteus
Another iconic prehistoric monster is being introduced as a 1:20 scale deluxe replica. The Devonian giant Dunkleosteus is being included in the new for 2018 releases. Like Estemmenosuchus, this model too, will have a moveable, articulated jaw.
A Dunkleosteus Model – New for 2018 from CollectA
CollectA 1:20 scale Deluxe Dunkleosteus model.
Dunkleosteus: this was a terrifying armoured fish of the Late Devonian era that could grow up to 6 metres in length. The skull was armoured and although some models show this as exposed bone plates, the CollectA model correctly shows it covered with skin. It did not possess teeth but had bone shears instead. As only the bone skull survives in the fossil record as the rest of the body was made of cartilage therefore, the rest of the body is based on other smaller and related species.
Devonian Prehistoric Fish
The new model adopts the idea that such a huge fish would have had to have had a heterocercal caudel fin rather like the shark in order to efficiently manoeuvre around. The CollectA replica comes with a movable jaw.
The introduction of this new scale model marks 145 years since the Dunkleosteus genus was erected (1873). CollectA had introduced a mini Dunkleosteus figure in their very popular mini prehistoric marine animal set, this set which features ammonites, a trilobite, marine reptiles and prehistoric fish was introduced this year. The mini Dunkleosteus could perhaps play the role of another species of placoderm in a Devonian dioramas that get constructed. We can’t wait to see how these models will be used together.
To view the CollectA mini prehistoric animal set and the other models in the CollectA Prehistoric Life series: CollectA Prehistoric Life.
Commenting on the introduction of this apex Devonian predator, designer Anthony Beeson stated:
“I have never liked reconstructions where the plates appear like the fish is wearing a suit of armour, so they are covered with skin. I have had second thoughts about the shape of the tail since producing the mini version and have now given him a heterocercal tail which would afford such a large animal a greater ability to manoeuvre in the water”.
CollectA Model Measurements
Here is the all-important measurement data for dinosaur fans and model collectors:
CollectA Deluxe 1:40 scale Iguanodon model – length 28 cm, height 11.5 cm – available from Everything Dinosaur early Spring
CollectA Deluxe 1:20 scale Estemmenosuchus – length 17.5 cm, height 10.5 cm – available from Everything Dinosaur mid 2018
CollectA Deluxe 1:2o scale Dunkleosteus – length 28 cm, height 6 cm – available from Everything Dinosaur early Spring
We look forward to posting up more news about 2018 CollectA releases, in the meantime, here is a link to our article on the first batch of CollectA models to be announced: New from CollectA 2018 (first batch).
By Mike|2023-08-25T07:58:04+01:00November 9th, 2017|Key Stage 1/2|Comments Off on Streethouse School – Dinosaurs
Barbara Hepworth Class Study Dinosaurs and Fossils
Children in Barbara Hepworth class (Year 5/6), at Streethouse Junior, Infant and Nursery have been studying dinosaurs, fossils and prehistoric animals this term. As well as a challenging and enriching scheme of work built around English, maths and science, the teaching team have been inspired by Dame Hepworth and introduced a dinosaur sculpting challenge for the children.
Barbara Hepworth was a celebrated English, 20th century, artist and sculptress who was one of the leading lights of modernism. I am sure Dame Hepworth would have been most impressed with the clay models that the children produced.
Our dinosaur and fossil expert, who had visited the school to deliver a morning of teaching activities with the class, was given a guided tour of the clay model exhibits. The budding artists were keen to demonstrate their knowledge by explaining what inspired them when it came to prehistoric animal model making. The clay models make a fine display amongst all the excellent examples of handwriting that were pinned up onto the spacious classroom walls.
Barbara Hepworth Class (Year 5/6) Focus on Dinosaurs
Another busy week at Everything Dinosaur, with several school visits and projects successfully completed. Take for example, a recent visit to Year 5/6 at Streethouse Primary in Yorkshire, to provide a provocation for this Key Stage 2 class as they begin their dinosaur and fossil themed topic. The varied and enriched scheme of work devised by the enthusiastic teaching team will run until the end of this term and Everything Dinosaur was invited to the school to provide a morning of dinosaur and fossil themed activities for the class.
The walls of the tidy and well-organised classroom already featured a number of dinosaur and prehistoric animal themed displays.
Posting Up Information About Life in the Past (Upper Key Stage 2)
Year 5/6 at Streethouse Primary are in Barbara Hepworth class, we are confident that this English 20th century sculptress would be most impressed with the clay prehistoric animal models the children had created. One of the benefits of a dinosaur themed topic is that it lends itself to all sorts of cross-curricular activities, the children eagerly discussed their models and there were certainly some skilfully crafted replicas on display, even winged dinosaurs!
Barbara Hepworth Class Produce Prehistoric Animal Clay Models
Year 5/6 children make clay model dinosaurs.
Picture credit: Everything Dinosaur
Answering Questions About Dinosaurs
Prior to the workshop, the children had prepared several questions about prehistoric animals, some of these questions along with answers researched by the children had been posted up around the classroom. The Everything Dinosaur workshop leader incorporated a number of questions into the morning of activities helping to support the children’s learning.
Year 5/6 Compile Questions About Life in the Past
How did birds evolve if the dinosaurs all got wiped out?
Picture credit: Everything Dinosaur
The above question links in nicely to some of the science curriculum areas associated with Year 6, fortunately, our dinosaur expert had brought plenty of resources with him to help the class explore in a little more detail the evolutionary relationship between avian and non-avian dinosaurs (birds and dinosaurs).
Why Does Tyrannosaurus rex Have Tiny Arms?
Another question, this time, raised by the class teacher, asked why does T. rex have tiny arms compared to the rest of its body? That’s a very challenging question, that ironically had just been covered in a recent presentation delivered to the annual conference of the Geological Society of America. A cast of a T. rex manual ungual (claw bone) came in handy to help explain that this latest theory suggests that the short arms of Tyrannosaurus rex were very effective weapons for slashing prey at close quarters.
Why does T. rex have tiny arms compared to the rest of his body?
All to soon, our morning of dinosaur and fossil themed activities came to an end. However, there was still time to set a couple of extension exercises for the class and to admire the partially complete “Jurassic landscape” that the children had been making. The class will be using ModRoc (plaster of Paris modelling materials), to create a prehistoric scene, all helping to reinforce learning about animals and their habitats. We use similar materials when protecting fossils in the field prior to their full removal. We look forward to seeing the finished dinosaur diorama.
Barbara Hepworth Class are Creating a Prehistoric Landscape
Making a prehistoric landscape.
Picture credit: Everything Dinosaur
To the conclude the morning, the children sang a song all about being a palaeontologist, they even managed to pronounce the word “Pachycephalosaurus” correctly – well done to all!
It’s that time of year, when our chums at CollectA give us official permission to post up pictures and provide information on the new for 2018 CollectA prehistoric animal models. There is so much going on at Everything Dinosaur that we have had a job to keep up, however, prior to publishing information about the second batch of models, here are our thoughts on the first of the new for 2018 CollectA introductions.
First up, representing the iguanodontoids is this beautiful Mantellisaurus, a dinosaur formally re-named and scientifically described in 2007. The genus name honours Gideon Mantell and it is great to see another model of a British dinosaur. At Everything Dinosaur, we have been helping to support the campaign team behind a bid to mount a life-size statue of this dinosaur in Gideon Mantell’s home town of Lewes (West Sussex). We sure the campaign team will be as equally excited about this new dinosaur model as we are.
This wonderfully coloured dinosaur is depicted in a drinking posture. Mantellisaurus atherfieldensis was more lightly built than Iguanodon bernissartensis and Dollodon bampingi. In addition, the forelimbs were smaller, this suggests that this Early Cretaceous plant-eating dinosaur spent most of its time as a biped, moving about on its hind legs. It may only have dropped down onto all fours to feed, or to drink, hence the drinking pose as shown in this well-designed model.
Designer Anthony Beeson remarked:
“I thought it about time that not only did someone do a Mantellisaurus but also had a dinosaur having a drink. I thought it would be good for children of all ages doing dioramas as well as advertising another British dinosaur.”
A Mantellisaurus skeleton (NHMUK R5764) is on display in one of the “Wonder Bays”, in the Hintze Hall of the Natural History Museum, London. This is one of the most complete dinosaur skeletons ever found in the British Isles and it is the only current dinosaur exhibit on display in the main hall of the museum.
NHMUK R5764 – Mantellisaurus atherfieldensis on Display at the London Natural History Museum
Mantellisaurus on display in the Hintze Hall.
Picture credit: The Trustees of the Natural History Museum
To view the current CollectA Prehistoric Life range available from Everything Dinosaur: CollectA Prehistoric Life.
Sciurumimus Takes Centre Stage
CollectA has a deserved reputation for producing unusual theropod models and in early 2018 a Sciurumimus (S. albersdoerferi) is being introduced. Known from a single, spectacular specimen found in a limestone quarry in Germany, this dinosaur was once thought to be a megalosaurid, but a more recent analysis has placed this meat-eater into the Coelurosauria clade. The amazing fossil, which is 98% complete, represents a very young animal, the entire skeleton measures 72 centimetres long. Just how big Sciurumimus grew too, nobody knows. Sciurumimus (pronounced Skear-roo-my-mus), may have been a giant, but one thing is for sure, as a baby, it was covered in “dino fuzz”.
CollectA Mantellisaurus = length around 15 cm, with a height over the hips of just over 5 cm.
CollectA Sciurumimus = length 13.3 cm, height 4.8 cm (it is going to be fun attempting to calculate a scale for this dinosaur model)!
Everything Dinosaur’s Commissioned Drawing of Sciurumimus albersdoerferi
Sciurumimus illustration.
Picture credit: Everything Dinosaur
The picture above shows the Sciurumimus illustration that we have prepared for our fact sheet so from the Jurassic, we now move on to something which is very much 21st century.
CollectA Prehistoric Animal Models and Augmented Reality
Augmented Reality (AR) is one of the fastest growing areas of technology at the moment. CollectA have made a connection between their prehistoric animal models and cutting-edge computer generated images and effects. In early 2018, CollectA will introduce a range of blind bags. Each one will contain a mini dinosaur model and a data card that can be scanned by smart devices to bring your very own prehistoric animal to life on the screen.
CollectA Unites the Prehistoric with Innovative Computer Generated Visual Effects
CollectA augmented reality.
Have pterosaurs fly under your nose, or see how a Brachiosaurus would walk! Bring your own prehistoric animals to life via your smart device. Dinosaurs and augmented reality, sounds like a very powerful combination indeed! Dinosaur fans and model collectors will be able to go “walking with virtual dinosaurs”, or, as there is a mosasaur in the twelve models chosen to launch this range, you can go “swimming with marine reptiles” if you prefer.
The mini prehistoric animals used in this exciting product extension are some of the models available in the CollectA Box of Mini Dinosaurs sets which have already proved to very popular.
We will post up more information and product news about new models from CollectA in a couple of days or so.
A Video Review of the Rebor “Pete” Velociraptor Replica
Earlier this week, those talented people at JurassicCollectables produced a video review of the new Rebor 1:18 scale Velociraptor figure called “Pete” and what a great opportunity this video provides for model collectors to get a really good look at this excellent figure. The video narrator comments about how close to the “Jurassic Park” raptors these figures look and asks help from viewers in determining which of the raptor gang from “Jurassic Park/Jurassic World” the Rebor figure most closely resembles.
The “Winston” Velociraptor Unboxing Video Review by Jurassic Collectables
This is a very detailed video, (it lasts for nearly fifteen minutes), the narrator shows the classy packaging and unboxes the figure before discussing its merits and comparing it to other Rebor 1:18 scale replicas including “Winston” and “Alex Delarge”. Just like the other Rebor Velociraptor offerings, the “Pete” replica stays true to the non-feathered principles of the first “Jurassic Park” dromaeosaurids and the viewer is given a guided tour around the dinosaur with a special focus on the beautifully crafted, skin texture.
“Pete” the Latest Rebor Velociraptor Model
The Rebor 1:18 scale Velociraptor replica “Pete”.
Picture credit: Everything Dinosaur
Why is this Rebor Replica Called “Pete”?
In the very informative video review from JurassicCollectables, lots of aspects of this particular model are covered, the size, the paintwork, the details of the sculpt and so forth, but the question as to why this model is called “Pete” is not answered. Let’s deal with that question to add a finishing touch to this very well-made video review.
Recent Rebor raptor models have been named after characters from the ground-breaking novel “A Clockwork Orange”, which was written by Anthony Burgess in 1962. This book was later made into a famous (or rather infamous), film of the same name directed by Stanley Kubrick.
The plot deals with the violent lives of a gang of delinquents called the droogs, in a dystopian vision of the future. The leader of the gang, played by Malcolm McDowell in the film, is called “Alex”, hence the recently introduced Rebor “Alex” figure. One of the gang members is named “Pete” and that’s how this new figure got its name. We could see more 1:18 scale Rebor Velociraptor replicas in the future, models named after the other droogs, namely Dim and Georgie.
Rebor “Pete” Named after a Gang Member from “A Clockwork Orange”
A cursorial (running Velociraptor) called “Pete from Rebor.
Picture credit: Everything Dinosaur
To view the Rebor Velociraptor “Pete” 1:18 scale figure and the rest of the Rebor range: Rebor Models and Figures.
A Model of a Running “Cursorial” Raptor
It is great to see in the video direct comparisons being made between Rebor “Pete” and other Rebor Velociraptor replicas such as the leaping “Alex”. The viewer can get a really good idea of how the Rebor pack of Velociraptors is coming together. The narrator takes care to discuss the dynamic, running pose of this figure, it certainly gives the impression that this dinosaur is moving at speed.
JurassicCollectables have an amazing YouTube channel packed with wonderful dinosaur model reviews and other very informative videos. Look out for all the super Rebor model reviews that are posted up on this channel.
Visit the YouTube channel of Jurassic Collectables here: JurassicCollectables on YouTube, to prevent you missing out on future videos, don’t forget to subscribe to the JurassicCollectables channel.
We look forward to seeing more JurassicCollectables video reviews of the Rebor range in the future.
By Mike|2023-08-24T14:34:16+01:00November 6th, 2017|General Teaching, Key Stage 1/2|Comments Off on Why Do Asteroids Always Land in Craters?
Why Do Asteroids Always Land in Craters?
With the need to work scientifically being emphasised in the national curriculum for England (science syllabus), Everything Dinosaur team members have been busy supporting teaching teams with their schemes of work. As well as providing all the usual assistance and support, staff at the Cheshire based company have just introduced a new pair of primary school lesson plan downloads to help support a dinosaur or space themed term topic. The lesson plan is entitled “Why do asteroids always land in craters?” The aim of this lesson plan is to challenge the Key Stage 1 children to create an experiment to test ideas about what happens when a space rock crashes.
Why Do Asteroids Always Land in Craters?
Resources suggested for the “why do asteroids always land in craters?” A lesson plan.
Picture credit: Everything Dinosaur
A Simple Experiment to Encourage Working Scientifically
Two downloads have been created, one aimed at KS1, the second targeted at KS2. Both these lesson plans challenge children to work scientifically. For example, the Key Stage 1 download focuses on exploring the physical properties of materials and encourages the use of simple, comparative tests, whilst the Key Stage 2 download challenges older children to devise a suitable experiment to test this idea about asteroid impacts. A list of suggested resources is provided in both downloads and the photographs and bullet points provided help with tailoring the exercise to meet the specific learning needs of the class.
Free Download Linked to Space and Dinosaur Term Topics
PDF download of teaching notes/lesson plan is available from Everything Dinosaur.
Picture credit: Everything Dinosaur
Teaching Notes and Extension Activities
The downloads are available free from Everything Dinosaur. These downloads are amongst a huge range of free dinosaur, fossil and prehistoric themed teaching resources available. All these materials have been checked, tested and approved by our own teaching team.
The “why do asteroids…” lesson plan includes helpful teaching notes with suggestions as to how to deliver this exercise. In addition, a series of extension ideas are listed, all designed to help teaching professionals differentiate and challenge more capable learners.
It seems when it comes to exploring how the dinosaurs died out, or learning about outer space, these handy downloads from Everything Dinosaur are going to have a big impact”.
New Paper Challenges the Idea of T. rex and Tiny, Useless Arms
Evolution is a very efficient process, either adapt and survive or fail to adapt and face extinction. That seems to be the general premise when it comes to “survival of the fittest”. However, one anatomical feature of the enormous theropod Tyrannosaurus rex seems to fly in the face of the theory of evolution, T. rex is famous for having tiny and puny arms. Are the tyrannosaurids sticking two figures up when it comes to natural selection? Not so, according to a new paper presented at the annual conference of the Geological Society of America (Seattle, Washington, USA).
Tyrannosaurus rex – Famous for its Disproportionately Small Arms
The “prey” is an unfortunate Struthiomimus, but look at those tiny arms.
Vestigial Limbs?
Ever since the first partial skeletons of T. rex were discovered and as more fossils of this Late Cretaceous carnivore came to light, palaeontologists have puzzled over those “puny” arms. At the turn of the Century, during the period of the Barnum Brown fossil discoveries that led to the formal scientific description of the “tyrant lizard king”, no arm bones were found in association with the dinosaur, so it was assumed, that like Allosaurus more than 80 million years before, T. rex had three-fingered hands.
Our fascination with the forelimbs of Tyrannosaurus rex had begun. It was as recently as 1989, when arm bones of Tyrannosaurus rex were finally found and the didactyl hands seen in other, closely related tyrannosaurids such as Albertosaurus and Gorgosaurus were confirmed.
An Early Reconstruction of the Skeleton of Tyrannosaurus rex
T. rex the second reconstruction by Osborn.
Picture credit: Lindahall.org
Palaeontologist Steven Stanley (University of Hawaii at Manoa), challenges the perception that this dinosaur’s arms were almost useless. He suggests that earlier tyrannosaurids gradually evolved smaller forelimbs as their skulls and jaws became more massive, a hypothesis with lots of consensus amongst palaeontologists, but those tiny arms were actually very effective slashing weapons, ideal for close quarter combat.
Debunking the Idea of “Tiny, Puny” Arms
The arms of the Tyrannosauridae were certainly disproportionately small when compared to their massive bodies, however, Professor Stanley contends that at around 1 metre in length, the arms may have been relatively small, but they were exceptionally strong and with their two-fingered claws, with talons measuring up to ten centimetres long, they would have been capable of inflicting deep wounds in any dinosaur that got close. Whether the arms had a role in subduing prey or whether they were used in intraspecific combat, remains contentious.
Many palaeontologists believe that the reduced arms of tyrannosaurids were a consequence of natural selection favouring the evolution of giant skulls and super-strong jaws. The heads of tyrannosaurs, took over the role of grasping prey from the forelimbs and as the skulls and jaws became increasingly robust, the arms gradually got smaller and smaller as natural selection solved the issue of trying to counterbalance an increasingly heavy front end for the animal.
Six Traits Indicate That the Arms were Slashing Weapons
In the scientific paper, Professor Stanley identifies six derived traits that demonstrate that the arms of T. rex were not vestigial and that they could have served as slashing weapons.
The short arms would have been ideal for close combat slashing, just as a small knife can be a very effective weapon in hand-to-hand combat.
A large and broad coracoid bone suggests the arms were very powerful. The arms of T. rex were slightly longer than the legs of a six-foot-tall man and of similar girth.
The arm bones themselves, particularly the humeri in a number of specimens are very thick and robust and the bones in the arm would have easily withstood the forces involved in slashing attacks.
Tyrannosaurs are famous for having just two-fingered hands, the loss of the third finger allowed 50% more pressure to be applied to each claw.
The humoral head articulating with the shoulder provided considerable mobility in the joint, all helpful when it comes to performing a slashing action.
The sharp, keratinous-tipped claws measured between 8-10 centimetres long in the largest specimens, these would have inflicted metre-long, parallel slashes into the hide of any dinosaur that got too close.
Scientists have proposed several theories as to how T. rex used its short hands. They may have played a role in helping to grasp a mate during reproduction, or perhaps they helped this 7 Tonne dinosaur to stand upright after lying on the ground. Those much-maligned appendages could have had other uses, as Professor Stanley contends. The muddy waters surrounding the use to which T. rex put its hands have been made even murkier somewhat by more recent fossil discoveries. In 2009, Everything Dinosaur reported on the discovery of Raptorex kriegsteini, a 3-metre-long tyrannosaur that had the same body proportions of its more massive (and later), relative. Find the Raptorex article here: Raptorex Upsets the Tyrannosaur Apple Cart.
More recently, (2016), the discovery of the Late Cretaceous theropod Gualicho (G. shinyae) from Argentina, added more confusion to this puzzle. Although, Gualicho was not closely related to T. rex and its kin, it also had substantially reduced limbs and two-fingered hands. Perhaps, if Steven Stanley is onto something, then Gualicho too, could have utilised its reduced limbs as slashing weapons.
“Its short, strong forelimbs and large claws would have permitted T. rex, whether mounted on a victim’s back or grasping it with its jaws, to inflict four gashes a metre or more long and several centimetres deep within a few seconds and it could have repeated this multiple times in rapid succession. Infliction of damage by slashing was widespread among other Theropod taxa, so in light of its formidable weaponry, why should T. rex not have engaged in this activity?”
“Stanley Knives” on a T. rex
In summary, Steven Stanley suggests that the most famous of all dinosaurs was an even more formidable and dangerous dinosaur than previously thought. It possessed four, razor sharp claws (“Stanley knives” as a colleague referred to them as), these were perfectly adapted for helping this predator subdue prey.
Rather than being “puny” and “relatively useless”, these didactyl hands had evolved into effective close-quarter weapons, just as like the skull and jaws. Several palaeontologists have commented on the paper, suggesting that in close proximity, the massive jaws of this hypercarnivore would have been much more deadly, however, the slashing claws could have provided additional weapons for juveniles which had yet to mature and develop those immensely powerful skulls.
Tiny But Formidable Arms?
A Tyrannosaurus rex museum exhibit.
Picture credit: Everything Dinosaur
The scientific paper: “Evidence that the Arms of Tyrannosaurus rex were not functionless but Adapted for Vicious Slashing” by Steven Stanley and published as a paper at the annual meeting of the Geological Society of America.
For life on Earth, the impact event that marked the end of the Mesozoic Era was made many times worse as the extra-terrestrial object caused the release of climate-active gases. As if the devastation was not bad enough, the high-velocity impact caused the release of huge quantities of sulphur and carbon dioxide into the atmosphere triggering a dramatic world-wide cooling and exacerbating the effect of this event. No wonder then, that around 70% of all terrestrial life died out.
Two scientific papers report on the consequences of this catastrophe. In the first, the effect of gases released into the atmosphere from the sedimentary rocks that were hit are modelled and in the second paper, scientists look at just how unfortunate the dinosaurs were. If the extra-terrestrial object had hit virtually anywhere else on Earth, the consequences for Cretaceous life would not have been so severe.
In simple terms, the dinosaurs were very unlucky, there was only a 13% chance of a mass extinction event occurring 66 million years ago when the object from space hit.
An Extra-terrestrial Object Hurtles Towards Earth 66 Million Years Ago
An extra-terrestrial impact event. The dinosaurs were very unlucky.
Picture credit: Deposit photos/Paul Paladin
A Global Effect
Writing in the journal “Geophysical Research Letters”, the authors of the first scientific paper report that the impact in the shallow sea of the Gulf of Mexico may have resulted in the expulsion of more than 300 billion tonnes of sulphur into the atmosphere. In addition, the rocks that the object hit also released vast quantities of carbon dioxide, somewhere around 400 billion tonnes of CO2. Some of the sulphur may have combined with water vapour to form sulphuric acid, this would have fallen back to Earth in the form of acid rain, further damaging plant life and upsetting food chains.
However, much of the gas would have remained high up in the atmosphere and behaved like aerosols, changing the amount of solar irradiation reaching the ground which led to surface temperatures plummeting.
The global effect was freezing temperatures for several years, a nuclear winter. The research team which includes scientists from the Imperial College London and Potsdam University, conclude that ocean temperatures could have been affected for hundreds of years. The abrupt climate change may explain why so many species become extinct.
The end-Cretaceous mass extinction event saw entire groups of animals and plants die out including the non-avian dinosaurs, the Pterosauria, several types of marine reptiles, as well as cephalopods such as the ammonites. In addition, there were major losses amongst brachiopods, bivalves, sea urchins and many different types of marine plankton also perished. Although, in comparison, groups such as the flowering plants (Angiosperms), amphibians, mammals and fishes were less affected, there were still extinctions.
Hitting the Earth in a very Bad Place
Plummeting temperatures and a sustained period of intense cold would have made survival for the likes of the Dinosauria, extremely difficult. Such a dramatic climate downturn would have devastated ecosystems, leaving animals like the non-avian dinosaurs and flying reptiles doomed. However, in a second paper published in the journal “Scientific Reports”, scientists from Tohoku University and the Meteorological Research Institute, Tsukuba (both in Japan), state that life on Earth 66 million years ago, was just unlucky.
According to the calculations of these scientists, there was only a thirteen percent chance of the mass extinction event that wiped out the dinosaurs. If the extra-terrestrial object had hit almost anywhere else, the consequences would not have been so severe and the Dinosauria et al might just have survived to the present day.
Examining the Consequences of the Yucatan Peninsula Impact
A devastating mass extinction could only occur if an asteroid struck a hydrocarbon-rich area (those marked in orange).
Picture credit: Kunio Kaiho (Tohoku University)
Climate Change Resulting from the Chicxulub Impact
The Japan-based researchers postulated that the severity of the climate change would vary depending on where the extra-terrestrial body hit. Areas with higher levels of sedimentary organic material would throw more soot into the upper parts of the atmosphere. More hydrocarbons present would result in greater releases of CO2. Those areas with sulphur-rich rocks would have released more sulphur. The team conclude that the effects of the impact were much more dramatic because the impact was in the Gulf of Mexico. To test their hypothesis, a series of impact scenarios were run using global climate models to assess changes in temperature.
When the Yucatan Peninsula Cretaceous geology was examined, the team concluded that the hydro-carbon rich strata would have thrown debris into the upper atmosphere that resulted in a drop of global temperature by an average of 8 to 11 degrees Celsius. On land, the temperature drop could have been as excessive as a fall of 17 degrees Celsius. The oceans did not fare much better, with average temperature drops of between 5 and 7 degrees Celsius at depths of up to fifty metres.
Putting this into context, our world is faced with global climate warming. The Paris Agreement, now ratified by 169 countries, has a central aim to keep the global temperature rise this century to below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius.
Studying the Rocks of the Yucatan Peninsula
The researchers looked at how widespread the sort of rocks found in the Yucatan Peninsula in the Cretaceous, were. They found that these types of rocks were mostly associated with marine coastal margins. The shallow seas permitted the concentration of algae which could deposit more organic matter into the sediments. These areas covered just thirteen percent of the Earth’s surface.
Had the asteroid struck somewhere in the other eighty-seven percent of the planet, then, although the impact event would have been catastrophic, it might not have been as bad as it was. The researchers even go as far as to state that some species of dinosaurs may have persisted beyond the Cretaceous. The Mammalia would not have had the chance to radiate and therefore the primates, including humans, might not have evolved at all.
Changes in Fauna over the Phanerozoic Based on Extinction Events
Looking at the probability of a mass extinction event (Chicxulub impact).
The graph above shows Phanerozoic faunal changes with approximately 13% probability following the Chicxulub asteroid impact. Changes in fauna are based on extinction rates. A consequence of the end Cretaceous extinction event was the demise of the Dinosauria and the rise of mammals.
