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12 02, 2019

Reflecting on the Eyes of Cretaceous Spiders

By | February 12th, 2019|Dinosaur and Prehistoric Animal News Stories, Geology, Main Page, Photos/Pictures of Fossils|0 Comments

Early Cretaceous Spiders Reveal Reflective Eyes

A team of scientists, including a researcher from the University of Kansas, writing in an academic journal (Journal of Systematic Palaeontology), have described spiders from the Early Cretaceous that had reflective eyes, an adaptation to permit these tiny predators to hunt at night.  The remarkable fossils were discovered in black shale beds from South Korea which form part of the Jinju Formation (Albian faunal stage) and the flattened fossils preserve the remains of spiders that lived between 113 and 110 million years ago.

The Light Reflective Properties of the Crescent-shaped Tapetum

UV light reveals the ancient tapetum of spiders.

The two tapetum can be seen as crescent-shaped objects on the anterior portion of the head.

Picture Credit: Paul Selden/University of Kansas

Two of the fossils from the extinct spider family Lagonomegopidae feature reflective eyes.  The fossils represent the first non-amber Lagonomegopidae to be described, with the first preservation of a spider eye tapetum recorded in the fossil record.

C0-author of the scientific paper, Paul Selden, Gulf-Hedberg Distinguished Professor of Geology and the Director of the Palaeontological Institute at Kansas University’s Biodiversity Institute and Natural History Museum, explained:

“Because these spiders were preserved in strange slivery flecks on dark rock, what was immediately obvious was their rather large eyes brightly marked with crescentic features.  I realised this must have been the tapetum — that’s a reflective structure in an inverted eye where light comes in and is reverted back into retina cells.  This is unlike a straightforward eye where light goes through and doesn’t have a reflective characteristic.”

Selden said that some contemporary spiders feature eyes with a tapetum, but the new paper is the first to describe the anatomical feature in a fossilised spider.  The research team said the discovery provides evidence for lagonomegopid enlarged eyes being posterior medians.

“In spiders, the ones you see with really big eyes are jumping spiders, but their eyes are regular eyes — whereas wolf spiders at night time, you see their eyes reflected in light like cats.  So, night-hunting predators tend to use this different kind of eye.  This was the first time a tapetum had been in found in fossil.  This tapetum was canoe-shaped — it looks a bit like a Canadian canoe.  That will help us place this group of spiders among other families.”

Selden’s collaborators were Tae-Yoon Park of the Korea Polar Research Institute and amateur fossil hunter Kye-Soo Nam of the Daejeon Science High School for the Gifted, who found the fossils preserved in the shale.

The description of the fossils increases the number of known spiders from the Jinju Formation from a single specimen to eleven.

Commenting on their remarkable state of preservation, Paul added:

“This is so rare because they’re very soft — they don’t have hard shells so they very easily decay.  It has to be a very special situation where they were washed into a body of water.  Normally, they’d float.  But here, they sank, and that kept them away from decaying bacteria, it may have been a low-oxygen condition.  These rocks also are covered in little crustaceans and fish, so there maybe was some catastrophic event like an algal bloom that trapped them in a mucus mat and sunk them, but that’s conjecture.  We don’t really know what caused this, but something killed off a lot of animals around the lake at one time or on an annual basis.”

According to Selden, the shale preserved the spider fossils in a manner that highlighted the reflectivity of the tapetum, a feature that may have been missed had the spiders been preserved in amber instead, as is more typical.

Preserved in the Black Shale an Almost Perfect Impression of an Early Cretaceous Spider

Fossilised remains of an Early Cretaceous spider with reflective eyes.

The black shale preserved perfect impressions of the ancient spiders.

Picture Credit: Paul Selden/University of Kansas

The discovery of these spiders will help researchers to piece together a better understanding of the environment that existed in South Korea during the Early Cretaceous.

Everything Dinosaur acknowledges the assistance of a press release from the University of Kansas in the compilation of this article.

11 02, 2019

Two Ancient Seed-eating Birds Described

By | February 11th, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Eofringillirostrum boudreauxi  and Eofringillirostrum parvulum Passerines from the Early Eocene

A scientific paper has just been published in the journal “Current Biology”, that describes two Early Eocene, seed-eating, perching birds (passerines).  The birds are closely related, assigned to the same genus but one fossil was discovered in Wyoming, the other comes from the famous Messel shales of Germany and they are separated by around 5 million years.  These species are amongst the oldest fossil birds to exhibit a finch-like beak and provide the earliest evidence for a diet focused on small, hard seeds in crown birds.  The discovery of these two early granivores, will help scientists to better understand the evolution and radiation of this important group of birds, that make up 65% of all extant bird species.

The Wyoming Specimen – Holotype of Eofringillirostrum boudreauxi

Eofringillirostrum boudreauxi holotype from the Green River Formation of Wyoming.

(A) Photograph and (B) line drawing of the holotype skeleton of Eofringillirostrum boudreauxi (FMNH PA 793).

Picture Credit: Current Biology

The Ancestors of Sparrows, Finches, Crows, Robins etc.

Passerines might be ubiquitous these days, but once they were rare and only made up a small proportion of avian biotas.  We still have a lot to learn about their evolution.

Commenting on the significance of the fossil discoveries, one of the co-authors of the paper Lance Grande (Field Museum, Chicago), stated:

“This [Eofringillirostrum boudreauxi] is one of the earliest known perching birds.  It’s fascinating because passerines today make up most of all bird species, but they were extremely rare back then.  This particular piece is just exquisite.  It is a complete skeleton with the feathers still attached, which is extremely rare in the fossil record of birds.”

The Wyoming specimen, E. boudreauxi, is the earliest example of a bird with a finch-like beak, similar to many of the birds you see today inhabiting parks and gardens.  This legacy is reflected in its name; Eofringillirostrum means “dawn finch beak”, whilst the specific epithet honours Terry and Gail Boudreaux, who donated the holotype to the Field Museum.

The Green River Formation

The Wyoming specimen heralds from the famous Early Eocene Green River Formation, extensive fine-grained deposits formed in a lacustrine environment.  The area is famous for its beautifully preserved but compressed vertebrate fossil specimens.

Lead author of the research, Daniel Ksepka from the Bruce Museum (Connecticut), commented on the importance of finding fossil birds with finch-like beaks adapted to eating seeds:

“These bills are particularly well-suited for consuming small, hard seeds.  Anyone with a birdfeeder knows that lots of birds are nuts for seeds, but seed-eating is a fairly recent biological phenomenon.”

The earliest birds probably ate insects, plant material and even fish, although a recent theory has been proposed that the ability to consume seeds may have helped some kinds of birds survive the catastrophic End-Cretaceous mass extinction event.

To read an article about this: Seed-eating may have Helped Birds Survive Mass Extinction Event

Comparing the Two Specimens

Both the Wyoming and the German specimens have similar shaped beaks, although the German fossil represents a slightly smaller type of bird.  Beak shape infers information about the bird’s diet and as such, beak shape plays a key role in avian radiations and is one of the most intensely studied aspects of avian evolution and ecology.

With two specimens that were both temporally and geographically dispersed the researchers were able to conclude that these types of birds were widespread during the Eocene.

The Messel Shale Passerine Specimen – Eofringillirostrum parvulum

Eofringillirostrum parvulum from the Messel Shales.

Holotype slab (IRSNB Av 128a) and (G) counter slab (IRSNB Av 128b) of Eofringillirostrum parvulum with enlargements showing details of (H) skull and (I) carpometacarpus.

Picture Credit: Current Biology

Found in Subtropical Habitats Not Open Plains

Whilst many Passeriformes (passerines or perching birds), are synonymous with open, grassland environments today, the researchers note that these fossil specimens occurred in subtropical palaeoenvironments.  Given that seed-eating (granivory), is a key adaptation that allows passerines to exploit open temperate environments, the seed-eating habit may have evolved prior to the movement of these types of birds into more open habitats.  The ability to consume and digest seeds may not have been a driver in allowing these types of birds to exploit new habitats, but this type of feeding behaviour would have proved to be extremely beneficial as the world became much cooler towards the end of Eocene and the once widespread rainforests gave way to more open landscapes.

Everything Dinosaur acknowledges the assistance of a press release from the Field Museum (Chicago), in the compilation of this article.

The scientific paper: “Oldest Finch-beaked Birds Reveal Parallel Ecological Radiations in the Earliest Evolution of Passerines” by Daniel T. Ksepka, Lance Grande and Gerald Mayr published in Current Biology.

8 02, 2019

New Species of Late Cretaceous Oviraptorid Named

By | February 8th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Gobiraptor minutus – The Diversity of the Oviraptoridae in the Late Cretaceous

A new species of oviraptorid dinosaur (Oviraptoridae family), has been described by an international team of scientists.  The little dinosaur was probably feathered and it possessed thickened jaws, an adaptation to feeding on hard food items such as seeds, nuts or the shells of bivalves, molluscs and crabs (durophagous).   The fossilised remains of a single, very young individual were found in the Altan Uul area of Ömnögovi Province, Mongolia, in strata from the famous Upper Cretaceous Nemegt Formation.  The new species has been named Gobiraptor minutus and it helps to demonstrate that this part of Asia in the Late Cretaceous was home to diverse variety of oviraptorids, many of which, probably occupied specialist niches within the ecosystem in a bid to minimise competition for resources.

A Life Reconstruction of Gobiraptor minutus

Gobiraptor minutus life reconstruction.

A life reconstruction of Gobiraptor minutus.

Picture Credit: Do Yoon Kim with additional annotation by Everything Dinosaur

Rare for the Altan Uul Area of Southern Mongolia

Oviraptorid fossil specimens are relatively rare in the Altan Uul area of the Gobi Desert, however, within the Upper Cretaceous deposits exposed within the Gobi Desert, some ten oviraptorid taxa have so far been named and described.  Gobiraptor increases the diversity of oviraptorids known from the Nemegt Formation and demonstrates that these types of Theropod dinosaurs were exceptionally abundant in the mesic environment* of that part of the world during the Late Cretaceous.

A mesic environment* – is a term used in ecology to describe an environment with a moderate amount of water.  Much of this part of Asia during the Late Cretaceous may be associated with a dry, arid environment, for example numerous types of other Theropod fossils come from strata that represent almost desert-like conditions.  These fossils are found in the older Barun Goyot Formation which was laid down under more arid conditions.  The rocks in which the fossils of Gobiraptor were found consist mainly of river channel deposits, indicating that the palaeoenvironment changed and the environment became considerably wetter.

Thus, the finding of a new member of the Oviraptoridae family in the Nemegt Formation, which consists mostly of river and lake deposits, confirms that these dinosaurs were extremely well adapted to wet habitats.

Fragmentary Fossils and Skeletal Reconstruction of Gobiraptor minutus

Gobiraptor minutus skeletal reconstruction.

Grey shaded bones indicate known fossil material.  Note scale bar on skeletal drawing – 10 cm.

Picture Credit: PLOS One

Robust and Thickened Jaws Hint at a Dietary Specialism

Gobiraptor minutus, can be differentiated from other members of the Oviraptorosauria clade in having unusually robust and thickened jaws.  This unique mandibular morphology suggests that Gobiraptor was adapted to feeding on hard food items, it used its strong jaws to crush, indicating potential niche partitioning in the palaeoenvironment to reduce competition amongst small Theropods and within the local population of oviraptorids.  Osteological analysis of the femur suggests that the fossil material represents a very young individual.

The phylogenetic analysis carried out by the researchers defines Gobiraptor as a derived oviraptorid closely related to three taxa from the Ganzhou region of southern China, but, ironically, the analysis suggests that it was rather distantly related to other Nemegt oviraptorids which, as the results of recent studies, are also not closely related to each other.

The authors propose that different dietary strategies may explain the wide taxonomic diversity and evolutionary success of this group of dinosaurs in this part of Asia.

Post-cranial Elements of G. minutus

Post-cranial elements of Gobiraptor.

Left femur in caudal view (A) and medial view (B).  Partial right humerous (C) and ilium (D).  (E) left metatarsal I and pedal digit I in medial view.  (F) left pedal digit IV in lateral view.  Scale bar = 5 cm.

Picture Credit: PLOS One

The genus name honours the Gobi Desert, whilst the specific epithet is from the Latin for small, a reflection on the small size of the holotype.

The scientific paper: “A New Baby Oviraptorid Dinosaur (Dinosauria, Theropoda) from the Upper Cretaceous Nemegt Formation of Mongolia” by Sungjin Lee, Yuong-Nam Lee , Anusuya Chinsamy, Junchang Lü, Rinchen Barsbold and Khishigjav Tsogtbaatar published in PLOS One.

7 02, 2019

Defensive Dicraeosaurids – Forward Facing Spikes Deter Predators

By | February 7th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Bajadasaurus pronuspinax – Sauropod Defences

A newly described Sauropod from northern Patagonia (Argentina), has provided palaeontologists with evidence to help explain why some of these long-necked dinosaurs evolved long, paired spines on the necks.  These features may have had a primary role as defensive structures helping to deter attacks from Theropod predators.  The dinosaur has been named Bajadasaurus pronuspinax and it has been assigned to the Dicraeosauridae family, a sister family to the Diplodocidae within the Sauropoda.  Dicraeosaurids are characterised by having relatively shorter necks and distinctive vertebrae which had long, paired neural spines.  The function of these spines has long been debated.  They have been interpreted as playing a role in visual communication, sexual display and thermoregulation, however, this newly described dinosaur suggests that within this family of long-necked dinosaurs they evolved as a form of defence.

Illustrating Bajadasaurus pronuspinax and the Fossil Find Location

Bajadasaurus skeletal reconstrution and fossil find location.

A skeletal reconstruction of Bajadasaurus, location map of fossil finds and drawing of the fossil material in situ.

Picture Credit: Gallina et al published in Scientific Reports

The image (above), shows a skeletal reconstruction of the head and neck of Bajadasaurus (A), with the preserved fossil material shown in white.  On the right of the image is a location map (B), showing the site of the fossil find, close to the Ezequiel Ramos Mexía lake in Neuquén Province, Argentina.  A line drawing is provided (C), that shows the association and the location of the fossils found at the dig site.

Interpreting Fossils One Cervical Vertebra at a Time

The authors of the scientific paper, propose that the elongated neural spines of this dinosaur always faced forward, presenting a formidable obstacle for any meat-eating dinosaur wanting to attack the animal’s neck.  However, it is worth noting that if the image (above), is studied, the theory of Bajadasaurus having a neck topped with defensive spikes, like some sort of Victorian railings is based on the discovery of a single neck bone, in the skeletal illustration placed in the position of the fifth cervical vertebra.  The appearance of B. pronuspinax is inferred by comparing these fossils to the better-known Amargasaurus (A. cazaui).  Until more fossils are found the appearance of Bajadasaurus and the orientation of those neural spines can only be speculated.

A Model of the Dicraeosaurid Amargasaurus

A model of Amargasaurus.

The Amargasaurus has been mounted onto a bespoke base.  The appearance of Bajadasaurus is based on a comparison with better-known, related dicraeosaurids such as Amargasaurus cazaui.

Picture Credit: Everything Dinosaur

Lead-author of the study, Pablo Gallina and his colleagues, propose that these neural spines may have been covered with keratin and therefore much longer than the spines themselves.  The extent of the neural spines, the length of the keratin sheaths that covered them and the direction they pointed in, remains unknown.  Until more fossils of Bajadasaurus are found, those elongated neural spines remain a mystery.

Naming a New Dinosaur

That one cervical spine forms the basis for the species epithet.  The genus honours Bajada (Spanish for downhill), a reference to the fossil find location – Bajada Colorada.  The species name means “bent over, forward spines”, we shall see if more fossil discoveries reaffirm this interpretation.  Importantly, the fossil material assigned to Bajadasaurus includes much of the skull, thanks to these fossils, the palatal bones, the braincase and a nearly complete left dentary, palaeontologists have a much better idea about the size and morphology of dicraeosaurid dinosaur skulls.

Skull Material Associated with Bajadasaurus pronuspinax and Line Drawing

Bajadasaurus and line drawing.

Skull of Bajadasaurus pronuspinax, specimen number MMCh-PV 75 and line drawing.

Picture Credit: Gallina et al published in Scientific Reports

The skull is quite small for a Sauropod, dicraeosaurids described to date were not as big as some of their diplodocid cousins.  Size estimates range from around 10 to 13 metres in length.  The size of Bajadasaurus is unknown, but based on these fossils, it is likely that this dinosaur was within this size range too.  The orbits are quite large and their position on the top of the skull suggests that when this dinosaur had its head down and it was feeding, it was capable of seeing ahead (forward-directed, stereoscopic vision).

Comparing Bajadasaurus to the Geologically Younger Amargasaurus

The strata of the Bajada Colorada Formation represent sediments laid down at the very beginning of the Cretaceous (Lower Cretaceous, Berriasian/Valanginian faunal stages).  Bajadasaurus roamed Patagonia some 140 million years ago.  Amargasaurus, lived in the same part of South American but around fifteen million years later.  The researchers suggest that the temporal difference between Bajadasaurus and Amargasaurus, supports the idea that the development of an array of defensive spines was likely adaptive over a long time period.  How effective these spines may have been against predators, is once again, open to speculation.  However, the presence of elongated neural spines would have given the impression of a larger animal with a thicker neck.  To a hungry, carnivorous dinosaur the appearance of a bigger more robust adversary may have been enough of a deterrent.

The scientific paper: “A New Long-spined Dinosaur from Patagonia Sheds Light on Sauropod Defence System” by Pablo A. Gallina, Sebastián Apesteguía, Juan I. Canale and Alejandro Haluza published as an open access article in the journal “Scientific Reports”.

5 02, 2019

Iconic Feather Fossil Did Not Belong to Archaeopteryx

By | February 5th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Single Feather Not From Archaeopteryx

One of the most significant fossils to have ever been found, an iconic fossil in vertebrate palaeontology – a single fossilised feather from the Upper Jurassic Solnhofen limestone, is not quite what it seems.  The feather, long thought to be from an Archaeopteryx, is probably not from the “urvogel” at all.  The feather most likely was lost by a dinosaur, before it was blown into a shallow, calm lagoon and preserved as a carbonised film for 150 million years.

The Iconic Single Feather Fossil – Once Synonymous with Archaeopteryx is Not What it Seems

The Berlin feather - preserved as a carbonised film.

The slab from the Berlin museum showing the iconic feather, so long associated with Archaeopteryx but now thought to have belonged to a dinosaur.

Picture Credit: Everything Dinosaur

An international research team which included Dr Michael Pittman (University of Hong Kong), have applied a novel, high-tech, imaging method called Laser-Stimulated Fluorescence (LSF), to  help solve a 150-year-old mystery and to confirm that this feather was not from Archaeopteryx.

Discovered in 1861

The specimen was discovered in 1861 and actually consists of a slab and counter slab component, housed in museums located in Berlin and Munich.  A year later, the fossil feather was formally described and heralded as coming from an Archaeopteryx (A. lithographica), although unlike most feather impressions associated with the dozen or so Archaeopteryx specimens known to science, this feather was preserved as a dark, carbonised film.  This was the first fossil feather ever discovered and at the time fossils of Archaeopteryx were heralded as evidence of a “missing link”, supporting Darwin’s recently published theory of natural selection.

The detailed scientific description published in 1862 commented upon a rather long quill visible on the fossil, but this is unseen today.  Even recent X-ray fluorescence and UV (ultraviolet), imaging studies did not end the controversy of the “missing quill”.  The original existence of this quill has therefore been debated and it was unclear if the single feather represented a primary, secondary, or primary covert feather from Archaeopteryx.

Writing in the academic journal Scientific Reports, the researchers outline their work using the LSF technology and demonstrate its potential for providing new information about extensively studied fossil specimens.  The application of Laser-Stimulated Fluorescence is being developed by Thomas G Kaye of the Foundation for Scientific Advancement, Sierra Vista, Arizona (USA) and Dr Pittman.

Dr Pittman stated:

“My imaging work with Tom Kaye demonstrates that important discoveries remain to be made even in the most iconic and well-studied fossils.”

Detecting the Geochemical Presence of the Lost Quill

The application of LSF technology permitted the scientists, which included lead-author of the study Tom Kaye, to detect the geochemical halo from the rachis, matching the 1862 description.

Views of the Isolated Solnhofen Feather – Not from Archaeopteryx

Images of the Solnhofen isolated feather.

The isolated feather viewed under natural light (top), the original drawing from 1862 by Hermann von Meyer and under (LSF) showing the halo of the missing quill (bottom). Scale bar is 1 cm.

Picture Credit: University of Hong Kong

The shape of the feather has led the researchers to discount the idea that it came from an Archaeopteryx.  Instead, they conclude that it probably came from an unknown species of feathered dinosaur that lived alongside Archaeopteryx in the Solnhofen Archipelago.

Daniela Schwarz, a co-author of the scientific paper based at the Museum für Naturkunde, Berlin, commented:

“It is amazing that this new technique allows us to resolve the 150-year-old mystery of the missing quill.”

This new insight into an iconic fossil specimen also suggests that the diversity of feathered dinosaurs was likely higher in the ancient island archipelago than previously thought.

Tom Kaye added:

“The success of the LSF technique here is sure to lead to more discoveries and applications in other fields.  But, you’ll have to wait and see what we find next!”

31 01, 2019

A Newly Described Archosauromorph from Antarctica

By | January 31st, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page, Photos/Pictures of Fossils|0 Comments

Antarctanax shackletoni – Rise of the Archosaurs

A team of researchers, including scientists from the Field Museum (Chicago, USA), the University of Witwatersrand (South Africa) and the Burke Museum (University of Washington, USA), have published a scientific paper announcing the discovery of an archosauriform archosauromorph, that roamed Antarctica in the Early Triassic.  The fossil discovery suggests that early Archosaurs were more geographically widespread than previously thought and demonstrates that the biota of Antarctica may have been very different from other parts of the super-continent Pangaea as the planet recovered from the End-Permian mass extinction event.

A Diverse Fauna in Antarctica During the Early Triassic

Antarctica around 250 million years ago (Antarctanax shackletoni is in the left foreground).

A typical scene in Antarctica during the Early Triassic.   Antarctanax is in the left foreground.

Picture Credit: Adrienne Stroup (Field Museum, Chicago)

The illustration above depicts a typical ecosystem that existed in Antarctica approximately 250 million years ago.

Along the banks of a river, three Archosaur inhabitants of the dense Voltzia conifer forest cross paths, Antarctanax shackletoni attempts to sneak up on an early titanopetran insect, an archosauromorph Prolacerta rests on a log, and an enigmatic large Archosaur pursues two unsuspecting Dicynodonts, (Lystrosaurus maccaigi).

“Antarctic King”

Commenting on the significance of the discovery of the iguana-sized animal, co-author of the scientific paper Brandon Peecook (Field Museum) stated:

“This new animal was an Archosaur, an early relative of crocodiles and dinosaurs.  On its own, it just looks a little like a lizard, but evolutionarily, it’s one of the first members of that big group.  It tells us how dinosaurs and their closest relatives evolved and spread.”

The fossil skeleton is far from complete.  The material was collected from a site representing Lower Fremouw Formation deposits in the central Transantarctic Mountains.  The fossils consist of cervical and dorsal vertebrae, a single humerus and foot bones.  The reptile has been named Antarctanax shackletoni.  The genus name means “Antarctic King”, although this ancient, basal member of the group of reptiles that was to give rise to the dinosaurs, pterosaurs, crocodiles and birds, was probably not an apex predator.  This cannot be stated with certainty, after all, only one fossil specimen has been found, but Antarctanax shackletoni co-existed with a number of other vertebrates including amphibians, synapsids and at least one large archosauriform, which may have been the top predator.

The species name honours the polar explorer Ernest Shackleton.  It is suggested that Antarctanax hunted insects as well as smaller vertebrates.

Antarctanax – Where it Lived and When

Brandon Peecook, a member of the Integrative Research Centre, at the Field Museum explained that this fossil find (made in the 2010/11 field season), is significant because it demonstrates that the ecosystem in Antarctica bounced back relatively quickly after the End-Permian mass extinction event and that  archosauriforms were quite widespread at this time.

He stated:

“The more we find out about prehistoric Antarctica, the weirder it is.  We thought that Antarctic animals would be similar to the ones that were living in southern Africa, [Karoo Basin biota] since those landmasses were joined back then, but we’re finding that Antarctica’s wildlife is surprisingly unique.”

The fauna of the Lower Fremouw Formation traditionally has been considered to represent a subset of the Lystrosaurus Assemblage Zone of the Karoo Basin of southern Africa, with discrepancies largely a result of pronounced differences in sampling intensity.  However, a review of recent changes to the fauna, as well as a reassessment of occurrences based on older literature, indicates that significant discrepancies, including the co-occurrences of taxa known from both earlier and later in time and the presence of endemic forms in Antarctica, exist between the faunas of the Lystrosaurus Assemblage Zone and Lower Fremouw Formation.  In essence, Antarctica 250 million years ago had a different ecosystem to that associated with the contemporaneous Karoo Basin deposits.

A Slab of Rock Containing Exposed Post-cranial Material Attributed to Antarctanax shackletoni

Antarctanax shackletoni fossils

Antarctanax shackletoni fossil material.

Picture Credit: Brandon Peecook, Field Museum

As life on Earth recovered in the Early Triassic, so the Archosaurs rapidly diversified and laid the foundation for the evolution of the Dinosauria, Pterosauria, crocodiles and those other Archosaurs still very much with us today – the Aves (birds).

Post-doctoral Fellow Peecook, went on to state:

“Before the mass extinction, Archosaurs were only found around the Equator, but after it, they were everywhere.   Antarctica had a combination of these brand-new animals and stragglers of animals that were already extinct in most places, what palaeontologists call ‘dead clades walking.’  You’ve got tomorrow’s animals and yesterday’s animals, co-habiting in a cool place.”

The fact that scientists have found Antarctanax helps bolster the idea that Antarctica was a place of rapid evolution and diversification after the mass extinction.

A spokesperson from Everything Dinosaur commented:

“Antarctica is an extremely difficult part of the world to prospect for fossils.  However, as more of the frozen continent is mapped and explored, so more fossil discoveries are going to occur.  Antarctanax shows that there was a diverse faunal assemblage on this part of Pangaea during the Early Triassic and this discovery will help palaeontologists to plot the evolution and distribution of Archosaurs.”

Everything Dinosaur acknowledges the assistance of a press release from the Field Museum (Chicago), in the compilation of this article.

The scientific paper: “A Novel Archosauromorph from Antarctica and an Updated Review of a High-latitude Vertebrate Assemblage in the Wake of the End-Permian Mass Extinction” by Brandon R. Peecook, Roger M. H. Smith and Christian A. Sidor published in the Journal of Paleontology.

23 01, 2019

Prehistoric Shark Named after Video Game

By | January 23rd, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Galagadon nordquistae – Shark Resident of Hell Creek

Perhaps the most famous exhibit at the Field Museum (Chicago), is the Tyrannosaurus rex specimen named “Sue”, the most complete T. rex fossil discovered to date.  A great deal of research has been carried out on the 66 million-year-old fossilised bones of this giant, meat-eating Theropod that measures over twelve metres in length.  However, the matrix that surrounded the fossil material has helped to shed light on another resident of the famous Hell Creek Formation of South Dakota.  Fossil teeth found in the matrix surrounding the bones of the most famous T. rex in the world has led to the naming and description of a prehistoric shark that lived in freshwater, say hello to Galagadon nordquistae.

A Life Reconstruction of the Late Cretaceous Shark G. nordquistae

Galagadon nordquistae life reconstruction.

A life reconstruction of the Late Cretaceous shark Galagadon nordquistae.

Picture Credit: Velizar Simeonovski (Field Museum)

A Small, Freshwater Predator

Ever since the preparation work on “Sue” began in the 1990’s, the leftover sediment (matrix), was carefully stored at the Field Museum.  Researchers examined this material searching for micro-fossils in a bid to build up a picture of what life was like in this part of Laramidia towards the end of the age of dinosaurs.  Teeth were found from a shark which would have measured around half a metre in length.

Peter Makovicky (Curator of Dinosaurs at the Field Museum) commented:

“This shark lived at the same as Sue the T. rex, it was part of the same world.  Most of its body wasn’t preserved, because sharks’ skeletons are made of cartilage, but we were able to find its tiny fossilised teeth.”

The shark, named Galagadon nordquistae, is described in a scientific paper published in the “Journal of Palaeontology”.

Named After a 1980s Video Game

Lead author of the research, Terry Gates (North Carolina State University), explained that the shark’s name was inspired by the stepped, triangular shape of the teeth that reminded the research team of the spaceships in the 1980s video game Galaga.  The species epithet honours Field Museum volunteer Karen Nordquist who discovered the fossilised teeth in the matrix material.

Fossil Teeth Reminded the Scientists of Video Game Spaceships

Galagadon fossil teeth.

Specimens of shark teeth (lingual view) assigned to Galagadon.  Scale bars = 1 mm.

Picture Credit: Terry Gates (North Carolina State University)/Journal of Paleontology

Commentating on her fossil find, Nordquist stated:

“It [a tooth] was so tiny, you could miss it if you weren’t looking really carefully.  To the naked eye, it just looks like a little bump, you have to have a microscope to get a good view of it.”

Tiny Teeth Change our View of the Prehistoric Environment

The tiny teeth are only about a millimetre wide, about the size of a pinhead.  Galagadon was small too, estimated at around thirty to sixty centimetres in length.

Dr Makovicky added:

“Galagadon was less than two feet long, it’s not exactly Jaws.  It’s comparable to bamboo sharks living today.  It probably had a flat face and was very likely camouflage-coloured, since its relatives today have a camouflage pattern.  It would have eaten small invertebrates and probably spent a fair amount of time lying on the bottom of the riverbed.”

Galagadon may not have been huge, but its discovery has forced scientists into a re-think over what they thought they knew about the area where the T. rex named “Sue” was found.  It had been thought that the fossil locality represented a lake formed from a partially dried-up river, the presence of a shark suggests there must have been at least some connection to the sea.

The shark has been classified as a member of the Orectolobiformes Order of sharks, making it distantly related to extant carpet sharks including bamboo sharks.  These types of shark are believed to have originated in the Jurassic and had a global distribution, today they are mostly restricted to waters in southeast Asia and Australia.

Co-author of the study, Eric Gorscak (Field Museum) explained:

“It’s surprising to find their fossils at the Sue locality.  During the Late Cretaceous, the continents continued to drift apart, further isolating dinosaurs and other land animals, and at the same time created the Atlantic and Indian oceans.  With occasional seaways connecting these young oceans, we have found fossils of marine life flourishing globally, including Galagadon and its relatives.”

Various Views of the Galagadon Teeth

Views of Galagadon teeth.

Galagadon teeth. Specimens in lingual view (1–4), labial view (5–8), lateral view (9–12), basal view (13–16), and occlusal view (17–20). Scale bars = 1 mm.

Picture Credit: Terry Gates (North Carolina State University)/Journal of Paleontology

Hell Creek – More than Flashy Dinosaurs

The study also reflects the importance of learning about fossils beyond big, flashy dinosaurs.  Each species discovered helps to build up a picture of the ecosystem in which the dinosaurs and other megafauna existed.

Karen Nordquist added:

“Most people, when they think of fossils, think of big huge dinosaur bones, but in the dirt, there are the bones of tiny animals.  When you get those bones and identify them, you get an idea of the whole environment, everything that lived with the big dinosaurs.  You learn so much from micro-sorting.”

The scientific paper: “New Sharks and Other Chondrichthyans from the Latest Maastrichtian (Late Cretaceous) of North America” by Terry A. Gates, Eric Gorscak and Peter J. Makovicky published in the Journal of Paleontology.

Everything Dinosaur acknowledges the help of a press release from the Field Museum (Chicago), in the compilation of this article.

21 01, 2019

100 million-year-old Cretaceous Hagfish Shakes Our Family Tree

By | January 21st, 2019|Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Research Changes Views over Evolution of Jawed Vertebrates

An international team of scientists, including researchers from Manchester University, have helped unravel the secrets hidden in the fossilised remains of an ancient hagfish, a slimy, eel-like fish whose descendants still swim the oceans of the world today.

Working in collaboration with researchers from the University of Chicago (Illinois, USA), the Manchester University team have identified the first detailed fossil of a hagfish.  The Manchester team were led by Professors Phil Manning and Roy Wogelius, powerful X-rays were used to provide a detailed examination of the fossil specimen, providing a fresh perspective on the evolution of jaws in animals with back bones (vertebrates).

The Tethymyxine tapirostrum fossil Specimen Being Prepared for Synchrotron Analysis

Tethymyxine tapirostrum fossil.

Tethymyxine tapirostrum fossil being prepared for synchrotron X-ray analysis.

Picture Credit: University of Manchester

The X-rays were produced using the Stanford Synchrotron Radiation Lightsource (SSRL), a cyclic particle accelerator at Stanford University (California).  Once the fossil had been scanned, the data produced helped answer the question as to when these ancient jawless fish branched-off the vertebrate evolutionary tree.

An Important Discovery

The discovery is incredibly important as it changes our view of the evolutionary lineage that gave rise to modern-day jawed vertebrates (gnathostomes), from bony fish to humans.  The scientific paper is being published in the “Proceedings of the National Academy of Sciences”.  The fossil, a specimen of a hagfish from the Late Cretaceous comes from Lebanon and it measures just over thirty centimetres long.  The fossil represents a species named Tethymyxine tapirostrum.

Commenting on the importance of this research, Professor Phil Manning (Chair of Natural History at the University of Manchester) stated:

“This is an extremely significant discovery as it recalibrates our understanding of the evolutionary history of all early vertebrates, an ancestral line that leads to all jawed beasties including us. Humans!”

Professor Manning added:

“This wonderful fossil plugs a 100-million-year gap in the fossil record and shows that hagfish are more closely related to the lamprey than to other fishes.  The chemical maps produced at SSRL enabled our team to see for the first time the anatomical features so crucial to the interpretation of this very distant relative.”

Lampreys are another form of ancient, blood-sucking, jawless fish also still in existence today.  These findings show that both the hagfish and lamprey evolved their eel-like body form and strange feeding systems after they branched off from the rest of the vertebrate line of ancestry about 500 million years ago, during the Cambrian geological period.

Professor Manning at the SSRL (Stanford University)

Professor Phil Manning at the Stanford Synchrotron Radiation Lightsource (SSRL).

Professor Manning at the Stanford Synchrotron Radiation Lightsource (SSRL).

Picture Credit: University of Manchester

Dr Tetsuto Miyashita, (Fellow in the Department of Organismal Biology and Anatomy at Chicago University), who led the research, explained:

“This is a major reorganisation of the family tree of all fish and their descendants.  This allows us to put an evolutionary date on unique traits that set hagfish apart from all other animals.”

The Bizarre Hagfish

The bizarre hagfish are entirely marine and are the only known living animals that possess a rudimentary skull but no vertebral column.  They do have very primitive vertebrae but instead of a back bone like other vertebrates they just have a modified notochord.  They have a unique defence mechanism to help them ward off ocean predators such as sharks.  They can produce copious amounts of slime, clouding the water in their proximity and clogging the gills of would-be attackers.  In some parts of Asia, such as South Korea, this slime is prized and used in cooking.

It was this ability to produce slime that made the Tethymyxine fossil all the more important and rare.  The discrete chemistry locked within the fossil could only be mapped using synchrotron-based imaging techniques developed by the Manchester/SSRL team.  Manchester University  is an established world leader in the synchrotron-based imaging of fossil remains.  This technique has permitted the team to identify the “chemical ghost” of the preserved soft tissue and slime glands of the fossil.  Soft tissues are rarely preserved as fossils, which is why there are so few examples of prehistoric hagfish for palaeontologists to study.

The detailed scans picked up the chemical signal for keratin, the same material that makes up your hair and nails.  Keratin is a crucial part of what makes the hagfish slime defence so effective.

Professor Wogelius, (Chair of Geochemistry at The University of Manchester), commented:

“Our team at Manchester has been using these increasingly sophisticated imaging techniques to help us better understand ancient fossils and resolve chemistry derived from both the organism and the environment in which they were preserved.”

Professor Manning added:

“This ‘chemical’ fossil has offered new and exciting evidence that has enabled a more robust reconstruction of the vertebrate family tree.  However, it was only made possible through the collaboration of an international team, as Darwin once said, ‘In the long history of humankind (and animal kind, too) those who learned to collaborate and improvise most effectively have prevailed’”.

15 01, 2019

The Left Femur of Aepyornis

By | January 15th, 2019|Main Page, Photos/Pictures of Fossils|0 Comments

A Thigh Bone from an “Elephant Bird”

Whilst on a recent visit to the Oxford University Museum of Natural History, a beautiful specimen of a femur from an extinct “elephant bird” was spotted in a display case on the ground floor.    The thigh bone is purported to come from the genus Aepyornis, we suspect that from the robust nature of the bone, this is from A. maximus, or the bone may have to be classified to the genus Vorombe, following a reassessment of the largest specimens.

The Robust Left Femur on Display at the Oxford University Museum of Natural History

Elephant bird left femur.

Aepyornis (elephant bird) left femur but possibly representing the genus Vorombe.

Picture Credit: Everything Dinosaur

Native to Madagascar

Following the first taxonomic revision of the Aepyornithidae for more than fifty years, the species formerly known as Aepyornis titan was renamed Vorombe titan and it is the largest member of the bird family known to science.  It has been calculated that V. titan stood around three metres tall and weighed approximately 800 kilograms.

Whether or not the left femur represents A. maximus or V. titan, one thing is for sure, that’s a very strong looking leg bone.

To read Everything Dinosaur’s article on the taxonomic revision of the Aepyornithidae: The World’s Largest Bird – Ever!

If you look carefully, where the internal structure of the bone is exposed, the honey-comb texture (pneumacity) can be observed.  This is a feature common to both avian and many non-avian dinosaurs.

14 01, 2019

Basilosaurus – The Apex Predator

By | January 14th, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Research Confirms Basilosaurus Was a Top Predator

Readers with a long memory might remember an episode from the BBC “Walking with Beasts” television series that first aired in 2001.  In this sequel to “Walking with Dinosaurs”, the focus was placed upon the evolution of the mammals after the dinosaur extinction.  “Whale Killer”,  which was episode two in the six-part series, told the story of a pregnant Basilosaurus (archaic whale), desperately searching for food to help the calf growing inside her.  Thanks to raids on Dorudon whales and their young, the Basilosaurus is able to successfully give birth and this episode ends with the mother swimming away with her new-born calf following close behind.

An Illustration of the Fearsome Early Toothed Whale Basilosaurus

PNSO Basilosaurus illustration.

An illustration of Basilosaurus.  The human figure provides scale.

Picture Credit: Everything Dinosaur

Analysis of Basilosaurus Stomach Contents

A team of researchers writing in the on-line, academic journal PLOS One, have published the results of stomach content analysis of Basilosaurus specimens from the Late Eocene-aged site at Wadi Al-Hitan in Egypt.  It is confirmed that Basilosaurus fed on smaller whales (juvenile Dorudon atrox) as well as large fish (Pycnodus mokattamensis).  The scientists, which included Manja Voss (Museum für Naturkunde Berlin) and Mohammed Sameh M. Antar from the Egyptian Environmental Affairs Agency, Cairo, state that this is the first direct evidence of Basilosaurus (B. isis) diet.

A Size Comparison Between an Adult Basilosaurus isis and an Adult Dorudon atrox

An adult Basilosaurus compared to an adult Dorudon whale.

Comparing an adult, fifteen-metre-long Basilosaurus isis museum mounted skeleton to a fully grown Dorudon atrox.

Picture Credit: PLOS One/University of Michigan

Basilosaurus – Top of a Tethys Ocean Ecological Pyramid

The Late Eocene Epoch was a time of dramatic change and global extinction.  The once mighty Tethys Ocean was very much reduced, but the first, giant, toothed whales had evolved and the research team cite Basilosaurus isis, the Late Miocene Livyatan melvillei, and the extant Orca (Orcinus orca) as three marine apex predators known from relatively short intervals of time during the Cenozoic.  This research confirms the predator-prey relationship between the two most frequently found fossil whales at the Wadi Al-Hitan location.  Bite marks on the preserved skulls of Dorudon whales suggest predation and not scavenging behaviour by Basilosaurus.

A Photomosaic of a Basilosaurus Specimen (WH 10001)

Basilosaurus scattered remains.

Photomosaic of Basilosaurus isis (WH 10001) from the Gehannam Formation of Wadi Al Hitan.

Picture Credit: PLOS One

The image above shows a photomosaic of a scattered and disarticulated Basilosaurus isis specimen from the Gehannam Formation of Wadi Al-Hitan.  The disarticulation of the fossil skeleton and the scattering suggests disturbance by scavengers and possibly long exposure on the seafloor prior to burial.

The researcher conclude that Basilosaurus was a top apex predator that hunted and ate its prey alive, rather than scavenging for scraps.  If the Wadi Al-Hitan site, represents a calving area for the Dorudon, then this would have made an ideal hunting spot for a hungry Basilosaurus.  The dramatic scenes in episode two of the “Walking with Beasts” television series, have more published scientific evidence to back up the screenplay.

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