It looks like the previous thread on this topic has been lost in database limbo, perhaps never to return. So, onward. :)
A new early species of tyrannosaur has been found, which helps fill in the story of the evolution of the mighty beasts. "Timurlengia euotica: New Species of Tyrannosaur Discovered in Uzbekistan" |
Sci-News (http://www.sci-news.com/paleontology/timurlengia-euotica-new-species-tyrannosaur-uzbekistan-03702.html)
Quote(https://i.imgur.com/kxDFX8u.jpg)
A reconstruction of Timurlengia euotica, named for the charismatic Central Asian ruler Tamerlane,
shows the species' long, slender legs, large head and teeth built sharp like a steak knife.
Image credit: Todd Marshall
Timurlengia euotica lived during the Cretaceous period, approximately 90 million years ago, according to an international team of paleontologists led by Dr. Steve Brusatte from the University of Edinburgh, UK.
This species fills a 20 million year gap in the fossil record of tyrannosaurs — the iconic group of dinosaurian carnivores that includes T. rex and Albertosaurus (http://dinopedia.wikia.com/wiki/Albertosaurus), and provides key insights into how the group evolved.
"Timurlengia euotica's skull was much smaller than that of T. rex (http://animals.nationalgeographic.com/animals/prehistoric/tyrannosaurus-rex/), indicating that it did not grow to the same enormous size," Dr. Brusatte and his colleagues said.
"However, key features of its skull reveal that its brain and senses were already highly developed."
The new species was about the size of a horse, and could weigh up to 250 kg. It had long legs and a skull studded with sharp teeth, and was likely a fast runner.
[Continues . . . (http://www.sci-news.com/paleontology/timurlengia-euotica-new-species-tyrannosaur-uzbekistan-03702.html)]
A cool addition to our ideas about one of the families of big, scary ancient reptiles.
"Study casts doubt on the idea of 'big fluffy T. rex'" |
BBC (http://www.bbc.co.uk/news/science-environment-40172587)
QuoteDespite its ancestors having feathers, Tyrannosaurus rex most likely had scaly skin, according to fossil evidence.
Researchers say the huge predator had scales much like modern reptiles rather than feathers or fluff.
The dinosaur may have ditched its feathers because it no longer needed insulation when it reached gigantic proportions, they propose.
But the findings are unlikely to end the long-running debate about the physical appearance of T. rex.
We don't need to throw out the image of a big fluffy T. rex quite yet, argued one palaeontologist.
Whether T.rex was clad in scales, feathers or both, has long been a mystery, largely due to a lack of fossil evidence.
Primitive feathers have been identified in some members of the Tyrannosaur group, leading to speculation that the king of reptiles also sported feathers.
In the latest twist, researchers analysed skin impressions from a T.rex skeleton known as Wyrex, unearthed in Montana.
They also looked at relatives that roamed during the Late Cretaceous in Asia and other parts of North America, including Albertosaurus and Gorgosaurus.
Skin patches from the neck, pelvis and tail of Wyrex show scaly, reptilian-like skin, says a team led by Dr Phil Bell of the University of New England, Australia.
[Continues . . . (http://www.bbc.co.uk/news/science-environment-40172587)]
The full paper is available for free: "Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution" |
Biology Letters (http://rsbl.royalsocietypublishing.org/content/13/6/20170092)
QuoteAbstract
Recent evidence for feathers in theropods has led to speculations that the largest tyrannosaurids, including Tyrannosaurus rex, were extensively feathered. We describe fossil integument from Tyrannosaurus and other tyrannosaurids (Albertosaurus, Daspletosaurus, Gorgosaurus and Tarbosaurus), confirming that these large-bodied forms possessed scaly, reptilian-like skin. Body size evolution in tyrannosauroids reveals two independent occurrences of gigantism; specifically, the large sizes in Yutyrannus and tyrannosaurids were independently derived. These new findings demonstrate that extensive feather coverings observed in some early tyrannosauroids were lost by the Albian, basal to Tyrannosauridae. This loss is unrelated to palaeoclimate but possibly tied to the evolution of gigantism, although other mechanisms exist.
I just can't picture a feathered Rex. If it wasn't for the tiny arms I might be willing to accept it but the flapping would just be ridiculous.
I think the 'big, fluffy
Tyrannosaurus rex' thing is a bit of an overstatement. Most of the illustrations I've seen have been along the lines of the image below:
(https://static.tumblr.com/854d0b383ac484759dd61a21d91d41e6/fcz7dod/K4jnsmo7f/tumblr_static_9tfbg7ecf3ks8k4kg000kk4k4_640_v2.jpg)
Anyway, a slightly older item that belongs in this thread: "New dinosaur species sheds light on evolution, provides facial makeover for tyrannosaurs" |
ScienceDaily (https://www.sciencedaily.com/releases/2017/03/170330103315.htm)
QuoteAn investigation by a team of scientists from Australia, Louisiana, Montana, New Mexico, and Wisconsin has identified and named a new species of the tyrannosaur clan: Daspletosaurus horneri -- "Horner's Frightful Lizard."
The species is named for renowned dinosaur paleontologist John "Jack" R. Horner, formerly curator at the Museum of the Rockies (MOR) in Bozeman, Montana. The tyrannosaur's name honors his discoveries of numerous dinosaur fossils and his mentorship of so many students that launched them to accomplished scientific careers. The type (name-bearing) specimens are stored in the research collections of the MOR.
The research is led by Thomas Carr, a professor in Carthage College's Biology Department and an expert on the evolution and growth of Tyrannosaurus rex and its closest relatives, collectively called tyrannosaurs.
[. . .]
In addition to adding a new species to the tyrannosaur family tree, the team's research provides new information about the mode of evolution and life appearance of tyrannosaurs -- specifically the face. This latest study, published today in Nature Publishing Group's Scientific Reports, found evidence for a rare, nonbranching type of evolution in tyrannosaurs and that tyrannosaurs had scaly, lipless faces and a highly touch-sensitive snout.
Carr said: "Daspletosaurus horneri was the youngest, and last, of its lineage that lived after its closest relative, D. torosus, which is found in Alberta, Canada. The close evolutionary relationship between the species taken with their geographic proximity and their sequential occurrence suggests that together they represent a single lineage that changed over geological time, where D. torosus has morphed into D. horneri."
[Continues . . . (https://www.sciencedaily.com/releases/2017/03/170330103315.htm)]
The full paper is available for free: "A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system" |
Scientific Reports (https://www.nature.com/articles/srep44942)
Wikipedia: Anagenesis (https://en.wikipedia.org/wiki/Anagenesis)
QuoteAbstract:
A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond.
We studied the excellent fossil record of the tyrannosaurid to test that hypothesis. Phylogenetic analysis places this new taxon as the sister species to Daspletosaurus torosus. However, given their close phylogenetic relationship, geographic proximity, and temporal succession, where D. torosus (~76.7–75.2 Ma) precedes the younger new species (~75.1–74.4 Ma), we argue that the two forms most likely represent a single anagenetic lineage. Daspletosaurus was an important apex predator in the late Campanian dinosaur faunas of Laramidia; its absence from later units indicates it was extinct before Tyrannosaurus rex dispersed into Laramidia from Asia. In addition to its evolutionary implications, the texture of the facial bones of the new taxon, and other derived tyrannosauroids, indicates a scaly integument with high tactile sensitivity. Most significantly, the lower jaw shows evidence for neurovasculature that is also seen in birds.
Still looks plenty fluffy to me, and I like it!
More like scruffy than fluffy. I suppose I can live with that.
I'd bet it tasted like chicken.
I always thought of something more like the feathers of a penguin or kiwi, smallish and tight.
Just can't work out what it is chasing in that pic.
Quote from: Fernanda
I'd bet it tasted like chicken.
You kill one and we'll cook it,
Quote from: OldGit on June 12, 2017, 09:35:52 AM
Quote from: Fernanda
I'd bet it tasted like chicken.
You kill one and we'll cook it,
Are today's weapons allowed? :P
I just find it rather funny that dinosaurs used to eat our rat-like ancestors, now we raise and eat their descendants. In fact, I ate a dinosaur for lunch today. :yum:
The illustration is of necessity dependent on the artist's imagination. I like it, though. Smile for the camera!
"Paleo Profile: The Large Ancestor Lizard" |
Scientific American (https://blogs.scientificamerican.com/laelaps/paleo-profile-the-large-ancestor-lizard/)
Quote(https://ichef-1.bbci.co.uk/news/660/cpsprodpb/17BA5/production/_96798179_crocodile.jpg)
Razanandrongobe has a nice lunch. Image credit: Fabio Manucci
In 2006, when paleontologist Simone Maganuco and colleagues named Razanandrongobe sakalavae, there wasn't very much to go on. All they had was a part of the front of the jaw and some teeth from some sort of archosaur - one of the ruling reptiles that included dinosaurs and crocodiles among their ranks. Now, thanks to some new fossils, we know a little bit more about what this blunt-toothed carnivore looked like.
What the whole body of Razanandrongobe looked like is still unclear. The known material is restricted to the jaws. But, Cristiano Dal Sasso, Maganuco, and coauthors report, it's enough to narrow down the identity of this chomper to a branch of ancient crocodiles called mesoeucrocodylians. But given that paleo fans love superlative meat eaters, what's making headlines is that this old croc was a carnivorous giant.
Based upon the available material, Dal Sasso and colleagues estimate that Razanandrongobe was the largest Jurassic croc in the terrestrial realm, far larger than today's Nile crocodile. More than that, the deep jaws and thick, coarsely-serrated teeth of Razanandrongobe hint that this croc could make the most of carcasses, crushing bone and other hard parts just like our old favorite Tyrannosaurus is thought to have done. With any luck, future fieldwork will reveal more of this exceptional Jurassic crusher.
[Continues . . . (https://blogs.scientificamerican.com/laelaps/paleo-profile-the-large-ancestor-lizard/)]
The BBC has a write-up as well: "Giant croc had teeth like a T. rex" (http://www.bbc.co.uk/news/science-environment-40492978)
The full paper is available for free: "
Razanandrongobe sakalavae, a gigantic mesoeucrocodylian from the Middle Jurassic of Madagascar, is the oldest known notosuchian" |
PeerJ (https://peerj.com/articles/3481/)
QuoteAbstract
Razanandrongobe sakalavae Maganuco, Dal Sasso & Pasini, 2006 is a large predatory archosaur from the Middle Jurassic (Bathonian) of the Mahajanga Basin, NW Madagascar. It was diagnosed on the basis of teeth and a fragmentary maxilla, but its affinities were uncertain. Here we describe new cranial remains (above all, an almost complete right premaxilla and a caudally incomplete left dentary) that greatly improve our knowledge on this enigmatic species and reveal its anatomy to be crocodylomorph.
The right premaxilla indicates that the rostrum was deep, wide, and not pointed; it bears five teeth that are sub-vertical and just slightly curved lingually; the mesial teeth are U-shaped in cross-section and have serrated carinae on the lingual side; the aperturae nasi osseae (external bony nares) are confluent and face rostrally; and there is no lateral groove at the premaxillomaxillary suture for reception of a hypertrophied lower caniniform tooth. The preserved portion of the left dentary has an edentulous tip and bears eight large mandibular teeth of which the mesial (1–3) are the largest, but none is a hypertrophied caniniform tooth; the mandibular (dentary) symphysis extends caudally to the level of the third tooth; the splenial is not preserved, but its sutural marks on the dentary indicate that it contributed to the mandibular symphysis for at least 20% of the symphyseal length in dorsal aspect.
On the basis of this new data, some previously uncertain features of the holotype maxilla—such as the margin of the suborbital fenestra, the contact surfaces for the palatine, the ectopterygoid, and the jugal—are now apparent. Testing of the phylogenetic position of the species within Crocodylomorpha indicates that R. sakalavae is a mesoeucrocodylian. It also represents one of the earliest events of exacerbated increase in body size along the evolutionary history of the group. In addition, it is by far the oldest notosuchian. A cranial reconstruction of this gigantic predator is also attempted here. The very robust jaw bones of R. sakalavae, coupled with its peculiar dentition, strongly suggest a diet that included hard tissue such as bone and tendon.
The results of a new analysis indicate that
Tyrannosaurus rex when fully grown would have been relatively slow moving; its bones wouldn't have been able to withstand the mechanical stress of running.
"Tyrannosaurus rex couldn't run, says new research" |
Phys.Org (https://phys.org/news/2017-07-tyrannosaurus-rex-couldnt.html)
QuoteIt is a classic chase scene in modern cinematic history. The image of a rampant Tyrannosaurus rex (T. rex) chasing Jeff Goldblum as he sits injured in the back of a 4x4 vehicle in Stephen Spielberg's original film adaptation of Jurassic Park.
But could a T. rex actually move that fast, or even run at all?
New research from the University of Manchester says the sheer size and weight of T. rex means it couldn't move at high speed, as its leg-bones would have buckled under its own weight load.
The research, published by journal PeerJ, looks extensively into the gait and biomechanics of the world's most famous Dinosaur and, using the latest high performance computing technology from N8 High Performance Computing (HPC), has created a new simulation model to test its findings.
Led by Professor William Sellers from the School of Earth and Environmental Sciences, the researchers have combined two separate biomechanical techniques, known as multibody dynamic analysis (MBDA) and skeletal stress analysis (SSA), into one simulation model, creating a new more accurate one.
Prof Sellers says the results demonstrate any running gaits for T. rex would probably lead to 'unacceptably high skeletal loads'. Meaning, in layman's terms, any running would simply break the dinosaur's legs. This contradicts the running speeds predicted by previous biomechanical models which can suggest anything up to 45mph.
[Continues . . . (https://phys.org/news/2017-07-tyrannosaurus-rex-couldnt.html#jCp)]
The full paper is available for free: "Investigating the running abilities of Tyrannosaurus rex using stress-constrained multibody dynamic analysis" |
PeerJ (https://peerj.com/articles/3420/)
QuoteAbstract:
The running ability of Tyrannosaurus rex has been intensively studied due to its relevance to interpretations of feeding behaviour and the biomechanics of scaling in giant predatory dinosaurs. Different studies using differing methodologies have produced a very wide range of top speed estimates and there is therefore a need to develop techniques that can improve these predictions.
Here we present a new approach that combines two separate biomechanical techniques (multibody dynamic analysis and skeletal stress analysis) to demonstrate that true running gaits would probably lead to unacceptably high skeletal loads in T. rex. Combining these two approaches reduces the high-level of uncertainty in previous predictions associated with unknown soft tissue parameters in dinosaurs, and demonstrates that the relatively long limb segments of T. rex—long argued to indicate competent running ability—would actually have mechanically limited this species to walking gaits. Being limited to walking speeds contradicts arguments of high-speed pursuit predation for the largest bipedal dinosaurs like T. rex, and demonstrates the power of multiphysics approaches for locomotor reconstructions of extinct animals.
^
I remember seeing stuff like that years ago. Wish I could remember more but I seem to remrmber one TV docu scaled up from ostrich legs, adding size/weight and letting software "tailor" the legs and gait to suit the stresses, inertia, momentum etc.. Yup, definitely got slower and shorter paced as the ratio increased.
Pity someone does not do, or publish, a metastudy on the subject.
I suppose this, from 2007, is one of those "earlier biomechanical models"!
That's better, but now I can't find the NS article!
We should genetically engineer dinosaurs that can run and have thick, armoured shells then send them into war zones
...yeah...
The largest and oldest (in terms of longevity)
Tyrannosaurus rex is reported from Canada. I wonder whether the Tyrannosaurs were like sharks--growing their entire lives.
"Paleontologists report world's biggest Tyrannosaurus rex" |
ScienceDaily (https://www.sciencedaily.com/releases/2019/03/190322163331.htm)
Quote(https://i.imgur.com/i7wVmpL.png)
The towering and battle-scarred 'Scotty' reported by UAlberta paleontologists is the world's largest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada.
Image credit: Amanda Kelley
QuoteUniversity of Alberta paleontologists have just reported the world's biggest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada. The 13-metre-long T. rex, nicknamed "Scotty," lived in prehistoric Saskatchewan 66 million years ago.
"This is the rex of rexes," said Scott Persons, lead author of the study and postdoctoral researcher in the Department of Biological Sciences. "There is considerable size variability among Tyrannosaurus. Some individuals were lankier than others and some were more robust. Scotty exemplifies the robust. Take careful measurements of its legs, hips, and even shoulder, and Scotty comes out a bit heftier than other T. rex specimens."
Scotty, nicknamed for a celebratory bottle of scotch the night it was discovered, has leg bones suggesting a living weight of more than 8,800 kg, making it bigger than all other carnivorous dinosaurs. The scientific work on Scotty has been a correspondingly massive project.
The skeleton was first discovered in 1991, when paleontologists including T. rex expert and UAlberta professor Phil Currie were called in on the project. But the hard sandstone that encased the bones took more than a decade to remove -- only now have scientists been able to study Scotty fully-assembled and realize how unique a dinosaur it is.
It is not just Scotty's size and weight that set it apart. The Canadian mega rex also lays claim to seniority.
"Scotty is the oldest T. rex known," Persons explains. "By which I mean, it would have had the most candles on its last birthday cake. You can get an idea of how old a dinosaur is by cutting into its bones and studying its growth patterns. Scotty is all old growth."
[Continues . . . (https://www.sciencedaily.com/releases/2019/03/190322163331.htm)]
A new Allosaurus. :sidesmile:
"New species of Allosaurus discovered in Utah" |
Phys.org (https://phys.org/news/2020-01-species-allosaurus-utah.html)
Quote(https://i.imgur.com/ZKA8cri.jpg)
Idealized skull of Allosaurus jimmadseni in lateral (A), dorsal (B) and posterior (C) views. Skeletal reconstructions of DINO 11541 (D) and MOR 693 (E). Missing elements in indicated in gray. A–C original artwork by Samantha Zimmerman; D and E are modified from artwork by Scott Hartman. Scale bar equals 10 cm for A–C; one m for D and E. [PeerJ (https://peerj.com/articles/7803/)]
QuoteA remarkable new species of meat-eating dinosaur has been unveiled at the Natural History Museum of Utah. Paleontologists unearthed the first specimen in early 1990s in Dinosaur National Monument in northeastern Utah. The huge carnivore inhabited the flood plains of western North America during the Late Jurassic Period, between 157-152 million years ago, making it the geologically oldest species of Allosaurus, predating the more well-known state fossil of Utah, Allosaurus fragilis. The newly named dinosaur Allosaurus jimmadseni, was announced today in the open-access scientific journal PeerJ.
The species belongs to the allosauroids, a group of small to large-bodied, two-legged carnivorous dinosaurs that lived during the Jurassic and Cretaceous periods. Allosaurus jimmadseni, possesses several unique features, among them a short narrow skull with low facial crests extending from the horns in front of the eyes forward to the nose and a relatively narrow back of the skull with a flat surface to the bottom of the skull under the eyes. The skull was weaker with less of an overlapping field of vision than its younger cousin Allosaurus fragilis. Allosaurus jimmadseni evolved at least 5 million years earlier than fragilis, and was the most common and the top predator in its ecosystem. It had relatively long legs and tail, and long arms with three sharp claws. The name Allosaurus translates as "different reptile," and the second part, jimmadseni, honors Utah State Paleontologist James H. Madsen Jr.
[. . .]
George Engelmann of the University of Nebraska, Omaha initially discovered the initial skeleton of the new species within Dinosaur National Monument in 1990. In 1996, several years after the headless skeleton was collected, the radioactive skull belonging to the skeleton using a radiation detector by Ramal Jones of the University of Utah. Both skeleton and skull were excavated by teams from Dinosaur National Monument.
[Continues . . . (https://phys.org/news/2020-01-species-allosaurus-utah.html)]
The full paper: "Cranial anatomy of
Allosaurus jimmadseni, a new species from the lower part of the Morrison Formation (Upper Jurassic) of Western North America" |
PeerJ (https://peerj.com/articles/7803/)
:popcorn:
It's the season, apparently.
"Argentine researchers find distant Tyrannosaurus relative" |
Phys.org (https://phys.org/news/2020-02-argentine-distant-tyrannosaurus-relative.html)
QuoteThe remains of a 90-million-year-old carnivorous dinosaur distantly related to Tyrannosaurus rex has been discovered in Argentine Patagonia by a team of paleontologists.
The four-meter-long (13-foot-long) theropod was discovered in February 2018 in the central Argentine province of Rio Negro.
Scientists have christened it Tralkasaurus cuyi, the National University of La Matanza's Scientific Disclosure Agency said on Thursday.
Tralkasaurus means "thunder reptile" in the indigenous Mapuche language common in Patagonia. Cuyi relates to the place the fossil remains were found, El Cuy.
Tralkasaurus would have been dwarfed by its distant cousin Tyrannosaurus rex which could grow to 14 meters in length.
"The size of the Tralkasaurus body is smaller than other carnivores in its group—the abelisaurids," said Dr Federico Agnolin, an investigator from the Argentine Museum of Natural Sciences.
[Continues . . . (https://phys.org/news/2020-02-argentine-distant-tyrannosaurus-relative.html)]
Maybe there's some discussion in the paper (https://www.sciencedirect.com/science/article/abs/pii/S0895981119304766) (paywalled, unfortunately) on why they believe this is an adult, rather than a juvenile of a known species.
A new paper describes fossil trackway evidence of bipedal ancestors of the crocodile. I'm sure they were very well mannered. I suppose this jolly bipedal crocodilomorph qualifies as "mysterious" because it's an ichnospecies: A species for which there are no bone fossils, only fossilized footprints or other fossilized evidence such as coprolites or nests.
"Mysterious crocodile relative may have walked on two legs" |
National Geographic (https://www.nationalgeographic.com/science/2020/06/fossil-footprints-crocodile-relative-walked-on-two-legs/)
Quote(https://i.imgur.com/KBqXkde.jpg)
Reconstruction of Batrachopus grandis, a proposed crocodylomorph that lived over 110-million-years ago and left tracks in the Jinju Formation of South Korea.
Illustration by Anthony Romilio, University of Queensland, Brisbane, Australia
Over 110 million years ago, during the Cretaceous period, the southern coastal area of South Korea, near the city Jinju, was covered by extensive lakes. The muddy shores were inhabited by frogs, lizards, turtles, and dinosaurs, all of which left their tracks in the muck. Whenever the water level rose, some of these footprints were filled with sand, allowing a fraction of them to be preserved.
Today, thousands of tracks can be found in this area, known as the Jinju Formation, says Martin Lockley, a paleontologist who specializes in trace fossils like footprints—known as an ichnologist—at the University of Colorado Denver. Lockley and colleagues in South Korea have studied the tracks at Jinju for decades, and for many years, they've been mystified by some of the largest footprints.
In 2019 they finally discovered detailed imprints from the creature, reported today in Scientific Reports. The tracks provide an impression of the animals' toes, the pads on the bottoms of their feet, and even the occasional patch of skin. These details have convinced Lockley and his colleagues that the footprints likely were left by crocodylomorphs, crocodile relatives, that were over nine feet long. They appear to have been unusual crocodilians, leaving imprints only from their hind feet, suggesting the animals were bipedal.
"[The imprints] really do look like they were made by big crocodilians," says ichnologist Anthony Martin, of Atlanta's Emory University, who was not involved in the new study. "Indeed, by ones that were walking on their rear feet and on land. That's pretty weird. But then again, the Cretaceous was a weird and wondrous time."
[Continues . . . (https://www.nationalgeographic.com/science/2020/06/fossil-footprints-crocodile-relative-walked-on-two-legs/)]
The paper is open access:
"Trackway evidence for large bipedal crocodylomorphs from the Cretaceous of Korea" |
Scientific Reports (https://www.nature.com/articles/s41598-020-66008-7)
QuoteAbstract:
Large well-preserved crocodylomorph tracks from the Lower Cretaceous (? Aptian) Jinju Formation of South Korea, represent the well-known crocodylomorph ichnogenus Batrachopus. The Korean sample includes multiple, narrow-gauge, pes-only trackways with footprint lengths (FL) 18–24 cm, indicating trackmaker body lengths up to ~3.0 m.
Surprisingly, the consistent absence of manus tracks in trackways, with well-preserved digital pad and skin traces, argues for bipedal trackmakers, here assigned to Batrachopus grandis ichnosp. nov.
No definitive evidence, either from pes-on-manus overprinting or poor track preservation, suggests the trackways where made by quadrupeds that only appear bipedal. This interpretation helps solve previous confusion over interpretation of enigmatic tracks of bipeds from younger (? Albian) Haman Formation sites by showing they are not pterosaurian as previously inferred. Rather, they support the strong consensus that pterosaurs were obligate quadrupeds, not bipeds.
Lower Jurassic Batrachopus with foot lengths (FL) in the 2–8 cm range, and Cretaceous Crocodylopodus (FL up to ~9.0 cm) known only from Korea and Spain registered narrow gauge trackways indicating semi-terrestrial/terrestrial quadrupedal gaits. Both ichnogenera, from ichnofamily Batrachopodidae, have been attributed to Protosuchus-like semi-terrestrial crocodylomorphs. The occurrence of bipedal B. grandis ichnosp. nov. is evidence of such adaptations in the Korean Cretaceous.
[Paragraph breaks added. - R]
Hat-tip to
Lark for this one. :boaterhat:
"Unusual New Species of Dinosaur Discovered – 'We Were Struck by Just How Hollow This Animal Was'" |
SciTechDaily (https://scitechdaily.com/unusual-new-species-of-dinosaur-discovered-we-were-struck-by-just-how-hollow-this-animal-was/)
Quote(https://i.imgur.com/lCpldJm.jpg)
Artists impression of the dinosaur's final moments.
Image credit: Trudie Wilson
Scientists in Southampton believe four bones recently found on the Isle of Wight belong to a new species of theropod dinosaur.
A new study by Palaeontologists at the University of Southampton suggests four bones recently found on the Isle of Wight belong to new species of theropod dinosaur, the group that includes Tyrannosaurus rex and modern-day birds.
The dinosaur lived in the Cretaceous period 115 million years ago and is estimated to have been up to four meters long.
The bones were discovered on the foreshore at Shanklin last year and are from the neck, back, and tail of the new dinosaur, which has been named Vectaerovenator inopinatus.
The name refers to the large air spaces in some of the bones, one of the traits that helped the scientists identify its theropod origins. These air sacs, also seen in modern birds, were extensions of the lung, and it is likely they helped fuel an efficient breathing system while also making the skeleton lighter.
The fossils were found over a period of weeks in 2019 in three separate discoveries, two by individuals and one by a family group, who all handed in their finds to the nearby Dinosaur Isle Museum at Sandown.
The scientific study has confirmed the fossils are very likely to be from the same individual dinosaur, with the exact location and timing of the finds adding to this belief.
[Continues . . . (https://scitechdaily.com/unusual-new-species-of-dinosaur-discovered-we-were-struck-by-just-how-hollow-this-animal-was/)]
The paper "A highly pneumatic 'mid Cretaceous' theropod from the British Lower Greensand" is noted as being "published soon" and apparently will be open access, but I haven't found it as yet.
A recently discovered large carnivorous dinosaur doesn't have really big teeth, but they're big enough. Sort of reminds me of Venom (https://en.wikipedia.org/wiki/Venom_(Marvel_Comics_character)), the comic book alien. It's looks scary, so that's what they called it.
Llukalkan means "one who causes fear" in the Mapuche language of the locals.
"New Species of Carnivorous Dinosaur Unearthed in Argentina" |
Sci-News (http://www.sci-news.com/paleontology/llukalkan-aliocranianus-09508.html)
Quote(https://i.imgur.com/Z7rdLBH.jpg)
Life reconstruction of Llukalkan aliocranianus.
Image credit: Jorge Blanco.
Llukalkan aliocranianus roamed our planet during the Late Cretaceous epoch, about 80 million years ago.
The dinosaur was a member of Abelisauridae, a family of big predators known from the ancient supercontinent Gondwana.
It grew to about 5 m (16.4 feet) in length, and had extremely powerful bite, very sharp teeth, huge claws, and keen sense of smell.
It also had a strange short skull with rough bones, so in life its head had bulges and prominences like some living reptiles.
"But the most distinctive feature of Llukalkan aliocranianus is a small posterior air-filled sinus in the middle ear zone that has not been seen in any other abelisaurid found so far," said Dr. Ariel Mendez, a paleontologist at the Patagonian Institute of Geology and Palaeontology.
"It means that this dinosaur likely heard differently to other abelisaurids — most probably better and similar to that of a modern day crocodile."
"This finding implies a different hearing adaptation from other abelisaurids, and likely a keener sense of hearing."
The fossilized cranial remains of Llukalkan aliocranianus were recovered from the Bajo de la Carpa Formation at La Invernada fossil area in northwestern Patagonia, Argentina.
According to the team, the ancient predator lived in the same small area and period of time as Viavenator exxoni, another species of furileusaurian abelisaurid from the Bajo de la Carpa Formation.
"This is a particularly important discovery because it suggests that the diversity and abundance of abelisaurids were remarkable, not only across Patagonia, but also in more local areas during the dinosaurs' twilight period," said Dr. Federico Gianechini, a paleontologist at the National University of San Luis.
[Continues . . . (http://www.sci-news.com/paleontology/llukalkan-aliocranianus-09508.html)]
A newly discovered large spinosaur from the Isle of Wight. ;D
(https://i.imgur.com/XOu3biT.jpg)
Image credit: Anthony Hutchings
"Europe's 'largest ever' predator dinosaur found on Isle of Wight" |
BBC (https://www.bbc.com/news/uk-england-hampshire-61743759)
QuoteRemains of Europe's largest ever land-based predator dinosaur have been discovered on the Isle of Wight, scientists say.
Palaeontologists at the University of Southampton identified the remains, which measured more than 32ft (10m) long and lived 125 million years ago.
The prehistoric bones belonged to a two-legged, crocodile-faced, predatory spinosaurid dinosaur.
PhD student Chris Barker, who led the research, said it was a "huge animal".
The remains, which include pelvic and tail vertebrae, were discovered on the south-west coast of the Isle of Wight.
The carnivore has been dubbed the "white rock spinosaurid", after the geological layer in which the remains were found.
"This was a huge animal, exceeding 10m in length and probably several tonnes in weight," Mr Barker said.
"Judging from some of the dimensions, it appears to represent one of the largest predatory dinosaurs ever found in Europe - maybe even the biggest yet known."
It would have lived at the beginning of a period of rising sea levels and would have stalked lagoonal waters and sandflats in search of food.
Co-author of the research, Darren Naish, said: "Because it's only known from fragments at the moment, we haven't given it a formal scientific name. We hope that additional remains will turn up in time."
Most of the fossils were found by Isle of Wight dinosaur hunter Nick Chase, who died just before the Covid pandemic.
[Continues . . . (https://www.bbc.com/news/uk-england-hampshire-61743759)]
The paper is open access:
"A European giant: a large spinosaurid (Dinosauria: Theropoda) from the Vectis Formation (Wealden Group, Early Cretaceous), UK" |
PeerJ (https://peerj.com/articles/13543/)
QuoteAbstract:
Postcranial elements (cervical, sacral and caudal vertebrae, as well as ilium, rib and limb bone fragments) belonging to a gigantic tetanuran theropod were recovered from the basal unit (the White Rock Sandstone equivalent) of the Vectis Formation near Compton Chine, on the southwest coast of the Isle of Wight. These remains appear to pertain to the same individual, with enormous dimensions similar to those of the Spinosaurus holotype and exceeding those of the largest European theropods previously reported.
A combination of features—including the presence of spinodiapophyseal webbing on an anterior caudal vertebra—suggest that this is a member of Spinosauridae, though a lack of convincing autapomorphies precludes the identification of a new taxon. Phylogenetic analysis supports spinosaurid affinities but we were unable to determine a more precise position within the clade weak support for a position within Spinosaurinae or an early-diverging position within Spinosauridae were found in some data runs.
Bioerosion in the form of curved tubes is evident on several pieces, potentially related to harvesting behaviour by coleopteran bioeroders [insect scavengers].
This is the first spinosaurid reported from the Vectis Formation and the youngest British material referred to the clade. This Vectis Formation spinosaurid is unusual in that the majority of dinosaurs from the Lower Cretaceous units of the Wealden Supergroup are from the fluviolacustrine deposits of the underlying Barremian Wessex Formation. In contrast, the lagoonal facies of the upper Barremian–lower Aptian Vectis Formation only rarely yield dinosaur material. Our conclusions are in keeping with previous studies that emphasise western Europe as a pivotal region within spinosaurid origination and diversification.
jeez
but did it set its guitar on fire?
Another large beastie with big teeth and tiny arms--suggests that there is a connection between the two traits. :D
"Big head, small arms: A newly discovered gigantic dinosaur evolved in a similar manner to
Tyrannosaurus rex" |
The Conversation (https://theconversation.com/big-head-small-arms-a-newly-discovered-gigantic-dinosaur-evolved-in-a-similar-manner-to-tyrannosaurus-rex-188678)
QuoteThe fossil record represents an amazing window into the endless forms of life that have existed across countless ages. By studying ancient species and ecosystems we can increase our understanding of what lived in the past and how the Earth was different compared to today. We can also use fossils to understand how evolution works and what is most likely to evolve under particular sets of circumstances.
This context is what makes Meraxes gigas, a newly named theropod dinosaur, so important for our understanding of dinosaur evolution and biodiversity.
I was part of the international team of palaeontologists, led by Juan Canale of the Ernesto Bachmann Palaeontological Museum, that named and described Meraxes gigas. The specimen was collected between 2012 and 2014 near Villa El Chocón in Argentina, in rocks of the ~95 million year old Huincul Formation.
[. . .]
Meraxes is particularly notable in what it tells us about the evolution of large size in dinosaurs. Its body plan — a large head and small arms — is very similar to that seen in tyrannosaurids like Tyrannosaurus rex, and abelisaurids like Carnotaurus.
These three groups of theropod dinosaurs are all distant relatives. Each independently evolved both large body size and the combination of a large head and small arms.
We analyzed the evolution of these changes in these three groups by examining changes in arm size relative to other body measurements, such as leg and body size. We found that not only did each group experience similar changes through evolution, but there appears to be a lower limit for how small the arms can be relative to the rest of the body. This may represent a developmental or mechanical constraint: the arm can only get so small relative to the body, regardless of other evolutionary pressures in this context.
There are several potential explanations for the size of the arms; the forelimbs themselves may have retained some function despite their reduced size. Our data most directly support the idea that arm reduction in these dinosaur groups is more likely tracking other traits rather than being the subject of evolutionary selective pressure itself. In other words, as the relative size of the skull increased over evolution, the arms decreased proportionally in size as an evolutionary trade-off.
[Continues . . . (https://theconversation.com/big-head-small-arms-a-newly-discovered-gigantic-dinosaur-evolved-in-a-similar-manner-to-tyrannosaurus-rex-188678)]
The paper (https://doi.org/10.1016/j.cub.2022.05.057) is behind a paywall.
QuoteSummary:
Giant carnivorous dinosaurs such as Tyrannosaurus rex and abelisaurids are characterized by highly reduced forelimbs that stand in contrast to their huge dimensions, massive skulls, and obligate bipedalism. Another group that follows this pattern, yet is still poorly known, is the Carcharodontosauridae: dominant predators that inhabited most continents during the Early Cretaceous and reached their largest sizes in Aptian-Cenomanian times.
Despite many discoveries over the last three decades, aspects of their anatomy, especially with regard to the skull, forearm, and feet, remain poorly known. Here we report a new carcharodontosaurid, Meraxes gigas, gen. et sp. nov., based on a specimen recovered from the Upper Cretaceous Huincul Formation of northern Patagonia, Argentina. Phylogenetic analysis places Meraxes among derived Carcharodontosauridae, in a clade with other massive South American species.
Meraxes preserves novel anatomical information for derived carcharodontosaurids, including an almost complete forelimb that provides evidence for convergent allometric trends in forelimb reduction among three lineages of large-bodied, megapredatory non-avian theropods, including a remarkable degree of parallelism between the latest-diverging tyrannosaurids and carcharodontosaurids. This trend, coupled with a likely lower bound on forelimb reduction, hypothesized to be about 0.4 forelimb/femur length, combined to produce this short-armed pattern in theropods.
The almost complete cranium of Meraxes permits new estimates of skull length in Giganotosaurus, which is among the longest for theropods. Meraxes also provides further evidence that carchardontosaurids reached peak diversity shortly before their extinction with high rates of trait evolution in facial ornamentation possibly linked to a social signaling role.
I see this one has made it into more mainstream media, so many may already have come across it. Still, it gets a post here.
(https://i.imgur.com/DuJm66a.png)
(https://i.imgur.com/e8m8VvO.png)
Fossil of juvenile Gorgosaurus libratus noting gut contents.
Image Credit: Royal Tyrrell Museum
"Amazing Fossil Preserves Teenage Tyrannosaur's Last Meal" |
Smithsonian (https://www.smithsonianmag.com/science-nature/amazing-fossil-preserves-teenage-tyrannosaurs-last-meal-180983398/)
QuoteWhat did the teenage tyrannosaur have for dinner? Whatever it wanted! That groaner of a dad joke isn't very funny—and it's also not accurate. Unlike their enormous adult relatives at the top of the food chain, it seems juvenile tyrannosaurs had to rely on prey more suitable for their smaller, nimbler physiques.
Sometimes that meant a smorgasbord of small, birdlike dinosaurs, which were apparently so plentiful that the young predators selected and devoured the meaty hind legs, leaving the rest for scavengers. Researchers announced that entrée was on the Late Cretaceous menu in a study published Friday in Science Advances.
How did scientists know the items in the 75-million-year-old diet? An incredible fossilized first was discovered in the Dinosaur Park Formation in Alberta, Canada: a young Gorgosaurus skeleton, fortunately preserved with its two last meals still in its stomach cavity. Each feast included a pair of hind legs severed from small, birdlike dinosaurs (Citipes elegans). "The juvenile tyrannosaur just ripped the legs off and swallowed them whole, that's what it looks like," says Darla Zelenitsky, a paleontologist at the University of Calgary and a co-author of the study.
Each pair of legs reveals different levels of digestion on the bone surfaces, showing they were eaten during two different meals some hours or days apart.
The unique find delivers some hard evidence for a long-held hypothesis: As they grew, tyrannosaurs adapted to hunt and eat different types of prey during different stages of their lives. Agile juvenile tyrannosaurs were able to run down, kill and subsist on animals like the smaller Citipes. Once they'd grown to massive adult size, they hunted equally substantial prey among the Late Cretaceous's huge herbivores like the duck-billed dinosaurs and the horned dinosaurs. "It's the first evidence that we have that tyrannosaurs drastically changed their diet as they grew from teens to adults, which has long been suspected based on their skeletons," says Zelenitsky.
[Continues . . . (https://www.smithsonianmag.com/science-nature/amazing-fossil-preserves-teenage-tyrannosaurs-last-meal-180983398/)]
The paper is open access:
"Exceptionally preserved stomach contents of a young tyrannosaurid reveal an ontogenetic dietary shift in an iconic extinct predator" |
Science Advances (https://www.science.org/doi/10.1126/sciadv.adi0505)
QuoteAbstract:
Tyrannosaurids were large carnivorous dinosaurs that underwent major changes in skull robusticity and body proportions as they grew, suggesting that they occupied different ecological niches during their life span. Although adults commonly fed on dinosaurian megaherbivores, the diet of juvenile tyrannosaurids is largely unknown.
Here, we describe a remarkable specimen of a juvenile Gorgosaurus libratus that preserves the articulated hindlimbs of two yearling caenagnathid dinosaurs inside its abdominal cavity. The prey were selectively dismembered and consumed in two separate feeding events.
This predator-prey association provides direct evidence of an ontogenetic dietary shift in tyrannosaurids. Juvenile individuals may have hunted small and young dinosaurs until they reached a size when, to satisfy energy requirements, they transitioned to feeding on dinosaurian megaherbivores. Tyrannosaurids occupied both mesopredator and apex predator roles during their life span, a factor that may have been key to their evolutionary success.
Just when you thought it was safe to go back into the water.
https://www.bbc.co.uk/news/science-environment-67650247
cool animals. a little earlier than the mosasaurs.
im not sure what the differences were
https://www.thoughtco.com/plesiosaurs-and-pliosaurs-the-sea-serpents-1093755
Some people still believe one of these is the Loch Ness Monster.
The chronology doesn't quite fit because Loch Ness is only about 10,000 years old after the last ice age.
i think the plesiosaur theory goes back to that image of the diving otter in the swimming pool that has been cropped and shown for years
(https://i.imgur.com/7XuiT2Ql.jpg)
i saw the whole image once and it originally included all the newspaper reporters feet and the edge of the swimming pool.
Yes but the tourist trade in North Scotland relies on that one image.
certainly not on the weather