Episode 504: There’s a New Stegosaur in City!. Baiyinosaurus was one of many earliest stegosaurs ever discovered (from the Center Jurassic); Debate on the evolution of the tyrannosaur Daspletosaurus; Miragaia updates; And our newest Di-Know-It-All Problem!
Information:
- There’s a brand new stegosaur, Baiyinosaurus baojiensis supply
- A brand new research reaffirms that Daspletosaurus species developed into each other (anagenesis) supply
- Elopteryx may be a wierd climbing dinosaur with a protracted tail, and synonymous with Balaur supply
Di-Know-It-All Problem:
You may win a big Spinosaurus tooth, fossilized leaf, and extra by profitable our Di-Know-It-All Problem! Every week from episode 502 to 509 we’ll learn a puzzle on the present which you’ll enter to win by answering questions. This week you possibly can enter at bit.ly/dinochallenge504 and if you happen to’re a patron you possibly can reply the patron query at patreon.com/posts/107966271. All the principles for the problem are at bit.ly/dinochallenge24
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The dinosaur of the day: Miragaia
- The newest research discovered the species Miragaia longicollum to be a synonym of Dacentrurus (which was named first), and that one other Miragaia species, Miragaia longispinus, is definitely Alcovasaurus
- A number of papers on all three of those dinosaurs, so going to undergo every individually after which discuss in regards to the newest research
- However first, a bit about stegosaurs…
- Stegosaurs identified for his or her plates and spines on their necks, backs, and tails
- Stegosaurs lived within the Center Jurassic to Early Cretaceous and have been present in North America, Europe, Asia, Africa, and South America
- First stegosaur fragments had been discovered within the 1840s, and the primary stegosaur skeletons had been discovered and described within the 1870s in North America and Europe
- Most stegosaurs identified from partial skeletons or fragments
- Dacentrurus
- Begin with Dacentrurus, as a result of it was named first
- Coated Dacentrurus in ep 252
- Stegosaur that lived within the Late Jurassic, and perhaps the Early Cretaceous, of what’s now Europe
- First stegosaur ever discovered and named was Dacentrurus armatus, named by Richard Owen in 1875
- Though it was named Omosaurus
- Genus identify Omosaurus means higher arm, and refers to its sturdy humerus
- Initially named Omosaurus armatus by Owen in 1875, then later Stegosaurus armatus by Lydekker in 1890
- Renamed to Dacentrurus in 1902 by Frederick Augustus, as a result of Omosaurus was already in use for a non-dinosaur
- Richard Lydekker tried to resolve the naming challenge by renaming it Stegosaurus, however didn’t realized Marsh had already named Stegosaurus armatus in 1877
- Kind species of Omosaurus is Omosaurus perplexus, named by Joseph Leidy in 1856
- Now a doubtful reptile that lived within the Late Triassic in what’s now North Carolina, U.S.
- Named based mostly on enamel, vertebrae, ribs, and an osteoderm (which have been misplaced)
- Enamel had been straight, conical, and pointed
- Leidy thought Omosaurus was a marine reptile, and the fossils may be referable to an animal already named
- Later considered a crocodilian, now considered probably a phytosaur, and a nomen dubium
- Kind species, Omosaurus armatus named in 1875 (then later Dacentrurus) based mostly on a skeleton present in Swindon, England
- Genus identify Dacentrurus means “tail stuffed with factors”
- Species identify armatus means “armed”, and refers back to the giant spike Owen thought was on the higher arm
- Omosaurus / Dacentrurus was sort of a wastebasket taxon
- Many species named however solely Dacentrurus armatus is legitimate
- Miragaia longicollum could also be a junior synonym
- Dacentrurus holotype is incomplete, which made issues complicated
- Estimated to be 26 to 30 ft (8 to 9 m) lengthy and weigh as much as 8 tons
- Had a broad intestine, brief hindlimbs, and comparatively lengthy forelimbs
- Had 12 neck bones
- Had spines on the tail
- In all probability had two rows of small plates on its neck and two rows of lengthy spikes on the tail
- Holotype is a partial skeleton that was present in Swindon, England
- Fossils present in 1874 in a clay pit, in lumps of hardened clay
- Holotype consists of components of the pelvis, again and tail vertebrae, a proper femur, and a few free vertebrae
- Additionally discovered an almost full left arm, components of the leg, a proper neck plate and a left tail spike
- The “Swindon” stegosaur is on show on the Pure Historical past Museum in London
- Casts of the bones are in all probability happening show on the Swindon’s new museum subsequent 12 months, in 2025
- Fossils present in England, France, Spain, and Portugal had been categorized as Dacentrurus (many had been fragmentary)
- An egg referred to Dacentrurus, present in Portugal (about 125 mm lengthy), that was discovered related to stegosaur bones
- A number of stegosaurs had been discovered through the years, together with a partial skeleton in 1942 from Pedras Muitas in Portugal, which led to extra curiosity in in search of fossils and dinosaurs in Portugal
- One skeleton was considered a sauropod (Astrodon pusillus), however later research in 1981 discovered it to be a juvenile stegosaur
- In 1991, Peter Galton redescribed all of the stegosaur fossils discovered and referred most of them to Dacentrurus armatus
- In 2008 Susannah Maidment discovered solely the holotype was Dacentrurus armatus, and a lot of the named species to be nomina dubia
- Stegosaur vertebrae present in Spain had been described as Dacentrurus armatus in 2013, and so they helped present some variation in Dacentrurus
- In 2021, fossils discovered from the Early Cretaceous of what’s now France (components of the braincase, vertebrae, and ribs) had been assigned to Dacentrurus
- To recap, a number of stegosaur fossils present in Europe have been referred to Dacentrurus
- Then got here Miragaia
- Earlier than Miragaia, nearly all stegosaur specimens present in Portugal and Spain had been categorized as Dacentrurus armatus
- Coated Miragaia in ep 116
- Stegosaurid that lived within the Late Jurassic in what’s now Portugal (Lourinhã Formation), and Wyoming, U.S. (Morrison Formation)
- Named in 2009 by Octávio Mateus, Susannah Maidment and Nicolai Christiansen
- Stegosaur, so regarded considerably like Stegosaurus, with plates on its neck, however with a for much longer neck, and spikes on the again
- Most stegosaurs had brief necks for his or her our bodies
- Had a long-neck, the longest identified neck of any stegosaur, with at the very least 17 neck vertebrae
- Had eight extra neck bones than the ancestors it developed from (basal Thyreophorans and ornithischians)
- Had extra neck bones than many sauropods
- A few of Miragaia’s neck bones was a part of the higher again however developed to operate like neck bones
- Lengthy neck could imply it may browse for meals different herbivores couldn’t attain
- Or perhaps the lengthy neck attracted mates
- Estimated to be about 20 to 21 ft (6 to six.5 m) lengthy and weigh about 2 tons
- Walked on all fours, had a small head and a protracted tail that led to spikes
- Thought to have shoulder spines, however later discovered to be a part of the tail
- Had two pairs of lengthy tail spines
- Had a pair of triangular plates that ran down its neck
- Had a beak with no enamel on the tip
- Had a notch within the tip of the snout that was formed like a W, when seen from above
- Kind species is Miragaia longicollum
- Two species: Miragaia longicollum and Miragaia longispinus (the second species is now thought of to be Alcovasaurus)
- Genus identify Miragaia is after the parish in Porto, Portugal and the geologic unit the place the fossils had been discovered
- Genus identify Miragaia means “great goddess of the Earth”
- Species identify longicollum means lengthy neck in Latin
- Holotype is an almost full entrance half of a skeleton with a partial cranium (consists of a lot of the snout, components of the jaws, 15 neck bones, again vertebrae, ribs, shoulder bones, a lot of the arms, and 13 bony plates plus a spike)
- Fossils discovered whereas constructing a street between the villages Miragaia and Sobral
- Again half of the skeleton in all probability destroyed within the building
- Fossils had been excavated in August 1999 and 2001
- Based mostly on histology, could be skeletally mature someday between 21 to 25 years outdated
- A juvenile was discovered on the identical location because the holotype, and consists of two partial again vertebrae and a partial pelvis
- Holotype of Miragaia was for some time considered Dacentrurus
- Miragaia longicollum prior to now has been often known as Dacentrurus
- Debate through the years as as to whether Miragaia is legitimate
- In 2010, Alberto Cobos and others stated all of the distinctive options of Miragaia had been on components of the skeleton that had been lacking from the Dacentrurus holotype present in England that lived across the identical time, and that in bones that overlapped, they regarded the identical
- They prompt Miragaia was a junior synonym of Dacentrurus
- In 2019, Francisco Costa and Octávio Mateus discovered Miragaia longicollum to be legitimate, after they described a specimen that was present in 1959 however wasn’t ready till 2015 to 2017 (probably the most full dinosaur present in Portugal, and consists of components of the back and front half of the skeleton, and tail bones)
- In addition they stated Alcovasaurus was a second species of Miragaia: Miragaia longispinus
- However then in 2024, Sergio Sánchez-Fenollosa, Fernando Escaso, and Alberto Cobos discovered Miragaia to be a junior synonym of Dacentrurus and for Alcovasaurus longispinus to be legitimate (will get into that)
- Again to the 2019 research: described a not too long ago ready, fairly full stegosaur discovered within the Lourinhã Formation in Portugal (MG 4863)
- Had been in storage for some time, not ready, and with no subject notes, solely recognized by the label “Atouguia da Baleia”, and a few of the fossils had been blended in with unprepared materials of the holotype of Dracopelta (an ankylosaur)
- Fossils had been rediscovered in 2009, after which a part of a 2015 thesis, and ultimately was nearly absolutely ready and studied
- Fossils from the identical particular person
- Skeleton is comparatively full and consists of a part of the cranium, neck, again, and tail vertebrae, a part of the pelvis, legs, components of the toes, fragments of plates, and extra
- Most full dinosaur described in Portugal and probably the most full stegosaur present in Europe, and one of the full stegosaurs on this planet, as of 2019
- Lots of the bones broke or had been crushed or twisted, however nonetheless fairly properly preserved
- Discovered MG 4863 to be a younger grownup, not absolutely grown, based mostly on particulars within the neck vertebrae and lack of seen sutures
- MG 4863 known as the “Rosetta stone” specimen
- With this new specimen, the skeleton of Miragaia was now nearly absolutely identified (lacking again and tail osteoderms)
- Discovered MG 4863 had the identical characters as Miragaia longicollum and might be distinguished from Dacentrurus, so it was referred to Miragaia longicollum
- MG 4863 had 4 components of sacral ribs, which in some stegosaurs has been prompt to point males (5 pairs doubtless females), however the variety of vertebrae fused collectively to type the sacral rod varies in stegosaurs, so not clear if this specimen is male
- Had 45 tail vertebrae
- Had giant spines over most or complete of its tail
- Based mostly on this specimen and the holotype of Miragaia, research discovered a number of detailed options (29 characters) that had been completely different from Dacentrurus, and that the 2 dinosaurs had been separate and legitimate
- MG 4863 now on show on the Museu Geológico de Lisboa
- Additionally discovered a number of similarities with Alcovasaurus longispinus
- Alcovasaurus
- Stegosaur that lived within the Late Jurassic in what’s now Wyoming, U.S. (Morrison Formation)
- Estimated to be about 21 ft (6.5 m) lengthy and weigh nearly 4 tons, or perhaps as much as over 5 tons
- Had a sacrum related by six pairs of sacral ribs (different stegosaurs have 4 or 5)
- Had a versatile tail
- Longest spike on the tail was 34 in (86 cm) lengthy, however the level was damaged, so could have been as much as nearly 39 in (99 cm) lengthy
- Fossils present in 1908, a partial skeleton, close to Alcova in Wyoming, U.S. (Morrison Formation)
- Fossils present in 1908, and was described in 1914 by Charles Whitney Gilmore as Stegosaurus longispinus
- Miragaia longispinus has been often known as Alcovasaurus longispinus, and earlier than that Natronasaurus, and earlier than that ?Kentrosaurus, and Stegosaurus
- Title Natronasaurus didn’t stick as a result of it was revealed in a self-published e-book that didn’t have an ISSN
- Fossils embrace 42 vertebrae, a part of the pelvis, the best femur, a number of ribs and tail spines
- Kind specimen was broken within the late Nineteen Twenties, when water pipes on the College of Wyoming burst and there was water injury
- Regarded as misplaced, however there’s nonetheless a proper femur and plaster casts of the tail spikes, in addition to photographs
- In 2016, Peter Galton and Kenneth Carpenter re-examined photographs and the fossils and named it the brand new genus Alcovasaurus
- Additionally referred a big spherical spike base to Alcovasaurus, which is misplaced, however there’s a forged (was discovered within the Nineteen Nineties)
- Kind species is Alcovasaurus longispinus
- Genus identify refers to Alcova, Wyoming
- Species identify means “lengthy backbone”
- The 2019 research by Francisco Costa and Octávio Mateus discovered Alcovasaurus was not distinct from Miragaia and renamed it Miragaia longispinus
- That brings us to the newest research, from 2024
- “A brand new specimen of Dacentrurus armatus Owen, 1875 (Ornithischia: Thyreophora) from the Higher Jurassic of Spain and its taxonomic relevance within the European stegosaurian variety”
Sergio Sánchez-Fenollosa, Fernando Escaso, Alberto Cobos
Zoological Journal of the Linnean Society
(thanks Sergio for sending us the paper!) - The gist is that Miragaia longicollum is now Dacentrurus armatus, and Miragaia longispinus is again to Alcovasaurus longispinus
- That signifies that the stegosaurs of the Late Jurassic of Europe are actually simply Dacentrurus armatus and Stegosaurus stenops (no extra Miragaia longicollum)
- How did we get right here?
- There’s a brand new stegosaur specimen from San Cristóbal web site in Teruel, Aragón, Spain (Villar del Arzobispo Formation)
- Fossils present in situ. One particular person
- Found in 2005 and partially excavated in 2007
- Fossils taken to Museo Aragonés de Paleontología
- Extra bones had been later excavated and ready however stay on web site (a part of a museographic and vacationer mission known as ‘Dinosaur Route’)
- Means a few of the fossils are within the subject, and researchers and guests can see it in a everlasting exhibit (lined by a protecting constructing)
- Fossils ready embrace 10 again vertebrae, a number of ribs, bones from the sacrum (across the decrease again), bones from the hips, and a thigh bone and shin bone (femur and tibia)
- Within the research, the crew re-examined all identified specimens of Dacentrurus and Miragaia, together with the brand new specimen (11 people in all)
- Examine described all of the fossils intimately, and in contrast them to different stegosaurs
- Miragaia has been debated earlier than (even authors who described it later stated it might be Dacentrurus sp)
- Miragaia was established as a separate species from Dacentrurus as a result of not sufficient overlapping fossils had been discovered (so the 2 dinosaurs couldn’t be in contrast), and due to this, the authors stated it makes issues unsure. Additionally stated the few fossils that do overlap look the identical
- The brand new specimen, CT-28, has options seen in Dacentrurus specimens and Miragaia specimens, so it helps fill in gaps and reply questions
- Discovered that a few of the options that made Miragaia distinctive had been attributable to particular person variation, and might be affected by the place of vertebrae being misidentified (the place in sequence it was situated), and by issues occurring within the fossilization course of distorting the bones
- Discovered a number of examples of particular person variation amongst all of the specimens
- For instance, there are 4 sacral vertebrae within the holotype of Dacentrurus, however there are 5 sacral vertebrae in different people). This isn’t uncommon, because it’s seen in different stegosaurs, together with Stegosaurus stenops and Kentrosaurus aethiopicus
- Mentioned extra specimens are wanted (hashtag extra fossils) to assist additional make clear
- There’s nonetheless unpublished materials which can provide much more insights
- Up to date the options that make Dacentrurus, Dacentrurus
- Discovered Dacentrurus had 10 distinctive options, based mostly on the holotype and referred specimens
- Contains particulars within the tail bones (brief neural spines), and particulars within the pelvic space
- Different particulars embrace having at the very least 17 neck vertebrae, the tip of the snout being drawn into some extent, and different particulars within the neural spines and vertebrae
- Discovered there have been fewer similarities between Alcovasaurus and Miragaia than Miragaia and Dacentrurus, particularly with the brand new CT-28 specimen
- Additionally discovered distinctive options in Alcovasaurus so it’s a separate genus
- Since Miragaia is taken into account to be Dacentrurus, Alcovasaurus is legitimate once more
Enjoyable Reality:
The ceratopsian Protoceratops is probably not the inspiration behind the legendary griffin.
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