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The Abelisauroid Thread

Comments

  • Registered Users, Registered Users 2 Posts: 30,746 ✭✭✭✭Galvasean


    Interesting that the hands reduced before the arms themselves. Hopefully this discovery can shed some light on that particular mystery. Also, the legs look far more useful for running than the stubby Majungasaurus which came later.

    skel01.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    If Majungasaurus was hunting mainly sauropods like Rapetosaurus, I don´t think it's strange that it wasn´t a great runner, although I did think it was bizarre when I first saw the new skeletal reconstructions XD

    On the other hand, Carnotaurus seems to have been a speed demon, and Rajasaurus had enormously powerful legs. Seems like a very diverse group :>
    images?q=tbn:ANd9GcSODHdkiBngIc9-au3JqTc_ApZcq545lySkTb3fKlbTENtnXm4x

    rajasaurus.jpg


  • Registered Users, Registered Users 2 Posts: 30,746 ✭✭✭✭Galvasean


    If Majungasaurus, as it appears to be the case, lived in areas prone to excessive drought stubby legs were probably good for walking over very long distances in search of water/food.
    What sort of environment did Carnotaurus inhabit?


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Galvasean wrote: »
    If Majungasaurus, as it appears to be the case, lived in areas prone to excessive drought stubby legs were probably good for walking over very long distances in search of water/food.
    What sort of environment did Carnotaurus inhabit?

    I don´t know, short stubby legs don´t seem like the ideal thing to me if one's walking long distances...

    My personal belief is that Carnotaurus was a diurnal, high speed hunter equivalent in many ways to our cheetahs. Fossil evidence supports this; thus, it is most likely that it lived in open habitats, some sort of plain or savannah-like environment and hunted agile, fast prey smaller than itself.


  • Registered Users, Registered Users 2 Posts: 30,746 ✭✭✭✭Galvasean


    Adam Khor wrote: »
    I don´t know, short stubby legs don´t seem like the ideal thing to me if one's walking long distances...

    I recall reading that shorter legs in hominins (different ballpark to dinosaurs I know) made for more energy efficient walking over long distances, while long legs allowed for great sprinting. I wonder if abelisaurids were of a similar persuasion.

    [quote=Adam Khor[/quote]
    My personal belief is that Carnotaurus was a diurnal, high speed hunter equivalent in many ways to our cheetahs. Fossil evidence supports this; thus, it is most likely that it lived in open habitats, some sort of plain or savannah-like environment and hunted agile, fast prey smaller than itself.[/QUOTE]

    I recall you put forward the very interesting idea that Carnotaurus' hornlets were used to prevent glare from the sun, similar to the black spots around cheetahs' eyes.


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  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Galvasean wrote: »
    I recall reading that shorter legs in hominins (different ballpark to dinosaurs I know) made for more energy efficient walking over long distances, while long legs allowed for great sprinting. I wonder if abelisaurids were of a similar persuasion.

    That's interesting. And puzzling... I would have thought that short legs would be the last one would want to travel long distances... most long distance animals I can think of have long legs, although almost none are quadrupeds, I give you that...
    Where did you read that?

    Galvasean wrote: »
    I recall you put forward the very interesting idea that Carnotaurus' hornlets were used to prevent glare from the sun, similar to the black spots around cheetahs' eyes.

    Yes, that's what I believe... unfortunately, no studies were made about Carnotaurus' scleral rings that I know of, so there's no way to confirm it, but I think the horns (combined with the rest of its anatomy) suggests a diurnal lifestyle in an open, posibly very hot environment. Just my idea, of course :pac:


  • Registered Users, Registered Users 2 Posts: 30,746 ✭✭✭✭Galvasean


    Adam Khor wrote: »
    That's interesting. And puzzling... I would have thought that short legs would be the last one would want to travel long distances... most long distance animals I can think of have long legs, although almost none are quadrupeds, I give you that...
    Where did you read that?

    In one of the many threads about ancient humans on this very forum if I remember correctly... However, it is entirely possible that I read / am remembering wrong. I can't find anything to support the notion on Google so I may well be mistaken.

    [quote=Adam Khor[/quote]
    Yes, that's what I believe... unfortunately, no studies were made about Carnotaurus' scleral rings that I know of, so there's no way to confirm it, but I think the horns (combined with the rest of its anatomy) suggests a diurnal lifestyle in an open, posibly very hot environment. Just my idea, of course :pac:[/QUOTE]

    Be sure to bookmark this thread so that when it is announced you can say 'I told you so!" :pac:


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    This study compares the neck of Carnotaurus to that of Majungasaurus. According to them, Carnotaurus had a much more robust and less S-shaped neck than Majungasaurus.
    What bothers me is that they suggest carnotaurines were "scavengers", which doesn´t fit with the recent studies that indicate speed adaptations in Carnotaurus at least. And isn´t it a mistake to begin with, trying to separate "scavengers" and "predators", especially when it comes to such large animals?
    If it can hunt, it can certainly scavenge- and even the most devoted scavengers, like vultures, will hunt once in a while...

    http://app.pan.pl/archive/published/app57/app20110129_acc.pdf

    Disney_dinosaur_carnotaurus.jpg


  • Registered Users, Registered Users 2 Posts: 30,746 ✭✭✭✭Galvasean


    Would the more robust neck lend itself better to strangling prey? (as has been suggested elsewhere on this forum)


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Perhaps... or perhaps it helped it bring down its prey more easily. If it was, as I believe, sort of a dinosaurian cheetah, it is then lacking one very important cheetah hunting tool, the enlarged dew claw no one talks about:
    images?q=tbn:ANd9GcQhQmdYghZetakjQ60wg3AYZqYvW5AEvwKgbm3aZ79mfhirSbIcoSAafny7Hg
    The cheetah uses this claw to hook its prey at high speed and throw it out of balance. Without this very important "tool", it would be extremely difficult for the cheetah to capture prey. Of course abelisaurus had nothing like this, they barely had arms at all, but what if Carnotaurus' long and robust neck had a similar function, and allowed it to bite down on its prey during the chase and grab/throw its prey out of balance without suffering any injury? As in, a reinforced neck that short-legged, slow moving Majungasaurus wouldn´t need...

    Carnotaurus_Dinos_Argentina_Colombo_008_%282%29.jpg


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  • Registered Users, Registered Users 2 Posts: 30,746 ✭✭✭✭Galvasean


    I can definitely see that working; running down smaller prey, grab it, then fling it causing injury. It also means the Carnotaurus doesn't risk injuring itself in a struggle.
    Just looking at that skeleton, I'm actually surprised that so many are content to cast Carnotaurus as a scavenger. You don't evolve sexy catwalk legs like that to amble about waiting for things to keel over and die.


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor




  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    If correctly interpreted this 115 cm footprint could have been made by the largest abelisaur known; at 12meters or more it would be in the same size class as Tyrannosaurus and the largest carcharodontosaurids.

    http://www.eartharchives.org/articles/giant-dinosaur-footprint-discovered-in-bolivia/

    abelisaurid_footprint.jpg

    Although fragmentary remains of giant abelisaurs have been found in northern Africa, the biggest officially known is the South American Pycnonemosaurus (8.9 meters) according to a recent study, followed by Carnotaurus at 7.8 meters. Ekrixinatosaurus has been said to measure up to 11 meters but it may have been relatively large headed and thus shorter than previously believed. I have yet to hear anything about the supossed giant abelisaurs from Kenya which were rumored to be about 12 meters long.


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Skorpiovenator gets the CAT treatment:

    Skorpiovenator was an abelisaur, related to Carnotaurus. Article is in Spanish.

    https://www.rionegro.com.ar/neuquen/mira-como-le-hicieron-una-tomografia-a-uno-de-los-dinosaurios-mas-letales-IY5346956

    image_content_9869480_20180705104344.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    For real, they named it Thanos. It's just a bunch of fragments tho, nothing to write home about.

    https://www.torredevigilancia.com/dinossauro-descoberto-no-brasil-e-nomeado-de-thanos/

    Thanos_simonattoi-novataxa_2019-Delcourt_et_Iori-paleoArt-Deverson_da_Silva-e1542578935753.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Morocco's Kem Kem beds are one of the sites where Spinosaurus fossils can be found. The authors think this may be from an abelisaur, tho. Very measly fossil- paleontology is frustrating like that...

    https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214055

    journal.pone.0214055.g002


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    The ornithomimosaurs appear to be a new species, notable for its very short, stubby forelimbs, and outside of family Ornithomimidae.

    http://paleo.mnhn.fr/fr/agenda/soutenance-these-lee-rozada-5940

    undefined.jpg?itok=_Qzd1vhD

    EDIT: These "ornithomimosaurs" apparently were noasaurid/elaphrosaur types after all, so I'm moving them to the correct thread.


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Vespersaurus was a noasaurid- a relative to the also unusual Masiakasaurus from Madagascar.

    It would've been 1 to 1.5 m long and is unique for being functionally monodactylous; it apparently walked with one single toe of its feet, the third or central one, while the other toes were kept raised from the ground to keep the claws sharp, and also possibly to reduce the contact surface with the hot desert sand. This may also have increased its running speed.

    Vespersaurus finally explains the mystery of the one-toed dinosaur footprints that had been found in the same area.

    Article is in Portuguese:

    https://jornal.usp.br/ciencias/ciencias-biologicas/nova-especie-de-dinossauro-e-descoberta-no-parana/

    20190626_00_dinossauro_vespersaurus_paranaensis_parana1-768x403.jpg



  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    As I understand it, this is about the same "French ornithomimosaur" mentioned in the article above, except it appears to be actually an elaphrosaur or noasaur-like ceratosaur (which would explain the stubby arms):

    http://petitcarnetpaleo.blogspot.com/2019/06/mimotweet-on-sest-trompe-sur-un-air.html


    w-MIMO-squelette%2B2017%2BEXPO.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Afromimus tenerensis, described as a possible ornithomimosaur from Africa, is probably a noasaurid after all:

    https://www.sciencedirect.com/science/article/pii/S1464343X19302250

    afromimus_by_cisiopurple-dbyfqea.png


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  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Possible abelisaurid trackway from Argentina (around 28 cm long) suggest gregarious behavior:

    https://www.sciencedirect.com/science/article/abs/pii/S0031018219306959

    These are from Candeleros Formation, which is where large abelisaur Ekrixinatosaurus came from:

    images?q=tbn%3AANd9GcSEpFB2XleA4xzM3mmQzf8nq2accii2FcRXsgqK8iLDMsdDKfvF


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Majungasaurus replaced all its teeth every two months, study suggests:

    http://www.sci-news.com/paleontology/majungasaurus-teeth-07854.html

    image_7854_2-Majungasaurus.jpg

    This is a faster replacement rate than seen in other theropods (such as Ceratosaurus or Allosaurus), and comparable to that of some sharks.

    Majungasaurus is better known for being the largest carnivorous dinosaur known from latest Cretaceous Madagascar, as well as one of the most complete abelisaurids in the world. Also, one of the first dinosaurs for which cannibalistic behavior was proven.

    images?q=tbn%3AANd9GcT3ZkFFGBtUuSqWxwtIi-RCpSSkqYidwri9VMGVyvXD4O3r9TQl

    images?q=tbn%3AANd9GcSZTvS9Ikwm3qxoTSll6X0isgcuwJ7J-mgCTejjMOftr2GqE0_V


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Tralkasaurus, a smallish abelisaurid from Argentina:

    https://www.sciencedirect.com/science/article/abs/pii/S0895981119304766

    73209865_2469105613369728_1080569578192086209_n.jpg?_nc_ht=scontent-yyz1-1.cdninstagram.com&_nc_cat=100&oh=e925e3f0fbd18a89ecb51e975610c4f2&oe=5E6D58B7


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor




  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Another similarly fragmentary abelisauroid (elaphrosaur?) from Argentina, Huinculsaurus. It would appear these creatures were very widespread,with finds practically in every continent (except Antarctica?)

    https://www.sciencedirect.com/science/article/pii/S0195667119301880

    Huinculsaurus%2Breconstruction%2Bcopia.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    More on the newly described abelisaurid Tralkasaurus:

    http://www.sci-news.com/paleontology/tralkasaurus-cuyi-08129.html

    image_8129-Tralkasaurus-cuyi.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    This year's paper describing the Kem Kem fauna includes Deltadromeus, one of the three mystery giant theropods of Northern Africa (the other two being the now better understood Carcharodontosaurus and Spinosaurus).

    https://zookeys.pensoft.net/article/47517/

    The paper proposes a noasaur/elaphrosaur affinity for Deltadromeus, and mentions remains of extraordinary size which, if scaled up following the proportions of the more complete specimens, would result in an animal around 16 m long.

    EWNVnVBXkAERD23?format=jpg&name=large

    Unfortunately, more remains are needed to understand Deltadromeus, as no skull material is known thus far. It will probably turn out to be as bizarre as Spinosaurus itself, once complete.


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Purported carcharodontosaur teeth from late Cretaceous Brazil more likely to belong to other theropod groups, including abelisaurids, new study finds:

    https://www.sciencedirect.com/science/article/abs/pii/S0031018220303151?via%3Dihub

    The study found that abelisaurids in this region and time were diverse in size, and some of them may have been among the largest, although without further remains it is difficult to know for sure.


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Practically complete skeleton of a Majungasaurus shows ample record of injuries, infections and other pathologies sustained throughout life, from septic arthritis to bites from other Majungasaurus .

    https://www.sciencedirect.com/science/article/pii/S0195667120302391

    images?q=tbn%3AANd9GcRqXtzHLmWQvKXsoo3eAxfjS06ZucG6nSgwtA&usqp=CAU


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  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    A new abelisaurid from early Cretaceous Brazil, Spectrovenator ("ghost hunter"), sheds light on the evolution of the abelisaur's unique cranial features. It was a smallish animal, nowhere near as big as its more famous relatives such as Carnotaurus.

    http://sciencepress.mnhn.fr/fr/periodiques/comptes-rendus-palevol/19/6

    Some have noted a resemblance to the 1998 Godzilla movie design. Can you see it?

    Spectrovenator.png

    EkIxtsaXgAAC5OJ.jpg


  • Registered Users, Registered Users 2 Posts: 5,279 ✭✭✭Adam Khor


    Yet another abelisaur from Argentina, this one quite fragmentary. It was named Niebla antiqua, meaning "ancient mist", and was considerably smaller than the likes of Carnotaurus or Abelisaurus, but had already reached adulthood.

    https://www.sciencedirect.com/science/article/abs/pii/S0895981120304582

    sin-titulo.jpg?w=713


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