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Spinosaurus News ~
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The “χ” of the Matter: Testing the Relationship between Paleoenvironments and Three Theropod Clades Sales , Lacerda, Horn, de Oliveira & Schultz, 2016
 *This image is copyright of its original author Fig 5. Reconstruction of the terrestrial paleoenvironmental setting of the Sao Khua Formation. In the center, a generalized spinosaurid feeds on a sauropod. This trophic relationship is hypothesized based on isolated tooth crowns found in association with a sauropod skeleton. In the background, a small pack of the ornithomimosaur theropod Kinnareemimus. Both sauropods and ornithomimosaurs (as part of the “herbivorous” theropods) were found to be positively associated with terrestrial paleoenvironments by Butler and Barrett. Abstract: "The view of spinosaurs as dinosaurs of semi-aquatic habits and strongly associated with marginal and coastal habitats are deeply rooted in both scientific and popular knowledge, but it was never statistically tested. Inspired by a previous analysis of other dinosaur clades and major paleoenvironmental categories, here we present our own statistical evaluation of the association between coastal and terrestrial paleoenvironments and spinosaurids, along with other two theropod taxa: abelisaurids and carcharodontosaurids. We also included a taphonomic perspective and classified the occurrences in categories related to potential biases in order to better address our interpretations. Our main results can be summarized as follows: 1) the taxon with the largest amount of statistical evidence showing it positively associated to coastal paleoenvironments is Spinosauridae; 2) abelisaurids and carcharodontosaurids had more statistical evidence showing them positively associated with terrestrial paleoenvironments; 3) it is likely that spinosaurids also occupied spatially inland areas in a way somehow comparable at least to carcharodontosaurids; 4) abelisaurids may have been more common than the other two taxa in inland habitats."
Interesting study about the many hypotheses on function of the dorsal sail in Spinosaurus.
The riddle of Spinosaurus aegyptiacus’ dorsal sail Gimsa, Sleigh & Gimsa, 2016 Abstract: "Spinosaurus aegyptiacus was probably the largest predatory dinosaur of the Cretaceous period. A new study shows that it was a semiaquatic hunter. The function of Spinosaurus’ huge dorsal ‘sail’ remains unsolved, however. Three hypotheses have been proposed: (1) thermoregulation; (2) humpback storage; or (3) display. According to our alternative hypothesis, the submerged sail would have improved manoeuvrability and provided the hydrodynamic fulcrum for powerful neck and tail movements such as those made by sailfish or thresher sharks when stunning or injuring prey. Finally, it could have been employed as a screen for encircling prey underwater."
Interesting document with many information on the holotype of the famous Spinosaurus.
New information regarding the holotype of Spinosaurus aegyptiacus Stromer, 1915 Smith et al., 2006
Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil Sales & Schultz, 2017
 *This image is copyright of its original author Fig 1. Map of northeastern Brazil showing the location of the Araripe and São Luís-Grajaú basins. The (likely) provenance of the holotypes of local spinosaurid taxa is indicated. Modified from Bittencourt and Langer [51]. Abstract: "Fossil sites from Brazil have yielded specimens of spinosaurid theropods, among which the most informative include the cranial remains of Irritator, Angaturama, and Oxalaia. In this work some of their craniodental features are reinterpreted, providing new data for taxonomic and evolutionary issues concerning this particular clade of dinosaurs. The mesial-most tooth of the left maxilla of the holotype of Irritator is regarded as representing the third tooth position, which is also preserved in the holotype of Angaturama. Thus, both specimens cannot belong to the same individual, contrary to previous assumptions, although they could have been the same taxon. In addition, the position of the external nares of Irritator is more comparable to those of Baryonyx and Suchomimus instead of other spinosaurine spinosaurids. In fact, with regards to some craniodental features, Brazilian taxa represent intermediate conditions between Baryonychinae and Spinosaurinae. Such a scenario is corroborated by our cladistic results, which also leave open the possibility of the former subfamily being non-monophyletic. Furthermore, the differences between spinosaurids regarding the position and size of the external nares might be related to distinct feeding habits and degrees of reliance on olfaction. Other issues concerning the evolution and taxonomy of Spinosauridae require descriptions of additional material for their clarification." 
Depending on just how aquatic Spinosaurus was, perhaps he should be drawn with webbed feet and a more alligator-like ( flattened ) tail.
Here's some big news:
A buoyancy, balance and stability challenge to the hypothesis of a semi-aquatic Spinosaurus Stromer, 1915 (Dinosauria: Theropoda) The key part of the abstract: "The software also showed that the center of mass of Spinosaurus was much closer to the hips than previously estimated, similar to that observed in other theropods, implying that this dinosaur would still have been a competent walker on land. With its pneumatised skeleton and a system of air sacs (modelled after birds), the Spinosaurus model was found to be unsinkable, even with its lungs deflated by 75%, and this would greatly hinder a semi-aquatic, pursuit predator. The conclusion is that Spinosaurus may have been specialized for a shoreline or shallow water mode of life, but would still have been a competent terrestrial animal." Here's a nice summary of the article.  (08-17-2018, 04:09 AM)tigerluver Wrote: Here's some big news:Spinosaurus in Jurassic park was running and sprinting around with the speed of cheetah... probably Hollywood a bit exaggerated its speed?  (09-12-2018, 08:03 PM)genao87 Wrote: I see, so the P. Tigers and the Cave "Lions" we can assume would be roughly the same size. Based in what we have, yes, I think that these two species were about the same size, for the moment. But taking in count my previous analisys about "average-sized" specimens and the rarity of the "maximum-sized" specimens, the tigers have the advantage as the few bones known are already as large as the largest cave "lion" specimens, which are know for a very large sample. About the Spinosaurus, I did not knew about that new study, thank you for sharing it! I was reading the conclusions but I am agree with Dr Ibrahim, the study is far from conclusive as this is just a simulation, also I am happy that new fossils will arrive and will provide more information, which is excelent. Other thing, I think, and many other too, that Spinosaurus was not like an Alligator in the water, but more like a Bear. This is nothing new, but it seems that is the contradiction in the Dr Henderson study. In fact, Henderson accept that in the interview! The final answer came from Dr David Hone: "swimming is by no means the litmus test for a life aquatic". Probably Spinosaurus had good swiming capabilities but that doesn't mean that they spend they entire life in the water. The articel says: “Herons aren't very good at swimming, but they spend most of their time knee-deep in water, wading around the edge of rivers,” he says. “ 'Semiaquatic' might be a push, but you're definitely talking about an animal whose ecology is fundamentally linked to water.” Spinosaurus was especifically linked to water, so it will be absurd that it will not have some "aquatic" habilities. Like I said, it was like a bear. Bears are not designed to dive, but they can do it for short times. So, that is the answer. Now, about Spinosaurus vs T.rex, no land predator, present or extinct, will be a rival for the Tyrannosaurus rex, on land at least. In the words of Dr Henry Orborn: "Tyrannosaurus is the most superb carnivorous mechanism among the terrestrial Vertebrata, in which raptorial destructive power and speed are combined". 
@GuateGojira :
About #960: you wrote : About the Spinosaurus, I did not knew about that new study, thank you for sharing it! I was reading the conclusions but I am agree with Dr Ibrahim, the study is far from conclusive as this is just a simulation, also I am happy that new fossils will arrive and will provide more information, which is excelent. Other thing, I think, and many other too, that Spinosaurus was not like an Alligator in the water, but more like a Bear. This is nothing new, but it seems that is the contradiction in the Dr Henderson study. In fact, Henderson accept that in the interview! The final answer came from Dr David Hone: "swimming is by no means the litmus test for a life aquatic". Probably Spinosaurus had good swiming capabilities but that doesn't mean that they spend they entire life in the water. The articel says: “Herons aren't very good at swimming, but they spend most of their time knee-deep in water, wading around the edge of rivers,” he says. “ 'Semiaquatic' might be a push, but you're definitely talking about an animal whose ecology is fundamentally linked to water.” Spinosaurus was especifically linked to water, so it will be absurd that it will not have some "aquatic" habilities. Like I said, it was like a bear. Bears are not designed to dive, but they can do it for short times. So, that is the answer. Now, about Spinosaurus vs T.rex, no land predator, present or extinct, will be a rival for the Tyrannosaurus rex, on land at least. In the words of Dr Henry Orborn: "Tyrannosaurus is the most superb carnivorous mechanism among the terrestrial Vertebrata, in which raptorial destructive power and speed are combined". Very happy to read such conclusions like these ones about the T.rex ! After having read the Jack Horner's book "The complete T.rex" I remember to have been in total disagreement with his theory i.e. the T. rex was a total scavenger. I prefered the Robert T. Bakker's depictions which were revolutionary. As for the spinosaurus, no one crocodile brought a sail-like dorsal as spinosaurus did. To imagine it swimming and diving in depth like a croc ? Very, very difficult !
My post was transferred, but not too well, here is what I said:
***************************** About the Spinosaurus, I did not knew about that new study (about the swiming capabilities), thank you for sharing it! I was reading the conclusions but I am agree with Dr Ibrahim, the study is far from conclusive as this is just a simulation, also I am happy that new fossils will arrive and will provide more information, which is excelent. Other thing, I think, and many other too, that Spinosaurus was not like an Alligator in the water, but more like a Bear. This is nothing new, but it seems that is the contradiction in the Dr Henderson study. In fact, Henderson accept that in the interview! The final answer came from Dr David Hone: "swimming is by no means the litmus test for a life aquatic". Probably Spinosaurus had good swiming capabilities but that doesn't mean that they spend they entire life in the water. The articel says: “Herons aren't very good at swimming, but they spend most of their time knee-deep in water, wading around the edge of rivers,” he says. “ 'Semiaquatic' might be a push, but you're definitely talking about an animal whose ecology is fundamentally linked to water.” Spinosaurus was especifically linked to water, so it will be absurd that it will not have some "aquatic" habilities. Like I said, it was like a bear. Bears are not designed to dive, but they can do it for short times. So, that is the answer. Now, about Spinosaurus vs T.rex, no land predator, present or extinct, will be a rival for the Tyrannosaurus rex, on land at least. In the words of Dr Henry Orborn: "Tyrannosaurus is the most superb carnivorous mechanism among the terrestrial Vertebrata, in which raptorial destructive power and speed are combined". ***************************** My next post, that is still in the "Freak Felids" topic is this: ***************************** Yes, T.rex was probably the most powerfull carnivore that ever existed, no animal had such a perfect design for predation, is a machine designed to kill whatever existed. The only backdown are the arms, but all the other parts of the body, brain and senses, tail, legs and specially the jaguar-like head are designed for predation. Dr Robert Bakker is one of the BEST paleontologist ever! Of course that I support his view about the T. rex! ![[Image: lolol.png]](https://wildfact.com/forum/images/smilies/wasm/lolol.png) Jack Horner, sadly, is just a bad joke now, specially with his "idea" of Triceratops=Torosaurus, that was the last nail in his coffin, it is just stupid! He was good, I don't know what happen to him. ![[Image: sad.png]](https://wildfact.com/forum/images/smilies/wasm/sad.png) About Spinosaurus, yes, I doubth that it will be able to dive, but it can surelly swim, and with that size, that was more than enoght to catch its giant prey. Oh yes, there were fishes as large as rhinos in his habitat!!! ****************************** Hope this leave clearly what I said.
@GuateGojira :
About #39: As concerns the spinosaurus I share the vision of this animal described in the "Dinosaurs planet" DVD (here the french version):  *This image is copyright of its original author  *This image is copyright of its original author ... According to which spinosaurus, fairly well, swam but didn't dive. And as you told too they were a lot of big fishs in the streams. 
Yikes...this love for T.Rex is hard to take. Its like a shot to my heart. But I have to take it. Seems the quadrupedal theory has been debunked a bit....still his legs are short than previous drawings. Maybe I should put my hopes for Sigilmassasaurus...small chance it was larger than Spino..or maybe that huge allosaurid Acrocanthosaurus . Spino not looking good against T. Rex. Hopefully those FOSSIL HUNTERS from the fossil forums may find some new bones about Spino. Sorry myself as well...didn't mean to go off topic.
*This image is copyright of its original author *This image is copyright of its original author
I've moved the Spinosaurus posts here. The study in post #36 could be of interest to the discussion.
Semi-aquatic adaptations in a spinosaur from the Lower Cretaceous of Brazil Aureliano et al., 2018
 *This image is copyright of its original author Highlights • Spinosaur histology is here described for the first time. • Extreme bone compactness (osteosclerosis) was present in Brazilian Spinosaurinae. • These modifications appeared millions of years before the Moroccan Spinosaurus. • One of the largest spinosaur specimens from the Early Cretaceous of South America. Abstract: "Spinosaurinae are known to have a strong relationship with aquatic environments, involving several anatomical adaptations. Nonetheless, this group of theropods remains enigmatic, due to the relative incompleteness of its fossil record. A large partial tibia from the Aptian-Albian Romualdo Formation, Northeast Brazil, is herein described through anatomical comparisons and paleohistological analyzes. It features characteristics previously only observed in Spinosaurus aegyptiacus, which includes a reduced fibular crest and an osteosclerotic condition. The later, a character supported as correlated with semi-aquatic habits in many limbed vertebrates. The results presented here support high bone compactness being already present in Brazilian Spinosaurinae millions of years before the Moroccan Spinosaurus. Furthermore, histological analyses demonstrate the Romualdo Formation specimen was a young subadult still growing fast by the time of its death, and suggests Araripe Basin Spinosaurinae could have grown larger than previously thought. This work contributes to a better paleobiological and ecological understanding of South American spinosaurs, and helps fill a gap in the macroevolutionary comprehension of Spinosaurinae. Ultimately, it also contributes to further advancing the paleoecological characterization of the Romualdo Formation." |
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