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For those of us fortunate to obtain specimens before the ban was put in place here is a study published earlier this year that looked at a fair number of teeth. The blog provides a good read for collectors plus other readings in their references.. Blog http://rexmachinablog.com/2019/09/04/thailand-spinosaur-teeth/ Paper https://www.researchgate.net/publication/332698408_Spinosaurid_theropod_teeth_from_the_Red_Beds_of_the_Khok_Kruat_Formation_Early_Cretaceous_in_Northeastern_Thailand Wongko et al. found in their study that two distinct spinosaur morphotypes were present. Surprisingly, the team concluded that at least two spinosaurs are represented in Khok Kruat.
So after following nizaar ibrahim's study in 2014 I learned that spinosaurus walked on four legs and it spend a lot of time in water being a good swimmer. But recently I saw that some new studies have been published and then some others and I have lost track so if someone could please inform me about the latest discoveries and tell me if spinosaurus was a good swimmer and if he walked on four it would be much appreciated.
Troodon posted a topic in Fossil NewsThis paper looks to confirm the semi-aquatic lifestyle of Spinosaurids using oxygen isototopes in their bones. Direct evidence concerning spinosaurid diet was inconclusive since it appears that they also fed on dinosaurs and pterosaurs. Because of the shape of their jaw/teeth and fish remains in their stomach, the hypothesis of spinosaurs as “crocodile mimics” has been widely accepted. However, their postcranial anatomy differs relatively little from that of the usual large theropods, and is not particularly suggestive of aquatic habits. So the paper concluded that stable oxygen isotopes unambiguously show for the first time that some dinosaurs, i.e., the spinosaurid theropods, used freshwater environments more as a living habitat than just as temporary hunting grounds. W020120622356922971023.pdf
Troodon posted a topic in General Fossil DiscussionI came across this paper in Fruitbat's library and it raised some questions so decided to see what others think. The paper studied Spinosaurid teeth that were found on the Iberian peninsula La Cantalera site and concluded that two morphotypes of spinosaurid teeth were recognized in the early Barremian of that site: both a Baryonychinae indet. and Spinosaurinae? indet. They ruled out attribution to other theropods or crocodylomorphs, although they remained cautious due to the scarce fossil record known. It also concluded that Spinosaurinae? indet. did not fit exactly with any of the described spinosaurine teeth, and regarded them as belonging to an unknown spinosaurine spinosaurid, probably closer to Spinosaurus than any other member of Spinosaurinae. So let's move forward in time to the Kem Kem. Ute Richter 2012 research described 3 morph types in the Kem Kem distinguished from each other by ornamentation and concluded that more than one species may be present.. Teeth from this region are typically straight but thin curved ones do show up like the one posted by indominus rex (see pic below) and some are attributed to croc's. So what if we had another morph type in this region a thin more curved tooth more like Suchomimus which is a Baryonychinae. The Spanish teeth suggest that these two families might coexist in the same fauna. I believe there are multiple species in the Kem Kem, Sigilmassasaurus for sure and Spinosaurus sp. but are there additional ones more aligned with Baryonchinae? Food for thought.... The Spanish teeth are described quite well: The mesial margin of the teeth is convex, while the distal margin is concave or straight. The cross-section varies between elliptical and subcircular. All teeth have mesial and distal carinae, but some teeth do not have serration on the mesial carina. Carinae are located on the mesiodistal axis of the crown and start close to the cervix. Denticles are chisel-shaped and their height and width vary between 0.1 and 0.12mm. Denticle density per mm ranges from 6 to 12. The denticle size density index values are close to one, so there is no difference between the mesial and the distal size of the denticles. The denticles are perpendicular to the margin of the teeth. Both faces of the teeth bear enamel ornamentation which consists of 6–7 ridges (on average) orientated apicobasally; the ridges do not reach the apex. https://www.researchgate.net/profile/Antonio_Alonso7/publication/276158392_On_the_spinosaurid_theropod_teeth_from_the_early_Barremian_Early_Cretaceous_Blesa_Formation_Spain/links/556c19a708aefcb861d619c9.pdf?origin=publication_detail