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Spinosaurus aegyptiacus

Canada DinoFan83 Offline
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( This post was last modified: 06-24-2021, 07:00 PM by DinoFan83 )

Spinosaurus (meaning "spine lizard") is a genus of spinosaurid dinosaur that lived in what now is North Africa during the upper Albian to upper Turonian stages of the Cretaceous period, about 112 to 93.5 million years ago. This genus was known first from Egyptian remains discovered in 1912 and described by German paleontologist Ernst Stromer in 1915. The original remains were destroyed in World War II, but additional material has come to light in the early 21st century. It is unclear whether one or two species are represented in the fossils reported in the scientific literature. The best known species is S. aegyptiacus from Egypt, although a potential second species, S. maroccanus, has been recovered from Morocco. The contemporary spinosaurid genus Sigilmassasaurus has also been synonymized by some authors with S. aegyptiacus, though other researchers propose it to be a distinct taxon. Another possible junior synonym is Oxalaia from the Alcântara Formation in Brazil.
Spinosaurus may have had the largest average size of of known specimens among all known carnivorous dinosaurs, much heavier than known specimens of T. rex and similar in size to or somewhat heavier than known specimens of giant carcharodontosaurids like Giganotosaurus and Carcharodontosaurus. The latest estimates suggests a weight of more than 12860 kg and a length of 15.8 meters for the 1 possible adult specimen (NHMUK R-16421) that can be estimated based on overlap with other specimens. Some other specimens (MSNM v4047, NMC 41852) may suggest similar sizes to these when they can be estimated from overlap with other specimens.
The skull of Spinosaurus was long, low and narrow, similar to that of a modern crocodilian, and bore straight conical teeth with no serrations. It would have had large, robust forelimbs bearing three-fingered hands, with an enlarged claw on the first digit. The distinctive neural spines of Spinosaurus, which were long extensions of the vertebrae (or backbones), grew to at least 1.65 meters (5.4 ft) long and were likely to have supported a large hump of muscle, akin to that of a modern-day bison.
Spinosaurus' hip bones were reduced, and the legs were very short in proportion to the body. Its long and narrow tail was deepened by tall, thin neural spines and elongated chevrons, forming a flexible fin or paddle-like structure. Spinosaurus is known to have eaten fish, and most scientists believe that it hunted both terrestrial and aquatic prey. Evidence suggests that it was highly semiaquatic, and lived both on land and in water as modern crocodilians do. Spinosaurus' leg bones had osteosclerosis (high bone density), allowing for better buoyancy control, and the paddle-like tail was likely used for underwater propulsion. Multiple functions have been put forward for the dorsal sail, including thermoregulation and display; either to intimidate rivals or attract mates. Spinosaurus lived in a humid environment of tidal flats and mangrove forests alongside many other dinosaurs, as well as fish, crocodylomorphs, lizards, turtles, pterosaurs, and plesiosaurs.
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Canada DinoFan83 Offline
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( This post was last modified: 06-24-2021, 07:07 PM by DinoFan83 )

Spinosaurus skeletal from Ibrahim et al. (2020).

*This image is copyright of its original author

Spinosaurus skeletal by SpinoInWonderland: https://www.deviantart.com/spinoinwonder...-827067720

*This image is copyright of its original author

Spinosaurus mounted skeleton by Mike Bowler. Note that this was mounted before the new tail was found.

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Spinosaurus skull by Steveoc86.

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Spinosaurus by Gustavo Monroy-Becerril.

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Nizar Ibrahim's estimates for Spinosaurus as reported on Reddit.

*This image is copyright of its original author
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( This post was last modified: 07-20-2021, 05:54 AM by DinoFan83 )

Spinosaurus by PaleoGeekSquared.

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Spinosaurus by GetAwayTrike.

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Large specimens of Purussaurus and Spinosaurus. The Purussaurus is also credited to Jorge W. Moreno-Bernal.

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Spinosaurus (13.66 tonnes) and Carcharodontosaurus (9.68 tonnes), skeletals by Ibrahim et al. 2020 and GetAwayTrike.

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Spinosaurus by KookaburraSurvivor.

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Spinosaurus by Miyess. Image cannot be posted here due to copyright issues.
https://www.deviantart.com/miyess/art/Spinosaurus-Skeletal-Reconstruction-873793633
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Spinosaurus for 2020

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Czech Republic Spalea Offline
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A very essential video about the Spinosaurus Aegypticus !

Ah, I forget it's in french ! But no problem for those who don't understand the Molière's language, ask me if you want some more info about it...





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Sarah Whelan: " Very simple paint up of my tiny updated Spino to show how much detail can be brought out with a little colour. I can't wait to start casting these little guys ? "


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Czech Republic Spalea Offline
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" The New Spinosaurus! ?


Art by cisiopurple on #DeviantArt
.
In recent decades, intensive research on non-avian dinosaurs has strongly suggested that these animals were restricted to terrestrial environments. Historical proposals that some groups, such as sauropods and hadrosaurs, lived in aquatic environments were abandoned decades ago. It has recently been argued that at least some of the spinosaurids—an unusual group of large-bodied theropods of the Cretaceous era—were semi-aquatic, but this idea has been challenged on anatomical, biomechanical and taphonomic grounds, and remains controversial. Here we present unambiguous evidence for an aquatic propulsive structure in a dinosaur, the giant theropod Spinosaurus aegyptiacus. This dinosaur has a tail with an unexpected and unique shape that consists of extremely tall neural spines and elongate chevrons, which forms a large, flexible fin-like organ capable of extensive lateral excursion. Using a robotic flapping apparatus to measure undulatory forces in physical models of different tail shapes, we show that the tail shape of Spinosaurus produces greater thrust and efficiency in water than the tail shapes of terrestrial dinosaurs and that these measures of performance are more comparable to those of extant aquatic vertebrates that use vertically expanded tails to generate forward propulsion while swimming.
--------------------
Visit our website ? ?
www.paleontologyworld.com ✔
(link in Bio) "


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Canada DinoFan83 Offline
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( This post was last modified: 06-25-2021, 11:52 PM by DinoFan83 )

Just going to copy down the overall methodology behind the new Spinosaurus size estimates for those who have not seen it in the other thread. 

Edit 2: Look at post #19 for my current estimates. This post won't be deleted because it has a lot of information and estimates that could be useful in the future for MSNM v4047 and NMC 41852, but for the moment, we still cannot estimate them.

IMPORTANT UPDATE: As per personal communication with SpinoInWonderland, he considers his 1.86 meter estimate for MSNM v4047 to be outdated because he suspects it is based on restored material, and this almost certainly means Ibrahim's latest skeletal used restored cranial material as well given its similarity to the aforementioned restoration. This means that because the juvenile Spinosaurus skulls that were thought to be complete are actually restored, we have not found any appropriately complete and non-restored cranial material at this time to fill in the lack of overlap between FSAC-KK 11888 and MSNM v4047.
Basically, although the estimates below (12260-13700+kg) for MSNM v4047 are still plausible, they cannot be confirmed because of lack in overlap with the neotype as well as a lack in gap-filling material and thus it is strongly advised to avoid estimating any size for it until better cranial material is found. The only probable adult Spinosaurus specimen that can be reasonably estimated from overlap is NHMUK R-16421, which as stated below is 10,940 kg with SpinoInWonderland's estimate of 38.7% larger than the neotype and with the new density estimate. This specimen is the average, maximum, and minimum probable adult size for the species that can be estimated at this time, and it still fits very well into Ibrahim's estimate of 10-12000 kg.

(06-13-2020, 05:07 PM)DinoFan83 Wrote: Here's a quote from SpinoInWonderland regarding the most recent information on Spinosaurus' size. 

"Ibrahim et al. (2020) has a volumetric estimate for the neotype, at 3865 litres. Using a mean density of 0.95 for Spinosaurus gives a mass estimate of ~3.67 tonnes. Scaling up to MSNM v4047 (32% greater dimensions as per Ibrahim et al. 2014) yields about ~8.44 tonnes. It has been argued that the chest of the new reconstruction is too deep, but then the scapulacoracoid is also placed too far back at the chest - these might cancel each other out. Henderson (2018) got a mass estimate too low as the chest they modellled for Spinosaurus was way too narrow than was indicated by the known material."

Asier Larramendi and Greg Paul also suggest 1.05
. This means 4100 kg for the neotype.
Based on the above, we get 10940 kg for NHMUK R-16421 (4100x1.387^3) based on SpinoInWonderland's work. This specimen would be 15.8 meters long based on his 11.4 meter estimate for the neotype.

Quote:As it turns out, correcting the model from Henderson (2018) gets a surprisingly large animal well in line with the estimations from Ibrahim (2020).
The model was 7 tonnes as-is, but not only does it have the ribcage only 63.4% as wide as the deepest point on the torso when it should have been a 1 to 1 width to depth ratio following the new model, the mounted skeletons, and Andrea Cau's attempts to articulate spinosaur ribs, it is also too pneumatic with a density of 0.833 when it should have been around 1, and it doesn't have the new tail which would have been around 1.5 times the mass of the old one judging by the neural spine depth.
The exact torso mass is not listed in the study so to tentatively estimate the corrected version, I'll assume the torso and tail in Henderson's model takes up roughly the same percentage of the animal's mass as SpinoInWonderland's old Spinosaurus (which was only apparently too small-headed and too elongated overall, for proportional size of each body part it should be fine).  

-Pneumaticity correction: Changing the pneumaticity from 0.833 to 1, Henderson's model goes to 8.4 tonnes.  

-Torso widening: Widening the torso about 57.7% (100/63.4=about 57.7) using the assumption that it was proportionally similar to SIW's old GDI (meaning a torso slightly over 55.7% of total mass), it goes up to 11.1 tonnes.  

-Tail mass increase: Increasing the tail mass 50% assuming proportional similarity to the GDI (meaning a tail about 20.8% of total mass), it goes up to 12.26 tonnes*, which compares favorably with the other estimations here.

Quote:I have an alternate size estimate for MSNM v4047 compared to what Ibrahim's suggestion would yield. It is based on the discrepancy between the new skull reconstruction in Ibrahim et al. 2020 for the neotype (122 cm) and SpinoInWonderland's estimate for MSNM v4047 (186 cm). Given that FSAC-KK 11888 and MSNM v4047 do not overlap, this is based on general similarities between the full skull reconstructions, and it looks to me as though both have been restored using criteria that was very similar if not the same.
Comparing both of them, it seems to me that the size difference between the 2 specimens is very likely 52.5% instead of 32.5%, and this is further supported by the fact that they are about the same shape; MSNM v4047 does not look any more elongate which would be misleading to go off of were it the case.
This would then result in an animal of at least 13.7 tonnes (assuming a density of at least 1 for the 3,864 liter neotype), and it would be some 17 meters in length taking the mean of the length estimates from Ibrahim (10.93 meters) and SpinoInWonderland (11.4 meters).
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Czech Republic Spalea Offline
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Sketch of a Spinosaurus catching a fish...





Artist: @holge.me
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" Water Dragon. Art: Jun-Seong-Yi "


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" Spinosaurus, by Jaemin Kim "


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"'River Monster' ?


Artwork by LDN-RDNT (Elden Ardiente) on DeviantArt.
In recent decades, intensive research on non-avian dinosaurs has strongly suggested that these animals were restricted to terrestrial environments. Historical proposals that some groups, such as sauropods and hadrosaurs, lived in aquatic environments were abandoned decades ago. It has recently been argued that at least some of the spinosaurids—an unusual group of large-bodied theropods of the Cretaceous era—were semi-aquatic, but this idea has been challenged on anatomical, biomechanical and taphonomic grounds, and remains controversial. Here we present unambiguous evidence for an aquatic propulsive structure in a dinosaur, the giant theropod Spinosaurus aegyptiacus. This dinosaur has a tail with an unexpected and unique shape that consists of extremely tall neural spines and elongate chevrons, which forms a large, flexible fin-like organ capable of extensive lateral excursion. Using a robotic flapping apparatus to measure undulatory forces in physical models of different tail shapes, we show that the tail shape of Spinosaurus produces greater thrust and efficiency in water than the tail shapes of terrestrial dinosaurs and that these measures of performance are more comparable to those of extant aquatic vertebrates that use vertically expanded tails to generate forward propulsion while swimming. "


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Czech Republic Spalea Offline
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" Spinosaurus ?

Artwork by Alexa Shamshoian
In recent decades, intensive research on non-avian dinosaurs has strongly suggested that these animals were restricted to terrestrial environments. Historical proposals that some groups, such as sauropods and hadrosaurs, lived in aquatic environments were abandoned decades ago. It has recently been argued that at least some of the spinosaurids—an unusual group of large-bodied theropods of the Cretaceous era—were semi-aquatic, but this idea has been challenged on anatomical, biomechanical and taphonomic grounds, and remains controversial. Here we present unambiguous evidence for an aquatic propulsive structure in a dinosaur, the giant theropod Spinosaurus aegyptiacus. This dinosaur has a tail with an unexpected and unique shape that consists of extremely tall neural spines and elongate chevrons, which forms a large, flexible fin-like organ capable of extensive lateral excursion. Using a robotic flapping apparatus to measure undulatory forces in physical models of different tail shapes, we show that the tail shape of Spinosaurus produces greater thrust and efficiency in water than the tail shapes of terrestrial dinosaurs and that these measures of performance are more comparable to those of extant aquatic vertebrates that use vertically expanded tails to generate forward propulsion while swimming. "





Thus, I'm just noting that the spinosaurus was the most aquatic known dinosaur.
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Czech Republic Spalea Offline
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" Amount of detail is amazing. Spinosaurus, by @julian_johnson1234 "


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Canada DinoFan83 Offline
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#15
( This post was last modified: 06-23-2021, 06:18 PM by DinoFan83 )

Spinosaurus skull reconstruction (MSNM v4047) by SpinoInWonderland.

*This image is copyright of its original author

Spinosaurus skulls by theropod1.

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Spinosaurus claw from theprehistoricstore.com. This claw is said to be 54 cm (that's more than half a meter!) long.

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