Episode 172 is all about Sauroposeidon/Paluxysaurus, a sauropod with a complicated history, whose name means “earthquake god lizard” / “Paluxy river lizard.”

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In this episode, we discuss:

News:

The dinosaur of the day: Sauroposeidon / Paluxysaurus

Complicated, so going to start with Sauroposeidon first Name means “earthquake god lizard” (named after the Greek god Poseidon, who’s associated with earthquakes) Sauropod that lived in the Cretaceous in what is now the US (fossils and tracks found in Oklahoma, Wyoming, Texas) Described in 2000 by Wedel,‭ ‬Cifelli‭, and ‬Sanders‭ Holotype found in 1994, at the Antlers Formation, by Bobby Cross, a dog trainer Dr. Richard Cifelli and a team from the Oklahoma Museum of Natural History excavated it later that year The first Sauroposeidon fossils described were four neck vertebrae, found in Oklahoma (near the Texas border). Each vertebrae was very long, the longest one was 4.6 ft (1.4 m). The vertebrae have tiny air cells and are thin, which made the neck lighter and easier to lift Thought the fossils were too large for an animal, and were instead tree trunks. But they are actually the longest known dinosaur neck vertebrae bones Matt Wedel, then a grad student, analyzed the vertebrae in 1999 and realized they weren’t tree trunks. Sent out a press release, which got a lot of media attention, and lots of inaccurate headlines of “the largest dinosaur ever” (probably tallest known, but not longest or heaviest) Matt Wedel said, “Sauroposeidon was an unexpected discovery, because it was a huge, gas-guzzling barge of an animal in an age of subcompact sauropods.” Not many sauropods have been found in North America in the Early Cretaceous, and most of them were shrinking in size, which makes Sauroposeidon stand out Type species is Sauroposeidon proteles Sauroposeidon was so large the ground probably shook when it walked Proteles means “perfect before the end” in ancient Greek, and refers to Sauroposeidon‘s being the last, most specialized sauropod known in North America from the Early Cretaceous Originally thought to be a brachiosaurid and closely related to Brachiosaurus and Giraffatitan Sauroposeidon‘s size is based on comparisons with vertebrae from the Giraffatitan specimen in Berlin’s Natural History Museum (most complete known brachiosaur, though it’s a composite) About 112 ft (34 m) long and weighed about 50-60 tons Could reach up to 59 ft (18 m) high with its neck extended Probably ate from the tops of trees Neck is estimated to be 37-39 ft (11-12 m) long, based on the assumption that it has the same proportions as Giraffatitan Had a more gracile neck than Giraffatitan, and if the rest of its body is just as slender, it may have weighed less (especially if it had an air sac system) Fossils found in Oklahoma show it lived in an environment similar to modern-day Louisiana (humid, with river deltas, bayous, and lagoons) Now how Paluxysaurus fits in Specimens from the Twin Mountains Formation in Texas (including a partial skull and tracks) were previously named Paluxysaurus jonesi and are now considered to be a junior synonym of Sauroposeidon They were reclassified in 2012 after a re-analysis by Michael D’Emic and Brady Foreman D’Emic and Foreman also reclassified additional specimens found in the Cloverly Formation in Wyoming as Sauropoesidon (and those show Sauropoeisdon may be more closely related to titanosaurs than brachisoaurids) At least seven individuals found between Texas (Twin Mountains Formation), Oklahoma (Antlers Formation), and Wyoming (Cloverly Formation)

D’Emic and Foreman suggested that sauropods from the Cloverly Formation were referable to Sauroposeidon based on shared derived characters of a juvenile cervial and the Sauroposeidon holotype, and that Paluxysaurus from Twin Mountains Formation was not distinguishable from the Cloverly sauropod and had the same characteristics as the Cloverly sauropod (which makes Paluxysaurus a junior synonym) Also tracks. Some paleontologists think that the footprints from the bed of the Paluxy River in Texas are of an Acrocanthosaurus stalking a Sauroposeidon Now Sauroposeidon is thought to be a basal somphospondyl (titanosauriform) instead of a brachiosaurid, which makes sense because it had some similar features, and other basal somphospondyls, such as Erketu and Qiaowanlong, have similar cervicals to Sauroposeidon Matt Wedel accepted all this in one of his blog posts, on Sauropod Vertebra Picture of the Week But back to Paluxysaurus Before becoming a synonym to Sauroposeidon, Paluxysaurus was mixed up with the sauropod Pleurocoelus Pleurocoelus was found in Maryland in the late 1800s, and the bones found in Texas were thought to be the same dinosaur (when the Paluxysaurus bones were found and described in 1974 by Wann Langston Jr., only Pleurocoelus was known from North American from the Early Cretaceous) Pleurocoelus was named in 1888 by Charles Marsh. It’s name means “hollow sided” and it lived in the Cretaceous. It’s not well known (partial skull and postcranial bones), and it may be a synonym of Astrodon Paluxysaurus (then Pleurocoelus) was found in a bonebed in the mid 1980s (students from the University of Texas at Austin found the bonebed, but work stopped on it in 1987, and the quarry didn’t reopen until 1993). All the sauropods in the bonebed looked to be the same genus. Found partial skull including teeth, partial neck, vertebrae from the back and tail, limb and girdle bones Found four individuals in a bone bed (may have been due to a flood, especially since petrified logs were found there that may have been washed down river) Pleuroceoelus became the Texas official state dinosaur in 1997, but in 2007 Peter Rose and others named the bones found in Twin Mountains Formation in Texas Paluxysaurus jonesi Paluxysaurus means Paluxy river lizard Paluxysaurus jonesi was named for the town of Paluxy and the Paluxy River, which are near the Jones ranch site where the fossils were found In 2009, Texas passed a resolution to amend the state dinosaur name to Paluxysaurus jonesi Fort Worth Museum of Science and History celebrated the name change by creating a full restoration of Paluxysaurus. It was a composite of all four specimens Initially thought to look similar to Brachiosaurus, but the reconstruction gave a lot of insights Found 60-70% of the bones needed to reconstruct Paluxysaurus Had slim teeth, which it used to grab food, and was built light Had a long neck and a tail nearly as long, as well as long front limbs, which made its back more level Had wide hips and a high shoulder Interestingly, found estimates that it was 70 ft (21 m) long and weighed up to 20 tons Also, these dinosaurs lived in a semi arid environment Anyway, full grown adult Sauroposeidon were probably safe from predators, but juveniles may have been prey for Acrocanthosaurus or Deinonychus or Utahraptor Other dinosaurs that lived in the same time and place included the sauropod Astrodon and the ornithopod Tenontosaurus. Other animals include amphibians, reptiles, fish, crocodilians, turtles, and early mammals



Fun Fact:

Humans and ground dwelling birds are essentially the only living animals which spend their entire adult lives walking & running bipedally (on 2 feet). One more thing humans have in common with dinosaurs.



This episode was brought to you by:

TRX Dinosaurs, which makes beautiful and realistic dinosaur sculptures, puppets, and exhibits. You can see some amazing examples and works in progress on Instagram @trxdinosaurs.

And by the Royal Tyrrell Museum, which is located in southern Alberta, Canada. Right now they are hosting their free-to-attend Winter speaker series (also on YouTube). More information can be found at tyrrellmuseum.com.