Episode 356 is all about Gastonia, an ankylosaur found fossilized in groups, possibly indicating that ankylosaurs weren’t as solitary as previously thought..
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In this episode, we discuss:
News:
- A tyrannosauroid and a hadrosaur were found from the Late Cretaceous in what is now New Jersey source
- Remains from ankylosaurs, titanosaurs, abelisauroids, and peirosaurids were found in Santa Cruz, Argentina source
- A large ceratopsian skull was excavated from near the Redwillow River in Northern Alberta, Canada source
- The natural history museum in Karlsruhe, Germany is planning to keep Ubirajara—and not return it to Brazil source
- Massachusetts is one step closer to getting an official state dinosaur after the bill passed its first committee source
The dinosaur of the day: Gastonia
- Ankylosaur that lived in the Early Cretaceous in what is now Utah, US (Cedar Mountain Formation)
- Looked like other ankylosaurs, walks on four legs, heavily armored, had a beak
- Estimated to be around 16 ft (5 m) long and weigh 1.9 tonnes
- Had a flat, broad body
- Body covered in round bony scutes
- Had a large pelvic shield with bony plates fused together
- Had large, triangular spikes on the top and sides of its body
- Had an expanded shinbone
- Had a long tail with no tail club
- The tail had triangular blades on the sides that could have sheared and left gashes (part of its defense)
- Had a relatively long neck
- Had at least two bone rings covering the neck
- Had an elongated, somewhat pointed skull
- No armor on the snout
- Had small horns on the cheeks (jugal horns) and the back of the skull (squamosal)
- Had a notch in the upper beak (beak was toothless)
- May have head butted. Braincase was somewhat flexible, which would help with absorbing shock. Also had a pretty thick skull
- Had forward facing eyes
- Herbivorous
- Hundreds of Gastonia bones have been found together
- Gastonia discovery helped show ankylosaurs may not have been solitary
- May have lived in herds
- Two species: Gastonia burgei and Gastonia lorriemcwhinneyae
- Gastonia burgei named in 1998 by Jim Kirkland
- Gastonia lorriemcwhinneyae named by Kinneer and others in 2016
- Genus name “Gastonia” is in honor of Robert Gaston, paleontologist and CEO of Gaston Design, Inc. (makes fossil replicas)
- Gaston found the fossils when he worked for a rock shop owner in Moab, Utah
- Species name “burgei” in honor of the former director of the College of Eastern Utah Prehistoric Museum, Donald Burge
- Species named for Lorrie McWhinney, who found the Gastonia bone bed in 1999; holotype is a skull roof
- Gastonia is also the name of a city in North Carolina, US
- Holotype of Gastonia burgei is the skull of an adult
- Type specimen (CEUM 1307) was found in a bonebed in Grand County, Utah (Yellow Cat Member of Cedar Mountain Formation)
- Bonebed included fossils of a few Gastonia, an iguanodontid, and Utahraptor
- The most common fossils in Cedar Mountain Formation were Gastonia
- May have been so common because it was so well protected against Utahraptor
- Lots of Gastonia fossils, but also lots of disarticulated material
- 1998 paper mentioned four partial skulls, a complete uncrushed skull, and lots of vertebrae and armor (said lots of fossils were scattered, so it was five individuals found at a minimum)
- Had characters of ankylosaurids and nodosaurids
- Had an ankylosaurid like skull
- Had a triangular skull
- Discovery of a second species of Gastonia adds to support of defining Polacanthidae as a family of ankylosaurs separate from Ankylosauridae and Nodosauridae as previously suggested by Carpenter in 2001, Kirkland and others in 2010, Loewen and Kirkland in 2013 and Loewen and others in 2014
- For specimens with certain shared nodosaurid and ankylosaurid like characters
- Polacanthidae not universally accepted partly because other analyses are restricted to skulls
- In 2016 Billy Kinneer, Kenneth Carpenter, and Allen Shaw redescribed Gastonia and named the new species, Gastonia lorriemcwhinneyae
- Gastonia lorriemcwhinneyae had a flat skull roof, compared to Gastonia burgei’s more domed head
- Gastonia has been found in Yellow Cat Quarry (Gaston Quarry) north of Arches National Park, Utah; Dalton Well Quarry north of Moab, Utah; Lorrie’s Site, near Yellow Cat Quarry (known from two skulls and two partial skulls (skull is one of the best early ankylosaur skulls known))
- Named the second species based on individuals found in a bone bed known as Lorrie’s Site (a predominantly monospecific bone bed of Gastonia)
- Possible the individuals died together from a drought or they drowned while crossing a swollen river
- Said most Cedar Mountain ankylosaurs are known from partial, usually single individuals, except Gastonia
- All three localities were bone beds
- Holotype type locality is Yellow Cat Quarry, had lots of bones that were mostly disarticulated and scattered, some bones badly crushed and distorted (hard to reconstruct the armor)
- In the Dalton Well Quarry: At least nine individuals found based on braincases and skulls (8 are subadults and one is an adult)
- Fossils may show gregarious behavior. A 2009 study found them to be at least partially articulated at the time of debris-flow reworking (the alternative that the group was killed and transported before burial is unlikely because the soft tissue should have resulted in articulated skeletons)
- Lorrie’s Site: Articulated bones found, most bones show damage (including crushing), and damage appears to be due to trampling
- Probably a gregarious herd or group that died together, possibly died congregating at a waterhole during a drought, then were scavenged and bones disarticulated, and remains transported and buried on a floodplain
- Or died from a mass drowning of a herd migrating while forging a river, based on distribution of bones being similar to wildebeest drowning mortalities with carcasses concentrated on a floodplain
- Either way, had some postmortem decay and disarticulation, then was buried
- Lived in a dry area with a short wet season, in a partly wooded area
- Other dinosaurs that lived around the same time and place include Hippodraco, Cedrorestes, Iguanacolossus, the sauropod Cedarosaurus, theropods Geminiraptor, Martharaptor, Nedcolbertia, Utahraptor, and Yurgovuchia
Fun Fact: Many modern dinosaurs (birds) can learn new sounds to impress mates. It’s possible that non-avian dinosaurs also used vocal mimicry to attract mates.
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