Episode 440: Fossilized ankylosaur larynx, sinus infections, and facial bite marks. Plus Trinity the T. rex was auctioned, a brief history of dinosaur jewelry, and dinosaur of the day Saurolophus

News:

• A fossilized larynx of an ankylosaur, Pinacosaurus, shows that they didn’t use their larynx to vocalize source
• Researchers found a surprising massive bony growth near the trachea of a Tarchia that was likely caused by an infection source
• Trinity the T. rex was auctioned for $6.1 million (USD) source
• Fukui Prefectural University in Japan will be offering dinosaur studies source
• There’s a family friendly dinosaur movie, The Adventures of Jurassic Pet 2: The Lost Secret source

Sponsors:

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The dinosaur of the day: Saurolophus

• Hadrosaurid that lived in the Late Cretaceous in what is now Alberta, Canada and Mongolia (Horseshoe Canyon Formation and Nemegt Formation)
• One of the few dinosaurs known from more than one continent
• Looks similar to Parasaurolophus, with the bulky body, could walk on all fours, had a long, horse-shaped head, and long tail, but the crest was different
• Crest was smaller, spike-like, and curved upwards at the back
• Crest goes up and back at about a 45 degree angle, and sticks out behind the skull
• Crest is mostly solid, but had a hollow base (where it attached to the skull)
• Crest is made of its nasal bones
• Longest skull bones are the nasal bones
• Crest grew as it aged
• Based on its scleral rings, Saurolophus may have been cathemeral (active throughout the day for short periods of time)
• Herbivorous, and could walk on all fours or on two legs
• Had a horseshoe-shaped lower jaw that wrapped around the toothless parts of the jaw to form a beak
• Cropped plants with its beak
• Had dental batteries with hundreds of teeth, which it constantly replaced
• Could grind its food, almost like chewing
• Could eat food that was up to 13 ft (4 m) above the ground
• Type species is Saurolophus osborni
• Genus name means “lizard crest”
• Named by Barnum Brown in 1912
• Second species is Saurolophus angustirostris
• Described by Anatoly Rozhdestvensky in 1952
• Brown found the Saurolophus osborni fossils in 1911
• First nearly complete dinosaur skeleton found in Canada
• Three Saurolophus osborni specimens have been found, including a virtually complete skull and skeleton
• Holotype of Saurolophus osborni was mounted on a panel behind glass, and shows the right side of the animal, at the AMNH
• The Russian Palaeontological Expedition to the Gobi Desert in 1947, led by I. A. Efremov, found a hadrosaur bonebed (later found to be Saurolophus angustirostris)
• Bonebed is known as “Dragon’s Tomb”
• So many well-preserved and articulated skeletons in Dragon’s Tomb, which has made it a favorite spot for poachers
• Saurolophus is about 20% of the fossils found in the Nemegt Formation
• At least 15 specimens known for Saurolophus angustirostris
• In 1930 Riabinin named Saurolophus kryschtofovici, but it’s no longer considered to be valid (based on part of a hip found from Heilongjiang Province, China but it’s too fragmentary, and it had been compared to an isolated but complete ischium that was later found to be Hypacrosaurus)
• In 2013, Albert Prieto-Márquez and Jonathan R. Wagner named Saurolophus morrisi, but that’s now considered to be Augustynolophus, the state dinosaur of California
• Brown thought Saurolophus and Trachodon were similar and related. Also compared the crest to that of a chameleon’s (thought it would be a spot where muscles attached and then connected to a frill in the back of the head like a basilisk lizard)
• Brown said the crest is “the most characteristic and striking feature of the skull”
• Peter Dodson thought the crest was used for identifying if the animal was male or female
• In 1981, Maryanska and Osmólska suggested the crest was used for thermoregulation
• James Hopson thought the crest was for display and suggested there were inflatable skin flaps over the nostrils as well
• Now there are just the two valid species: osborni and angustirostris
• Both species have the same head crests, and lots of other similarities, so in the past scientists questioned if both species were valid
• In 2011, Phil Bell redescribed both Saurolophus angustirostris and Saurolophus osborni (in two different papers)
• Found the two species to be distinct and valid, and each had unique characters (not just due to individual variation)
• Saurolophus osborni was estimated to be about 27 to 28 ft (8.2 to 8.5 m) long and weigh about 3 tonnes, with a skull about 3.3 ft (1 m) long
• Saurolophus angustirostris is estimated to be up to 43 ft (13 m) long, and possibly even bigger, and weigh up to 11 tonnes
• Saurolophus angustirostris had a 20% longer skull, and the front of its snout went more upward than Saurolophus osborni
• Largest known Saurolophus angustirostris skull is about 4 ft (1.22 m) long
• Found differences in the details of the skull too
• Unclear which species came first
• In 2012 Phil Bell studied the skin impressions of both species, which were found on multiple individuals
• Skin from the face of Saurolophus osborni known from a single fragment from a right dentary
• No skin found on S. osborni forelimb, but “entire forelimb of S. angustirostris covered in a uniform arrangement of 1–2 mm wide pebbles even in relatively large individuals”
• Skin found in pelvic region of S. angustirostris (small patch on a subadult)
• Skin found on part of the foot of S. osborni
• Skin on hindlimb of S. angustirostris also found in adults and subadults
• At least two patches of faintly preserved skin found on a juvenile Saurolophus angustirostris
• Patches of miscellaneous skin also found (unclear where on the body they came from)
• Found lots of scales, including: polygonal (range from four to six-sided), pebbly scales that are small and rounded, shell scales that are asymmetrical and somewhat trapezoidal in shape, and irregular scales (no obvious geometrical sides), shield scales that are circular and are typically flat or domed
• Found differences in the patterns and shapes of the scales, enough to differentiate the two species
• Skin found on the tails of both species
• Lots of differences in the tail scales
• On Saurolophus osborni, the tail scales were more clustered and it may have had more of a spotted coloration
• Saurolophus angustirostris had scales on its tail that made vertical patterns, which may mean it had striped colors on its tail
• In 2018, Phil Bell and others studied the sedimentology and taphonomy of Dragon’s Tomb
• Ivan A. Efremov’s team found seven hadrosaurid skeletons lying close together (discovered in 1948 by V. Pronin)
• Collected at least four skeletons, or parts of four skeletons, and had to transport them by camel (couldn’t get vehicles to the site)
• Lots of expeditions have also visited the site
• Dragon’s Tomb has a bonebed of mostly Saurolophus angustirostris, with juveniles, subadults, and adults
• One tyrannosaur skeleton found, probably Tarbosaurus
• Found the bonebed was at least about 21,500 sq ft or 2000 sq m, and there may be over 100 Saurolophus skeletons in the bonebed
• Estimated the minimum number of Saurolophus individuals in the bonebed is 21
• Shows gregarious, or social, behavior of Saurolophus angustirostris
• Evidence of a catastrophic mass death (they were killed and buried rapidly)
• Based on the skeletons being well preserved and complete, likely bonebed happened because of a flood, or multiple floods that happened quickly (days to weeks in one year)
• One left arm of a nearly complete Saurolophus angustirostris had heavy damage from bite marks. The rest of the skeleton was fine, so it’s likely a tyrannosaurid scavenged the arm, probably Tarbosaurus
• “Unfortunately, the reliability of this locality for yielding beautiful and complete specimens of Saurolophus angustirostris has made it a target of illegal fossil poachers, and in recent years untold numbers of specimens have been illegally plundered and/or destroyed”
• Poaching started sometime after 2001
• In 2015 Leonard Dewaele and others described a small, partial nest of Saurolophus angustirostris, that probably came from the Dragon’s Tomb in the Nemegt Formation
• Unclear where exactly the fossils came from. Fossils were poached then ended up in Japan by way of a collector from Europe, then donated to the Royal Belgian Institute of Natural Sciences, which repatriated the fossils to Mongolia. They’re now at the Institute of Paleontology and Geology of the Mongolian Academy of Sciences
• Said there were three, maybe four, babies and two fragmentary eggshells in the block they prepared
• Babies were considered to be perinates (just born) because the length of their skulls were less than 5% the length of the adult skulls
• Skull length estimated to be about 2.3 in (6 cm) long
• No nasal crest, may have broken off or possible baby Saurolophus didn’t have a crest (yet)
• But, adult crests are so robust it’s unlikely the crest broke off
• Other skull bones were similar to those in adult Saurolophus (how they knew the babies were Saurolophus)
• Had upwardly directed snouts like adult Saurolophus
• Eggshell fragments found look similar to other eggs associated with more basal hadrosauroids
• Arm bones found from three, maybe four, individuals
• Babies were probably close to each other and nest-bound when they died
• Unclear if the babies had just hatched or were still in the eggs when they died, but they were dead and partly decomposed when they were buried by river sediment
• A partially articulated skeleton (includes the skull, neck vertebrae, part of the tail, the right leg, and more) and the rest of the bones being disarticulated suggests some of the perinates were more decomposed than others
• Studied the sediments surrounding the fossils
• They were buried by river sediment probably during the wet summer season
• Probably died within a relatively short time interval
• Fragile bones are well preserved and a partially articulated skull show the bones weren’t moved far before being buried
• Babies didn’t have the spike-like crest, which probably means the crest grew as Saurolophus grew up
• Also as it grew, its snout grew proportionally longer
• Ducky from Land Before Time is probably a Saurolophus, though there’s some debate around this
• In the 1997 Land Before Time Sing Along Songs video, Ducky is a Saurolophus
• Ducky had a head crest like Saurolophus
• But Ducky was portrayed inconsistently in the series. Apparently the Land Before Time website, which no longer exists, called Ducky both Trachodon and Parasaurolophus, and in merch Ducky is labeled as Parasaurolophus
• In the Horseshoe Canyon Formation, other dinosaurs that lived around the same time and place as Saurolophus included the ornithopods Hypacrosaurus and Parksosaurus, the ankylosaur Anodontosaurus, the pachycephalosaur Sphaerotholus, the ornithomimid Ornithomimus, the theropods Atrociraptor and Albertonykus, and the larger theropod tyrannosaurid Albertosaurus
• In the Nemegt Formation, there were streams and rivers and shallow lakes. Other dinosaurs that lived around the same time and place as Saurolophus included the hadrosaurid Barsboldia, the pachycephalosaurs Homalocephale and Prenocephale, the ankylosaur Saichania, the titanosaurs Nemegtosaurus and Opisthocoelicaudia, the alvarezsaur Mononykus, troodontids such as Zanabazar, oviraptorosaurs including Rinchenia and Nemegtomaia, ornithomimosaurs Anserimimus and Gallimimus, theropods Deinocheirus and Therizinosaurus, and the larger theropod tyrannosaurid Tarbosaurus

Fun Fact:

Birds can recover very fast from near extinction.

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