In our 161st episode, we got to chat with Mark Hallett and Dr. Mathew J. Wedel, the creators of the book, The Sauropod Dinosaurs: Life in the Age of Giants, published in 2016 by Johns Hopkins University Press. (Big thank you to Mark, who gave us some amazing images to share, including his artwork for his 2018 calendar!)

Mark is a paleoartist and author, whose work has been featured in Life, Smithsonian, Natural History and National Geographic magazine, as well as books, art galleries, and museums all over the world. He was also the artist consultant for the movies Jurassic Park and Dinosaur.

Matt is a vertebrate paleontologist who studies sauropod dinosaurs and the evolution of pneumatic bones in dinosaurs and birds and an associate professor of anatomy at Western University of Health Sciences. He co-authored the papers naming the dinosaurs Sauroposeidon, Brontomerus, and Aquilops. And he co-founded the website Sauropod Vertebra Picture of the Week.

You can also learn more about their work and passions at Artists for Conservation and Prehistoric Times.

Episode 161 is also about Apatosaurus, a sauropod whose name means “deceptive lizard.”

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In this episode, we discuss:

News:

The dinosaur of the day: Apatosaurus

Sauropod that lived in the Jurassic in what is now North America Name means “deceptive lizard” Named in 1877 by Othniel Charles Marsh (named the first known species, Apatosaurus ajax) The Apatosaurus holotype was found in 1860 in Gunnison County, Colorado Marsh gave Apatosaurus its name because of its chevron bones, which are similar to mosasaurs (and not other dinosaurs) When this skeleton was being excavated and transported, its bones were mixed with another Apatosaurus speciman (originally described as Atlantosaurus immanis), so some features it’s unclear if they belong to Apatosaurus or Atlantosaurus Marsh said the difference between Apatosaurus and Atlantosaurus was the number of sacral vertebrae (Apatosaurus had three and Atlantosaurus had four) Lots of Apatosaurus species have been named, based on fragments (Marsh named many species during the Bone Wars) Marsh named Apatosaurus ajax in 1877 after Ajax, a Greek mythology hero (holotype is incomplete, and hasn’t been studied as much as other species) Atlantosaurus inmanis may be a junior synonym of Apatosaurus ajax Marsh named Apatosaurus grandis in 1877, but then he reassigned it to Morosaurus in 1878. Morosaurus is now considered to be a synonym of Camarasaurus There’s also Apatosaurus parvus, which was first described in 1902 by Peterson and Gilmore as Elosaurus, then reclassified as Apatosaurus in 1994. In 2015, it was reassigned to Brontosaurus Also, Apatosaurus minimus, originally described in 1904 as Brontosaurus by Osborn. Henry Mook named it Apatosaurus minimus in 1917, then in 2012 Mike Taylor and Matt Wedel described material as “Apatosaurus” minimus, so it’s unclear In 1957 Albert-Félix de Lapparent and Georges Zbyweski named Apatosaurus alenquerensis, based on material found in Portugal, but in 1990 this was reclassified as Camarasaurus and in 1998 it was renamed Lourinhasaurus In 1994 James Filla and Patrick Redman named Apatosaurus yahnahpin, which in 1998 Bakker made the type species of new genus Eobrontosaurus, and Tschopp reclassified as Brontosaurus in 2015 William Holland named Apatosaurus louisae in 1916, based on a partial skeleton found in Utah For a long time Brontosaurus was thought to be a junior synonym of Apatosaurus In 1879, Marsh named Brontosaurus excelsus Elmer Riggs described a diplodicid found in Colorado in 1903. He thought where it was found was similar in age to where Marsh found Brontosaurus. Riggs compared the skeleton with Brontosaurus and Apatosaurus ajax, and found that the holotype for Apatosaurus ajax was a juvenile, and that the features that distinguished Brontosaurus and Apatosaurus were not valid. Apatosaurus was named first, which is why Brontosaurus was thought to be a junior synonym. Bob Bakker argued in the 1990s that Brontosaurus and Apatosaurus were two separate genera Tschopp and others reclassified Brontosaurus as a valid genus in 2015, though not everyone agrees (more in episode 100) The name Brontosaurus stuck around, even when it wasn’t considered to be a valid genus Elmer Riggs had published his findings in an obscure journal, so not many people knew about his conclusions at the time Also, Brontosaurus/Apatosaurus was the first sauropod skeleton mounted (specimen number 460, occasionally assigned to Apatosaurus, was mounted in the American Museum of Natural History. It was found in 1898 by Walter Granger in Wyoming. The mounted skeleton were missing the head, feet, and parts of the tail, so Apatosaurus feet and parts of the tail found in the same quarry were used. The skull was sculpted based on the “”the biggest, thickest, strongest skull bones, lower jaws and tooth crowns from three different quarries”, probably from Camarasaurus (only other sauropod at the time with known good skull material). Adam Hermann oversaw the mount, and he sculpted a stand-in skull by hand. Osborn said it was “largely conjectural and based on that of Morosaurus” (now Camarasaurus). The mount was labeled as Brontosaurus Because AMNH was so popular, Brontosaurus became one of the most well known dinosaurs The name Brontosaurus was used in pop culture (Gertie the Dinosaur, The Lost World, and as the logo of the Sinclair oil company, as well as Dino in the Flintstones, and as a dinosaur stamp in 1989) Apatosaurus had a skull similar to Diplodocus, though for a long time it was thought to be similar to Camarasaurus Skull was relatively small An Apatosaurus skull was found in 1909 in an expedition led by Earl Douglass, in the Carnegie Quarry at Dinosaur National Monument. It was found near the Apatosaurus louisae specimen (named after Louise Carnegie, Andrew Carnegie’s wife). The skull was similar to Diplodocus. Douglass and William H. Holland, and other scientists, thought it was an Apatosaurus skull but not everyone agreed (like Henry Fairfeld Osborn, who mounted an Apatosaurus skeleton with a Camarasaurus skull cast in the American Museum of Natural History). Holland defended this view in 1914, but he did not mount a head on the Carnegie Museum skeleton (possibly he was waiting for an articulated skull and neck to be found to confirm it was the right skull). Holland died in 1934 and museum staff put a Camarasaurus skull on the mount Yale Peabody Museum sculpted a skull for their mount, based on the lower jaw of a Camarasaurus and Marsh’s 1891 illustration In the 1970s John Stanton McIntosh and David Berman redescribed Diplodocus and Apatosaurus skulls, and they found that Apatosaurus skull was similar to Diplodocus, and that many skulls thought to be Apatosaurus were actually Diplodocus. They reassigned skulls In 1979, the Carnegie Museum mounted the first true Apatosaurus skull In 2011 the first articulated Apatosaurus skull was described (specimen had similar cervical vertebrae as Apatosaurus ajax and different neck and skull features from Apatosaurus louisae) Mossbrucker found the first Apatosaurus ajax snout in 2013 Brigham Young University has a specimen with a well preserved skull and skeleton, and a preserved braincase, found in western Colorado Apatosaurus was found in the Morrison Formation in Colorado, Oklahoma, New Mexico, and Utah Apatosaurus was the second most common sauropod found in the Morrison Formation (Camarasaurus was the first) The most complete Apatosaurus found so far is nicknamed Einstein Apatosaurus may have been more solitary than other dinosaurs in the Morrison Formation Other dinosaurs that lived in the same time and place include Allosaurus, Camarasaurus, Diplodocus, Stegosaurus Carnivores that lived around the same time and place included Ceratosaurus, Allosaurus, Torvosaurus Part of the family Diplodocidae (other dinosaurs include Diplodocus, Supersaurus, Barosaurus) Part of the subfamily Apatosaurinae (named in 1929); only other genus in the subfamily is Brontosaurus Apatosaurus had a stockier build than Diplodocus On average was about 69-75 ft (21-22.8 m) long, and weighed about 18-25 short tons (though some were longer and weighed more) Apatosaurus had necks that were different from other diplodocids, and may have used them for intraspecific combat Had paired spines, which gave it a wide, thick and long neck, and a deep chest Lots of debate over how flexible or inflexible its neck was Some say Apatosaurus may have had an inflexible neck, held horizontally to a slightly upwards angle (may have been niche partitioning so different types of sauropods could live together) A 2009 study argued that Apatosaurus may have held its neck high and had a flexible neck, based on comparisons with extant animals Some debate over how Apatosaurus used its neck for feeding (high browser, low browser). Kent Stevens and Michael Parrish in 1999 and 2005 said Apatosaurus had a wide neck range of movement. In 2013, Matthew Cobley and others said it had limited neck movement due to large muscles and cartilage, and also that sauropods like Diplodocus may have moved their whole bodies to eat and may have spent more time foraging. However, Taylor found that Apatosaurus had a flexible neck A 2013 study looked at the flexibility of ostrich necks (the most similar to sauropod necks) and found that previous models of neck flexibility didn’t account for soft tissues so it’s unclear how flexible and how high Apatosaurus necks could be held Apatosaurus probably kept its tail above the ground, for counterbalance Had tall neural spines Had a slender tail, which is different from other diplodocids May have used its tail as a whip to create loud sounds In 1997, Nathan Myhrvold and Philip Currie did a computer simulation of an Apatosaurus tail, and found it could make a whiplike sound of more than 200 decibels Tail was probably too slender at the tip, so couldn’t hurt predators and be used as a weapon, and may have been damaged if used for attacking One Apatosaurus tail has been found with a pathology, caused by a growth defect Apatosaurus, like many other sauropods, were originally thought to have been semi-aquatic, though people no longer think this is true (definitely terrestrial) Quadrupedal, with forelimbs being slightly shorter than hindlimbs Sauropod trackways show they may have moved up to 12-19 mi (20-30km) per hour Apatosaurus probably had a similar respiratory system as birds, with air sacs in the neck (helped make the bones lighter) May have had a warm blooded metabolism (had a large body mass, with a relatively small surface area which means the body has thick internal organs and the outer layers of tissue insulate the internal layers, so there is a high base temperature). This may mean Apatosaurus metabolism may have worked similarly to mammals. Another reason Apatosaurus may have had a warm blooded metabolism is based on how fast juveniles grew Apatosaurus grew quickly as a juvenile and became near full size around 10 years, based on a study in 1999 Thomas Lehman and Holly Woodward found in 2008 that Apatosaurus may have grown 25 tons in 15 years, peaking at 11,000 lb (5,000 kg) in one year, based on growth lines and length-to-mass ratios. Another method with limb length and body mass, found Apatosaurus grew 1,150 lb (520 kg) per year, and reached full weight at 70 years old. But these estimates are not considered to be reliable, since old growth lines would have been messed up by bone remodeling Some specimen’s ages have been estimated. Eva Griebeler and others in 2013 found that one specimen reached maturity at age 21 and died at age 28, and another reached maturity at age 19 and died at age 31 Lots of juvenile Apatosaurus have been found. Juveniles tend to have shorter necks and tails, and a bigger difference between the length of their forelimbs and hindlimbs Apatosaurus footprints were found in Morrison, Colorado, in 2008, that indicated juveniles could run on two legs Had a claw on each forelimb and three claws on each hindlimb Claw on the forelimb may have been used for defense (unlikely though based on shape and size), also possibly used for feeding, but most likely used to grab things like tree trunks, when rearing up Herbivore, and had chisel-like teeth A general browser, that kept its head elevated Could probably eat 880 lb (400 kg) of food per day Had gut microbes to help them digest vegetation, and they may have swallowed lots of food without chewing In 2014 there was a hoax article going around that claimed John Moore University in the UK cloned a baby Apatosaurus nicknamed “Spot”, and included a picture of a hairless baby kangaroo There’s an Apatosaurus song, by Storybots, on Youtube. It’s a kids song and not that scientifically accurate, but kind of catchy (one of the lines is, “my neck’s so long, and so strong”)



Fun Fact:

Bone cores from horns don’t always tell the whole story about the shape of the overall horn. Often keratin coverings add extra curves or length not clear by the bone alone.

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