Episode 274 is all about Haplocanthosaurus, a relatively small sauropod measuring a measly 49 ft long and 13 tons in weight.

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In this episode, we discuss:

News:

Big Al is now Allosaurus jimmadseni and no longer Allosaurus fragilis source

A new set of sauropod tracks in Texas could be swim tracks—or maybe not source

Storm Ciara in the UK uncovered a new 130 million year old dinosaur footprint source

Colin Trevorrow shared a video of what looks like a Nasutoceratops puppet from Jurassic World 3 source

The dinosaur of the day: Haplocanthosaurus

Sauropod that lived in the Late Jurassic in what is now Colorado, US, and possibly Wyoming (Morrison Formation)

Rare sauropod in the Morrison Formation

One of the smallest sauropods from the Morrison Formation

Estimated to be about 49 ft (14.8 m) long and weigh 13 tons

Relatively small bodied and relatively short tail

No skull found, which makes it hard to classify (may be a close relative of Camarasaurus?)

Mostly found vertebrae

Some debate over phylogeny but a 2015 study found it to be a diplodocoid

Two species: Haplocanthosaurus priscus (type) and Haplocanthosaurus delfsi

Genus name means “simple spined lizard”

First described from specimens collected at the Marsh-Felch Quarry in Colorado

John Bell Hatcher was recently appointed curator of vertebrate paleontology at the Carnegie Museum in 1901, and reopened the Marsh-Felch quarry in Garden Park, Colorado, where he and his team found two medium-sized, partial skeletons of Haplocanthosaurus priscus

Hatcher named Haplocanthosaurus in 1903, as Haplocanthus. But four months later changed the name to Haplocanthosaurus because Haplocanthus was “essentially preoccupied” (it was the name of a fish that Louis Agassiz named in 1844)

However, the fish was spelled “Haplacanthus”, not “Haplocanthus”

Turns out Hatcher didn’t need to rename the dinosaur. Because the spelling of the fish was different, the name Haplocanthus was valid, until a petition was sent to the ICZN and they ruled in 1991 that Haplocanthosaurus was the correct name because of widespread use (like how they ruled that T. rex was the valid name)

Hatcher published a monograph in 1903 and then named a second species, Haplocanthosaurus utterbacki, but this is now considered to be a juvenile Haplocanthosaurus priscus

Haplocanthosaurus delfsi was named in the 1950s, based on a specimen nicknamed Happy

Happy was found in 1954 and estimated to be 72 ft (22 m) long and weigh about 25 tons

Happy was collected between 1945 to 1957 in Fremont County, Colorado. Excavations were led by Edwin Delfs, who as an undergrad biology major at Yale at the time. Local rancher Joe Rhode did the bulldozer work

Happy was found lying on its left side, and mostly articulated (skull missing, neck bent backward in death pose), also missing other elements, including parts of the tail

Happy was about 35-50% larger than the holotype of Haplocanthosaurus priscus, and was named a new species: Haplocanthosaurus delfsi

Also found turtle fragments, isolated theropod tooth, crocodile Eutretauranosuchus, around Happy

Happy was restored (about 70% real fossils, the only Haplocanthosaurus complete enough to display), and missing parts modeled or cast from specimens in the AMNH; skull and mandible modeled in a “generalized sauropod fashion”

Can now see Happy at the Cleveland Museum of Natural History

May be up to ten specimens assigned to Haplocanthosaurus (not all are yet confirmed). One is nicknamed “Big Monty” (found in Montana) and thought to be 110 ft (33 m) long, but controversial and not much known about the specimen (found by Nate Murphy, who runs the private company Judith River Dinosaur Institute, that finds, excavates, and prepares fossils; Nate estimates the 110 ft length, Cary Woodruff believes it’s smaller, based on one of the 3-ft long vertebra, which is not big for sauropods, and thinks it’s not a new species but that it is a rare Haplocanthosaurus)

Fun Fact: While the Dinosaurs arose following a 100 million year ice age, there was little to no ice during the entire Mesozoic. Still, sea level changed frequently from tectonic plate activity and other climate changes.

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