Sauropod Vertebra Picture of the Week

Turns out that if Mike and I don’t post about sauropods for a while, people start doing it for us! This very interesting project by Tom Johnson of Loveland, Colorado, first came to my attention when Tom emailed Mark Hallett about it and Mark kindly passed it on to me. I got in touch with Tom and asked if he’d be interested in writing it up for SV-POW!, and here it is. Many thanks to Tom for his willingness to share his work with us. Enjoy! – Matt Wedel

– – – – – – – – – – – – – – – – – – – –

The sauropod formerly known as Apatosaurus in the American Museum of Natural History was the first permanently mounted sauropod dinosaur in the world, and for many years, the most famous (Brinkman 2010). The greater part of the skeleton consists of the specimen AMNH 460 from the Nine Mile Crossing Quarry north of Como Bluff, Wyoming, supplemented with bones from other AMNH specimens from Como Bluff, Bone Cabin Quarry, and with plaster casts of the forelimbs of the holotype specimen of Brontosaurus excelsus (YPM 1980) at the Yale Peabody Museum.

A herd of Brontosaurus skeleton models parading before four box covers issued between the 1950s and 1990s.

Like many aging boomer dinophiles, my dinosaur epiphany was the result of books, movies, and toys available in the 1950s, but especially a series of plastic model dinosaur skeletons that appeared around 1958. The Brontosaurus was my personal favorite, and, like the Tyrannosaurus and Stegosaurus models in the series, was very obviously based on the AMNH mount. The models were reissued at least three times over the years and can still be found either “mint in box” or more often in various stages of completion.

Apatosaurus lousiae 1/12 scale skeleton, modelled by Phil Platt, assembled and photographed by Brant Bassam. Image courtesy of BrantWorks.com.

The crème de la crème today, of course, is the 1:12 scale Apatosaurus skeleton model by Phil Platt, available from Gaston Design in Fruita, Colorado. A particularly nice example is the one completed and mounted by Brant Bassam of BrantWorks. The Platt skeleton is a replica in the true sense of the word. The plastic models are pretty crude in comparison, as cool as they appeared to us as kids.

I was interested in skeletal illustrations I have seen of Tyrannosaurus rex, which compare the completeness of various specimens by showing the actual bones included by coloring them red. A 2005 study of Apatosaurus by Upchurch et. al. examined eleven of the most complete Apatosaurus individuals, and I was interested to see the actual bones known for each specimen. Using published descriptions, red markers, and copies of a skeletal silhouette of Apatosaurus (permission obtained from the artist), I prepared a comparison of the most completely known Apatosaurus specimens. It was clear, of course, that Apatosaurus louisae (CM 3018) is the most complete specimen of the Apatosaurus/Brontosaurus group. But it also was apparent that old AMNH 460 included a substantial portion of the skeleton, even if it is a composite.

I grabbed some additional markers and, using the illustration of the mount in William Diller Matthew’s popular book Dinosaurs (Matthew 1915, fig. 20, which I trust is in the public domain by now), I color-coded the bones according to the composition as listed in Matthew’s (1905) article:

• AMNH 460, Nine-Mile Crossing Quarry: 5th, 6th, 8th to 13th cervical vertebrae; 1st to 9th dorsal; 3rd to 19th caudal; all ribs; both coracoids; “parts of” sacrum and ilia; both ischia and pubes; left femur and astragalus; and “part of” the left fibula. RED
• AMNH 222, Como Bluff: right scapula, 10th dorsal vertebra, right femur and tibia. GREEN
  (Visitors to AMNH: you can see the rest of AMNH 222 under the feet of the hunched-over Allosaurus)
• AMNH 339, Bone Cabin Quarry: 20th to 40th caudal vertebrae. LIGHT BLUE
• AMNH 592, Bone Cabin Quarry: metatarsals of the right hind foot. VIOLET
• YPM 1980, Como Bluff: left scapula, forelimb long bones (casts). YELLOW
• The remaining parts of the skeleton are either modeled in plaster or are unspecified (“a few toe bones”). BLACK

It occurred to me that I might have sufficient spare parts of old ITC and Glencoe Brontosaurus models to create a three-dimensional version. I did, and painting prior to assembly definitely made the job easier.

There are obviously limitations to using Matthew’s (1915) reconstruction (e.g., only 13 cervicals) and the model (12 cervicals). It is also not clear from Matthew’s description how much of the sacrum and ilia were restored. Nevertheless, the painted model does provide a colorful, if crude, visualization of the composition of the composite.

Here are some more photos of the finished product:

A view from the front of the model, compared with a historical AMNH photo of the forelimbs and pelvic girdle.

Long considered a specimen of Brontosaurus excelsus or Apatosaurus excelsus, AMNH 460 was referred to Apatosaurus ajax by Upchurch et. al. in 2005. In the most comprehensive analysis of diplodocid phylogeny to date, Tschopp et. al. (2015) found AMNH 460 to be an “indeterminate apatosaurine” pending a “detailed analysis of the specimen.” What to call it? Oh, yeah, that’s been covered in another post!

This is a nostalgia shot for the old brontophiles. Notice that the Triceratops is entering the lake for a swim!

Tom Johnson with the mounted skeleton of Amphicyon, a Miocene “bear-dog”,
in the Raymond Alf Museum of Paleontology in Claremont, California.

References

• Brinkman , Paul D. (2010). The Second Jurassic Dinosaur Rush, University of Chicago Press, 2010.
• Matthew, William Diller, (1905). “The Mounted Skeleton of Brontosaurus,” The American Museum Journal, Vol. V, No. 2, April.
• Matthew, W.D. (1915). Dinosaurs, With Special Reference to the American Museum Collections, American Museum of Natural History, New York.
• Tschopp, Emanuel, Octávio Mateus, and Roger Benson. (2015). “A Specimen-Level Phylogenetic Analysis and Taxonomic Revision of Diplodocidae (Dinosauria, Sauropoda).” Ed. Andrew Farke. PeerJ 3 (2015): e857.
• Upchurch, P., Tomida, Y., Barrett, P.M. (2005). “A new specimen of Apatosaurus ajax (Sauropoda: Diplodocidae) from the Morrison Formation (Upper Jurassic) of Wyoming, USA”. National Science Museum Monographs (Tokyo) 26 (118): 1–156.