Apatosaurus

*Apatosaurus ajax*

* Official Jurassic Park Artwork
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***Apatosaurus*** (/əˌpætɵˈsɔrəs/) is a genus of sauropod dinosaurs that lived about 150 million years ago, during the Jurassic Period (Kimmeridgian and Tithonian ages). It was one of the largest land animals that ever existed. The name *Apatosaurus* means 'deceptive lizard', so-given because the chevron bones were similar to those of a prehistoric marine lizard, *Mosasaurus*. The composite term *Apatosaurus* comes from the Greek names *apate* (ἀπάτη/*apatelos* ἀπατηλός) meaning "deception"/"deceptive" and *sauros* (σαῦρος) meaning "lizard".

The cervical vertebrae were less elongated and more heavily constructed than those of *Diplodocus* and the bones of the leg were much stockier (despite being longer), implying a more robust animal. The tail was held above the ground during normal locomotion. Like most sauropods, *Apatosaurus* had only a single large claw on each forelimb, with the first three toes on the hind limb possessing claws.

Fossils of *Apatosaurus* have been found in the Nine Mile Quarry and Bone Cabin Quarry in Wyoming and at sites in Colorado, Oklahoma and Utah, present in stratigraphic zones 2-6.

## Description

*Apatosaurus* was a large, long-necked quadrupedal animal with a long whip-like tail. Its forelimbs were slightly shorter than its hindlimbs. One measurement places the total length of *Apatosaurus* at 24 meters (80 ft) and its weight at 24-32 tons, roughly the weight of four elephants.

The skull was small in proportion to the size of the animal. The jaws were lined with spatulate teeth, which resembled chisels, suited to a herbivorous diet.

## Classification

*Apatosaurus* is a member of the family Diplodocidae, a clade of gigantic sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including *Diplodocus*, *Supersaurus*, *Suuwassea*, and *Barosaurus*. Within the subfamily Apatosaurinae, *Apatosaurus* may be most closely related to *Suuwassea*, *Supersaurus* and *Brontosaurus*.

In 1877, Othniel Charles Marsh published the name of the holotype species *Apatosaurus ajax*, which he called after the hero Ajax from Greek mythology. Since then, two partial skeletons of *A. ajax* have been found, including part of a skull. He followed this in 1879 with a description of another, more complete specimen, which he thought represented a new genus and named *Brontosaurus excelsus*. In 1903, Elmer Riggs decided that *Brontosaurus excelsus* was so similar to *Apatosaurus ajax* that it belonged in the same genus. Riggs then re-classified the species as *Apatosaurus excelsus*. According to the rules of the ICZN (which governs the scientific names of animals), the name *Apatosaurus*, having been published first, had priority as the official name; *Brontosaurus* was a junior synonym and therefore discarded from formal use.

*Apatosaurus excelsus* is known from six partial skeletons, including part of a skull, which have been found in the United States, in Colorado, Oklahoma, Utah, and Wyoming. *Apatosaurus louisae* was named by William Holland in 1915 in honor of Mrs. Louise Carnegie, wife of Andrew Carnegie who funded field research to find complete dinosaur skeletons in the American West. *Apatosaurus louisae* is known from one partial skeleton which was found in Colorado in the United States. *Apatosaurus parvus* was originally known as *Elosaurus parvus*, but was reclassified as a species of *Apatosaurus* in 1994. This synonymy was upheld in 2004.

*Apatosaurus yahnahpin* was named by Filla and Redman in 1994. Robert T. Bakker made *A. yahnahpin* the type species of a new genus, *Eobrontosaurus* in 1998, so it is now properly *Eobrontosaurus yahnahpin*.

## History

Othniel Charles Marsh, a Professor of Paleontology at Yale University, described and named an incomplete juvenile skeleton of *Apatosaurus ajax* in 1877. Two years later, Marsh announced the discovery of a larger and more complete specimen at Como Bluff, Wyoming — which, because of discrepancies including the size difference, Marsh misidentified as belonging to an entirely new genus and species. He dubbed the new species *Brontosaurus excelsus*, meaning "thunder lizard", from the ancient Greek **brontē/βροντη** meaning 'thunder' and **sauros/σαυρος** meaning 'lizard', and from the Latin *excelsus*, "to exceed in number", referring to the greater number of sacral vertebrae than in any other genus of sauropod known at the time.

The finds, representing the largest dinosaur discovered at the time, were nearly complete, lacking only a head, feet, and portions of the tail. They were then prepared for what was to be the first ever mounted display of a sauropod skeleton, at Yale's Peabody Museum of Natural History in 1905. The missing bones were created using pieces from known close relatives of *Brontosaurus*. Sauropod feet that were discovered at the same quarry were added, as well as a tail fashioned to appear as Marsh believed it should, and a composite model of what he felt the skull of this massive creature might look like. This was not a delicate *Diplodocus*-style skull, which would later turn out to be more accurate,), but was composed of "the biggest, thickest, strongest skull bones, lower jaws and tooth crowns from three different quarries", consisting primarily of those of *Camarasaurus*, the only other sauropod for which good skull material was known at the time. This method of reconstructing incomplete skeletons based on the more complete remains of related dinosaurs continues in museum mounts and life restorations to-date.

Despite the much-publicized debut of the mounted skeleton, which cemented the name *Brontosaurus* in the public consciousness, Elmer Riggs had published a paper in the 1903 edition of *Geological Series of the Field Columbian Museum* which argued that *Brontosaurus* was not different enough from *Apatosaurus* to warrant its own genus, and created the combination *Apatosaurus excelsus*: "In view of these facts the two genera may be regarded as synonymous. As the term 'Apatosaurus' has priority, 'Brontosaurus' will be regarded as a synonym."

Despite this, at least one paleontologist—Robert Bakker—argued in the 1990s that *A. ajax* and *A. excelsus* are in fact sufficiently distinct that the latter continues to merit a separate genus. In 2015 Emanuel Tschopp, Octávio Mateus, and Roger Benson released a paper that argued that *Apatosaurus excelsus*, originally classified as *Brontosaurus excelsus*, had enough morphological differences from other species of *Apatosaurus* that it warranted being reclassified as a separate genus again. The conclusion was based on a comparison of 477 morphological characteristics across 81 different dinosaurs. Among the many notable differences were the wider - and presumably stronger - neck of other *Apatosaurus* species compared to *A. excelsus*. Other species previously assigned to *Apatosaurus*, such as *Elosaurus parvus* and *Eobrontosaurus yahnahpin* were also reclassified as *Brontosaurus*. However, some are skeptical of the large number of sauropod taxa in the Morrison, instead grouping taxa like *Brontosaurus* and *Apatosaurus* together.

## Palaeobiology

Early on, it was believed that *Apatosaurus* was too massive to support its own weight on dry land, so it was theorized that the sauropod must have lived partly submerged in water, perhaps in a swamp, but recent findings do not support this. In fact, like its relative *Diplodocus*, *Apatosaurus* was a grazing animal with a very long neck and a long tail that served as a counterweight. One study found that diplodocid necks were less flexible than previously believed, and that sauropods like *Apatosaurus* were adapted to low browsing or ground feeding.

In 2008, footprints of juvenile *Apatosaurus* were reported from Quarry Five in Morrison, Colorado. Discovered in 2006 by Matthew Mossbrucker, these footprints show that juveniles could run on their hind legs in a manner similar to that of the modern basilisk lizard.

### Posture

In the early 20th century, diplodocids like *Apatosaurus* were often portrayed with their necks held high up in the air, allowing them to graze from tall trees. More recently, scientists have argued that the heart would have had trouble sustaining sufficient blood pressure to oxygenate the brain. Furthermore, more recent studies have shown that the structure of the neck vertebrae would not have permitted the neck to bend far upwards. However, subsequent studies demonstrated that all tetrapods appear to hold their necks at the maximum possible vertical extension when in a normal, alert posture, and argued that the same would hold true for sauropods barring any unknown, unique characteristics that set the soft tissue anatomy of their necks apart from other animals. *Apatosaurus* like *Diplodocus* would have held its neck at about a 45 degree angle with the head pointed downwards in a resting posture.

### Physiology

With *Apatosaurus* possessing such a large body mass, combined with a long neck, physiologists have had problems determining how the animals managed to breathe.

Beginning with the assumption that *Apatosaurus*, like crocodilians, did not have a diaphragm, the dead-space volume (the amount of unused air remaining in the mouth, trachea and air tubes after each breath) has been estimated at about 184 liters for a 30 ton specimen.

Its tidal volume (the amount of air moved in or out during a single breath) has been calculated based on the following respiratory systems:

* 904 liters if avian
* 225 liters if mammalian
* 19 liters if reptilian.

On this basis, its respiratory system could not have been reptilian, as its tidal volume would not have been able to replace its dead-space volume. Likewise, the mammalian system would only provide a fraction of new air on each breath. Therefore, it must have had either a system unknown to modern science or an avian system, i.e. multiple air sacs and a flow-through lung. Furthermore, an avian system would only need a lung volume of about 600 liters compared to a mammalian requirement of 2,950 liters, which would exceed the available space. The overall thoracic volume of *Apatosaurus* has been estimated at 1,700 liters allowing for a 500-liter, four-chambered heart (like birds, not three-chambered like reptiles) and a 900-liter lung capacity. That would allow about 300 liters for the necessary tissue. Assuming *Apatosaurus* had an avian respiratory system and a reptilian resting-metabolism, it would need to consume only about 262 liters (69 gallons) of water per day.

### Tail

An article that appeared in the November 1997 issue of *Discover Magazine* reported research into the mechanics of *Apatosaurus* tails by Nathan Myhrvold, a computer scientist from Microsoft. Myhrvold carried out a computer simulation of the tail, which in diplodocids like *Apatosaurus* was a very long, tapering structure resembling a bullwhip. This computer modeling suggested that sauropods were capable of producing a whip-like cracking sound of over 200 decibels, comparable to the volume of a cannon.

## Cultural influence

The length of time taken for Marsh's misclassification to be brought to public notice meant that the name *Brontosaurus*, due to its association with one of the largest known dinosaurs, became so famous that it persisted long after the name had officially been abandoned in scientific use. The terms "brontosaurus", "brontosaurs", and "brontosaurians" are often used to refer generically to any of the sauropod dinosaurs.

In 1989, the U.S. Post Office issued four "dinosaur" stamps, featuring *Tyrannosaurus*, *Stegosaurus*, "Pteradon" (misspelling of *Pteranodon*), and *Brontosaurus*. The inclusion of these last two led to complaints of "fostering scientific illiteracy", due to *Pteranodon* being a pterosaur and not a dinosaur, and *Brontosaurus* being an invalid taxon. The Post Office defended itself (in Postal Bulletin 21744) by saying, "Although now recognized by the scientific community as *Apatosaurus*, the name "*Brontosaurus*" was used for the stamp because it is more familiar to the general population." Stephen Jay Gould supported this position in his essay "Bully for Brontosaurus", though he echoed Riggs' original argument that "Brontosaurus" is a synonym for "Apatosaurus". Nevertheless, he noted that the creature has developed and continues to maintain an independent existence in the popular imagination.

*Brontosaurus* has often been depicted in cinema; the 1925 silent film *The Lost World* featured, using special effects by Willis O'Brien, a battle between a *Brontosaurus* and an *Allosaurus*. The 1933 movie *King Kong* featured a *Brontosaurus*, as did the 2005 remake, described using the fictional scientific name "Brontosaurus baxteri", or Baxter's Thunder-Lizard, after a character in the film. The 1933 *Brontosaurus* was inaccurately portrayed as a carnivore. The brontosaur of the 2005 film is noticeably different from the modern view of *Apatosaurus*, with a square head, low-hanging tail, and snake-like neck reminiscent of 1930s period depictions of the species in art.

When George Lucas made his special edition of *Star Wars Episode IV: A New Hope* in 1997, he added some large, long-necked animals based on the *Brachiosaurus* digital model from *Jurassic Park*. At an early stage he altered the CG department's suggested name "Bronto," taken from *Brontosaurus*, to "Ronto".

In the TV sitcom *Dinosaurs*, Fran's friend Monica is an *Apatosaurus* real estate agent (shown as a bright blue neck and head, wearing a pearl necklace) voiced by Suzie Plakson.

Cabazon, California features several lifesize dinosaur sculptures, including an *Apatosaurus*-shaped building titled "Dinny the Dinosaur" (pronounced "Dine-ee").

## JPInstitute.com Description

Apatosaurus is one of the most famous of the giant Jurassic plant-eaters. It was a huge, long-necked dinosaur, longer than two school buses and weighing as much as 7 elephants! If you look at older dinosaur books, you might not find Apatasaurus, but you will see Brontosaurus. This was the name that was used for this dinosaur when the wrong head was mistakenly put on its body! For years an Apatasaurus body stood with the head of Camarasaurus on the end of its neck. This was named Brontosaurus and was one of the most popular dinosaurs for many years.

Apatosaurus is a fairly typical member of the diplodocid family - long neck, pillar like legs, long tapering tail and enormous size. It had, like the other family members, peg-like teeth in a head that seemed very small for such a large creature. Compared to Diplodocus, Apatosaurus has a shorter, thicker neck and a larger, heavier body. There is much speculation about how much these creatures needed to eat and how such a small head could ingest enough food to fuel such a large body. Some scientists have stated that these huge, small-headed creatures would have needed to eat every waking moment in order to provide enough food to keep such a large body alive. Apatosaurus seemed to have every adaptation needed for continuous eating, including having nostrils on the top of its head, so breathing would not interfere with eating.

In order to facilitate the processing of food, which it could not chew with its teeth, Apatosaurus probably swallowed stones that it kept in a gizzard similar to that found in a chicken. The tough plant fibers would spend time in the gizzard stewing and being ground up by the stones.

## Dinosaur Field Guide Description

Apatosaurus ("deceptive lizard") looks very much like Diplodocus, its closest relative. On the inside, however, it is very different. Apatosaurus is very massive, with thick bones and a stocky body. Diplodocus is slender, with thinner bones. Apatosaurus was one of the very
first dinosaurs to have a picture of its completely restored skeleton published in newspapers. This happened in the 1880s, and the dinosaur's immense size made world headlines, One feature that Apatosaurus has in common with other closely related sauropods, or giant plant-eaters, is that the openings for its nostrils are on top of its head, behind its eyes. (Normally nostrils are located at the end of the snout, as in the Ornithischia, the other major group of plant-eating dinosaurs.) This setup enabled Apatosaurus to breathe through an air passage to the rear of its throat--like a human-making it possible to chew a mouthful of plants and breathe at the same time. If you want to see why this is important,
pinch your own nose closed and try chewing without breathing through your mouth. Be careful not to choke! The study of Apatosaurus has had a
major influence on the study of all dinosaurs. In the 1970s, a study of its skeleton was used to show how sauropods lived on land, and not in the
water as had been assumed for many decades. In 1979, it was learned that the wrong head had been mounted on every Apatosaurus skeleton in museums
since the 1880s (the older mounts had heads based on Camarasaurus). In the 1990s, a study of Apatosaurus bones showed that its head and neck were not held vertically as had been portrayed in many illustrations. The science of how a body can or cannot function is called functional morphology, and Apatosaurus is one of the best dinosaurs for use in this study because of its large size.

### Fun Facts

One species of Apatosaurus was named after a millionaire's wife in the hope it would bring more funding!

### Trivia

Apatosaurus was once considered to be a different animal from the sauropod called Brontosaurus. Now we know they are the same dinosaur.

## Appearance in Jurassic Park and other media

### *Jurassic Park*

*Apatosaurus* appears as a background dinosaur in Jurassic World, although it has a major scene where one died by its wounds from the *Indominus rex*. A teaser for the Jurassic World: Fallen Kingdom reveals that five more *Apatosaurus* have managed to survived the rampage of the *Indominus rex* before her death, but they and the other dinosaurs will now face a new danger in the form of an impending volcanic eruption. The Apatosaurus were also seen in Dominion.

### *The Land Before Time*

Many characters in *The Land Before Time* are *Apatosaurus*. Examples of *Apatosaurus* in the series include the main protagonist Littlefoot, his mother, his father, and his grandparents. Others include Littlefoot's distant cousin Ali, her mother, Ali's friend Rhett and the herd to which they belong, led by the matriarch known as the Old One.

### *We're Back! A Dinosaur's Story*

where Rex mistakenly befriends an Apatosaurus balloon.

## Links

http://web.archive.org/web/20040805170233fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_apato.html

## References

1. ↑ Foster, J. (2007). "Appendix." *Jurassic West: The Dinosaurs of the Morrison Formation and Their World*. Indiana University Press. pp. 327-329.
2. ↑ Holtz, Thomas R. Jr. (2008) *Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages* Supplementary Information
3. ↑ Taylor, M.P. and Naish, D. (2005). "The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda)." *PaleoBios*, **25**(2): 1–7. (download here)
4. ↑ Harris, J.D. (2006). "The significance of *Suuwassea emiliae* (Dinosauria: Sauropoda) for flagellicaudatan intrarelationships and evolution." *Journal of Systematic Palaeontology*, **4**(2): 185–198.
5. ↑ 5.0 5.1 Template:Cite journal
6. ↑ Carpenter, K. and McIntosh, J. (1994). "Upper Jurassic sauropod babies from the Morrison Formation", In: K. Carpenter, K. F. Hirsch, and J. R. Horner (eds.), *Dinosaur Eggs and Babies*. Cambridge University Press, Cambridge 265–278
7. ↑ Upchurch, Paul; Tomida, Yukimitsu; and Barrett, Paul M. (2004). "A new specimen of *Apatosaurus ajax* (Sauropoda: Diplodocidae) from the Morrison Formation (Upper Jurassic) of Wyoming, USA." *National Science Museum monographs* 26: i-118 ISSN:13429574
8. ↑ Bakker, R.T. (1998). "Dinosaur mid-life crisis: the Jurassic-Cretaceous transition in Wyoming and Colorado". In: S.G. Lucas, J.I. Kirkland, & J.W. Estep (eds.) Lower and Middle Cretaceous Terrestrial Ecosystems; New Mexico Museum of Natural History and Science Bulletin, 14: 67–77.
9. ↑ Template:Cite book
10. ↑ McIntosh, J.S. and Berman, D.S. (1975). "Description of the palate and lower jaw of the sauropod dinosaur *Diplodocus* (Reptilia: Saurischia) with remarks on the nature of the skull of *Apatosaurus*." *Journal of Paleontology*, **49**(1): 187–199.
11. ↑ Bakker, Robert (1994). "The Bite of the Bronto" *Earth* 3:(6):26–33.
12. ↑ Bakker, R.T. (1998). "Dinosaur mid-life crisis: the Jurassic-Cretaceous transition in Wyoming and Colorado". In: S.G. Lucas, J.I. Kirkland, & J.W. Estep (eds.) *Lower and Middle Cretaceous Terrestrial Ecosystems; New Mexico Museum of Natural History and Science Bulletin*, 14: 67–77.
13. ↑ Template:Cite web
14. ↑ Template:Cite journal
15. ↑ Template:Cite book
16. ↑ Template:Cite web
17. ↑ Taylor, M.P., Wedel, M.J., and Naish, D. (2009). "Head and neck posture in sauropod dinosaurs inferred from extant animals". *Acta Palaeontologica Polonica* 54 (2), 2009: 213-220 abstract
18. ↑ Paladino, F.V., Spotila, J.R., and Dodson, P. (1997). "A Blueprint for Giants: Modeling the Physiology of Large Dinosaurs." In Farlow, J.O. and Brett-Surman, M.K. (eds.), *The Complete Dinosaur*, Indiana University Press, 491–504. doi0253333490.
19. ↑ Zimmer, C. (1997). "Dinosaurs in Motion." *Discover*, 1 Nov 1997. [1] Accessed 27 Jul 2008.
20. ↑ " Topics of The Times; Leapin' Lizards!" *The New York Times*, 1989-10-11. Last accessed 2008-06-08.
21. ↑ Gould, S.J. (1991). *Bully for Brontosaurus: Reflections in Natural History*, W. W. Norton & Co., 540pp.
22. ↑ Template:Cite web
23. ↑ "I loved Monica (always thought she was a Brontosaurus...)" personal communication from Suzie Plakson dated Jan. 4, 2010