Supersaurus

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Supersaurus
Temporal range: Late Jurassic,
153–145  Ma
Supersaurus-Holotype-BYU9025-PerspectiveWarp.png
A cast of BYU 9025, a scapulocoracoid, the holotype of Supersaurus, Dinosaur Journey Museum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade:† Sauropodomorpha
Clade:† Sauropoda
Superfamily:† Diplodocoidea
Family:† Diplodocidae
Subfamily:† Diplodocinae
Genus:† Supersaurus
Jensen, 1985 [1]
Type species
†Supersaurus vivianae
Jensen, 1985 [1]
Other Species
Synonyms
Genus synonymy
Species synonymy (S. vivianae)
  • Dystylosaurus edwini
    Jensen, 1985
  • Ultrasauros macintoshi
    (Jensen, 1985) Olshevsky, 1991 [formerly Ultrasaurus , preoccupied]

Supersaurus (meaning "super lizard") is a genus of diplodocid sauropod dinosaur that lived in North America during the Late Jurassic period. The type species, S. vivianae, was first discovered by Vivian Jones of Delta, Colorado, in the middle Morrison Formation of Colorado in 1972. The fossil remains came from the Brushy Basin Member of the formation, dating between 153 to 145 million years ago. [3] It is among the longest dinosaurs ever discovered, with the three known specimens reaching 33–40 meters (108–131 ft) in length, with the largest individual possibly exceeding 40 meters (130 ft) in size. [4] [5] Mass estimates for the WDC and BYU specimens tend to be around 35–44 metric tons (39–49 short tons) in body mass. [5] A potential second species, S. lourinhanensis ( Dinheirosaurus ), is known from Portugal and has been dated to a similar time. [6]

Contents

Discovery

Supersaurus moal.jpg
Supersaurus.jpg
A reconstructed skeleton, Museum of Ancient Life, Utah, USA

Supersaurus is present in stratigraphic zone 5 of the Morrison, dating from the Tithonian. [7] The original fossil remains of Supersaurus were discovered in the Dry Mesa Quarry in 1972. This find yielded only a few bones: mainly the shoulder girdle, an ischium, and tail vertebrae. Paleontologist James A. Jensen described Supersaurus; he designated a scapulocoracoid BYU 9025 (originally labeled as BYU 5500) as the type specimen. This shoulder girdle stood some 2.4 meters (7.9 ft) tall, if placed on end. The specimen was given the name "Supersaurus" informally as early as 1973, [8] [9] but was not officially described and named until more than a decade later, in 1985. [1] Sauropod researcher Jack McIntosh at one time thought that the BYU Supersaurus material might represent a large species of Barosaurus but later felt that there was evidence for Supersaurus being a valid genus. [10]

A reconstruction of WDC DMJ-021, nicknamed "Jimbo", Wyoming Dinosaur Center Jimbo Supersaurus.jpg
A reconstruction of WDC DMJ-021, nicknamed "Jimbo", Wyoming Dinosaur Center

A much more complete specimen WDC DMJ-021, was found in Converse County, Wyoming in 1986 by Brandon Flyr and Bart Lesco while out hiking and was reported to the people who owned the land at the time. The discovery was later named "Jimbo" in 1996 by the family that purchased the land, it was described and assigned to Supersaurus in 2007. The specimen represented approximately 30% of the skeleton. Its bones are being held at the Wyoming Dinosaur Center. A comparison of WDC DMJ-021 and other specimens previously assigned to Supersaurus was done in order to help decide what material from the Dry Mesa Quarry belonged to the genus. It indicated that a series of tail vertebrae and an ulna may have belonged to some other diplodocid. [11]

Ultrasauros

James A. Jensen with the reconstructed front leg of Ultrasauros James A. Jensen.jpg
James A. Jensen with the reconstructed front leg of Ultrasauros

Jensen, who described the original Supersaurus specimen, simultaneously reported the discovery of another gigantic sauropod, which would later be named "Ultrasaurus" macintoshi [1] (later renamed Ultrasauros macintoshi). The type specimen (the specimen used to define a new species) of Ultrasauros, being a backbone (dorsal vertebra, labeled BYU 9044), was later found to have come from Supersaurus. In fact, it probably belonged to the original Supersaurus specimen, which was discovered in the same quarry in 1972. Therefore, Ultrasauros became a junior synonym of Supersaurus, which had been named first and thus retains priority, and the name Ultrasauros was abandoned. [12]

Other bones that were found at the same location and originally thought to belong to Ultrasauros, like a shoulder girdle (scapulocoracoid, BYU 9462), actually belonged to Brachiosaurus , possibly a large specimen of Brachiosaurus altithorax. [12] The Brachiosaurus bones indicate a large, but not record-breaking individual, a little larger than the "Brachiosaurus" brancai ( Giraffatitan brancai) mount in the Berlin's Natural History Museum. [13]

Dorsal vertebra BYU 9044, the holotype of Ultrasauros, now assigned to Supersaurus Museum of Ancient Life Supersaurus vivianae dorsal vertebra.JPG
Dorsal vertebra BYU 9044, the holotype of Ultrasauros, now assigned to Supersaurus Museum of Ancient Life

Originally, these Supersaurus and Brachiosaurus bones were believed to represent a single dinosaur that was estimated to reach about 25 to 30 meters (82 to 98 ft) long, 8 meters (26 ft) high at the shoulder, 15 meters (49 ft) in total height, and weighing maybe 70 t (77 short tons). At the time, mass estimates ranged up to 180 tons, [14] which placed it in the same category as the blue whale and the equally problematic Bruhathkayosaurus .

The naming of the chimeric Ultrasauros has a similarly complicated history. Ultrasaurus (with the final "u") was the original choice, and was widely used by the media after the discovery in 1979. However, the name of a new species must be published with a description to become official. [15]

Pelvis BYU 130185, currently assigned to Supersaurus, Museum of Ancient Life - Thanksgiving Point Supersaurus vivianae pelvis.JPG
Pelvis BYU 130185, currently assigned to Supersaurus, Museum of Ancient Life - Thanksgiving Point

Before Jim Jensen published his discovery in 1985, another paleontologist, Kim Haang Mook, used the name Ultrasaurus in a 1983 publication to describe what he believed was a giant dinosaur in South Korea. This was a different, much smaller dinosaur than Jensen's find, but Kim thought it represented a similarly gigantic animal because he confused a humerus for an ulna. While the logic of naming was incorrect, the Ultrasaurus from Kim's find fulfilled the requirements for naming and became regarded as a legitimate, if dubious genus. [13] [15] Thus, because Jensen did not publish his own "Ultrasaurus" find until 1985, Kim's use retained its official priority of name, and Jensen was forced to choose a new name (in technical terms, his original choice was "preoccupied" by Kim's sauropod). In 1991, at his suggestion, George Olshevsky changed one letter, and renamed Jensen's sauropod Ultrasauros, with the final "o". [15]

When it was later discovered that the new name referred to bones from two separate, and already known species, the name Ultrasauros was considered invalid and became a junior synonym for Supersaurus. Since the holotype of the Ultrasaurus was a dorsal vertebrae of the Supersaurus, so Ultrasauros is not a junior synonym for Brachiosaurus. The name Supersaurus was kept instead of Ultrasaurus as the animal is a diplodocid and Ultrasaurus had always referred to a brachiosaurid. [12]

Additional synonyms

Another diplodocid dinosaur found near the original Supersaurus quarry, known from a backbone (dorsal vertebra type specimen BYU 5750), was named Dystylosaurus edwini and is now also considered to be a specimen of Supersaurus vivianae. Hence, Dystylosaurus has also become a junior synonym of Supersaurus. [16]

Description

Diagram showing the size of Supersaurus (orange) compared with selected giant sauropods Longest dinosaurs2.svg
Diagram showing the size of Supersaurus (orange) compared with selected giant sauropods
Life restoration of Supersaurus based primarily on Wyoming Dinosaur Center's more complete "Jimbo" Supersaurus dinosaur.png
Life restoration of Supersaurus based primarily on Wyoming Dinosaur Center's more complete "Jimbo"

Supersaurus is among the largest dinosaurs known from good remains and quite possibly the longest discovered thus far, with the WDC specimen reaching 33–36 meters (108–118 ft) in length, the BYU specimen reaching perhaps 39 meters (128 ft) and a third specimen potentially exceeding 40 meters (130 ft) in size. [4] [5] The WDC and BYU specimens are estimated to have weighed 35–44 metric tons (39–49 short tons) in body mass. [5] [11] [17] A study in 2024 also found the Jimbo specimen to be skeletally mature at the time of its death and among the oldest known dinosaurs. While the result obtained was 225 years, the study strongly states that a value this high is extremely unlikely and more reflects the limitations of the methodology in calculating the age of exceptionally old individuals. [5] The same study found the age of a 33 meters (108 ft)Diplodocus hallorum to be 60 years old, which makes it among the oldest known dinosaurs too, but considered the age of Jimbo to be even greater due to the extensive remodeling of the bone. In fact, the study suggests Jimbo was so old that its exact age cannot be reliably calculated by the applied methodology. [5] Thus, despite the lack of a truly reliable age value, the Jimbo specimen of Supersaurus can be considered as possibly the oldest dinosaur known thus far. The study also suggests that, due to Jimbo's skeletal maturity, the size range displayed by the three known Supersaurus specimens, which ranges from 33–40 meters (108–131 ft), can be considered an average adult size for the species. [5]

The first described specimens of Supersaurus were individual bones that suggested a large diplodocid. A large cervical vertebra BYU 9024 from the same quarry was later assigned to Supersaurus. [18] . This vertebra measures 1.38 m (4.5 ft) in length and is the longest cervical known. [19] This enormous vertebra was reclassified as a Barosaurus vertebra, by Mike Taylor and Matt Wedel. [20] However Brian Curtice has reassigned it to Supersaurus on the basis of additional specimens. [4] Michael Benton also agreed with the reclassification, giving the Supersaurus BYU 9024 specimen an approximate length of up to an impressive 50 metres (160 ft), which would have made it the longest animal to ever live. [21]

The assignment of the more complete specimen, WDC DMJ-021, to Supersaurus suggests that in most respects it was very similar in anatomy to Apatosaurus but less robustly built with especially elongated cervical vertebrae, resulting in one of the longest-known sauropod necks. [11]

Classification

Most studies of diplodocid relationships have found it to contain two primary subgroups: Diplodocinae (containing those diplodocids more closely related to Diplodocus than to Apatosaurus) and Apatosaurinae (diplodocids more closely related to Apatosaurus than to Diplodocus). Originally, it was thought that Supersaurus was related to the long-necked diplodocid Barosaurus , and therefore a member of the subfamily Diplodocinae, however, with the assignment of the more complete WDC DMJ-021 most later studies found Supersaurus to be a close relative of the familiar Apatosaurus in the group Apatosaurinae. [11] However, some later studies cast doubt on this paradigm. One comprehensive study of diplodocoid relationships published by Whitlock in 2011 found Apatosaurus itself to lie at the base of the diplodocid family tree, and other "apatosaurines", including Supersaurus, to be progressively more closely related to Diplodocus (making them diplodocines). [22]

Restoration Supersaurus NT small.jpg
Restoration

In 2015, a specimen-level phylogenetic study of diplodocids found that Dinheirosaurus lourinhanensis grouped with Supersaurus. The study considered that it should be a new species of Supersaurus, in a new combination S. lourinhanensis. [6]

Diplodocidae

Related Research Articles

<i>Apatosaurus</i> Sauropod dinosaur genus from Late Jurassic period

Apatosaurus is a genus of herbivorous sauropod dinosaur that lived in North America during the Late Jurassic period. Othniel Charles Marsh described and named the first-known species, A. ajax, in 1877, and a second species, A. louisae, was discovered and named by William H. Holland in 1916. Apatosaurus lived about 152 to 151 million years ago (mya), during the late Kimmeridgian to early Tithonian age, and are now known from fossils in the Morrison Formation of modern-day Colorado, Oklahoma, New Mexico, Wyoming, and Utah in the United States. Apatosaurus had an average length of 21–23 m (69–75 ft), and an average mass of 16.4–22.4 t. A few specimens indicate a maximum length of 11–30% greater than average and a mass of approximately 33 t.

<span class="mw-page-title-main">Sauropoda</span> Extinct clade of saurischian dinosaurs

Sauropoda, whose members are known as sauropods, is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads, and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include Apatosaurus, Argentinosaurus, Alamosaurus, Brachiosaurus, Camarasaurus, Diplodocus, and Mamenchisaurus.

<span class="mw-page-title-main">Diplodocidae</span> Extinct family of dinosaurs

Diplodocids, or members of the family Diplodocidae, are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the Earth, including Diplodocus and Supersaurus, some of which may have reached lengths of up to 42 metres (138 ft).

<i>Barosaurus</i> Diplodocid sauropod dinosaur genus from Upper Jurassic Period

Barosaurus was a giant, long-tailed, long-necked, plant-eating sauropod dinosaur closely related to the more familiar Diplodocus. Remains have been found in the Morrison Formation from the Upper Jurassic Period of Utah and South Dakota. It is present in stratigraphic zones 2–5.

<i>Cetiosauriscus</i> Genus of reptiles (fossil)

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<i>Brontosaurus</i> Genus of diplodocid sauropod dinosaur

Brontosaurus is a genus of herbivorous sauropod dinosaur that lived in present-day United States during the Late Jurassic period. It was described by American paleontologist Othniel Charles Marsh in 1879, the type species being dubbed B. excelsus, based on a partial skeleton lacking a skull found in Como Bluff, Wyoming. In subsequent years, two more species of Brontosaurus were named: B. parvus in 1902 and B. yahnahpin in 1994. Brontosaurus lived about 156 to 146 million years ago (mya) during the Kimmeridgian and Tithonian ages in the Morrison Formation of what is now Utah and Wyoming. For decades, the animal was thought to have been a taxonomic synonym of its close relative Apatosaurus, but a 2015 study by Emmanuel Tschopp and colleagues found it to be distinct. It has seen widespread representation in popular culture, being the archetypal "long-necked" dinosaur in general media.

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<span class="mw-page-title-main">Wyoming Dinosaur Center</span>

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<i>Dinheirosaurus</i> Genus of reptiles (fossil)

Dinheirosaurus is a genus of diplodocid sauropod dinosaur that is known from fossils uncovered in modern-day Portugal. It may represent a species of Supersaurus. The only species is Dinheirosaurus lourinhanensis, first described by José Bonaparte and Octávio Mateus in 1999 for vertebrae and some other material from the Lourinhã Formation. Although the precise age of the formation is not known, it can be dated around the early Tithonian of the Late Jurassic.

<span class="mw-page-title-main">Dry Mesa Quarry</span>

The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, United States, near the town of Delta. Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period, among them Ceratosaurus, Supersaurus, and Torvosaurus. The quarry is found within the Uncompahgre National Forest.

<span class="mw-page-title-main">Neosauropoda</span> Extinct clade of dinosaurs

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<span class="mw-page-title-main">Apatosaurinae</span> Extinct subfamily of dinosaurs

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<i>Diplodocus</i> Genus of diplodocid sauropod dinosaurs (fossil)

Diplodocus is an extinct genus of diplodocid sauropod dinosaurs known from the Late Jurassic of North America. The first fossils of Diplodocus were discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a Neo-Latin term derived from Greek διπλός (diplos) "double" and δοκός (dokos) "beam", in reference to the double-beamed chevron bones located in the underside of the tail, which were then considered unique.

<i>Brachiosaurus</i> Sauropod dinosaur genus from the late Jurassic Period

Brachiosaurus is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154 to 150 million years ago. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in the Colorado River valley in western Colorado, United States. Riggs named the dinosaur Brachiosaurus altithorax; the generic name is Greek for "arm lizard", in reference to its proportionately long arms, and the specific name means "deep chest". Brachiosaurus is estimated to have been between 18 and 22 meters long; body mass estimates of the subadult holotype specimen range from 28.3 to 46.9 metric tons. It had a disproportionately long neck, small skull, and large overall size, all of which are typical for sauropods. Atypically, Brachiosaurus had longer forelimbs than hindlimbs, which resulted in a steeply inclined trunk, and a proportionally shorter tail.

<i>Uteodon</i> Genus of reptiles (fossil)

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<i>Kaatedocus</i> Extinct genus of reptiles

Kaatedocus is a genus of flagellicaudatan sauropod known from the middle Late Jurassic of northern Wyoming, United States. It is known from well-preserved skull and cervical vertebrae which were collected in the lower part of the Morrison Formation. The type and only species is Kaatedocus siberi, described in 2012 by Emanuel Tschopp and Octávio Mateus.

<i>Maraapunisaurus</i> Lost specimen of giant sauropod dinosaur from Colorado

Maraapunisaurus is a genus of sauropod dinosaur from the Late Jurassic Morrison Formation of western North America. Originally named Amphicoelias fragillimus, it has sometimes been estimated to be the largest dinosaur specimen ever discovered. Based on surviving descriptions of a single fossil bone, scientists have produced numerous size estimates over the years; the largest estimate M. fragillimus to have been the longest known animal at 58 metres (190 ft) in length with a mass of 150 tonnes. However, because the only fossil remains were lost at some point after being studied and described in the 1870s, evidence survived only in contemporary drawings and field notes.

References

  1. 1 2 3 4 Jensen, J.A. (1985). "Three new sauropod dinosaurs from the Upper Jurassic of Colorado". The Great Basin Naturalist. 45 (4): 697–709. doi: 10.5962/bhl.part.4439 .
  2. ↑ Bonaparte, J.; Mateus, O. (1999). "A New Diplodocid, Dinheirosaurus lourinhanensis gen. et sp. nov., from the Late Jurassic Beds of Portugal" (PDF). Revista del Museo Argentino de Ciencias Naturales. 5 (2): 13–29. ISSN   0524-9511. Archived from the original (PDF) on September 28, 2007.
  3. ↑ Kowallis, B.J.; Christiansen, E.H.; Deino, A.L. (1991). "Age of the Brushy Basin Member of the Morrison Formation, Colorado Plateau, western USA". Cretaceous Research. 12 (5): 483–493. Bibcode:1991CrRes..12..483K. doi:10.1016/0195-6671(91)90003-U.
  4. 1 2 3 Curtice, Brian (2021). "New Dry Mesa Dinosaur Quarry Supersaurus vivianae (Jensen 1985) axial elements provide additional insight into its phylogenetic relationships and size, suggesting an animal that exceeded 39 meters in length" (PDF). p. 92. Archived (PDF) from the original on October 8, 2022.
  5. 1 2 3 4 5 6 7 Woodruff, D.C.; Curtice, B.D.; Foster, J.R. (2024). "Seis-ing up the Super-Morrison formation sauropods". Journal of Anatomy. doi:10.1111/joa.14108.
  6. 1 2 Tschopp, Emanuel; Mateus, Octávio; Benson, Roger B. J. (2015). "A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)". PeerJ. 3: e857. doi: 10.7717/peerj.857 . PMC   4393826 . PMID   25870766. Open Access logo PLoS transparent.svg
  7. ↑ Foster, J. (2007). "Appendix". Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pp. 327–329.
  8. ↑ George, J. (May 13, 1973). "Supersaurus, giant of the giants". Denver Post, Empire Magazine. pp. 14ff.
  9. ↑ George, J. (June 1973). "Supersaurus, the biggest brute ever". Reader's Digest . pp. 51–56.
  10. ↑ McIntosh, John S. (2005). "The genus Barosaurus Marsh (Sauropoda, Diplodocidae)". In Tidwell, Virginia; Carpenter, Ken (eds.). Thunder-lizards: The Sauropod Dinosaurs. Bloomington: Indiana University Press. pp. 38–77. ISBN   0-253-34542-1.
  11. 1 2 3 4 Lovelace, David M.; Hartman, Scott A.; Wahl, William R. (2008). "Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny". Arquivos do Museu Nacional. 65 (4): 527–544. ISSN   0365-4508.
  12. 1 2 3 Curtice, Brian D.; Stadtman, Kenneth L.; Curtice, Linda J. (1996). "A re-assessment of Ultrasauros macintoshi (Jensen, 1985)". In Morales, M. (ed.). The Continental Jurassic: Transactions of the Continental Jurassic Symposium (PDF). Vol. 60. Museum of Northern Arizona Bulletin. pp. 87–95.
  13. 1 2 Paul, G.S. (1988). "The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, Giraffatitan, and a comparison of the world's largest dinosaurs" (PDF). Hunteria. 2 (3): 1–14.
  14. ↑ McGowan, C. (1992). Dinosaurs, Spitfires and Sea Dragons. Harvard University Press. ISBN   978-0674207707.
  15. 1 2 3 "Supersaurus, Ultrasaurus and Dystylosaurus in 2019, part 1: what we know now". Sauropod Vertebra Picture of the Week. June 13, 2019.
  16. ↑ Curtice, B.; Stadtman, K. (2001). "The demise of Dystylosaurus edwini and a revision of Supersaurus vivianae". In McCord, R.D.; Boaz, D. (eds.). Western Association of Vertebrate Paleontologists and Southwest Paleontological Symposium - Proceedings 2001. Mesa Southwest Museum Bulletin. Vol. 8. pp. 33–40.
  17. ↑ Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 214. ISBN   978-1-78684-190-2. OCLC   985402380.
  18. ↑ Jensen, James A. (1987). "New Brachiosaur Material from the Late Jurassic of Utah and Colorado". The Great Basin Naturalist. 47 (4): 592–608. ISSN   0017-3614. JSTOR   41712373.
  19. ↑ Wedel, Mathew J.; Cifelli, R.L.; Sanders, R.K. (March 2000). "Sauroposeidon proteles, a new sauropod from the Early Cretaceous of Oklahoma" (PDF). Journal of Vertebrate Paleontology. 20 (1): 109–114. doi:10.1671/0272-4634(2000)020[0109:SPANSF]2.0.CO;2. S2CID   55987496. Archived from the original (PDF) on October 31, 2007. Retrieved October 17, 2016.
  20. ↑ Taylor, Mike (2019). "Supersaurus, Ultrasaurus and Dystylosaurus in 2019, part 2: what we found in Utah". Archived from the original on September 21, 2022.
  21. ↑ Benton, Michael (October 31, 2023). Dinosaur Behavior: An Illustrated Guide. Princeton University Press. pp. 94–95. ISBN   9780691244297.
  22. ↑ Whitlock, John A. (2011). "A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda)". Zoological Journal of the Linnean Society. 161 (4): 872–915. doi: 10.1111/j.1096-3642.2010.00665.x .
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