Maraapunisaurus

Maraapunisaurus
Temporal range: Late Jurassic,
150 Ma
↓
Original illustration, dating to c. 1878, of E. D. Cope's M. fragillimus specimen
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: †Sauropodomorpha
Clade: †Sauropoda
Superfamily: †Diplodocoidea
Family: †Rebbachisauridae
Genus: †Maraapunisaurus
Carpenter, 2018
Species:
†M. fragillimus
Binomial name
†Maraapunisaurus fragillimus
Synonyms
Comparison of Maraapunisaurus (left) with the rebbachisaurids Rebbachisaurus (center) and Histriasaurus (right).
Neural spine of Maraapunisaurus as drawn by E.D. Cope with parts labeled. The key rebbachisaurid features are the spinopostzygapophyseal laminae that extends dorsomedially from the postzygapophyses to join and form the postspinal lamina, and the pneumatic neural spine and arch. Other rebbachisaurid features include the rather simple ("attenuated") structure of the neural spine and the respective inclinations of the centrodiapophyseal lamina and the postzygodiapophyseal laminae.

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 (150 long tons; 170 short tons). 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.

More recent studies have made a number of suggestions regarding the possibility of such an animal. One analysis of the surviving evidence, and the biological plausibility of such a large land animal, has suggested that the enormous size of this animal were over-estimates due partly to typographical errors in the original 1878 description.[1] More recently, it was suggested by paleontologist Kenneth Carpenter that the species is a rebbachisaurid, rather than a diplodocid sauropod. He therefore used Limaysaurus instead of Diplodocus as a basis for size estimates. This resulted in a smaller, 31-metre (102 ft) animal, and he dismissed the idea that there must have been typographical errors.[2] Since then, somewhat larger size estimates have been made, placing Maraapunisaurus at 70[3] ―120[4] tons in mass and 35–40 metres (115–131 ft) long, which still makes Maraapunisaurus the third longest animal to have ever lived behind Bruhathkayosaurus and Supersaurus specimen BYU 9024, as well as having the tallest and largest neural spine out of any animal (2.7-metre (8.9 ft)).[5][3]

  1. ^ Woodruff, C; Foster, JR (2015). "The fragile legacy of Amphicoelias fragillimus (Dinosauria: Sauropoda; Morrison Formation – Latest Jurassic)". PeerJ PrePrints. doi:10.7287/peerj.preprints.838v1.
  2. ^ Carpenter, Kenneth (2018). "Maraapunisaurus fragillimus, N.G. (formerly Amphicoelias fragillimus), a basal Rebbachisaurid from the Morrison Formation (Upper Jurassic) of Colorado". Geology of the Intermountain West. 5: 227–244. doi:10.31711/giw.v5i0.28.
  3. ^ a b MOLINA-PEREZ, RUBEN. LARRAMENDI, ASIER. (2020). DINOSAUR FACTS AND FIGURES : the sauropods and other sauropodomorphs. New Jersey: Princeton University Press. p. 254. ISBN 978-0-691-19069-3. OCLC 1125972915.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. ^ Paul, Gregory S. (2019). "Determining the largest known land animal: A critical comparison of differing methods for restoring the volume and mass of extinct animals" (PDF). Annals of the Carnegie Museum. 85 (4): 335–358. doi:10.2992/007.085.0403. S2CID 210840060.
  5. ^ Paul, Gregory S. (2019). "Determining the largest known land animal: A critical comparison of differing methods for restoring the volume and mass of extinct animals" (PDF). Annals of the Carnegie Museum. 85 (4): 335–358. doi:10.2992/007.085.0403. S2CID 210840060.