Muttaburrasaurus

Last updated

Muttaburrasaurus
Temporal range: Early Cretaceous (Albian), [1] 112–103  Ma
Muttaburrasaurus mount.jpg
Mounted skeleton
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Neornithischia
Clade: Ornithopoda
Clade: Rhabdodontomorpha
Genus: Muttaburrasaurus
Bartholomai & Molnar, 1981
Species:
M. langdoni
Binomial name
Muttaburrasaurus langdoni
Bartholomai & Molnar, 1981

Muttaburrasaurus was a genus of herbivorous iguanodontian ornithopod dinosaur, which lived in what is now northeastern Australia sometime between 112 and 103 million years ago [1] during the early Cretaceous period. It has been recovered in some analyses as a member of the iguanodontian clade Rhabdodontomorpha. [2] After Kunbarrasaurus , it is Australia's most completely known dinosaur from skeletal remains. It was named after Muttaburra, the site in Queensland, Australia, where it was found.

Contents

The dinosaur was selected from twelve candidates to become the official fossil emblem of the State of Queensland. [3] [4]

Discovery

Holotype skull Muttaburrasaurus skull.jpg
Holotype skull

The species was initially described from a partial skeleton found by grazier Doug Langdon in 1963 at Rosebery Downs Station beside Thomson River near Muttaburra, in the Australian state of Queensland, which also provides the creature's generic name. The remains were collected by paleontologist Dr Alan Bartholomai and entomologist Edward Dahms. After a lengthy preparation of the fossils, it was named in 1981 by Bartholomai and Ralph Molnar, who honoured its discoverer with its specific name langdoni. [5]

The holotype, specimen QM F6140, was found in the Mackunda Formation dating to the Albian-Cenomanian. It consists of a partial skeleton with skull and lower jaws. The underside of the skull and the back of the mandibula, numerous vertebrae, parts of the pelvis, and parts of the front and hind limbs have been preserved.

Some teeth have been discovered further north, near Hughenden, [6] and south at Lightning Ridge, [6] in northwestern New South Wales. At Lightning Ridge there have been found opalised teeth and a scapula that may be from a Muttaburrasaurus. A skull, known as the "Dunluce Skull", specimen QM F14921, was discovered by John Stewart-Moore and 14-year-old Robert Walker on Dunluce Station, between Hughenden and Richmond in 1987. It originates from somewhat older layers of the Allaru Mudstone and was considered by Molnar to be a separate, yet unnamed species, a Muttaburrasaurus sp. [6] The same area produced two fragmentary skeletons in 1989. There have also been isolated teeth and bones found at Iona Station southeast of Hughenden.

Reconstructed skeleton casts of Muttaburrasaurus, sponsored by Kellogg Company, have been put on display at a number of museums, including the Queensland Museum, Flinders Discovery Centre and National Dinosaur Museum in Australia.

Description

Scale comparition with human Muttaburrasaurus Scale.svg
Scale comparition with human

Muttaburrasaurus was about 8 metres (26 ft) and weighed around 2.8 metric tons (3.1 short tons). [7] The femur of the holotype has a length of 1,015 millimetres (40.0 in).

Life restoration Muttaburrasaurus NT.jpg
Life restoration

Whether Muttaburrasaurus is capable of quadrupedal movement has been debated; it was originally thought to be an "iguanodontid"; thought recent studies indicate a rhabdodont position. Ornithopods this basal were incapable of quadrupedal movement. Originally reconstructing Muttaburrasaurus with a thumb spike, Molnar later doubted such a structure was present. [6] The foot was long and broad, with four toes.

The skull of Muttaburrasaurus was rather flat, with a triangular cross-section when seen from above; the back of the head is broad but the snout pointed. The snout includes a strongly enlarged, hollow, upward-bulging nasal muzzle that might have been used to produce distinctive calls or for display purposes. However, as no fossilised nasal tissue has been found, this remains conjectural. This so-called bulla nasalis was shorter in the older Muttaburrasaurus sp., as is shown by the Dunluce Skull. The top section of the bulla of the holotype has not been preserved, but at least the second skull has a rounded profile. [6]

Classification

Reconstructed skull Muttaburrasaurus langdoni TMAG 20171118-036.jpg
Reconstructed skull

Molnar originally assigned Muttaburrasaurus to the Iguanodontidae. Later authors suggested more basal euornithopod groups such as the Camptosauridae, Dryosauridae or Hypsilophodontidae. Studies by Andrew McDonald indicate a position in the Rhabdodontidae. [2] [8] A 2022 phylogenetic analysis recovered Muttaburrasaurus and Tenontosaurus as basal rhabdodontomorphs and found them to likely represent sister taxa to Rhabdodontidae. [9]

The following cladogram was recovered by Dieudonné and colleagues in 2016: [10]

Iguanodontia

However, in 2024, Fonseca and colleagues considered Muttaburrasaurus to be outside Rhabdodontomorpha, and instead classified it as a member of the Gondwanan clade Elasmaria, alongside Fostoria dhimbangunmal . [11]

Palaeobiology

Statue in Hughenden, Queensland, Australia Hughenden-dinosaur-outback-queensland-australia.JPG
Statue in Hughenden, Queensland, Australia

Muttaburrasaurus had very powerful jaws equipped with shearing teeth. Whereas in more derived ornithopod species the replacement teeth alternated with the previous tooth generation to form a tooth battery, in Muttaburrasaurus they grew directly under them and only a single erupted generation was present, thus precluding a chewing motion. An additional basal trait was the lack of a primary ridge on the teeth sides, which show eleven lower ridges. In 1981 Molnar speculated that these qualities indicated an omnivorous diet, implying that Muttaburrasaurus occasionally ate carrion. In 1995 he changed his opinion, suspecting that Muttaburrasaurus's dental system is evolutionarily convergent with the ceratopsian system of shearing teeth. They would have been an adaptation for eating tough vegetation such as cycads. [12]

Related Research Articles

<i>Iguanodon</i> Ornithopod dinosaur genus from Early Cretaceous period

Iguanodon, named in 1825, is a genus of iguanodontian dinosaur. While many species found worldwide have been classified in the genus Iguanodon, dating from the Late Jurassic to Early Cretaceous, taxonomic revision in the early 21st century has defined Iguanodon to be based on one well-substantiated species: I. bernissartensis, which lived during the Barremian to early Aptian ages of the Early Cretaceous in Belgium, Germany, England, and Spain, between about 126 and 122 million years ago. Iguanodon was a large, bulky herbivore, measuring up to 9–11 metres (30–36 ft) in length and 4.5 metric tons in body mass. Distinctive features include large thumb spikes, which were possibly used for defense against predators, combined with long prehensile fifth fingers able to forage for food.

<i>Qantassaurus</i> Extinct genus of dinosaurs

Qantassaurus is a genus of basal two-legged, plant-eating elasmarian ornithischian dinosaur that lived in Australia about 125-112 million years ago, when the continent was still partly south of the Antarctic Circle. It was described by Patricia Vickers-Rich and her husband Tom Rich in 1999 after a find near Inverloch, and named after Qantas, the Australian airline.

<i>Leaellynasaura</i> Extinct genus of dinosaurs

Leaellynasaura is a genus of small herbivorous ornithischian dinosaurs from the late Aptian to early Albian stage of the Early Cretaceous, around 118-110 million years ago. It was first discovered in Dinosaur Cove, Australia. The only known species is Leaellynasaura amicagraphica. It was described in 1989, and named after Leaellyn Rich, the daughter of the Australian palaeontologist couple Tom Rich and Patricia Vickers-Rich who discovered it. The specific name, amicagraphica, translates to "friend writing" and honours both the Friends of the Museum of Victoria and the National Geographic Society for their support of Australian paleontology.

<i>Ouranosaurus</i> Extinct genus of dinosaurs

Ouranosaurus is a genus of herbivorous basal hadrosauriform dinosaur that lived during the Aptian stage of the Early Cretaceous of modern-day Niger and Cameroon. Ouranosaurus measured about 7–8.3 metres (23–27 ft) long and weighed 2.2 metric tons. Two rather complete fossils were found in the Elrhaz Formation, Gadoufaoua deposits, Agadez, Niger, in 1965 and 1970, with a third indeterminate specimen known from the Koum Formation of Cameroon. The animal was named in 1976 by French paleontologist Philippe Taquet; the type species being Ouranosaurus nigeriensis. The generic name is a combination of ourane, a word with multiple meanings, and sauros, the Greek word for lizard. The specific epithet nigeriensis alludes to Niger, its country of discovery. And so, Ouranosaurus nigeriensis could be interpreted as "brave lizard originating from Niger".

<i>Camptosaurus</i> Extinct genus of dinosaurs

Camptosaurus is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America and possibly also Europe. The name means 'flexible lizard'.

<i>Minmi paravertebra</i> Ankylosaurian dinosaur species from early Cretaceous Period

Minmi is a genus of small herbivorous ankylosaurian dinosaur that lived during the early Cretaceous Period of Australia, about 120 to 112 million years ago.

<i>Altirhinus</i> Extinct genus of dinosaurs

Altirhinus is a genus of hadrosauroid ornithopod dinosaur from the Early Cretaceous period of Mongolia.

<i>Arrhinoceratops</i> Extinct species of dinosaurs

Arrhinoceratops is a genus of herbivorous ceratopsian dinosaur. The name was coined as its original describer concluded it was special because the nose-horn was not a separate bone, however further analysis revealed this was based on a misunderstanding. It lived during the latest Campanian/earliest Maastrichtian stage of the Late Cretaceous, predating its famous relative Triceratops by a few million years, although it was contemporary with Anchiceratops. Its remains have been found in Canada.

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

Iguanodontidae is a family of iguanodontians belonging to Styracosterna, a derived clade within Ankylopollexia.

<i>Cumnoria</i> Extinct genus of dinosaurs

Cumnoria is a genus of herbivorous iguanodontian dinosaur. It was a basal iguanodontian that lived during the Late Jurassic period in what is now Oxfordshire, United Kingdom.

<i>Talenkauen</i> Extinct genus of dinosaurs

Talenkauen is a genus of basal iguanodont dinosaur from the Campanian or Maastrichtian age of the Late Cretaceous Cerro Fortaleza Formation, formerly known as the Pari Aike Formation of Patagonian Lake Viedma, in the Austral Basin of Santa Cruz, Argentina. It is based on MPM-10001A, a partial articulated skeleton missing the rear part of the skull, the tail, and the hands. The type and only species is Talenkauen santacrucensis.

<i>Lurdusaurus</i> Extinct genus of dinosaurs

Lurdusaurus is a genus of massive and unusually shaped iguanodont dinosaur from the Elrhaz Formation in Niger. It contains one species, L. arenatus. The formation dates to the Early Cretaceous, roughly 112 million years ago. Lurdusaurus has a highly atypical body plan for an iguanodont, with a small skull, long neck, rotund torso, and powerful forelimbs and claws, somewhat reminiscent of a ground sloth. Its metacarpals are fused and reinforced into a large block, and the thumb spike is remarkably enormous. These would have allowed the hand to have functioned almost like a ball-and-chain flail. Lurdusaurus is estimated to have been 7–9 m (23–30 ft) long and 2 m high when on all-fours, but its stomach would have been only 70 cm off the ground. It may have weighed 2.5–5.5 t, conspicuously heavy for an iguanodontid this size.

Ralph E. Molnar is a paleontologist who had been Curator of Mammals at the Queensland Museum and more recently associated with the Museum of Northern Arizona. He is also a research associate at the Texas natural Science Centre. He co-authored descriptions of the dinosaurs Muttaburrasaurus, Kakuru, Minmi and Ozraptor, as well as the mammal Steropodon.

<i>Mantellisaurus</i> Extinct genus of dinosaurs

Mantellisaurus is a genus of iguanodontian dinosaur that lived in the Barremian and early Aptian ages of the Early Cretaceous Period of Europe. Its remains are known from Belgium (Bernissart), England, Spain and Germany. The type and only species is M. atherfieldensis. Formerly known as Iguanodon atherfieldensis, the new genus Mantellisaurus was erected for the species by Gregory Paul in 2007. According to Paul, Mantellisaurus was more lightly built than Iguanodon and more closely related to Ouranosaurus, making Iguanodon in its traditional sense paraphyletic. It is known from many complete and almost complete skeletons. The genus name honours Gideon Mantell, the discoverer of Iguanodon.

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

Rhabdodontidae is a family of herbivorous iguanodontian ornithopod dinosaurs whose earliest stem members appeared in the middle of the Lower Cretaceous. The oldest dated fossils of these stem members were found in the Barremian Castrillo de la Reina Formation of Spain, dating to approximately 129.4 to 125.0 million years ago. With their deep skulls and jaws, Rhabdodontids were similar to large, robust iguanodonts. The family was first proposed by David B. Weishampel and colleagues in 2003. Rhabdodontid fossils have been mainly found in Europe in formations dating to the Late Cretaceous.

<i>Hippodraco</i> Extinct genus of dinosaurs

Hippodraco is a genus of iguanodontian ornithopod dinosaur from the Early Cretaceous Cedar Mountain Formation of Utah, United States. The genus contains a single species, H. scutodens, known from a partial skeleton belonging to an immature individual.

<i>Iguanacolossus</i> Extinct genus of dinosaurs

Iguanacolossus is a genus of iguanodontian ornithopod dinosaur that lived in North America during the Early Cretaceous period. It is known from UMNH VP 20205, the associated holotype with a large partial skeleton of a single individual.

<i>Oohkotokia</i> Extinct genus of dinosaurs

Oohkotokia is a genus of ankylosaurid dinosaur within the subfamily Ankylosaurinae. It is known from the upper levels of the Two Medicine Formation of Montana, United States. The discovery of Oohkotokia supports that Ankylosaurine dinosaurs existed and flourished continuously in Montana and/or Alberta throughout the late Campanian and early Maastrichtian stages in the Late Cretaceous period. It was a large, heavily built, quadrupedal, herbivore, that could grow up to 5 metres (16 ft) long and weigh up to 2 metric tons.

<span class="mw-page-title-main">Rhabdodontomorpha</span> Clade of iguanodont dinosaurs

Rhabdodontomorpha is a clade of basal iguanodont dinosaurs. This group was named in 2016 in the context of the description, based on Spanish findings of an early member of the Rhabdodontidae. A cladistic analysis was conducted in which it was found that Muttaburrasaurus was the sister species of the Rhabdodontidae sensu Weishampel. Therefore, Paul-Emile Dieudonné, Thierry Tortosa, Fidel Torcida Fernández-Baldor, José Ignacio Canudo and Ignacio Díaz-Martínez defined Rhabdodontomorpha as a nodal clade: the group consisting of the last common ancestor of Rhabdodon priscus Matheron, 1869 and Muttaburrasaurus langdoni Bartholomai and Molnar, 1981; and all its descendants. Within the clade Zalmoxes and Mochlodon are also included. The clade is characterized by the following synapomorphies:

Iani is an extinct genus of rhabdodontomorph iguanodontian dinosaur from the Late Cretaceous Cedar Mountain Formation of Utah, United States. The genus contains a single species, I. smithi, known from a partial skeleton including the skull. Its discovery serves as a link between the genus Tenontosaurus and the Rhabdodontidae, with both along with Iani being members of the clade Rhabdodontomorpha.

References

  1. 1 2 Holtz, Thomas R. Jr. (2012) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix.
  2. 1 2 McDonald, Andrew T.; Kirkland, James I.; DeBlieux, Donald D.; Madsen, Scott K.; Cavin, Jennifer; Milner, Andrew R. C.; Panzarin, Lukas (2010). "New Basal Iguanodonts from the Cedar Mountain Formation of Utah and the Evolution of Thumb-Spiked Dinosaurs". PLOS ONE. 5 (11): e14075. Bibcode:2010PLoSO...514075M. doi: 10.1371/journal.pone.0014075 . PMC   2989904 . PMID   21124919.
  3. "Queensland's new State fossil emblem". Queensland Government. The State of Queensland. Retrieved 7 April 2023.
  4. "The dinosaur Queenslanders dig". Media Statements. The State of Queensland. 22 October 2022. Retrieved 7 April 2023.
  5. Bartholomai, A.; Molnar, R.E. (1981). "Muttaburrasaurus: a new Iguanodontid (Ornithischia:Ornithopoda) dinosaur from the Lower Cretaceous of Queensland". Memoirs of the Queensland Museum. 20 (2): 319–349.
  6. 1 2 3 4 5 Molnar, Ralph E. (1996). "Observations on the Australian ornithopod dinosaur, Muttaburrasaurus"". Memoirs of the Queensland Museum. 39 (3): 639–652.
  7. Paul, G.S. (2010). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 286.
  8. McDonald, Andrew T. (2012). Farke, Andrew A. (ed.). "Phylogeny of Basal Iguanodonts (Dinosauria: Ornithischia): An Update". PLOS ONE. 7 (5): e36745. Bibcode:2012PLoSO...736745M. doi: 10.1371/journal.pone.0036745 . PMC   3358318 . PMID   22629328.
  9. Poole, Karen E. (25 October 2022). "Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality". Palaeontologia Electronica . 25 (3). doi: 10.26879/702 . Retrieved 25 February 2023.
  10. Dieudonné, Paul-Emile; Tortosa, Thierry; Torcida Fernández-Baldor, Fidel; Canudo, José Ignacio; Díaz-Martínez, Ignacio (22 June 2016). Farke, Andrew A. (ed.). "An Unexpected Early Rhabdodontid from Europe (Lower Cretaceous of Salas de los Infantes, Burgos Province, Spain) and a Re-Examination of Basal Iguanodontian Relationships". PLOS ONE. 11 (6): e0156251. Bibcode:2016PLoSO..1156251D. doi: 10.1371/journal.pone.0156251 . ISSN   1932-6203. PMC   4917257 . PMID   27333279.
  11. Fonseca, A. O.; Reid, I. J.; Venner, A.; Duncan, R. J.; Garcia, M. S.; Müller, R. T. (2024). "A comprehensive phylogenetic analysis on early ornithischian evolution". Journal of Systematic Palaeontology. 22 (1). 2346577. Bibcode:2024JSPal..2246577F. doi:10.1080/14772019.2024.2346577.
  12. Molnar, R.E. (1995). A. Sun; Y. Wang (eds.). Possible convergence in the jaw mechanisms of ceratopians and Muttaburrasaurus. Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, short papers. Beijing: China Ocean Press. pp. 115–117.

Further reading