Ichthyovenator

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Ichthyovenator
Temporal range:
Lower Cretaceous
Ichthyovenator laosensis.jpg
Replica of the type fossils
Scientific classification
Kingdom:
Class:
Superorder:
Order:
Suborder:
Superfamily:
Family:
Subfamily:
Genus:
Ichtyovenator

Kellner et al., 2011
Species:
Ichtyovenator laosensis

Allain et al., 2012

Ichthyovenator was a meat-eating theropod dinosaur. It was from the Early Cretaceous, about 113 to 125 million years ago. Its fossils were found in Laos in 2010.[1] Ichthyovenator was a spinosaurid, they were crocodile-like dinosaurs that ate fish.[2]

It is one of three spinosaurids found in Asia, the other two are Siamosaurus, and "Sinopliosaurus" fusuiensis.[1][3][4]

Discovery and naming[change | change source]

The first bones found from Ichthyovenator

The first parts of the skeleton were found in 2010. They include: One rib, part of the animal's backbones (or vertebra), and most hip bones. They did not find the skull.

The only known species is Ichthyovenator laosensis. It was named and described by Ronan Allain and his colleagues in 2012. It was found in the Grès supérieurs Formation.

The name Ichthyovenator comes from the Greek word for "fish" and the Latin word for "hunter", The name refers to the fact that it ate fish. The species name is laosensis, because it lived in what is now Laos.[1]

While Ichthyovenator was being described, paleontologists were still digging up more of its bones.[1]

Ronan Allain was one of Ichthyovenator's original describers. In 2014, he mentioned that more of Icthyovenator's skeleton was dug up in 2012. He wrote this in the Journal of Vertebrate Paleontology. These new bones include: several teeth, a hip bone, most neck bones, and a few back and tail bones. The description of the new bones has not been officially published.[5]

In 2015, some of Ichthyovenator's bones were compared to the ones of Sigilmassasaurus. Sigilmassasaurus is another spinosaurid.[6]

Description[change | change source]

Size of Ichthyovenator compared to a human

Paleontologists estimate Ichthyovenator was about 8.5 metres (28 feet) long. That's about as big as Baryonyx, one of its close relatives.

It had a half-meter sail or hump on its back, similar to Suchomimus, or Spinosaurus.[7] Ichthyovenator's sail was unusual because it was split in two at the hips. Scientists don't know why it was like that.[1]

Classification[change | change source]

Life restoration of Ichthyovenator laosensis. The colors are based on penguins and other semi-aquatic animals

Ichthyovenator was first classified as a spinosaurid, inside the subfamily baryonychinae. This is the same subfamily that includes Baryonyx and Suchomimus.[1]

In 2014 it was found that Ichthyovenator was part of the subfamily spinosaurinae instead. This was because of specific features on its teeth, and because its backbones look much like the ones of Sigilmassasaurus.[5][8]

Some sources say Ichthyovenator might not have been a spinosaurid. They say it may have been a sail-backed carcharodontosaurid, and that it was related to Concavenator. But this hypothesis has not been published in an academic place.[9]

The diagram below is called a cladogram. It shows how Ichthyovenator is related to other dinosaurs in its family tree. This cladogram is by Allain et al. (2012):[1]

Spinosauroidea
Megalosauria

TorvosaurusTorvosaurus tanneri Reconstruction (Flipped).png




EustreptospondylusEustrept1DB1 (Flipped).jpg




DubreuillosaurusDubreuillosaurus NT Flipped.png



Afrovenator Afrovenator Abakensis by PaleoGeek.jpg





Spinosauridae


IrritatorIrritator Life Reconstruction.jpg



SpinosaurusSpinosaurus by Joschua Knüppe.png





IchthyovenatorIchthyovenator laosensis by PaleoGeek (Flipped).jpg




SuchomimusSuchomimustenerensis (Flipped).png



BaryonyxBaryonyx walkeri restoration.jpg







References[change | change source]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Allain, R.; Xaisanavong, T.; Richir, P.; Khentavong, B. (2012). "The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the early cretaceous of Laos". Naturwissenschaften 99 (5): 369–377. doi:10.1007/s00114-012-0911-7. PMID 22528021. https://link.springer.com/article/10.1007%2Fs00114-012-0911-7. 
  2. Rayfield, Emily J. 2011. “Structural Performance of Tetanuran Theropod Skulls, with Emphasis on the Megalosauridae, Spinosauridae and Carcharodontosauridae.” Special Papers in Palaeontology 86 (November). https://www.researchgate.net/publication/250916680_Structural_performance_of_tetanuran_theropod_skulls_with_emphasis_on_the_Megalosauridae_Spinosauridae_and_Carcharodontosauridae.
  3. Buffetaut, E.; and Ingevat, R. (1986). Unusual theropod dinosaur teeth from the Upper Jurassic of Phu Wiang, northeastern Thailand. Rev. Paleobiol. 5: 217-220.
  4. Buffetaut, E.; Suteethorn, V.; Tong, H.; Amiot, R. (2008). "An Early Cretaceous spinosaur theropod from southern China". Geological Magazine 145 (5): 745–748. doi:10.1017/S0016756808005360. 
  5. 5.0 5.1 Allain, Ronan (2014). "New material of the theropod Ichthyovenator from Ban Kalum type locality (Laos): Implications for the synonymy of Spinosaurus and Sigilmassasaurus and the phylogeny of Spinosauridae". Journal of Vertebrate Paleontology Programs and Abstracts. http://vertpaleo.org/GlobalPDFS/SVP-2014-Program-and-Abstract-Book-9-18-2014.aspx. 
  6. Evers, Serjoscha W.; Rauhut, Oliver W.M.; Milner, Angela C.; McFeeters, Bradley; Allain, Ronan (2015-10-20). "A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the “middle” Cretaceous of Morocco" (in en). PeerJ 3: e1323. doi:10.7717/peerj.1323. ISSN 2167-8359. https://peerj.com/articles/1323/. 
  7. Hecht, Jeff. 1998. “Fish Swam in Fear.” New Scientist. November 21. https://www.newscientist.com/article/mg16021610-300-fish-swam-in-fear/.
  8. Evers, Serjoscha W.; Rauhut, Oliver W.M.; Milner, Angela C.; McFeeters, Bradley; Allain, Ronan (2015-10-20). "A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the “middle” Cretaceous of Morocco" (in en). PeerJ 3: e1323. doi:10.7717/peerj.1323. ISSN 2167-8359. https://peerj.com/articles/1323/. 
  9. Mortimer, Mickey (2017). "Megalosauroidea". The Theropod Database.

Other websites[change | change source]

Data related to Ichthyovenator at Wikispecies