Name: Limusaurus ‭(‬Mud lizard‭)‬.
Phonetic: Le-moo-sore-us.
Named By: X.‭ ‬Xu,‭ ‬J.‭ ‬M.‭ ‬Clark,‭ ‬J.‭ ‬Mo,‭ ‬J.‭ ‬Choiniere,‭ ‬C.‭ ‬A.‭ ‬Forster,‭ ‬G.‭ ‬M.‭ ‬Erickson,‭ ‬D.‭ ‬W.‭ ‬E.‭ ‬Hone,‭ ‬C.‭ ‬Sullivan,‭ ‬D.‭ ‬A.‭ ‬Eberth,‭ ‬S.‭ ‬Nesbitt,‭ ‬Q.‭ ‬Zhao,‭ ‬R.‭ ‬Hernandez,‭ ‬C.-K Jia,‭ ‬F.-L.‭ ‬Han,‭ & ‬Y.‭ ‬Guo‭ ‬-‭ ‬2009.
Classification: Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Saurischia,‭ ‬Theropoda,‭ ‬Ceratosauria.
Species: L.‭ ‬inextricabilis‭ (‬type‭)‬.
Diet: Herbivore‭?
Size: Around‭ ‬1.7‭ ‬meters long.
Known locations: China,‭ ‬Junggar Basin‭ ‬-‭ ‬Shishugou Formation.
Time period: Oxfordian of the Jurassic.
Fossil representation: Almost complete articulated remains from two sub adults.

       Although known from very well preserved remains,‭ ‬there is still quite a bit of mystery surrounding Limusaurus.‭ ‬Study of the bones has revealed that it is a member of the Ceratosauria‭ (‬the first one known from Asia‭)‬,‭ ‬a group of theropods defined by the type genus Ceratosaurus.‭ ‬However the one specimen where the skull has been preserved indicates that Limusaurus did not have teeth and instead made do with a beak-like mouth.‭ ‬Additionally gastroliths have also been found along with Limusaurus remains,‭ ‬the presence of which is usually a herbivorous trait.‭
       These characteristics are very similar to the later ornithomimosaurs of the Cretaceous,‭ ‬many of which have also been found with toothless beak-like mouths and gastroliths.‭ ‬However there is no one rule as to what ornithomimosaurs ate‭ (‬though a few select genera are a little easier to ascertain‭) ‬because the‭ ‘‬beak could have been used to crop plants or catch small vertebrates like lizards.‭ ‬While gastroliths are usually associated with the grinding of plants it is not entirely unknown for predators to also have them,‭ ‬particularly piscivores.‭ ‬Another well-known example of a theropod dinosaur having gastroliths is Lourinhanosaurus,‭ ‬a theropod thought to be similar to dinosaurs like Sinraptor and Allosaurus.‭ ‬For this reason Limusaurus may have been a herbivore,‭ ‬specialist carnivore or perhaps even an omnivore,‭ ‬speculations that will carry on in the absence of definitive evidence to prove one above the others.‭
       Limusaurus is also noted for having four digits on its hands,‭ ‬something which reveals it to be a primitive form‭ ‬of‭ ‬theropod.‭ ‬Additionally these digits are composed of numbers II,‭ ‬III,‭ ‬IV and V,‭ ‬with digit I being reduced to give the appearance of a‭ ‘‬four fingered‭’ ‬hand.‭ ‬This is in contrast to previous theories about theropods since digit reduction was thought to take place on the ulna side of the hand rather than the radius side‭ (‬the fore arms of vertebrates are made up of two bones called the ulna and radius‭) ‬as seen in Limusaurus.‭ ‬Because Limusaurus is so far only known from sub adult remains it is quite possible that it may have grown slightly larger than the‭ ‬1.7‭ ‬meters stated above.
       Limusaurus is far from being the only theropod dinosaur known from the Shishugou Formation with other genera including Sinraptor,‭ ‬Guanlong,‭ ‬Monolophosaurus,‭ ‬Zuolong and Haplocheirus.‭ ‬Other types of dinosaur from this formation include the sauropod Mamenchisaurus and the basal ceratopsian Yinlong.

Further reading
- A Jurassic ceratosaur from China helps clarify avian digital homologies. - Nature 459(7249):940-944. - X. Xu, J. M. Clark, J. Mo, J. Choiniere, C. A. Forster, G. M. Erickson, D. W. E. Hone, C. Sullivan, D. A. Eberth, S. J. Nesbitt, Q. Zhao, R. Hernández, C.-k. Jia, F.-l. Han & Y. Gou - 2009.
- Reply to "Limusaurus and bird digit identity". - Nature Precedings - X. Xu, J. Clark, J. Choiniere, D. Hone & C. Sullivan - 2011.
- New anatomical details of the basal ceratosaur Limusaurus and implications for the Jurassic radiation of Theropoda. - Abstract of Papers. 74th Annual Meeting Society of Vertebrate Paleontology. - Journal of Vertebrate Paleontology. p. 235. - J. Stiegler & S. Wang & X. Xu - 2014.
- Limusaurus inextricabilis (Theropoda: Ceratosauria) gives a hand to evolutionary teratology: a complementary view on avian manual digits identities. - Zoological Journal of the Linnean Society. 176 (3): 674–685. - G. Guinard - 2016.


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