Ratchasimasaurus

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title: "Ratchasimasaurus" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["hadrosauroidea", "dinosaur-genera", "aptian-dinosaurs", "fossil-taxa-described-in-2011", "dinosaurs-of-thailand"] description: "Extinct genus of dinosaurs" topic_path: "general/hadrosauroidea" source: "https://en.wikipedia.org/wiki/Ratchasimasaurus" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct genus of dinosaurs ::

| fossil_range = Aptian ~ | image = Ratchasimasaurus suranareae 02.jpg | image_caption = Mounted skeleton | taxon = Ratchasimasaurus | authority = Shibata, Jintasakul & Azuma, 2011 | type_species = Ratchasimasaurus suranareae | type_species_authority = Shibata, Jintasakul & Azuma, 2011 ::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/2e/Ratchasimasaurus_suranareae_03.jpg" caption="Different angle of the mounted skeleton"] ::

Ratchasimasaurus (meaning "Nakhon Ratchasima lizard") is a genus of iguanodontian ornithopod dinosaur from Early Cretaceous (Aptian stage) Khok Kruat Formation of Nakhon Ratchasima province in northeastern Thailand. The type and only species is R. suranareae, named after Thao Suranari, a 19th-century war heroine.

Discovery and naming

Ratchasimasaurus was initially known as the "Probactrosaurus-like" iguanodontian and is only known from the holotype (specimen NRRU-A2064), a complete left dentary with no teeth that was found in the Khok Kruat Formation in Thailand by a local farmer near a pond, The genus was named in 2011 by Shibata, Jintasakul & Azuma. The holotype is currently housed in The Northeastern Research Institute of Petrified Wood and Mineral Resources (NRIPM) and a mounted skeleton exists in River City, Bangkok.

Description

One autapomorphy (unique characteristic) of Ratchasimasaurus is its elongated and flat ramus of the dentary. Ratchasimasaurus shows both primitive and derived characters for Iguanodontia, such as "a caudally inclined coronoid process and alveolar trough with a primitive crown impression, and a derived buccal shelf between the tooth row and the coronoid process". The length of the dentary is 198.1 mm.

References

References

1. "Phylogeny and Biogeography of Iguanodontian Dinosaurs, with Implications from Ontogeny and an Examination of the Function of the Fused Carpal-Digit I Complex".
2. (2011). "A new iguanodontian dinosaur from the Lower Cretaceous Khok Kruat Formation, Nakhon Ratchasima in northeastern Thailand". Acta Geologica Sinica (English Edition).

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