Concavispina is an extinct genus of thalattosaur reptile from the early Late Triassic (Carnian stage) Xiaowa Formation of Guangling, Guizhou, southern China.

It is thought to be most closely related to Xinpusaurus, as both taxa share three derived characters: a maxilla that is curved upward at its anterior end, a humerus (upper arm bone) that is wider near the shoulder than near the elbow, and the presence of less than five cervicals (neck vertebrae).

[1] Like all thalattosaurs, Concavispina was a marine reptile that probably swam by lateral undulation or side-to-side movement of its elongated body.

Xinpusaurus's teeth are generally taller than wide, similar to "crunching" guild marine predators (such as thalattosuchians and some large ichthyosaurs) which preferred armored crustaceans and fish but were not too specialized to avoid softer prey.

[1] A phylogenetic analysis of Concavispina in 2013 produced the following result, with Xinpusaurus as its closest relative within the clade Thalattosauroidea:[1] Petrolacosaurus kansensis Youngina capensis Prolacerta broomi Miodentosaurus brevis Endennasaurus acutirostris Anshunsaurus huangguoshuensis Anshunsaurus wushaensis Askeptosaurus italicus Paralonectes merriami Concavispina biseridens Xinpusaurus suni Clarazia schinzi Hescheleria ruebeli Agkistrognathus campebelli Nectosaurus halius Thalattosaurus alexandrae Thalattosaurus borealis