Shuotheriidae is a small family of Jurassic mammaliaforms whose remains are found in China, Great Britain and possibly Russia. They have been proposed to be close relatives of Australosphenida (which often controversially includes monotremes), together forming the clade Yinotheria. However, some studies suggest shuotheres are closer to therians than to monotremes,Rougier, Guillermo W.; Martinelli, Agustín G.; Forasiepi, Analía M.; Novacek, Michael J., New Jurassic mammals from Patagonia, Argentina : a reappraisal of australosphenidan morphology and interrelationships; American Museum Novitates, no. 3566, 2007Tom Rich, Patricia Vickers Rich, Palaeobiogeography of Mesozoic Mammals – Revisited, Article · January 2012 or that australosphenidans and therians are more closely related to each other than either are to shuotheres, with a 2024 study suggesting that shuotheriids were closely related to Docodonta outside of the Mammalia crown group.
References
Further reading Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo, Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure (New York: Columbia University Press, 2004), 214–215.