The genus Xenachoffatia ("for Xena Choffat") was named by Hahn G. and Hahn R. in 1998. The primary species Xenachoffatia oinopion (Hahn & Hahn, 1998) was found in Kimmeridgian (Upper Jurassic) Camadas de Guimarota of Guimarota, Portugal. The classification is based on three upper molars.
References
Hahn & Hahn (1998), "Neue Beobachtungen an Plagiaulacoidea (Multituberculata) des Ober-Juras. 3. Der Bau der Molaren bei den Paulchoffatiidae." (New observations on the skull and jaw constructions in Paulchoffatiidae Multituberculata, Upper Jurassic.) Berliner Geowissenschaftlich Abhandlungen, E, 28, p. 39-84.
Hahn, G. & Hahn, R. (2000), "Multituberculates from the Guimarota mine", p. 97-107 in Martin T & Krebs B (eds), Guimarota - A Jurassic Ecosystem, Verlag Dr. Friedrich Pfeil, München.
Kielan-Jaworowska, Z. & Hurum, J.H. (2001), "Phylogeny and Systematics of multituberculate mammals", Paleontology44, p. 389-429.
Much of this information has been derived from [1] Multituberculata Cope, 1884.
With thanks to David Marjanovic for additional info.