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UA 8699
UA 8699 (University of Antananarivo specimen 8699)〔Krause, 2001, p. 497〕 is a fossil mammalian tooth from the Cretaceous of Madagascar. A broken lower molar about 3.5 mm (0.14 in) long, it is from the Maastrichtian of the Maevarano Formation in northwestern Madagascar. Details of its crown morphology indicate that it is a boreosphenidan, a member of the group that includes living marsupials and placentals. David W. Krause, who first described the tooth in 2001, interpreted it as a marsupial on the basis of five shared characters, but in 2003 Averianov and others noted that all those are shared by zhelestid placentals and favored a close relationship between UA 8699 and the Spanish zhelestid ''Lainodon''. Krause used the tooth as evidence that marsupials were present on the southern continents (Gondwana) as early as the late Cretaceous and Averianov and colleagues proposed that the tooth represented another example of faunal exchange between Africa and Europe at the time.
==Discovery and context==
UA 8699 was discovered in a joint study by Stony Brook University and the University of Antananarivo (UA) and placed in the collections of the latter as specimen 8699. It was found at a locality named MAD93-95 in the Anembalemba Member of the Maevarano Formation, which is Maastrichtian (latest Cretaceous) in age. The locality is in the Mahajanga Basin of northwestern Madagascar.〔 Several other mammals have been recovered from similarly aged Madagascar deposits, but most are also known from very limited material. These include the gondwanathere ''Lavanify'', an indeterminate multituberculate, and a few other indeterminate teeth, as well as a nearly complete skeleton representing an otherwise unknown mammalian lineage.〔Krause et al., 2006, pp. 186–188〕 In a 2001 ''Nature'' paper, David Krause announced the discovery of UA 8699 and argued for marsupial affinities of the specimen. Because the specimen is so fragmentary, he refrained from assigning a new scientific name to the tooth.〔 Two years later, Alexander Averianov, David Archibald, and Thomas Martin favored a placental interpretation in a paper in ''Acta Palaeontologica Polonica'', noting that the specimen was essentially similar to the zhelestid ''Lainodon''.〔Averianov et al., 2003, p. 149〕 In a 2006 review of some of the Cretaceous vertebrates of Madagascar, Krause and colleagues continued to consider the specimen as a marsupial and announced that an upcoming paper by Case would make the case for marsupial affinities more fully.〔Krause et al., 2006, p. 187〕
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