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''Agathaeromys'' is an extinct genus of oryzomyine rodents from the Pleistocene of Bonaire, West Indies. Two species are known, which differ in size and some details of tooth morphology. The larger ''A. donovani'', the type species, is known from hundreds of teeth, found in four localities that are probably 900,000 to 540,000 years old. ''A. praeuniversitatis'', the smaller species, is known from 35 teeth found in a single fossil site, which is probably 540,000 to 230,000 years old. Although material of ''Agathaeromys'' was first described in 1959, the genus was not formally named and diagnosed until 2010. It probably belongs to "clade D" within the oryzomyine group, together with many other island-dwelling species. The molars of both species possess several accessory crests in addition to the main cusps. In addition to some differences in features of the chewing surface of the molars, ''A. donovani'' has more roots on its lower molars than does ''A. praeuniversitatis''. ==Taxonomy== Material of ''Agathaeromys'' was first described by Dirk Hooijer in 1959 in the same paper that first named the extinct giant rat of Curaçao, ''Megalomys curazensis''. Hooijer described a few fossil teeth and jaws from Fontein, Bonaire, as an indeterminate species of ''Thomasomys'' ("''Thomasomys'' sp.") and considered them to be similar to species now placed in ''Delomys''.〔Hooijer, 1959, p. 18; Zijlstra et al., 2010, p. 861〕 In his 1974 monograph on the geology of the ABC islands (Aruba, Bonaire, and Curaçao—three Dutch islands off northwestern Venezuela), Paul Henri de Buisonjé listed ''Thomasomys'' sp. from additional fossil sites on Bonaire and additionally mentioned ''Oryzomys'' sp. from a different Bonaire site, Seroe Grandi.〔De Buisonjé, 1974, pp. 83, 186–187, 216–217〕 Although the Bonaire material represented one of the few fossil records of ''Thomasomys'', it was only rarely mentioned in the literature.〔Zijlstra et al., 2010, p. 861〕 In 2010, Jelle Zijlstra, Anneke Madern, and Lars van den Hoek Ostende reviewed the material. They considered it unlikely that the Bonaire "''Thomasomys''" would belong to the southern Brazilian genus ''Delomys'' or to ''Thomasomys'', which occurs only in the mountains of the Andes.〔 Using a cladistic analysis of the Sigmodontinae, they provided evidence that the Bonaire material belonged to the tribe Oryzomyini, rather than Thomasomyini (which includes ''Thomasomys'').〔Zijlstra et al., 2010, fig. 6〕 They carried out another cladistic analysis focused on Oryzomyini, which suggested that the Bonaire "''Thomasomys''" and the material from Seroe Grandi (De Buisonjé's "''Oryzomys'' sp.") were closely related, but distinct from any recognized oryzomyine genus.〔Zijlstra et al., 2010, fig. 7〕 Therefore, they named a new oryzomyine genus, ''Agathaeromys'', with two species: ''Agathaeromys donovani'' (type species) for the material previously identified as ''Thomasomys''; and ''Agathaeromys praeuniversitatis'' for the material from Seroe Grandi.〔Zijlstra et al., 2010, p. 862〕 The name ''Agathaeromys'' combines the Greek words ' "good", ' "air", and ' "mouse", referring to the name of the island of Bonaire and to the "fresh air" that contributions by Marcelo Weksler and colleagues brought to the classification of Oryzomyini.〔Zijlstra et al., 2010, p. 862; cf. Weksler, 2006; Weksler et al., 2006〕 The name ''donovani'' honors Stephen Donovan for his contributions to the scientific knowledge of the Caribbean〔Zijlstra et al., 2010, p. 863〕 and ''praeuniversitatis'' refers to Leiden University's Pre-University College, which provided an opportunity for Zijlstra to participate in the project that led to the identification of ''Agathaeromys''.〔Zijlstra et al., 2010, p. 866〕 Although Zijlstra and colleagues could not precisely determine the position of ''Agathaeromys'' within Oryzomyini, their results suggest that it occupies a position near the base of "clade D", one of the major subgroups of Oryzomyini. This clade contains a number of species only occurring on islands—including members of ''Aegialomys'', ''Agathaeromys'', ''Megalomys'', ''Nesoryzomys'', ''Noronhomys'', ''Oryzomys'', and ''Pennatomys''. Zijlstra and colleagues suggested that this is related to the high proportion of semiaquatic and non-forest species in clade D—most other oryzomyines are forest dwellers.〔Zijlstra et al., 2010, pp. 870–871; Turvey et al., 2010, p. 766〕 However, subsequent phylogenetic studies based on variations of the same data set used by Zijlstra and colleagues did not corroborate this placement. In their 2012 description of ''Megalomys georginae'', Turvey and colleagues recovered ''Agathaeromys'' outside each of the major groups of Oryzomyini.〔Turvey et al., 2012, fig. 3〕 Zijlstra placed ''Agathaeromys'' within "clade C" in a clade with ''Oligoryzomys victus'' and an undescribed fossil species of ''Oligoryzomys'' from Aruba in his 2012 paper naming ''Dushimys''.〔Zijlstra, 2012, fig. 3〕 As a whole, Oryzomyini includes over a hundred species in about thirty genera.〔Weksler, 2006, pp. 1, 10; Weksler et al., 2006, p. 1, table 1〕 Oryzomyini is one of several tribes within the subfamily Sigmodontinae of the family Cricetidae, which encompasses hundreds of other species of mainly small rodents, distributed chiefly in Eurasia and the Americas.〔Musser and Carleton, 2005〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Agathaeromys」の詳細全文を読む スポンサード リンク
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