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''Oryzomys antillarum'', also known as the Jamaican rice rat,〔Goldman, 1918, p. 44; Turvey and Helgen, 2008〕 is an extinct rodent of Jamaica. A member of the genus ''Oryzomys'' within the family Cricetidae, it is similar to ''O. couesi'' of mainland Central America, from where it may have dispersed to its island during the last glacial period. ''O. antillarum'' is common in subfossil cave faunas and is also known from three specimens collected live in the 19th century. Some historical records of Jamaican rats may pertain to it. The species probably became extinct late in the 19th century, perhaps due to the introduction of the small Asian mongoose, competition with introduced rodents such as the brown rat, and habitat destruction. ''Oryzomys antillarum'' was a medium-sized rat, similar in most respects to ''Oryzomys couesi''. The head and body length was and the skull was about long. The upperparts were reddish and graded into the yellowish underparts. The tail was about as long as the head and body, sparsely haired, and darker above than below. The species differed from ''O. couesi'' in having longer nasal bones, shorter incisive foramina (perforations of the front part of the palate), and more robust zygomatic arches (cheekbones). ==Taxonomy== In his 1877 monograph on North American rodents, Elliott Coues mentioned two specimens of ''Oryzomys'' from Jamaica in the collections of the United States National Museum (USNM). According to Coues, the specimens were similar to the marsh rice rat (''Oryzomys palustris'') of the United States, but different in color. Although he wrote that they probably represented a separate form, he refrained from giving a scientific name to them because of the possibility that the form had already received a name he did not know of.〔Coues, 1877, p. 116, footnote; Thomas, 1898, p. 177〕 The species was first formally described by Oldfield Thomas in 1898 based on a specimen that had been in the British Museum of Natural History since 1845. He recognized it as a separate species of ''Oryzomys'', ''Oryzomys antillarum'', but wrote that it was related to the mainland Central American ''O. couesi''. Thomas suspected that the species was already extinct on Jamaica, but that it or a similar rice rat could still be found in the unexplored interior of Cuba or Hispaniola.〔 Revising North American ''Oryzomys'' in 1918, Edward Alphonso Goldman retained ''O. antillarum'' as a separate species, but conceded that it was so similar to mainland ''O. couesi'' that it may have been introduced on Jamaica.〔Goldman, 1918, pp. 44–45〕 In 1920, Harold Anthony reported that remains of ''O. antillarum'' were common in coastal caves, suggesting that the species had previously been an important part of the diet of the barn owl (''Tyto alba'').〔Anthony, 1920, p. 166〕 In 1942, Glover Morrill Allen doubted that it was even a distinct species〔Allen, 1942, p. 88〕 and in his 1962 Ph.D. thesis, Clayton Ray, who examined numerous cave specimens, agreed and retained it as only a "weakly differentiated subspecies" of ''Oryzomys palustris'' (which by then included ''O. couesi'' and other Mexican and Central American forms), ''Oryzomys palustris antillarum''.〔Ray, 1962, p. 47〕 Philip Hershkovitz came to the same conclusion in a 1966 paper.〔 After ''O. couesi'' of Mexico and Central America was again classified as a species distinct from the marsh rice rat (''O. palustris'') of the United States, the Jamaican form came to be regarded as a subspecies of the former, ''Oryzomys couesi antillarum''.〔 In a 1993 review, Gary Morgan reinstated the animal as a distinct species closely related to ''O. couesi'', citing an unpublished paper by Humphrey, Setzer, and himself.〔 Guy Musser and Michael Carleton, writing for the 2005 third edition of ''Mammal Species of the World'', continued to classify the Jamaican form as part of ''O. couesi'', but did not reference Morgan.〔Musser and Carleton, 2005, p. 1147〕 However, in a 2006 review of the contents of ''Oryzomys'', Marcelo Weksler and colleagues listed ''O. antillarum'' as a separate species, citing Morgan,〔Weksler et al., 2006, table 1, footnote e〕 and in a 2009 paper on western Mexican ''Oryzomys'' Carleton and Joaquín Arroyo-Cabrales did the same.〔Carleton and Arroyo-Cabrales, 2009, p. 116〕 According to the classification by Carleton and Arroyo-Cabrales, ''Oryzomys antillarum'' is one of eight species in the genus ''Oryzomys'', which occurs from the eastern United States (''O. palustris'') into northwestern South America (''O. gorgasi'').〔Carleton and Arroyo-Cabrales, 2009, p. 106〕 ''O. antillarum'' is further part of the ''O. couesi'' section, which is centered around the widespread Central American ''O. couesi'' and also includes various other species with more limited and peripheral distributions.〔Carleton and Arroyo-Cabrales, 2009, p. 117〕 Many aspects of the systematics of the ''O. couesi'' section remain unclear and it is likely that the current classification underestimates the true diversity of the group.〔Carleton and Arroyo-Cabrales, 2009, p. 107〕 ''Oryzomys'' previously included many other species, which were progressively removed in various studies culminating in the 2006 paper by Weksler and colleagues, which excluded more than forty species from the genus.〔Weksler et al., 2006, table 1〕 All are classified in the tribe Oryzomyini ("rice rats"), a diverse assemblage of American rodents of over a hundred species,〔Weksler, 2006, p. 3〕 and on higher taxonomic levels in the subfamily Sigmodontinae of family Cricetidae, along with hundreds of other species of mainly small rodents.〔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「Oryzomys antillarum」の詳細全文を読む スポンサード リンク
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