|
The sapayoa or broad-billed sapayoa (''Sapayoa aenigma'') is a suboscine passerine found in lowland rainforests in Panama and northwest South America. As the epithet ''aenigma'' ("the enigma") implies, its relationships have long been elusive. It is easy to overlook, but appears to be common in a wide range and is not considered threatened by the IUCN.〔〔BLI (2004)〕 ==Taxonomy and systematics== It has always been considered a monotypic genus, ''Sapayoa'', and historically regarded as a New World suboscine; in particular, it was assigned to the manakin family (Pipridae). However, the species was listed as ''incertae sedis'' (position uncertain) in the Sibley-Ahlquist taxonomy, because "preliminary DNA-DNA hybridization comparisons ... indicate that this species is either a relative of the Old World Eurylaimidae or a sister group of all other Tyrannida, as suggested by earlier biochemical studies .... In any event, it is not a close relative of manakins or any other recent tyrannoid."〔Sibley & Munroe (1990)〕 More recent research suggests that it is not a New World suboscine at all, but an Old World suboscine. In 2004, it was shown that the sapayoa is an outlier to the New World suboscines.〔Chesser (2004)〕 In an earlier analysis based on nDNA myoglobin intron 2 and GAPDH intron 11 sequence data, the authors found the sapayoa "as a deep branch in the group of broadbills and pittas of the Old World tropics."〔Fjeldså et al. (2003)〕 Accordingly, the sapayoa would be the last surviving New World species of a lineage that evolved in Australia-New Guinea when Gondwana was in the process of splitting apart. The sapayoa's ancestors are hypothesized to have reached South America via the Western Antarctica Peninsula. Nowadays, the sapoyoa is sometimes placed in the family Eurylaimidae with the broadbills.〔E.g. Banks et al. (2008), Remsen et al. (2009)〕 Others tentatively place the sapayoa in the asity family Philepittidae〔Kemp & Sherley (2003), though it is not clear whether it was Kemp and Sherley or Perrins who decided to include the broad-billed sapayoa in the Philepittidae.〕 otherwise found only in Madagascar and sometimes included in the broadbill family. However, the divergence between the broadbills and the sapayoa found in the 2003 study is only slightly less deep than that between the sapayoa and the pittas.〔 It is even possible though unlikely that the present species is actually closer to the pittas than to the broadbills. Consequently, it is suggested to place the sapayoa in its own monotypic family, Sapayoidae,〔E.g. Irestedt et al. (2006)〕 as is done here. 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「sapayoa」の詳細全文を読む スポンサード リンク
|