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''Atheris'' is a genus of venomous vipers known as bush vipers.〔Spawls S, Branch B. 1995. ''The Dangerous Snakes of Africa''. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN 0-88359-029-8.〕 They are found only in tropical subsaharan Africa (excluding southern Africa)〔 and many species have isolated and fragmented distributions due to their confinement to rain forests.〔Mallow D, Ludwig D, Nilson G. 2003. ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. 359 pp. ISBN 0-89464-877-2.〕 In an interesting example of convergent evolution, they show many similarities to the arboreal pit vipers of Asia and South America.〔 Ten species are currently recognized. ==Description== They are relatively small in size, with adults ranging in total length (body + tail) from for ''A. katangensis'' to a maximum of for ''A. squamigera''.〔 All species have a broad, triangular head that is distinct from the neck. The canthus is also distinct and the snout is broad. The crown is covered with small imbricate or smooth scales, none of which is enlarged. The eyes are relatively large with elliptical pupils. The eyes are separated from the supralabials by 1–3 scale rows and from the nasal by 2–3 scales.〔 The body is slender, tapering, and slightly compressed. The dorsal scales are overlapping, strongly keeled and have apical pits. Laterally these are smaller than the middorsals. Midbody there are 14–36 rows of dorsal scales. There are 133–175 rounded ventral scales. The subcaudal scales are single and number 38–67.〔〔 The tail is strongly prehensile and can support the body while suspended from a branch or a twig.〔Mehrtens JM. 1987. ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X.〕 Members of this genus come in an amazing variety of colors and patterns, often within a single species. ''A. ceratophora'' and ''A. squamigera'' are particularly variable. 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「Atheris」の詳細全文を読む スポンサード リンク
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