The Ancestry of the Genus Nautilus
The Ancestry of the Genus Nautilus
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鹦鹉螺属的祖先
DOI：
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发表时间：
2010
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影响因子：
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通讯作者：
Tatsuro Matsumoto
中科院分区：
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作者：
C. Teichert;Tatsuro Matsumoto
已知鹦鹉螺属至少有6个现存物种，它们栖息在太平洋西南部、菲律宾、印度尼西亚和澳大利亚热带海域的一个界限分明的大区域内（见Saunders（1981 b）和本卷第三部分）。这些事件中最令人困惑的方面是，鹦鹉螺似乎在之前的前全新世岩石中没有祖先;即，在上新世和更新世的岩石中，没有真正记录过鹦鹉螺的代表，实际上也没有任何种类的鹦鹉螺。唯一有出版物提到上新世的是在俄勒冈州海岸发现的一个“真正的鹦鹉螺”标本（Dall，1909年，第21页），但从未描述过标本及其地层位置，米勒（1947年，第9页）倾向于不考虑这一记录。最多，它是模糊的和无证的。此外，1909年对“真正的鹦鹉螺”的定义与今天的定义不同。由于上新世和更新世的海相岩石在现生鹦鹉螺的分布区广泛暴露，没有任何关于这一时期鹦鹉螺的记录，这表明现生鹦鹉螺的直系祖先一定非常罕见，以至于到目前为止它们都没有被发现，这不仅仅是因为没有人“费心去寻找它们”（沃德，1984年）。
The genus Nautilus is known to be represented by at least six extant species that inhabit a well-circumscribed large area in the southwestern Pacific Ocean, the Philippines, Indonesia, and the tropical seas of Australia [see Saunders (1981b) and Part III of this volume]. The most puzzling aspect of these occurrences is that Nautilus seems to have no ancestors in the immediately preceding pre-Holocene rocks; i.e., no representatives of Nautilus, indeed no nautilids of any kind, have ever been authentically recorded from rocks of Pliocene and Pleistocene age. The only published mention of a Pliocene occurrence is that of a single specimen of a "true Nautilus" from the coast of Oregon (Dall, 1909, p. 21), but the specimen and its stratigraphie position were never described, and Miller (1947, p. 9) was inclined to discount this record. At most, it is obscure and undocumented. Also, the definition of a "true Nautilus" in 1909 differed from that of today. Since marine Pliocene and Pleistocene rocks are widely exposed in the area of distribution of living Nautilus, the fact that no documented records of any nautilids of those ages exist suggests that the immediate ancestors of living Nautilus must have been so rare that up until now they have escaped detection and not only because nobody "has taken the trouble to look for them" (Ward, 1984).