胎盤菊石
胎盘菊石属 化石时期：白堊紀晚期
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| Placenticeras meeki的化石 | |
科学分类 
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| 界： | 动物界 Animalia |
| 门： | 軟體動物門 Mollusca |
| 纲： | 頭足綱 Cephalopoda |
| 目： | †菊石目 Ammonitida |
| 科： | †胎盘菊石科 Placenticeratidae |
| 属： | †胎盘菊石属 Placenticeras Meek, 1876[1] |
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胎盤菊石（學名：Placenticeras），又名平盤菊石、餅菊石，是生存在晚白堊紀海洋中的一屬菊石。牠們可能是所有已知的菊石中游速最快的，透過噴水的動力來追逐獵物、逃避兩棲動物與魚類的攻擊。[2]其化石在亞洲、歐洲和美洲都有發現。[1]
特徵
胎盤菊石具有緊壓的、內旋的殼，腹狹窄，有散發光彩的厚實真珠質層。牠們最大可長到50公分長，其巨大的體型和流線型的殼體使牠們在水中能快速游動。[2]
物種[1]
- Placenticeras bidorsatum
- Placenticeras cumminsi
- Placenticeras fritschi
- Placenticeras grossouvrei
- Placenticeras kolbajense
- Placenticeras maherndli
- Placenticeras mediasiaticum
- Placenticeras memoriaschloenbachi
- Placenticeras orbignyanum
- Placenticeras paraplanum
- Placenticeras placenta
- Placenticeras polyopsis
- Placenticeras pseudoplacenta
- Placenticeras semiornatum
- Placenticeras syrtale
- Placenticeras tamulicum
- Placenticeras vredenburgi
- Placenticeras whitfieldi
參考文獻
- ^ 1.0 1.1 1.2 Fossilworks: Placenticeras. [2018-06-01]. （原始内容存档于2016-03-22） （英语）.
- ^ 2.0 2.1 Walker, Cyril; Ward, David. Fossils. Smithsonian Handbooks revised, illustrated. Dorling Kindersley. 2002: 149. ISBN 0789489848.
- Arkell et al., 1957, Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L. Geological Soc. of America, Univ of Kansas Press. R.C. Moore, (Ed)
- W. A. Cobban and Hook, S. C. 1983 Mid-Cretaceous (Turonian) ammonite fauna from Fence Lake area of west-central New Mexico. Memoir 41, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.
- W. A. Cobban and Hook, S. C. 1979, Collignoniceras woollgari wooollgari (Mantell) ammonite fauna from Upper Cretaceous of Western Interior, United States. Memoir 37, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.
- Discovering Fossils: How to Find and Identify Remains of the Prehistoric Past (Fossils & Dinosaurs) by Frank A. Garcia, Donald S. Miller, and Jasper Burns