對筆石
对笔石科的一属半索动物
對筆石屬（學名：Didymograptus）是正筆石目下的一屬筆石，生存於奧陶紀的海洋中，是一種群居性浮游生物。[2]其化石分佈於美洲、歐洲、亞洲、澳大利亞和新西蘭等地。
對筆石屬 化石時期：奧陶紀
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| Didymograptus murchisoni | |
科學分類 
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| 界： | 動物界 Animalia |
| 門： | 半索動物門 Hemichordata |
| 綱： | 羽鰓綱 Pterobranchia |
| 目： | †正筆石目 Graptoloidea |
| 科： | †均分筆石科 Dichograptidae |
| 屬： | †對筆石屬 Didymograptus McCoy, 1851[1] |
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特徵
物種
本屬包括以下物種：[1]
- Didymograptus (Expansograptus) abnormis Hsu, 1934
- Didymograptus (Expansograptus) acriculus Keble & Harris, 1934
- Didymograptus (Expansograptus) adamantinus T.S.Hall, 1914
- Didymograptus (Didymograptus) artus Elles & Wood, 1901
- Didymograptus (Expansograptus) asperus Harris & Thomas, 1938
- Didymograptus (Expansograptus) aureus T.S.Hall, 1914
- Didymograptus (Expansograptus) balticus Tullberg, 1938
- Didymograptus bartrumi Benson & Keble, 1935
- Didymograptus (Didymograptellus) bidens Keble, 1927
- Didymograptus (Expansograptus) constrictus J.Hall, 1865
- Didymograptus (Expansograptus) cuspidatus Ruedemann, 1904
- Didymograptus demissus (Törnquist, 1901)
- Didymograptus (Expansograptus) dilatans T.S.Hall, 1914
- Didymograptus distinctus Harris & Thomas, 1935
- Didymograptus (Expansograptus) ellesae Ruedemann, 1908
- Didymograptus (Expansograptus) elongatus Harris & Thomas, 1914
- Didymograptus ensjoensis Monsen, 1937
- Didymograptus eocaduceus Harris, 1933
- Didymograptus euodus Lapworth, 1875
- Didymograptus (Expansograptus) extensus J.Hall, 1858
- Didymograptus filiformis (Tullberg, 1880)
- Didymograptus hemicyclus Harris, 1933
- Didymograptus holmi (Törnquist, 1901)
- Didymograptus (Expansograptus) latus T.S.Hall, 1907
- Didymograptus (Corymbograptus) mundus T.S.Hall, 1914
- Didymograptus (Expansograptus) nicholsoni Lapworth, 1875
- Didymograptus (Expansograptus) nitidus J.Hall, 1858
- Didymograptus pacificus Ruedemann, 1947
- Didymograptus paraindentus Berry, 1960
- Didymograptus (Expansograptus) perditus T.S.Hall, 1914
- Didymograptus (Expansograptus) procumbens T.S.Hall, 1914
- Didymograptus protobalticus (Monsen, 1937)
- Didymograptus (Didymograptellus) protobifidus Elles, 1933
- Didymograptus pusillus (Tullberg, 1880)
- Didymograptus (Expansograptus) similis J.Hall, 1865
- Didymograptus spinulosus Perner, 1895
- Didymograptus (Didymograptus) stabilis Elles & Wood, 1901
- Didymograptus (Didymograptus) stavus Legg, 1976
- 瑞典對筆石 Didymograptus (Expansograptus) suecicus Tullberg, 1880
- Didymograptus (Expansograptus) superstes Lapworth, 1876
- Didymograptus taylori T.S.Hall, 1899
- Didymograptus turgidus (Lee, 1974)
- Didymograptus undulatus (Törnquist, 1901)
- Didymograptus uniformis Elles & Wood, 1901
- Didymograptus (Corymbograptus) v-deflexus Harris, 1924
- Didymograptus (Expansograptus) validus Toernquist, 1901
- Didymograptus (Expansograptus) vicinus Harris & Thomas, 1938
參考文獻
- ^ 1.0 1.1 Fossiilid.info: Didymograptus. [2017-11-25]. （原始內容存檔於2020-11-27） （英語）.
- ^ 2.0 2.1 Walker, Cyril; Ward, David. Fossils. Smithsonian Handbooks revised, illustrated. Dorling Kindersley. 2002: 48. ISBN 0789489848.