| 名稱 對筆石屬化石 | Name Didymograptus Graptolite fossil |
| 地質年代 奧陶紀 | Geological Age Ordovician |
| 描述 筆石綱動物是一類已絕種的海洋群體動物，普遍生活在古生代的海洋，是古生代的標準化石。它們在寒武紀時代出現， 在奧陶紀時代分佈最廣、最繁盛 ，但在石炭紀卻未能逃過絕滅的命運。筆石化石通常保存於泥岩中，常呈炭質薄膜，好像用鉛筆書寫在岩石上的痕跡，因此被命名為「筆石」。 筆石綱動物是群體生活的動物。它具有一條好像骨骼的纖維，這條「骨骼」連貫著很多個體，稱為「胎管」，它們串連起來組成一組「苞管」，發育成群體；苞管亦可再獨立個別藏有游動孢子的囊。群體筆石的苞管數目不一，囊的排序亦不一樣，所以古生物學家就利用苞管的數目和囊的排序來鑑定不同種類的筆石化石。筆石化石可分為兩個目，第一目是營固生活的樹形筆石目；第二類是漂游生活的正筆石目。 | Description Didymograptus is an extinct genus of graptolites with four rows of cups. They lived during the Middle Ordovician, to Late Ordovician. Fossil graptolites are thin, often shiny, markings on rock surfaces that look like pencil marks, and their name comes from the Greek for ‘writing in the rocks’. Graptolites are the remains of intricate colonies, some of which accommodated up to 5000 individual animals; these individuals lived in a skeleton of collagen, similar to the material from which our finger nails are made. We focus on the two main groups of graptolites: the cone-like, largely bottom-living dendroids, and the planktonic graptoloids. They lived between the Cambrian and Carboniferous periods, about 520 to 350 million years ago. |
| 地點 彭布羅克郡，威爾斯，英國 | Location Pembrokeshire, Wales |
| 參考 Reference https://www.bgs.ac.uk/discoveringGeology/time/Fossilfocus/graptolite.html https://www.earthsciences.hku.hk/shmuseum/chi/earth_evo_05_01_8.php | |
| 編者 由 3D(2) 陳永鏘 於30/5/2019編寫 顏綾老師 於8/4/2020最後編改 | Editor Created by 3D (2) Chan Wing Cheong on 30/5/2019 Last modified by Ms. Ngan Ling as on 8/4/2020 |
