絶滅した海洋生物がタイの保護区に隠されていた Extinct marine creatures hidden in Thai sanctuary
2023-11-20 カリフォルニア大学リバーサイド校(UCR)
◆これらの発見は、地球の歴史で最も日付がつけにくい時期の一部である約4.97億〜4.85億年前の後期カンブリア時代のtuff(凝灰岩)から得られ、これにより地球の進化と絶滅のクロニクルが解明され、現代の課題に対処する手助けになる可能性があります。
<関連情報>
- https://news.ucr.edu/articles/2023/11/20/trilobites-rise-ashes-reveal-ancient-map
- https://onlinelibrary.wiley.com/doi/full/10.1002/spp2.1516
タイのカンブリア紀-オルドビス紀タルタオ層群の三葉虫とその地質環境 Trilobites of Thailand’s Cambrian–Ordovician Tarutao Group and their geological setting
Shelly J. Wernette, Nigel C. Hughes, Paul M. Myrow, Apsorn Sardsud
Papers in Palaeontology Published: 04 October 2023
DOI:https://doi.org/10.1002/spp2.1516
Abstract
Tuff-bearing upper Cambrian to lowermost Ordovician strata on Ko Tarutao island, Satun province, southernmost peninsular Thailand, contain a rich trilobite fauna relevant to global biostratigraphy, peri-Gondwanan palaeogeography and shifting evolutionary mode. This area of Sibumasu, a lower Palaeozoic marginal Gondwanan terrane, is shown to have been closely associated with Australia, North China (Sino-Korea) and other continental fragments from the supercontinent’s northern equatorial sector, including South China at that time. Shared faunas also suggest a Kazakhstani and Laurentian association. Collections from eight sections yielded 10 newly discovered species and one new genus from ancient shoreface and inner shelf siliciclastic deposits. With the new taxa and revision of taxa known previously, we refine the age of the upper two formations of the Tarutao Group to the middle of Cambrian Stage 10, and lower–middle Tremadocian. Two biozones are erected for Sibumasu: the Eosaukia buravasi Zone, encompassing all Cambrian sections from Ko Tarutao, and the Asaphellus charoenmiti Zone, encompassing the Tremadocian fauna discussed herein. The new genus is Tarutaoia and new species are Tsinania sirindhornae, Pseudokoldinioidia maneekuti, Pagodia? uhleini, Asaphellus charoenmiti, Tarutaoia techawani, Jiia talowaois, Caznaia imsamuti, Anderssonella undulata, Lophosaukia nuchanongi and Corbinia perforata. Other taxa reported for the first time from Tarutao are Mansuyia? sp., Parakoldinioidia callosa Qian, Pseudagnostus sp., Homagnostus sp., Haniwa mucronata Shergold, Haniwa sosanensis? Kobayashi, Lichengia simplex Shergold, Pacootasaukia sp., Wuhuia? sp., Plethopeltella sp., Apatokephalus sp., Akoldinioidia sp. 1 and Koldinioidia sp.
