篠山侏角龍屬

篠山侏角龍屬; 化石時期：早白堊世，阿爾布階 PreЄ Є O S D C P T J K Pg N
科學分類
界：	動物界 Animalia
門：	脊索動物門 Chordata
綱：	蜥形綱 Sauropsida
總目：	恐龍總目 Dinosauria
目：	†鳥臀目 Ornithischia
演化支：	†頭飾龍類 Marginocephalia
亞目：	†角龍亞目 Ceratopsia
下目：	†新角龍下目 Neoceratopsia
屬：	†篠山侏角龍屬 Sasayamagnomus; Tanaka et al., 2024
模式種
	†三枝氏篠山侏角龍; Sasayamagnomus saegusai; Tanaka et al., 2024

篠山侏角龍（學名：Sasayamagnomus，意為「來自篠山的侏儒」）是新角龍類恐龍的一個屬，來自日本兵庫縣早白堊世大山下組（英語：Ohyamashimo Formation）。屬下包括單一物種三枝氏篠山侏角龍（S. saegusai）。^[1]估計正模標本長達80公分（2.6英尺），儘管該標本尚未生長完全。^[2]

發現與命名

篠山侏角龍發現於兵庫縣丹波篠山市的宮田微脊椎動物地（Miyada microvertebrate site），已知化石包括17塊腦顱骨骼、右喙骨及一個左脛骨。材料中保存的2個右鼻骨表明其中至少含2具個體。^[1]其正式描述之前曾在2023年的一篇會議摘要上公布。^[3]

其於2024年被正式描述為新角龍類新屬新種。屬名取自發現化石的篠山盆地及拉丁語單詞「侏儒」。種名致敬丹波地區恐龍發掘活動的領導者，也是兵庫縣脊椎動物古生物學研究的卓越貢獻者——三枝春雄（Haruo Saegusa）博士。^[1]

正模標本為MNHAH D1-060516。^[1]

分類

Tanaka等人將篠山侏角龍納入系統發育分析，並發現其與鷹角龍及黎明角龍共處同一演化支。^[1]

古生態學

篠山侏角龍發現於大山下組（篠山群），後者年代為早白堊世末的阿爾布階中早期。^[4]這些層位主要由砂岩、泥岩及礫岩構成。沉積環境（英語：depositional environment）代表具有半濕潤（英語：Subhumid temperate climate）至半乾旱氣候的河流系統。^[5]恐龍牙齒在該層各地都很常見，包括屬於其它獸腳類（馳龍科、鐮刀龍下目及暴龍超科）及蜥腳類、甲龍類和禽龍類的牙齒。^[6]已描述了幾個蛋化石類群（英語：ootaxa），包括姬蛋屬（英語：Himeoolithus）、纖長蛋屬（英語：Subtiliolithus）、日本蛋屬（英語：Nipponoolithus）及稜柱形蛋屬（英語：Prismatoolithus）。^[7]地層中還發現了怪蜥類（英語：Monstersauria）的雙刃齒蜥、巨龍形類蜥腳下目丹波巨龍及傷齒龍科獸腳類寐獵龍。^[8]^[9]^[4]篠山群還有其它化石動物群，但原始描述中並未提及其發現於該地層，如真獸類的篠山獸（英語：Sasayamamylos）、^[10]石龍子亞目的厚頜蜥（英語：Pachygenys）^[11]及兩種蛙類——兵庫蛙（英語：Hyogobatrachus）與丹波蛙（英語：Tambabatrachus）。^[12]

參見

角龍類研究歷史（英語：Timeline of ceratopsian research）

參考資料

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 Tanaka, Tomonori; Chiba, Kentaro; Ikeda, Tadahiro; Ryan, Michael J. A new neoceratopsian (Ornithischia, Ceratopsia) from the Lower Cretaceous Ohyamashimo Formation (Albian), southwestern Japan. Papers in Palaeontology. September 2024, 10 (5). doi:10.1002/spp2.1587.
^ 兵庫県で発見の角竜類の化石新属新種と確認 | お知らせ・トピックス. 岡山理科大學. [2024-09-04] （日語）.
^ Tanaka, Tomonori; Chiba, Kentaro; Ikeda, Tadahiro; Kubota, Katsuhiro. Phylogenetic position of a ceratopsian dinosaur from the Lower Cretaceous Ohyamashimo Formation (Albian) of the Sasayama Group in Tambasasayama City, Hyogo, Japan (PDF). The Palaeontological Society of Japan. 2023.
^ ^4.0 ^4.1 Kubota, K.; Kobayashi, Y.; Ikeda, T. Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Scientific Reports. 2024, 14. 16392. PMC 11272788 . doi:10.1038/s41598-024-66815-2 .
^ Hayashi, Keiichi; Fujita, Saki; Koarai, Kazuto; Matsukawa, Masaki. Stratigraphy and paleoenvironment of the Cretaceous Sasayama Group in the Sasayama area, Hyogo Prefecture, western Japan. The Journal of the Geological Society of Japan. 2017-09-15, 123 (9): 747–764. ISSN 0016-7630. doi:10.5575/geosoc.2017.0016  （英語）.
^ Kubota, Katsuhiro. 日本産の中生代恐竜化石目録 2022年版 [A list of Mesozoic dinosaur fossils from Japan in 2022] (PDF). Bulletin of the Gunma Museum of Natural History: 157–170.
^ Tanaka, Kohei; Zelenitsky, Darla K.; Therrien, François; Ikeda, Tadahiro; Kubota, Katsuhiro; Saegusa, Haruo; Tanaka, Tomonori; Ikuno, Kenji. Exceptionally small theropod eggs from the Lower Cretaceous Ohyamashimo Formation of Tamba, Hyogo Prefecture, Japan. Cretaceous Research. 2020, 114: Article 104519. Bibcode:2020CrRes.11404519T. S2CID 219449961. doi:10.1016/j.cretres.2020.104519.
^ Ikeda, T.; Ota, H.; Tanaka, T.; Ikuno, K.; Kubota, K.; Tanaka, K.; Saegusa, H. A fossil Monstersauria (Squamata: Anguimorpha) from the Lower Cretaceous Ohyamashimo Formation of the Sasayama Group in Tamba City, Hyogo Prefecture, Japan. Cretaceous Research. 2021, 130: Article 105063. S2CID 239230916. doi:10.1016/j.cretres.2021.105063 .
^ Saegusa, H.; Ikeda, T. A new titanosauriform sauropod (Dinosauria: Saurischia) from the Lower Cretaceous of Hyogo, Japan. Zootaxa. 2014, 3848 (1): 1–66. PMID 25112425. doi:10.11646/zootaxa.3848.1.1 .
^ Kusuhashi, Nao; Tsutsumi, Yukiyasu; Saegusa, Haruo; Horie, Kenji; Ikeda, Tadahiro; Yokoyama, Kazumi; Shiraishi, Kazuyuki. A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan. Proceedings of the Royal Society B: Biological Sciences. 2013-05-22, 280 (1759): 20130142. ISSN 0962-8452. PMC 3619506 . PMID 23536594. doi:10.1098/rspb.2013.0142 （英語）.
^ Ikeda, Tadahiro; Ota, Hidetoshi; Saegusa, Haruo. A new fossil lizard from the Lower Cretaceous Sasayama Group of Hyogo Prefecture, western Honshu, Japan. Journal of Vertebrate Paleontology. 2015-01-02, 35 (1): e885032. ISSN 0272-4634. doi:10.1080/02724634.2014.885032 （英語）.
^ Ikeda, Tadahiro; Ota, Hidetoshi; Matsui, Masafumi. New fossil anurans from the Lower Cretaceous Sasayama Group of Hyogo Prefecture, Western Honshu, Japan. Cretaceous Research. 2016-06-01, 61: 108–123. ISSN 0195-6671. doi:10.1016/j.cretres.2015.12.024.

[Sasayamagnomus-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 Tanaka, Tomonori; Chiba, Kentaro; Ikeda, Tadahiro; Ryan, Michael J. A new neoceratopsian (Ornithischia, Ceratopsia) from the Lower Cretaceous Ohyamashimo Formation (Albian), southwestern Japan. Papers in Palaeontology. September 2024, 10 (5). doi:10.1002/spp2.1587.

[2] 兵庫県で発見の角竜類の化石新属新種と確認 | お知らせ・トピックス. 岡山理科大學. [2024-09-04] （日語）.

[PSJ2023_ceratops-3] Tanaka, Tomonori; Chiba, Kentaro; Ikeda, Tadahiro; Kubota, Katsuhiro. Phylogenetic position of a ceratopsian dinosaur from the Lower Cretaceous Ohyamashimo Formation (Albian) of the Sasayama Group in Tambasasayama City, Hyogo, Japan (PDF). The Palaeontological Society of Japan. 2023.

[Hypnovenator-4] 4.0 ^4.1 Kubota, K.; Kobayashi, Y.; Ikeda, T. Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Scientific Reports. 2024, 14. 16392. PMC 11272788 . doi:10.1038/s41598-024-66815-2 .

[SasayamaStrat-5] Hayashi, Keiichi; Fujita, Saki; Koarai, Kazuto; Matsukawa, Masaki. Stratigraphy and paleoenvironment of the Cretaceous Sasayama Group in the Sasayama area, Hyogo Prefecture, western Japan. The Journal of the Geological Society of Japan. 2017-09-15, 123 (9): 747–764. ISSN 0016-7630. doi:10.5575/geosoc.2017.0016  （英語）.

[List2022-6] Kubota, Katsuhiro. 日本産の中生代恐竜化石目録 2022年版 [A list of Mesozoic dinosaur fossils from Japan in 2022] (PDF). Bulletin of the Gunma Museum of Natural History: 157–170.

[Tanaka2020-7] Tanaka, Kohei; Zelenitsky, Darla K.; Therrien, François; Ikeda, Tadahiro; Kubota, Katsuhiro; Saegusa, Haruo; Tanaka, Tomonori; Ikuno, Kenji. Exceptionally small theropod eggs from the Lower Cretaceous Ohyamashimo Formation of Tamba, Hyogo Prefecture, Japan. Cretaceous Research. 2020, 114: Article 104519. Bibcode:2020CrRes.11404519T. S2CID 219449961. doi:10.1016/j.cretres.2020.104519.

[Morohasaurus-8] Ikeda, T.; Ota, H.; Tanaka, T.; Ikuno, K.; Kubota, K.; Tanaka, K.; Saegusa, H. A fossil Monstersauria (Squamata: Anguimorpha) from the Lower Cretaceous Ohyamashimo Formation of the Sasayama Group in Tamba City, Hyogo Prefecture, Japan. Cretaceous Research. 2021, 130: Article 105063. S2CID 239230916. doi:10.1016/j.cretres.2021.105063 .

[Tambatitanis-9] Saegusa, H.; Ikeda, T. A new titanosauriform sauropod (Dinosauria: Saurischia) from the Lower Cretaceous of Hyogo, Japan. Zootaxa. 2014, 3848 (1): 1–66. PMID 25112425. doi:10.11646/zootaxa.3848.1.1 .

[10] Kusuhashi, Nao; Tsutsumi, Yukiyasu; Saegusa, Haruo; Horie, Kenji; Ikeda, Tadahiro; Yokoyama, Kazumi; Shiraishi, Kazuyuki. A new Early Cretaceous eutherian mammal from the Sasayama Group, Hyogo, Japan. Proceedings of the Royal Society B: Biological Sciences. 2013-05-22, 280 (1759): 20130142. ISSN 0962-8452. PMC 3619506 . PMID 23536594. doi:10.1098/rspb.2013.0142 （英語）.

[11] Ikeda, Tadahiro; Ota, Hidetoshi; Saegusa, Haruo. A new fossil lizard from the Lower Cretaceous Sasayama Group of Hyogo Prefecture, western Honshu, Japan. Journal of Vertebrate Paleontology. 2015-01-02, 35 (1): e885032. ISSN 0272-4634. doi:10.1080/02724634.2014.885032 （英語）.

[12] Ikeda, Tadahiro; Ota, Hidetoshi; Matsui, Masafumi. New fossil anurans from the Lower Cretaceous Sasayama Group of Hyogo Prefecture, Western Honshu, Japan. Cretaceous Research. 2016-06-01, 61: 108–123. ISSN 0195-6671. doi:10.1016/j.cretres.2015.12.024.

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