針鼴蝦屬

布氏針鼴蝦; 化石時期：514–509 Ma PreЄ Є O S D C P T J K Pg N ▼ 寒武紀第四期
	針鼴蝦的附肢復原圖。
	針鼴蝦的全身復原圖。
科學分類
界：	動物界 Animalia
門：	節肢動物門 Arthropoda
綱：	†恐蝦綱 Dinocaridida
目：	†放射齒目 Radiodonta
科：	†篩蝦科 Tamisiocarididae
屬：	†針鼴蝦屬 Echidnacaris; Paterson, García-Bellidob & Edgecombe, 2023
種：	†布氏針鼴蝦 E. briggsi
二名法
	†Echidnacaris briggsi; (Nedin, 1995)

布氏針鼴蝦（學名：Echidnacaris briggsi）為針鼴蝦屬（學名：Echidnacaris）的唯一一個種，也是模式種。是節肢動物門、恐蝦綱、射齒目、篩蝦科底下的一個屬。^[1]原本是位在奇蝦屬（學名：Anomalocaris ）的布氏＂奇蝦＂（學名： "Anomalocaris" briggsi），之後對於針鼴蝦的系統發生學證明了針鼴蝦並不是奇蝦，而是獨立一個屬。^[1]針鼴蝦是除了奇蝦屬的戴氏奇蝦（Anomalocaris daleyae）外，唯一一個分佈在澳洲的放射齒目動物。^[1]^[2]^[3]^[4]^[5]^[6]^[7]^[8]

發現與命名

針鼴蝦的化石是在澳洲南部袋鼠島的鴯鶓灣頁岩（英語：Emu Bay Shale）被發現的，目前被發現的這些標本被存放在南澳州立博物館（South Australian Museum）。原本針鼴蝦被克里斯多福·內丁（Christopher Nedin）於1995年發表的，當時命名為布氏奇蝦（ Anomalocaris briggsi）^[9]，發表十幾年後因被懷疑是否為奇蝦屬，到2023年，針鼴蝦才重新歸類為新的屬。針鼴蝦的名字是以生活在澳洲的針鼴俗名－echidna，因為針鼴蝦附肢上有許多的小刺；caris是拉丁語的螃蟹，是恐蝦綱的常用作學名的字尾。^[1]

描述

前附肢

前附肢最長可達到17.5公分，總共有14節包含連接頭部與前附肢的1節柄節和13節螯節。柄節後緣的中間部分具有一個缺口，而在上方和下方分別有比較大和小的圓形突出。每節與每節的中間會有一個非常細的三角形節間膜。第一節往後的節、它的背緣會比腹緣還要長，且愈後會愈短，節的高也是。每一節都有一對從腹側凸出的內葉，柄節內葉長度佔了整個節的高約度95~100%，上面還有更細的輔助刺，往前附肢的外側邊緣有七根小刺，而在內側僅有一根在刺的最尖端凸出。其它節上的內葉會從直的會稍微彎曲。第一螯節的刺上面的外側比柄節的還要至少多1根的小刺。第二節到第十節的在外側的刺增加至13根，而內側多了六根。^[1]

頭部骨片

骨片是由兩個標本存留下來，且是單獨的骨片。頭部骨片呈橢圓形，最長可達到85.2公釐，寬則是61.1公釐。^[1]

口錐

針鼴蝦的口錐外觀似圓形，直徑7.7公分。口錐裡面的三塊大齒板會被不同寬度的八或九塊中型齒板隔開，在中央會有小的個開口，有時候發現大齒板會凸進開口。大齒板尺寸接近相等。且在內部的邊緣（開口的邊緣）有三到四顆齒狀突出物，而中型的只有兩個。大、中齒板的內半部都許多大小不一的凸出，且凸出物的尖端是指向開口處。^[1]

參考資料

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 ^1.7 Paterson, John R.; García-Bellido, Diego C.; Edgecombe, Gregory D. The early Cambrian Emu Bay Shale radiodonts revisited: morphology and systematics. Journal of Systematic Palaeontology. 2023-01, 21 (1). ISSN 1477-2019. doi:10.1080/14772019.2023.2225066.
^ Van Roy, Peter, and Odd Erik Tetlie. "A spinose appendage fragment of a problematic arthropod from the Early Ordovician of Morocco." Acta Palaeontologica Polonica 51.2 (2006): 239-246.
^ Vinther, Jakob; Stein, Martin; Longrich, Nicholas R.; Harper, David A. T. A suspension-feeding anomalocarid from the Early Cambrian. Nature. 2014-03, 507 (7493). ISSN 0028-0836. doi:10.1038/nature13010.
^ Cong, C; Ma, M; Hou, H; Edgecombe, E; Strausfeld, S. Brain structure resolves the segmental affinity of anomalocaridid appendages. MorphoBank datasets. 2015 [2024-03-14].
^ Paterson, John R.; Edgecombe, Gregory D.; García-Bellido, Diego C. Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology. Science Advances. 2020-12-04, 6 (49). ISSN 2375-2548. doi:10.1126/sciadv.abc6721.
^ Nedin, Christopher. Anomalocaris predation on nonmineralized and mineralized trilobites. Geology. 1999, 27 (11). ISSN 0091-7613. doi:10.1130/0091-7613(1999)027<0987:aponam>2.3.co;2.
^ Lee, Michael S. Y.; Jago, James B.; García-Bellido, Diego C.; Edgecombe, Gregory D.; Gehling, James G.; Paterson, John R. Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia. Nature. 2011-06, 474 (7353). ISSN 0028-0836. doi:10.1038/nature10097.
^ Daley, Allison C.; Paterson, John R.; Edgecombe, Gregory D.; García‐Bellido, Diego C.; Jago, James B. New anatomical information on Anomalocaris from the Cambrian Emu Bay Shale of South Australia and a reassessment of its inferred predatory habits. Palaeontology. 2013-03-04, 56 (5). ISSN 0031-0239. doi:10.1111/pala.12029.
^ Nedin, Christopher. Palaeontology and palaeoecology of the Lower Cambrian Emu Bay Shale Lagerstätten, Kangaroo Island, South Australia (PDF). The Paleontological Society Special Publications. 1992, 6. ISSN 2475-2622. doi:10.1017/s2475262200007814.

[:0-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 ^1.7 Paterson, John R.; García-Bellido, Diego C.; Edgecombe, Gregory D. The early Cambrian Emu Bay Shale radiodonts revisited: morphology and systematics. Journal of Systematic Palaeontology. 2023-01, 21 (1). ISSN 1477-2019. doi:10.1080/14772019.2023.2225066.

[2] Van Roy, Peter, and Odd Erik Tetlie. "A spinose appendage fragment of a problematic arthropod from the Early Ordovician of Morocco." Acta Palaeontologica Polonica 51.2 (2006): 239-246.

[3] Vinther, Jakob; Stein, Martin; Longrich, Nicholas R.; Harper, David A. T. A suspension-feeding anomalocarid from the Early Cambrian. Nature. 2014-03, 507 (7493). ISSN 0028-0836. doi:10.1038/nature13010.

[4] Cong, C; Ma, M; Hou, H; Edgecombe, E; Strausfeld, S. Brain structure resolves the segmental affinity of anomalocaridid appendages. MorphoBank datasets. 2015 [2024-03-14].

[5] Paterson, John R.; Edgecombe, Gregory D.; García-Bellido, Diego C. Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology. Science Advances. 2020-12-04, 6 (49). ISSN 2375-2548. doi:10.1126/sciadv.abc6721.

[6] Nedin, Christopher. Anomalocaris predation on nonmineralized and mineralized trilobites. Geology. 1999, 27 (11). ISSN 0091-7613. doi:10.1130/0091-7613(1999)027<0987:aponam>2.3.co;2.

[7] Lee, Michael S. Y.; Jago, James B.; García-Bellido, Diego C.; Edgecombe, Gregory D.; Gehling, James G.; Paterson, John R. Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia. Nature. 2011-06, 474 (7353). ISSN 0028-0836. doi:10.1038/nature10097.

[8] Daley, Allison C.; Paterson, John R.; Edgecombe, Gregory D.; García‐Bellido, Diego C.; Jago, James B. New anatomical information on Anomalocaris from the Cambrian Emu Bay Shale of South Australia and a reassessment of its inferred predatory habits. Palaeontology. 2013-03-04, 56 (5). ISSN 0031-0239. doi:10.1111/pala.12029.

[9] Nedin, Christopher. Palaeontology and palaeoecology of the Lower Cambrian Emu Bay Shale Lagerstätten, Kangaroo Island, South Australia (PDF). The Paleontological Society Special Publications. 1992, 6. ISSN 2475-2622. doi:10.1017/s2475262200007814.

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