大頭海蛇

大頭海蛇
	John Lort Stokes 1846 發現於澳洲
保护状况
	; 无危（IUCN 3.1）
科学分类
界：	动物界 Animalia
门：	脊索动物门 Chordata
纲：	爬行綱 Reptilia
目：	有鳞目 Squamata
亚目：	蛇亚目 Serpentes
科：	眼镜蛇科 Elapidae
属：	海蛇屬 Hydrophis
种：	大頭海蛇 H. stokesii
二名法
	Hydrophis stokesii; (Gray, 1846)
異名
	Hydrus stokesii ; Gray, 1846; Hydrophis stokesii ; — Günther, 1864; Distira stokesi ; — Boulenger, 1890; Astrotia stokesii ; — Wall, 1921; Disteira stokesii ; — Grandison, 1978;

大頭海蛇（學名：Hydrophis stokesii）又名棘鱗海蛇、史托克斯海蛇。是一種體型較大的蛇種，隸屬於眼鏡蛇科。有時被歸為獨立屬，稱為Astrotia。此種為特有種，分布於熱帶印太洋區的海域中。

詞源

其種小名stokesii與通俗名稱「Stokes's sea snake」皆為紀念英國皇家海軍海軍上將John Lort Stokes而命名。^[3]

外型描述

大頭海蛇是體型最粗壯、最重的海蛇之一，擁有所有海蛇中最長的毒牙。^[4] 其毒牙長度足以穿透潛水衣。^[5] 腹部中段的腹鱗擴大，形成一道明顯的縱脊（keel），該縱脊常常斷裂為兩個疣狀結節。^[6]其體色變異極大，^[7] 從乳白、褐色到黑色皆有，經常有寬大的黑色背部橫帶或黑色環紋。^[8]

其吻鱗深度與寬度相等；鼻鱗短於額鱗，長度為前額鱗縫合線的兩倍以上；額鱗長於寬，與其與吻鱗的距離相等或略長；具一枚前眼鱗與兩枚後眼鱗，上唇鱗有9至10枚，第4、第5與第6枚包圍眼睛，若未分裂則形成一列眼下鱗；具兩或三列重疊的前顳鱗；無下頜盾鱗。頸部有39至47列鱗片，身體中段有48至53列。腹鱗通常僅在身體最前段明顯，後段則成對出現且不大於周圍鱗片；鱗片排列緊密，具尖端。^[8]

總體長度為1.5米（5英尺）。

地理分布

本種分布範圍自印度、巴基斯坦與斯里蘭卡至南海與台灣海峽。亦可見於熱帶澳洲的各海域。

人類互動

目前無已知人類因大頭海蛇而死亡的案例。^[4]本種常作為混獲被捕獲，例如澳洲的蝦類漁業。^[1]

習性

大頭海蛇有時會形成上千隻的大型遷徙群，在馬六甲海峽形成長達數公尺的漂流帶。^[4] 為卵胎生，每年交配季會產下少量幼蛇，每胎約5條。^[9]

^ ^1.0 ^1.1 Sanders, K.; White, M.-D.; Courtney, T.; Lukoschek, V. Hydrophis stokesii. The IUCN Red List of Threatened Species. 2018: e.T176708A136257093 [amended version of 2010 assessment] [20 November 2021]. doi:10.2305/IUCN.UK.2010-4.RLTS.T176708A136257093.en .
^ "Hydrophis stokesii ". The Reptile Database. www.reptile-database.org.
^ Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Astrotia stokesii, p. 255).
^ ^4.0 ^4.1 ^4.2 O'Shea, Mark, Venomous Snakes of the World, New Holland Publishers: 144, 2008, ISBN 978-1-84773-086-2
^ Williamson, John A.; Fenner, Peter J.; Burnett, Joseph W.; Rifkin, Jacqueline F., Venomous and Poisonous Marine Animals: A Medical and Biological Handbook, UNSW Press: 403, 1996, ISBN 978-0-86840-279-6
^ Greene, Harry W.; Fogden, Patricia; Fogden, Michael, Snakes, University of California Press: 236, 2000, ISBN 978-0-520-22487-2
^ Gopalakrishnakone, P., Sea Snake Toxinology, NUS Press: 177, 1994, ISBN 978-9971-69-193-6
^ ^8.0 ^8.1 Boulenger, G.A., The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia, London: Secretary of State for India in Council. (Taylor and Francis, printers). xviii + 541 pp. (Distira stokesii, p. 408)., 1890
^ Tomascik, Tomas, The ecology of the Indonesian seas, Tuttle Publishing: 1140, 1997, ISBN 978-962-593-163-0

[iucn_status_20_November_2021-1] 1.0 ^1.1 Sanders, K.; White, M.-D.; Courtney, T.; Lukoschek, V. Hydrophis stokesii. The IUCN Red List of Threatened Species. 2018: e.T176708A136257093 [amended version of 2010 assessment] [20 November 2021]. doi:10.2305/IUCN.UK.2010-4.RLTS.T176708A136257093.en .

[2] "Hydrophis stokesii ". The Reptile Database. www.reptile-database.org.

[3] Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Astrotia stokesii, p. 255).

[oshea-4] 4.0 ^4.1 ^4.2 O'Shea, Mark, Venomous Snakes of the World, New Holland Publishers: 144, 2008, ISBN 978-1-84773-086-2

[5] Williamson, John A.; Fenner, Peter J.; Burnett, Joseph W.; Rifkin, Jacqueline F., Venomous and Poisonous Marine Animals: A Medical and Biological Handbook, UNSW Press: 403, 1996, ISBN 978-0-86840-279-6

[6] Greene, Harry W.; Fogden, Patricia; Fogden, Michael, Snakes, University of California Press: 236, 2000, ISBN 978-0-520-22487-2

[7] Gopalakrishnakone, P., Sea Snake Toxinology, NUS Press: 177, 1994, ISBN 978-9971-69-193-6

[Boulenger-8] 8.0 ^8.1 Boulenger, G.A., The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia, London: Secretary of State for India in Council. (Taylor and Francis, printers). xviii + 541 pp. (Distira stokesii, p. 408)., 1890

[9] Tomascik, Tomas, The ecology of the Indonesian seas, Tuttle Publishing: 1140, 1997, ISBN 978-962-593-163-0

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