Psammodynastes pulverulentus papenfussi

Mock Viper

茶 斑蛇

保育等級: 保育類 (第二級)

家族
黃頷蛇科,Boiginae 亞科
Colubridae, subfamily Boiginae
最大體長
65 cm
台灣棲地分布
分布全台包跨蘭嶼海拔 1000 公尺以下區域。
世界棲地分布
台灣特有亞種。
外觀描述
Small snake; total length up to 65 cm (less in males), but most animals are smaller. There are 13-17 (17 at mid-body) rows of scales, which are smooth but not glossy. Head is elongate oval to slightly triangular and distinct from neck; body is slender; tail is long. Eye is large; iris is medium to dark brown, dappled and flecked with light brown and pupil is broadly elliptical on vertical axis. There is a prominent angular ridge from upper eye to end of snout. Tongue is dark brown to black; teeth are long, well developed, resembling fangs in upper jaw. There are three pairs of chin plates. Upper head is light to dark brown or even chocolate with a darker, longitudinal ''Y'' whose arms extend forward onto the ridge between eye and snout, basing at the posterior margin of the parietals, and extending posteriorly along the mid-dorsal line. The supralabials are lighter in color, mottled with white, dirt yellow or black. Upper body and tail are light to dark brown or even chocolate, tinged with scattered, diffuse, deep red and/or scattered deposits of diffuse dark brown to black which is more prominent anteriorly. Ventral head is white to light gray, mottled with tan, black or gray; the deposits of black on the infralabials may form a longitudinal line. Ventral body is light gray to dark gray brown, mottled with brown or gray pigment which concentrates to form light longitudinal lines. Anal scale is entire, and subcaudals are paired.
生態描述
茶斑蛇頭形略成三角形且具有後溝牙( rear-fanged = opistoglyphous 請見附註 (1)),在日、夜間皆有可能出沒。牠的略成三角的頭形很容易讓人誤會牠是屬於腹蛇類的毒蛇,也因此得到了「Mock viper (偽蝮蛇)」的英文俗名。大部分有毒的黃頷蛇科蛇類的毒性都被認為是對人體無害的,因為通常不是毒腺小,就是毒性不強,甚至還有的是因為輸毒系統不發達;而茶斑蛇毒性遠比真正的蝮蛇科小很多。牠的牙齒構造適合獵取有鱗片的脊椎動物,像是石龍子科的蜥蜴與其牠蛇類。不過分布在台灣的亞種也吃蛙類。
個體體色範圍很廣泛,可能是深褐色、紅褐色、灰色、黃色,甚至是灰黑色。有些身上有黑色小斑點,而有些幾乎沒有任何的黑斑。
通常可以在平原、沼澤、溼地甚至是稻田以及森林中發現牠的存在。不過紀錄上幾乎不會靠近人類居住的區域。雖然屬於陸棲蛇類,但是還是可以在灌木叢上等較低矮的職務上發現其蹤影。
胎生,每年陸續約略產下 3 - 10 隻的幼蛇。初生幼蛇形似成蛇,每條長度約 15 - 18 cm。
此蛇種有強烈的攻擊性,並且有著類似蝮蛇科蛇類的防禦行為。當動物被牠螫咬會有不輕的傷勢。
與其牠具有後溝牙的蛇類相同,毒液的成分無人知曉。慶幸的是目前並沒有任何有關遭到茶斑蛇攻擊而中毒身亡的紀錄。不過傷口會腫脹、發紅且肌肉酸痛。另外由傷口會有出血症狀可猜測其毒液含有抗凝血毒素。
相關文章請見 - 茶斑蛇是不是擁有前溝牙? ( "Does the Mock Viper Resemble a Protoelapid?" (Jackson & Fritts, 1996) )(PDF)
學名與俗名
Psammodynastes: "此種名是希臘文 psammos = 沙, dynastes = 統治者。但是茶斑蛇並非生活在沙漠地區,可能是因為屬名 Psammophis 來自一個生活在沙漠環境的種群。" (A Field Guide to the Snakes of Borneo, Stuebing & Inger, 1999);
pulverulentus: "來自拉丁文 pulveris = 灰暗的,, lentus = 充滿的,意指牠灰暗的體色" (A Field Guide to the Snakes of Borneo, Stuebing & Inger, 1999)。
papenfussi: 得自美國爬蟲學家 Theodore J. Papenfuss
茶斑蛇、紫砂蛇、褐山蛇。
附註
(1) "Opisthoglyphous"(有後溝牙的蛇)指的是上顎後方進化出增大的牙齒方便更穩固的咬住獵物的蛇種,類似無溝槽(無毒牙)的蛇類,但是有微毒。後溝牙會隨著蛇嘴的閉合而斜上向上顎方向收入溝槽,並不會垂直往下導致戳傷自己。白話一點又稱 "rear-fanged snakes". (Source)
翻譯:周信甫