棘胸蛙（學名：_Quasipaa spinosa_），又名石蛤、石雞、山雞、石凍、飛魚、石鱗、石蛙、石蛤蟆、石蝦蟆、石坑蛙等，是兩生綱無尾目叉舌蛙科的一種動物。其肉可食用。本物種的中文名稱及學名均源於其雄蛙胸前的大型胸棘。其體型在蛙類來說算是大型，因為已知可長至超過 10 cm（4 英寸），使牠們贏得香港體型最大蛙類的美譽。



分類學

近年的分子種系發生學分析認為本物種事實上由三條不同的譜系組成。因此，名義上的 _Quasipaa spinosa_ 可能代表一個隱藏物種複合體。譜系在地理上是不同的；在雲南省找到一個譜系，中國東南部（安徽省、 浙江省、福建省北部和江西省) 還有一個譜系，第三個譜系位於中國中南部（南部福建省、江西省、湖南省、廣東省和廣西壯族自治區）。在該分析中，小棘蛙位於 _Quasipaa spinosa_ 內。它的複合種是越南的 _Quasipaa acanthophora_。

The complete 粒線體 DNA (18,012 base pairs in length) of _Quasipaa spinosa_ has been sequenced, helping to shed light into the 系統發生樹 of _Quasipaa_ and related frogs.



分佈、棲息地及習性

本物種棲息於中華人民共和國長江以南（包括香港）地域的山溪水坑內或石洞岩隙中。由於水體相通，估計亦同時分佈於越南、寮國及緬甸三國的淡水水域，但缺乏相關文獻報告的支持。

習性晝伏夜出，主要食物為昆蟲及其幼體。每年 11 月 - 翌年 4 月冬眠。

No certain records exist from Vietnam, earlier records may refer to _Quasipaa acanthophora_ described in 2009 as a new species from that country. It may also have been mixed with _多疣棘蛙_ and _雙團棘胸蛙_.

_Quasipaa spinosa_ is associated with rocky streams in evergreen forests and open countryside on hills and mountains. Its altitude range is about 200－1,500 米（660－4,920 英尺） above sea level.



形態特徵及生命週期

成年個體體長 8-20 厘米，體重 200-350 克。背面黑灰色、淺棕色或黃褐色。背面、側面和四肢皮膚上生有肉疣，有的時候疣上生黑色角質刺。

The most distinctive characteristic of _Quasipaa spinosa_ are the keratinized skin spines in the chest of males. It is dark brown in colour, interspersed with dense, yellowish mottling.

_Quasipaa spinosa_ are moderately large frogs: males grow to a snout–vent length of about 80 mm（3.1 英寸） and females to 82 mm（3.2 英寸） or more, up to 128 mm（5.0 英寸） in snout–vent length. It is the largest frog in 香港. Later studies has shown that usually males are larger than females, but with considerable overlap between sexes. Body size is positively correlated with maximum temperature and rainfall. Mean body weight among males may reach at least 133 g（4.7 oz）.

_Quasipaa spinosa_ breeds in streams, laying the eggs in water under stones. Reproduction takes place in April–October. Male frogs call near slow-flowing sections of streams or around pools adjacent to streams. The advertisement call consists of three to seven notes, the last being the longest. Pairs in amplexus are found within the chorus area.

Population demography of _Quasipaa spinosa_ has been studied for two populations in the 大帽山 in Hong Kong. These populations exhibit high site fidelity. Populations have low densities (13–42 frogs per 100 m of stream) and female-biased sex ratio. Each female produced an average 1.26 juveniles that survived until the age of 2 years. Annual survival was low, 38–65%.



用途

因為肉味鮮美，生長速度快而且個大，是主要的食用蛙類之一。_Quasipaa spinosa_ is an important food and medicinal resource in China and considered as a delicacy. Populations are heavily harvested, and overcollection is implicated in population declines. In 江西省 province alone, the value of production of _Quasipaa spinosa_ for domestic consumption is of the same magnitude as global trade of frog meat. _Quasipaa spinosa_ are also farmed, but farming operations are likely based on tadpoles or juveniles sourced from wild population, instead of captive breeding. Thus, farming may not reduce the pressure on wild populations.



保育

過往本物種的數量曾經有大量，但由於遭到大量捕殺，目前已被國際自然保護聯盟列為易危物種，因為在最近期的三代，其數量已下跌了超過三成。捕殺主要還是被捕獲與人類食用；其次是因為農業及水壩的興建導致的棲息地破壞。當物種的數量變得愈來愈少，即使是中等數量的下跌亦已足以令物種的滅絕風險提過。在中國，棘胸蛙是江西省和安徽省的重點保護野生動物之一。另外棘胸蛙也被廣泛養殖用作食品，以避免野外再有人去捕捉棘胸蛙作食用。

_Quasipaa spinosa_ is not designated as a State Protected Animal in China, and there are no regulations for its protection, except in protected areas. However, sale of wild _Quasipaa spinosa_ is now forbidden in 福建省，and farmed frogs need to be certified. Whether these regulations are enforced is not yet known, but they have potential to help wild populations.



寄生蟲

棘胸蛙體內的寄生蟲均為纖毛蟲，計有多粒韋氏腸腎蟲（_Sicuophora multigranularis_，舊作 _Wichtermania multigranularis_ Xiao et al., 2002）。Wichtherman 根據 Cheng 在福建採集的棘腹蛙體內的標本，發現棘蛙韋氏腸腎蟲（_Wichtermania (Nyctotherus) cheni_）。



參考文獻