About Quasipaa spinosa (David, 1875)
Description and life cycle: The most distinctive characteristic of Quasipaa spinosa is the keratinized skin spines on the chest of males. This species is dark brown, with dense, yellowish mottling scattered across its body. Quasipaa spinosa are moderately large frogs: males grow to a snout–vent length of about 80 mm (3.1 in), while females reach 82 mm (3.2 in) or more, with a maximum recorded snout–vent length of 128 mm (5.0 in). It is the largest frog species found in Hong Kong. Later studies have found that males are usually larger than females, though there is considerable overlap in body size between the sexes. Body size in this species is positively correlated with maximum temperature and rainfall. The mean body weight of males can reach at least 133 g (4.7 oz). Quasipaa spinosa breeds in streams, laying eggs underwater under stones. Reproduction occurs between April and October. Males call from slow-flowing stream sections or pools adjacent to streams. Their advertisement call is made up of three to seven notes, with the final note being the longest. Amplexed pairs are found within the male chorus area. The population demography of Quasipaa spinosa has been studied for two populations in Hong Kong’s Tai Mo Shan Country Park. These populations show high site fidelity. They occur at low densities, ranging from 13 to 42 frogs per 100 meters of stream, and have a female-biased sex ratio. On average, each female produces 1.26 juveniles that survive to two years of age. Annual survival rate is low, between 38% and 65%. Distribution and habitat: Quasipaa spinosa is found in China south of the Yangtze River, including Hong Kong. Its presence is expected in Vietnam, Laos, and Myanmar, but there are no confirmed records from Vietnam. Earlier records of Quasipaa spinosa from Vietnam may actually refer to Quasipaa acanthophora, a species newly described from the country in 2009. Quasipaa spinosa has also historically been confused with Quasipaa verrucospinosa and Nanorana yunnanensis. This species is associated with rocky streams in evergreen forests and open hill and mountain countryside. It occurs at altitudes between approximately 200 and 1,500 meters (660 to 4,920 feet) above sea level.
