Amolops (commonly known as cascade frogs or sucker frogs) is a
genus of
true frogs (
familyRanidae) native mainly to eastern and south-eastern Asia. These frogs are closely related to such genera as Huia, Meristogenys, Odorrana, Pelophylax and Rana, but still form a distinct lineage among the core
radiation of true frogs.[1] They are commonly known as "
torrent frogs" after their favorite
habitat - small rapid-flowing mountain and hill streams - but this name is used for many similar-looking frogs regardless of whether they are loosely related.
Several
species are highly
convergent with other Ranidae "torrent frogs". A. archotaphus and its relatives for example very much resemble Odorrana livida. In another incidence of convergent evolution yielding
adaptation to habitat, the
tadpoles of Amolops, Huia, Meristogenys as well as Rana sauteri have a raised and usually well-developed sucker on their belly. This is useful in keeping in place in rocky torrents, where these frogs grow up. But as Odorrana and Staurois from comparable
habitat prove, this sucker is by no means a necessity and other means of adaptation to torrent habitat exist.[2]
Species
The delimitation of this genus has proven complicated, with many
species believed to belong elsewhere. Due to the degree of
convergent evolution,
DNA sequence studies are very helpful in assigning species to the genera, though the possibility of past
hybridization cannot be discounted in
Ranidae.[1]
New species are described on a regular basis. At least one undescribed species is known to exist, a very distinct form from
Phetchaburi in
Thailand that is possibly closer to A. marmoratus than to most others.[3]
Cai, Hong-xia; Che, Jing, Pang, Jun-feng; Zhao, Er-mi & Zhang, Ya-ping (2007): Paraphyly of Chinese Amolops (Anura, Ranidae) and phylogenetic position of the rare Chinese frog, Amolops tormotus. Zootaxa1531: 49–55.
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