Huia is a group of true frogs found in Southeast Asia. Many 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 closely related. A seemingly less ambiguous name is huia frogs; however, the supposed genus seems actually to be a polyphyletic "wastebin taxon" and might contain only a fraction of the dozens of species placed here by some authors.
Several species of Amolops and Odorrana are highly convergent with Huia. O. absita for example is highly similar in habitus to the completely allopatric H. masonii. Though the latter might not be a member of Huia in the strictest sense, it is at least a very close relative.
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.
For as it seems, even in the revised delimitation the genus is still paraphyletic with Meristogenys. Either the latter genus is included here, or Huia is restricted to the type species (the Hole-in-the-head Frog, H. cavitympanum) and what might be its closest living relatives (e.g. an undescribed species from Sumatra), or some species of Huia - e.g. the Sumatran Torrent Frog (H. sumatrana) - are split off again. The former alternatives seem to be more advisable as long as the interrelationships of Huia and Meristogenys species as well as the closely related Clinotarsus are as badly resolved as they are at present. Meristogenys tadpoles are furthermore characterized by a split and ridged upepr lip not found in the Hole-in-the-head Frog, indicating that the genera ought to be kept separate.
New species are being discovered regularly, exacerbating the taxonomic uncertainties.
Sumatran Torrent Frog group''