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Family : RANIDAE
Species : Amolops larutensis
Size (snout to vent) :
Female 7.5 cm, Male 4.5 cm

The Larut Torrent Frog is a relatively large species of the genus Amolops: females may reach up to 7.5 cm snout-vent length.

This species appears to be both diurnal and nocturnal: they can be found sitting on wet boulders or streamside vegetation next to fast-flowing streams.

As is typical of the genus Amolops, the tadpoles have a modified lower lip, which acts as a sucker, allowing them to cling to rocks in the swiftest of river currents. (See example of the tadpole of the closely-related Tuberculated Torrent Frog Amolops gerutu).

Body size of adult frogs appears to be markedly smaller in lowland areas compared to highland areas (Chan, K. O. et al, 2018).

Prior to 2018, two closely-related species, Amolops australis and Amolops gerutu, were formerly considered to be part of the Amolops larutensis species complex, but are now considered as unique species (Chan, K. O. et al, 2018).

Amolops larutensis is now considered to be restricted to stream and river systems in the western parts of Peninsular Malaysia (excluding Johor state), and can easily be found in the  highland locations of Maxwell Hill (= Bukit Larut), Cameron Highlands, Fraser's Hill and Genting Highlands.

Torrent frogs in western parts of extreme southern Thailand are probably also Amolops larutensis.


Fig 1 : Small adult seen around noon on a large boulder in the middle of a fast-flowing torrent at Ulu Chepor, Perak, Peninsular Malaysia. 

Fig 2 : Large nocturnal adult on streamside vegetation at Fraser's Hill, Peninsular Malaysia.

Fig 3 : Small nocturnal adult in typical streamside posture.  Fraser's Hill, Peninsular Malaysia. Note the dark patterning (vermiculations) on the rear part of the right thigh: this is a diagnostic characteristic of the species.

Fig 4 : Large nocturnal adult perched on fallen tree trunk.  Fraser's Hill, Peninsular Malaysia.

Fig 5 : Brief interspecific amplexus was observed between a male Amolops larutensis and a female Odorrana hosii (Poisonous Rock Frog) at Lata Ulu Chepor, Perak, Peninsular Malaysia.


References :

Chan, K. O., Abraham, R. K., Grismer, J. L., & Grismer, L. (2018). Elevational size variation and two new species of torrent frogs from Peninsular Malaysia (Anura: Ranidae: Amolops Cope). Zootaxa, 4434(2), 250-264.