previous amphibian    next amphibian   

Family : RANIDAE
Species : Sylvirana mortenseni
Size (snout to vent) :
Female 6.0 cm (mean),  Male 6.3 cm (mean)

Sylvirana mortenseni ('Mortensen's Frog' or Ko Chang Island Frog) was formerly treated as a synonym of Sylvirana nigrovittata (i.e. once considered to be the same species), but it is now treated as a species in its own right. It is closely related to other frogs in the Sylvirana nigrovittata species complex, such as Sylvirana malayana ('Malayan Black-striped Frog).

Based on a photograph by Attapol Rujirawan from Ko Chang Island, Thailand, Sylvirana mortenseni is described in Sheridan & Stuart (2018) as: "Dorsum and dorsolateral fold brown with few small dark brown spots. Canthus rostralis dark brown, lores brown. Temporal region yellow-beige. Limbs pale brown or beige. Hindlimbs with medium brown crossbands, and yellow coloration on anterior and posterior surfaces. Lip creamy white. Upper one-quarter of iris bronze, lower three quarters of iris dark brown. Chin and chest creamy white with brown mottling. Flank brown, fading to creamy coloration ventrally."

Sylvirana mortenseni occurs in Cambodia, Laos and eastern Thailand. 

Featured here are 2 frogs from a forested stream in Khao Yai National Park, Thailand; these are considered to be Sylvirana mortenseni based on their colouration and patterning, and their geographic location. An additional example from Siem Reap, Cambodia is also included here.

Fig 1 : Pair from a shaded, forest stream at Khao Yai National Park, Thailand (approximate elevation of 1000 metres).

Fig 2 : Grassland, wetlands and diverse forest at  Khao Yai National Park, Thailand, in the west of the known geographic range of Sylvirana mortenseni.

Fig 3 : Example from Siem Reap, Cambodia found in an ornamental garden. 


References :

Sheridan JA, Stuart BL (2018) Hidden species diversity in Sylvirana nigrovittata (Amphibia: Ranidae) highlights the importance of taxonomic revisions in biodiversity conservation. PLoS ONE 13(3): e0192766.