The morphology of the larval oral disc, nostril, skin, and vent tube of tadpoles of Andean stream dwelling Hyloscirtus (Hylidae: Hylinae: Cophomantini) was studied. A wide variation of larval tooth row number is compiled from literature and from observations of Colombian specimens in museums. The marginal papillae are precursors of the tooth rows. The submarginal papillae are organized parallel to the anterior tooth rows and are precursors of the flaps or accessory tooth rows. There is no particular tooth row formula, and no particular marginal papillae arrangement for a species or a recognized species group in the genus. The number of tooth rows and of accessory tooth rows increase with development and size of the tadpole. Two species groups are identified inside Hyloscirtus based on the tooth row formulae, upper jaw sheath morphology, and shape of the nostril of tadpoles. The two groups identified here are different from the three species groups currently recognized for the genus and show well-delimited geographic distributions through the northern Andes. Nostril shape of one species group of Hyloscirtus recognized here is putatively present in all Cophomantini. Spots on the venter associated with neuromasts are present in all the tadpoles of Hyloscirtus studied, and presumably the same as the ones found in some Hypsiboas and Aplastodiscus (Hylidae: Hylinae: Cophomantini). A saccular structure associated with the vent tube covers developing hindlimbs of all tadpoles of Hyloscirtus, and is proposed as a morphological synapomorphy of the genus.