We provide the first descriptions of the tadpole and advertisement call of Mantidactylus argenteus. Calls consist of 6–15 short and rather melodious notes, with a dominant frequency at 4100–4400 Hz and are emitted from arboreal positions during the day. The larva is an Orton type IV tadpole, with oval body shape and dorsally positioned eyes. The oral disc is bordered with papillae, the labial tooth row formula is 2(2)/3(1–3), the upper jaw sheath is strongly curved and M-shaped, and the lower jaw is strongly curved in the middle and V-shaped, and jaw sheaths are largely unpigmented. Specimens from different series present little variation of this general morphology, except some specimens with a labial tooth row formula of 2(2)/2(1–2) but the same general and oral disc morphology. Based on larval features, the position of M. argenteus within the subgenus Blommersia cannot be confirmed since only few characters are shared with other known tadpoles of this subgenus.