The tadpole of <i>Chiasmocleis altomontana</i> (Anura: Microhylidae)

The tadpole of <i>C. altomontana</i> is the largest among the Atlantic Forest species and the second largest of the genus, after <i>C. anatipes</i>. Like all species of the genus, the tadpole of <i>C. altomontana</i> is exotrophic, suspension feeder, Orton type II, and occurs in lentic temporary environments. Overall, <i>C. altomontana</i> shows subtle differences in dorsal fin height, dorsal fin insertion, tail tip, and snout in lateral view from its congeners. The spiracle of <i>C. anatipes</i> is ventral, single, covering the vent tube, as in all other microhylids. The species has a larger tail and interorbital distance than its congeners. All species of the Atlantic Forest clade are clustered together in the morphospace, suggesting little disparity, while those of the Amazonian clade are more spread, suggesting higher morphological disparity. <i>Chiasmocleis altomontana</i> was close to its sister species, <i>Chiasmocleis mantiqueira</i>, while <i>C. anatipes</i> differs greatly in terms of shape from the remaining species of the genus. Our results can improve our understanding of the morphological diversity of microhylid tadpoles and reduce the diversity shortfall in anuran larval forms.