_baudini_ \ _cyanosticta_ \ / + _phaeota_ _sordida_ \ / / + puma_ / \ \/ _sila_ \ /_____/ \ / \ / \ / | | Prototype [Illustration: FIG. 17. Hypothesized phylogenetic relationships of the species of _Smilisca_.] Certain aspects of this proposed phylogeny warrant further comment. Features such as the deposition of additional bone that roofs the skull or that forms lateral projections from the frontoparietals, like those in _S. baudini_ and _phaeota_, are minor alterations of dermal elements and not basic modifications of the architecture of the skull. Consequently, we hypothesize the independent development of these dermal changes in _S. baudini_ and _phaeota_. Similar kinds of dermal modifications have evolved independently in many diverse groups of frogs. Likewise, we propose the parallel development of stream-adapted tadpoles in _S. sordida_ and _sila_; in both cases the tadpoles adapted to changing environmental conditions (see following section on evolutionary history). Tadpoles of _S. sordida_ already had two rows of labial papillae before entering the streams; subsequently the tadpoles developed complete rows of papillae, ventral mouths and long tails having low fins. Possibly the tadpoles of _S. sila_ had two rows of labial papillae prior to their adapting to stream conditions; in the process of adapting they developed ventral mouths and long tails having low fins. Similar modifications in tadpoles have occurred in many diverse groups of Middle American hylids, such as _Plectrohyla_, _Ptychohyla_, the _Hyla uranochroa_ group, and the _Hyla taeniopus_ group.