First description of buccopharyngeal anatomy in Pelodryadinae larvae: Morphological comparison and systematic implications (Anura: Hylidae: Pelodryadinae: Litoria rubella and Ranoidea caerulea).

Pelodryadinae, the Australian tree frogs, is a monophyletic group endemic to the Australo-Papuan region. Although we have a relatively good knowledge about tadpoles' phenotypic diversity in terms of external morphology, information about internal anatomy is rare for the subfamily; for instance, their buccopharyngeal cavity is completely unknown. Herein I describe for the first time the buccopharyngeal anatomy of two pelodryadins: Litoria rubella and Ranoidea caerulea. I compare my results with available evidence from Phyllomedusidae, that is, the sister clade to Pelodryadinae, and briefly comment on buccopharyngeal cavity within Hylidae. Both species can be readily distinguished based on lateral ridge, postnarial, buccal roof arena, infralabial papillae, and lingual papillae. Variation between the two species may suggest a large diversity within Pelodryadinae. Pelodryadinae and Phyllomedusinae present similar buccopharyngeal morphologies, although Agalychnis callidryas has a unique morphology and putative apomorphic transformations can be observed in Pithecopus + Phyllomedusa, Ranoidea, and Phasmahyla.