**5. Discussion**

## *5.1. Evolutionary Relationships of Glassfrogs and Other Anurans*

Historically, glassfrogs have been thought to be closely related to hylids [93,94,298,320–324], although Jiménez de la Espada [83] considered *Centrolene geckoidea* to be a Neotropical representative of *Rhacophorus*, and Taylor [15] believed the South African heleophrynid frogs and glassfrogs were closely related. Noble, as early as 1931 [321], suggested a close a ffinity between glassfrogs and *Allophryne ruthveni*, which he described as a "toothless *Centrolenella*". The hypothesis by Noble has been supported by molecular and morphological studies [2,8,11–14,325–328], but see Haas [329], and by now it is well established that Allophrynidae is the sister family of Centrolenidae.

## *5.2. Evolutionary Relationships and Generic Placement within Centrolenidae*

The molecular evolutionary trees of glassfrogs, constructed since 2008, have been accompanied by a reinterpretation of the systematics, biogeography, richness patterns, behavior, and speciation of the group ([1,3,19], this work). Continuous and collaborative e fforts have allowed a better taxon and gene sampling, increasing the accuracy of the inference of evolutionary relationships [330–340].

Our phylogenetic sampling includes 75% of the described diversity of Centrolenidae and all but three *("Centrolene" medemi*, *Nymphargus buenaventura*, *N*. *laurae)* of the known Ecuadorian species. All genera are supported and congruen<sup>t</sup> with the taxonomy proposed by Guayasamin et al. [1]. Thus, recognized genera within Centrolenidae are stable and meet the stability criteria described by Guayasamin et al. [1] and Vences et al. [341]. However, relationships among genera are not fully resolved and further genetic data are necessary. At the species level, relationships are stable and well supported in most cases, allowing straightforward generic placement and facilitating recognition of cryptic species. Among Ecuadorian species, only one species, *"Centrolene" medemi*, still has an uncertain generic placement. A full species list of Centrolenidae and their current generic placement is provided in Table S1.
