Evolution in the Genus Rhinella: A Total Evidence Phylogenetic Analysis of Neotropical True Toads (Anura: Bufonidae)

Abstract

True toads of the genus Rhinella are among the most common and diverse group of Neotropical anurans. These toads are widely distributed throughout South America, inhabiting a great diversity of environments and ecoregions. Currently, however, the genus is defined solely on the basis of molecular characters, and it lacks a proper diagnosis. Although some phenetic species groups have traditionally been recognized within Rhinella, the monophyly of some of them have been rejected in previous phylogenetic analyses, and many species remain unassigned to these poorly defined groups. Additionally, the identity and taxonomy of several species are problematic and hinder the specific recognition and description of undescribed taxa. In this work, we first perform phylogenetic analyses of separate mitochondrial and nuclear datasets to test the possible occurrence of hybridization and/or genetic introgression in the genus. The comparative analysis of both datasets revealed unidirectional mitochondrial introgressions of an unknown parental species into R . horribilis ("ghost introgression") and of R . dorbignyi into R . bernardoi; therefore, the mitochondrial and nuclear datasets of these species were considered separately in subsequent analyses. We performed total-evidence phylogenetic analyses that included revised molecular (four mitochondrial and five nuclear genes) and phenotypic (90 characters) datasets for 83 nominal species of Rhinella, plus several undescribed and problematic species and multiple outgroups. Results demonstrate that Rhinella was nonmonophyletic due to the position of R . ceratophrys, which was recovered as the sister taxon of Rhaebo nasicus with strong support. Among our outgroups, the strongly supported Anaxyrus + Incilius is the sister clade of all other species of Rhinella. Once R . ceratophrys is excluded, the genus Rhinella is monophyletic, well supported, and composed of two major clades. One of these is moderately supported and includes species of the former R . spinulosa Group (including R . gallardoi); the monophyletic R . granulosa, R . crucifer, and R . marina Groups; and a clade composed of the mitochondrial sequences of R . horribilis. The other major clade is strongly supported and composed of all the species from the non-monophyletic R . veraguensis and R . margaritifera Groups, the former R . acrolopha Group, and R . sternosignata. Consistent with these results, we define eight species groups of Rhinella that are mostly diagnosed by phenotypic synapomorphies in addition to a combination of morphological character states. Rhinella sternosignata is the only species that remains unassigned to any group. We also synonymize nine species, treat three former subspecies as full species, and suggest that 15 lineages represent putative undescribed species. Lastly, we discuss the apparently frequent occurrence of hybridization, deep mitochondrial divergence, and "ghost introgression"; the incomplete phenotypic evidence (including putative character systems that could be used for future phylogenetic...

A New Species of Toad (Anura: Bufonidae: Rhinella) from Northern Peru

“…Webbing formula follows the standards of Myers and Duellman [25], whereas all other terminology is that of Duellman [26] and Duellman and Lehr [27]. Taxonomy of Rhinella and its species groups follow Pereyra et al [3]. Format of the description follows the standards of Duellman and Mendelson [28] and Lötters and Köhler [29].…”

“…The Neotropical genus Rhinella Fitzinger, 1826 [1] contains 97 species of toads [2]. Pereyra et al [3] performed a total-evidence-based phylogenetic analysis of Rhinella that included revised molecular and phenotypic datasets for 83 nominal species. The authors recognized the monophyly of Rhinella (once R. ceratophrys is excluded) and two major clades (Rhinella marina Clade, Rhinella margaritifera Clade) that contain eight Rhinella species groups [3].…”

“…Twenty-nine species of Rhinella occur in Peru, of which 13 (= 45%) are endemic to Peru [2]. The 29 Peruvian species of Rhinella are assigned to five species groups: festae Group, margaritifera Group, marina Group, spinulosa Group, and veraguensis Group [3][4][5][6]. The festae species Group was recognized by Moravec et al [6] based on molecular characters and included eight species [6,7]: R. chavin (Lehr, Köhler and Ponce, 2001) [8]; R. festae (Peracca, 1904) [9]; R. lilyrodriguezae Cusi, Moravec, Lehr and Gvoždík, 2017 [7]; R. macrorhina (Trueb, 1971) [10], R. manu Chaparro, Pramuk and Gluesenkamp, 2007 [5], R. nesiotes (Duellman and Toft, 1979) [11], R. rostrata (Noble, 1920) [12], and R. yanachaga Lehr, Pramuk, Hedges and Córdova, 2007 [13].…”

“…The festae species Group was recognized by Moravec et al [6] based on molecular characters and included eight species [6,7]: R. chavin (Lehr, Köhler and Ponce, 2001) [8]; R. festae (Peracca, 1904) [9]; R. lilyrodriguezae Cusi, Moravec, Lehr and Gvoždík, 2017 [7]; R. macrorhina (Trueb, 1971) [10], R. manu Chaparro, Pramuk and Gluesenkamp, 2007 [5], R. nesiotes (Duellman and Toft, 1979) [11], R. rostrata (Noble, 1920) [12], and R. yanachaga Lehr, Pramuk, Hedges and Córdova, 2007 [13]. Pereyra et al [3] revised the festae species Group, provided a diagnosis for its members, and recognized anatomical and morphological synapomorphies. Thus, the festae species Group is currently considered to contain the following 19 species [3,6,7,14] which are distributed in Panama, Colombia, Ecuador, Peru, and Bolivia (Figure 1): R. acrolopha (Trueb, 1971) [10], R. arborescandens (Duellman and Schulte, 1992) [4], R. chavin, R. chullachaki Castillo-Urbina, Glaw, Aguilar-Puntriano, Vences and Köhler, 2021 [14], R. festae, R. lilyrodriguezae, R. lindae (Rivero and Castaño, 1990) [15], R. macrorhina, R. manu, R. multiverrucosa (Lehr, Pramuk and Lundberg, 2005) [16], R. nesiotes, R. nicefori (Cochran and Goin, 1970) [17], R. paraguas Grant and Bolívar-G., 2014 [18], R. rostrata, R ruizi (Grant, 2000) [19], R. tacana (Padial, Reichle, McDiarmid and De la Riva, 2006) [20], R. tenrec (Lynch and Renjifo, 1990)…”

“…provided a diagnosis for its members, and recognized anatomical and morphological synapomorphies. Thus, the festae species Group is currently considered to contain the following 19 species [3,6,7,14] which are distributed in Panama, Colombia, Ecuador, Peru, and Bolivia (Figure 1): R. acrolopha (Trueb, 1971) [10], R. arborescandens (Duellman and Schulte, 1992) [4], R. chavin, R. chullachaki Castillo-Urbina, Glaw, Aguilar-Puntriano, Vences and Köhler, 2021 [14], R. festae, R. lilyrodriguezae, R. lindae (Rivero and Castaño, 1990) [15], R. macrorhina, R. manu, R. multiverrucosa (Lehr, Pramuk and Lundberg, 2005) [16], R. nesiotes, R. nicefori (Cochran and Goin, 1970) [17], R. paraguas Grant and Bolívar-G., 2014 [18], R. rostrata, R ruizi (Grant, 2000) [19], R. tacana (Padial, Reichle, McDiarmid and De la Riva, 2006) [20], R. tenrec (Lynch and Renjifo, 1990) [21], R. truebae (Lynch and Renjifo, 1990) [21], and R. yanachaga. Herpetological surveys of the Río Abiseo National Park in northern Peru, Departamento San Martín, in the late 1990s led to the discovery of six new species of anurans: four Phrynopus [22], one Pristimantis [23], one Gastrotheca [24], and an unknown species of Rhinella.…”