Ranitomeya

Brown, Jason L., Twomey, Evan, Amézquita, Adolfo, Souza, Moisés Barbosa De, Caldwell, Jana- Lee P., Lötters, Stefan, May, Rudolf Von, Melo-Sampaio, Paulo Roberto, Mejía-Vargas, Daniel, Perez-Peña, Pedro, Pepper, Mark, Poelman, Erik H., Sanchez-Rodriguez, Manuel & Summers, Kyle, 2011, A taxonomic revision of the Neotropical poison frog genus Ranitomeya (Amphibia: Dendrobatidae) 3083, Zootaxa 3083 (1), pp. 1-120 : 8-10

History of Ranitomeya

George A. Boulenger, more than a century ago, described the first species in this group, Dendrobates fantasticus and D. reticulatus ( Boulenger 1884 "1883"). In 1975, Philip A. Silverstone published the first comprehensive monograph dealing with specific relationships of the genus Dendrobates (a group containing Ranitomeya sensu Grant et al. 2006 ). Using adult and tadpole morphology he proposed the minutus group, containing six species: altobueyensis , fulguritus, minutus , opisthomelas , quinquevittatus and steyermarki . The main characters used to define this group were larval: emarginate (laterally indented) oral disc and dextral anus (though he lacked data for quinquevittatus and steyermarki ). Soon after, Charles W. Myers and John W. Daly began publishing their seminal research on the systematics of Central and South American dendrobatids. Their addition of alkaloid profiles, vocalization data and behavioral data to traditional taxonomic methods clarified many of the coarse relationships within this group and led to the description of numerous new species. In 1980, they described Dendrobates bombetes and resurrected D. reticulatus , assigning them and an undescribed species that was eventually named D. claudiae by Jungfer et al. (2000) to Silverstone’s minutus group. Furthermore, they hypothesized that abditus , bombetes and opisthomelas formed a monophyletic group delimited by ‘median gap that interrupts the papillate fringe on the posterior (lower) edge of the oral disc’ ( Myers & Daly 1980). Shortly after, Myers removed D. fantasticus from synonymy with D. quinquevittatus and placed D. vanzolinii , D. fantasticus , D. captivus , D. quinquevittatus , and D. reticulatus (removing the latter two from the minutus group) in a suggested monophyletic assemblage delimited by ‘distinctively reticulated limbs,’ which was dubbed the quinquevittatus group ( Myers 1982).

Five years later, Myers placed the remaining members of the minutus group into a new genus, Minyobates (with steyermarki as the type species), based on the following characters: cephalic amplexus present, very small size (12–19.5 mm snout to vent length), oblique lateral stripe present (though he qualified this by noting that this feature is also absent in some Minyobates ), and larvae with lateral indentations of the oral disc of the mouth and a dextral anus (Myers 1987). The establishment of a new genus was hurried to preceed the expected name Ranitomeya , which shortly after was coined by Luc Bauer, a Dutch amateur herpetologist, in a privately published paper ( Bauer 1988). Ranitomeya at that time contained the former Dendrobates species reticulatus (as the type species), captivus , fantasticus , imitator , mysteriosus , quinquevittatus and vanzolinii , and was completely ignored in the scientific literature, presumably because it posed several problems under the International Code of Zoological Nomenclature (ICZN, see Grant et al. 2006 for a detailed discussion).

Caldwell & Myers (1990) further restricted D. quinquevittatus and the quinquevittatus group to D. quinquevittatus sensu stricto and its suggested sister taxon D. castaneoticus , united by their shared absence of the inner metacarpal tubercle. They placed this group as sister to the clade united by pale limb reticulation (i.e., Ranitomeya of Grant et al. 2006). This clade was referred to as the ventrimaculatus group, and it comprised all other members of the quinquevittatus group exclusive of quinquevittatus sensu stricto, but the authors did not propose additional synapomorphies to support this arrangement. More than a decade later, Rainer Schulte privately published a book on Peruvian dendrobatids in which he described five new species and proposed several novel systematic relationships, including the designation of eight species groups ( Schulte 1999). His classifications did not consider much of the works of previous authors (not allowing him to classify all taxa in previously established groups) and some proposed groups were paraphyletic in the illustrated diagrams. More importantly, synapomorphies and the criteria from which the groups were designated were largely not mentioned. A fair scientific assessment of these groups cannot be made and these groups will not be considered herein (see Table 1); for a detailed discussion of Schulte’s work see Lötters & Vences (2000).

In the late 1990s, Kyle Summers and collaborators started using molecular phylogenetics to look at the specific relationships among a few members of the genus Ranitomeya (Summers et al. 1997) . Since, numerous studies have addressed the molecular phylogenetics of this group (e.g., Summers et al. 1999; Clough & Summers 2000; Vences et al. 2000; Symula et al. 2001, 2003; Santos et al. 2003, 2009; Darst & Cannatella 2004; Brown et al. 2006, 2008c; Grant et al. 2006; Noonan & Wray 2006; Roberts et al. 2006a; Twomey & Brown 2008).

Using primarily molecular phylogenetics, Grant et al. (2006) revised the entire family Dendrobatidae , dividing Dendrobates sensu Silverstone (1975) into five genera: Adelphobates , Dendrobates , Minyobates , Oophaga , and Ranitomeya . Grant et al. (2006) placed the former members of the minutus group sensu Myers (1982), minus Minyobates steyermarki , as well as most members of the ventrimaculatus group sensu Caldwell & Myers (1990), minus captivus and mysteriosus , in the genus Ranitomeya (an available name under the ICZN). Only steyermarki was retained in Minyobates . These placements were well supported by prior phylogenies ( Vences et al. 2000, 2003; Noonan & Wray 2006; Roberts et al. 2006a). The definition of Ranitomeya contained 24 species ( Table 1) and is currently the most widely accepted taxonomy for this group (though see below). In 2008, Twomey & Brown described a new genus, Excidobates , removing captivus from Adelphobates and placing it in its own group together with mysteriosus (an affinity originally suggested by Myers 1982), which was sister to the genus Ranitomeya ( Twomey & Brown 2008) . They also suggested that future taxonomies may be better off by restricting the use of Ranitomeya to the ventrimaculata group sensu Caldwell & Myers (1990) and placing the minuta group into a separate, at that time, unnamed genus. Roberts et al. (2006a) and Twomey & Brown (2008), collectively, further subdivided the ventrimaculata group into three smaller groups: reticulata , vanzolinii and ventrimaculata ( Table 1), in part to help accommodate the numerous new species being described within this genus.

More recently, in online supplemental material, Santos et al. (2009) proposed to synonymize Adelphobates , Dendrobates , Excidobates , Minyobates , Oophaga and Ranitomeya back into Dendrobates . We will use here the previously described taxonomy following Grant et al. (2006) and Twomey & Brown (2008). For further comments on this matter see discussion.

The genus Ranitomeya currently comprises two reciprocally monophyletic clades: the minuta group and a clade containing the ventrimaculata , reticulata and vanzolinii groups. The minuta group is trans-Andean; its members have long, rattle-like advertisement calls and typically possess dark limbs and coarsely blotched venters. The ventrimaculata , reticulata and vanzolinii groups comprise a motley clade of Amazonian frogs, most of which possess pale limb reticulation and some permutation of dorsolateral stripes.