Species New to Science's Journal

[Herpetology • 2024] Phyllobates samperi & P. bezosi • Molecular Phylogenetics uncovers Two New Species in the Genus Phyllobates (Anura: Dendrobatidae): the terrible frog gets two new sisters

Phyllobates samperi & P. bezosi

Amézquita, Vargas-Salinas, Ramos, Palacios-Rodríguez, Salazar, Quiroz, Bolívar, Galindo-Uribe & Mazariegos-H, 2024.

DOI: 10.3897/zookeys.1212.126733

Abstract

True poison-dart frogs (Phyllobates, Dendrobatidae) evolved the ability to secrete batrachotoxins, the most powerful alkaloids known to date. The genus comprises five species whose systematics, at first glance, appeared clear. The most derived clade would include two Colombian species (P. terribilis and P. bicolor) with the highest toxicity, the largest body size, and predominantly yellow body colouration. The other three species (P. aurotaenia, P. vittatus, and P. lugubris) are less toxic on average, have smaller size, and are predominantly black with bright dorsolateral stripes. Recent research has revealed the existence of two major lineages among the three Colombian species. The northern lineage appears to result from a complex evolutionary history, including perhaps introgression among yellow and black taxa. The southern lineage instead revealed the existence of new clades closely related to P. terribilis, black and yellow, that arguably deserve their recognition as new species. Here, available evidence is combined to support the erection of southern populations of P. aurotaenia as a new highly toxic species, sister to P. terribilis, and much closer to it than to any other yellow or black-bodied species, Phyllobates samperi sp. nov. Their common ancestor is sister to an additional yellow species, which we also describe here as Phyllobates bezosi sp. nov. Both new species can be externally diagnosed using colouration. Our previous and current analyses also suggest the existence of additional taxa and corroborate multiple transitions in colouration across these hypertoxic taxa.

Key words: Chocoan region, Colombia, hypertoxic frogs, molecular phylogenetics, Phyllobates

Dorsal and ventral view of Phyllobates species in Colombia, including the narrow-banded (P. aurotaenia AT, Atrato in Fig. 1) and broad-banded (P. aurotaenia SJ, San Juan in Fig. 1) morphs of P. aurotaenia. The tree topology follows the results depicted in Fig. 1.

Colour variation among individuals of Phyllobates bezosi sp. nov. (HT: holotype) including A dorsal and B ventral images for adult individuals and C three froglets, which exhibit the typical colouration with dorsolateral lines that characterises juvenile Phyllobates. To compare with juveniles of this species, we add a single image D of P. samperi sp. nov.

 Phyllobates samperi sp. nov.

Diagnosis: Phyllobates samperi sp. nov. is a small to medium-sized dendrobatid with an adult SVL of 21–27 mm (24.5 ± 1.6 mm, mean ± SD, n = 17). It is mostly pitch-black, with a narrow golden yellow/orange complete dorsolateral stripe (sensu Grant et al. 2006) extending from the snout, along the outer margin of the upper eyelid, to the dorsum near the dorsal base of the thigh. The ends of the stripe do not meet at the urostyle. Some individuals exhibit a few yellow/orange specks on the forearms, legs and/or venter. We assign this species to Phyllobates based on other studies with more extensive outgroup sampling, including molecular (Santos et al. 2009) and combined (with morphological traits) phylogenetic analyses (Fig. 1; Grant et al. 2006, 2017; Márquez et al. 2020). We also use the following combination of traits: finger I longer than finger II, maxillary teeth present, call of the trill type (Myers and Daly 1976; Myers et al. 1978), and the ability to secrete batrachotoxin (T. Escovar, M.C. González, and A. Amézquita, pers. obs.).

Etymology: The species is named honouring Colombian biologist Cristian Samper, for his lasting impact on the world of conservation science and environmental stewardship. As founding director of the Alexander von Humboldt Biodiversity Institute of Colombia, President and CEO of the Wildlife Conservation Society, Director of the Smithsonian National Museum of Natural History and Managing Director of the Bezos Earth Fund, Samper is a leading voice in global conservation efforts, overseeing initiatives that span across 65 countries to protect 11.6 million square kilometres of wild places. Samper’s expertise in biodiversity and policy has been instrumental in shaping international dialogues around conservation, making him a respected figure in the intersection of science, governance, and activism.

Systematics and estimated distribution of the seven Phyllobates species. Distribution was estimated from GBIF records (GBIF2023a–f), some of which were excluded based on well-acknowledged information (e.g., the genus distribution in South America is cis-Andean and not trans-Andean) as well as studies addressing distribution with the support of molecular data (Márquez et al. 2012; Márquez et al. 2020; González-Santoro et al. 2023). Dots with a point in the middle denote the localities in western Colombia that were sampled for molecular phylogenetic analyses in the current and previous studies (Márquez et al. 2020). Squares denote type localities for all species except P. bicolor. The tree topology follows the results depicted in Fig. 1. Frog icon colouration is approximate and should not be used to obtain diagnostic traits. See Fig. 4 for a colour diagnosis of the Colombian species.

 Phyllobates bezosi sp. nov.

Diagnosis: Phyllobates bezosi sp. nov. is a medium-sized dendrobatid with an adult snout-to-vent length (SVL) of 31–36 mm (33.6 ± 1.7 mm, mean ± SD, n = 9). Body dorsal colouration is predominantly orange to yellow, with mid-dorsal black bands or blotches, usually incomplete and poorly defined, more frequently near the urostyle or between the eyes (Fig. 7). Laterally, the trunk shows suffusion of yellow into black. Dorsal surface of the limbs with irregular orange-to-yellow blotches on a predominantly black background. More yellow is generally found near the limb insertions. We also assign this species to Phyllobates based on other studies with more extensive outgroup sampling, including molecular (Santos et al. 2009) and combined (with morphological traits) phylogenetic analyses (Fig. 1; Grant et al. 2006, 2017; Márquez et al. 2020). We also use the following combination of traits: finger I longer than finger II, maxillary teeth present, and call of the trill type (Myers and Daly 1976; Myers et al. 1978).

Etymology: The species is named honouring American entrepreneur Jeff Bezos, for his contributions to environmental conservation, particularly through the Bezos Earth Fund. The fund aims to combat climate change and preserve the natural world by funding scientists, NGOs, and other local communities dedicated to environmental action. The fund’s investments in conservation, restoration initiatives, food systems, clean energy, and sustainable development reflect a commitment to stewarding the planet for future generations. The considerable financial resources allocated for environmental causes symbolise an important step in mobilising private capital for public good, particularly in an era urgently demanding climate solutions. The name of this new remarkable species is expected to highlight this hallmark decision.

Adolfo Amézquita, Fernando Vargas-Salinas, Iván Ramos, Pablo Palacios-Rodríguez, Erika Nathalia Salazar, Michelle Quiroz, Wilmar Bolívar, Diana M. Galindo-Uribe and Luis A. Mazariegos-H. 2024. Molecular Phylogenetics uncovers Two New Species in the Genus Phyllobates (Anura: Dendrobatidae): the terrible frog gets two new sisters. ZooKeys. 1212: 217-240. DOI: doi.org/10.3897/zookeys.1212.126733