A new species of <i>Atelopus</i> (Amphibia: Bufonidae) from eastern Panama

A new species of the genus Atelopus , Atelopus fronterizo sp. nov. , from eastern Panama is described herein based on molecular, morphological, and bioacoustic evidence. The new species can be distinguished from its congeners occurring in the region by a combination of the following characters: (1) phalangeal reduction in thumb; (2) SVL (females only) (35.1-50.1; n =13), HW/SVL (0.23-0.34; n =59), EYND/HW (0.27-0.39; n =60), TIBL/SVL (0.41-0.56; n =58), and HAL/SVL (0.22-0.28; n =49); (3) dorsal color pattern with green or yellow background and extensive dark olive blotches forming transversal bands or mottling; (4) advertisement call duration 176-235 ms with 19-34 pulses, average pulse rate 131.69 pulses/s, and dominant frequency 2 422.50-2 606.50 Hz. The new species is nested within the Central American clade of Atelopus . The minimum Kimura-2-parameter (K2P) genetic divergence between Atelopus fronterizo sp. nov. and its most phylogenetically similar congeners ( A . certus and A . glyphus ) is >2.6% for 16S and >4.9% for COI (Table 1). The phylogenetic relationship is strongly supported by ultrafast bootstrap values for the maximum-likelihood trees of both genetic markers (16S, 96; COI , 100, Figure 1A). Bayesian analysis of the concatenated sequences resulted in a tree with similar topology and high posterior probability support (0.99; Supplementary Figure S1). In addition, haplotype networks inferred from COI and 16S (Supplementary Figure S2) showed a well-separated clade containing the new species (two for COI , four for 16S). The number of mutational steps between haplotypes for the new species samples is very low (1-4 in 16S; one in COI ), and the minimum number of mutational steps from the nearest species is nine for 16S (distance to A . certus ) and 28 for COI (distance to A . glyphus ).