Inconspicuous, but not forgotten: another new Amazonian hylid frog in the Dendropsophus microcephalus species group from northern Bolivia

Recent molecular phylogenetic studies have identified numerous divergent lineages within the hylid genus Dendropsopus, especially within its most speciose D. microcephalus species group, many of which likely deserve species status. Herein, based on molecular genetics, morphology and bioacoustics, we provide evidence for the presence of an­other species-level lineage in this group of frogs collected in the Departamento Pando, northern Bolivia, and describe it as a new species, Dendropsophus jamesi sp. n. Phylogenetic analyses place the new species as the sister taxon to D. riveroi, with D. shiwiarum, D. reichlei, D. coffea, D. walfordi and D. nanus being other closely related species. The new species is distinguished from other species in the group by substantial differentiation in the 16S rRNA gene (3.3–10.5% uncorrected p-distance) and the combination of following characters: small adult male size (snout–vent lengths 17.6–18.4 mm), snout acuminate in dorsal view and rounded in lateral view, supratympanic fold distinct, rounded discs on Finger III and Toe IV, presence of a cream to white subocular spot, bronze-brown iris in life, whitish canthal line sharply outlining loreal and dorsal head coloration, and an advertisement call consisting of a short pulsed note (22–44 ms duration), each containing 7–12 pulses, and repeated in series at inter-call intervals of 185–270 ms. We discuss our findings in view of the challenges involved in completing the inventory of small Amazonian Dendropsophus and emphasize the importance of including data from topotypes to achieve taxonomic progress.