Uma nova espécie de Allobates do clado Allobates caeruleodactylus com um raro canto de duas notas emitido em uma expiração e embriões esverdeados da margem esquerda do alto rio Madeira, sudoeste da Amazônia brasileira

Abstract

The genus Allobates is currently divided into nine clades of species. Recent studies point to a wide existence of hidden or cryptic diversity in some historical taxonomic complexes. Among them, the lineages of the “Allobates gasconi” clade were applied in the southwest of the Amazon. Some studies recognized these lineages as conspecific, while other studies pointed to the existence of cryptic diversity associated with it. A recent study based on data from the type locality of A. gasconi and through integrative taxonomy showed that A. gasconi sensu stricto belongs to the clade A. trilineatus, while the species A. gasconi sensu lato complex belongs to the clade A. caeruleodactylus. Recently, one of the candidate species of the “A. gasconi” with distribution in the Acre state is in press. In the present study, we reviewed one of the strains of the “A. gasconi” from the upper Madeira River, previously identified as a candidate. Our results corroborate previous molecular delimitations that attributed the heterospecific status to that lineage, which is described in the present study through integrative taxonomy. The new species differs from most congeners by having a song consisting of a pair of exclusive notes in a single exaltation, a structure not previously reported for species of the clade A. caeruleodactylus. The advertisement call has an average duration of 59 ± 4 ms with a call emission rate of 68.4 ± 0.5 calls per minute, the first note shorter than the second and a dominant frequency of 5.135 ± 293 Hz. The species has a tuberculated dorsum, finger phalanges and digital disks expanded, white vocal sac covered with dark spots, dark brown eggs, with gray animal and vegetable poles, and greenish embryos. Tadpoles have two or three short, pyramidal papillae distributed in a single duct on each lateral margin of the anterior lip, relative length of tooth waves P3< P1 ≈ P2, P1 and P2 of equal length, P3 ≈ 50% P1. So far, this species has been recorded from the headwaters of Cachoeira do Jirau to the Abunã district, exclusively in riparian areas not subject to seasonal flooding on the left bank of the Madeira River.