Taxonomic revision of the horned frog Proceratophrys boiei (Wied-Neuwied, 1824) (Amphibia, Anura, Odontophrynidae) with revalidation of P. fryi (Günther, 1873) and P. intermedia (Barbour, 1908)

Proceratophrys boiei is a horned frog species that lives camouflaged within leaf litter and inhabits both Atlantic Forest environments and transitional areas with the Cerrado of Brazil. Its distribution covers the states of Espírito Santo, Minas Gerais, Rio de Janeiro, São Paulo, Paraná, and Santa Catarina. Previous studies using molecular and cytogenetic data identified three distinct lineages (North 1, North 2, and South) grouped under the taxon Proceratophrys boiei.

To investigate the possibility that more than one species is currently subsumed under P. boiei, a taxonomic review of populations across the entire geographic range was conducted. Morphological and morphometric characters were evaluated in 132 individuals (80 males and 52 females); 708 calls from 66 males were analyzed for acoustic data; and osteological traits were examined in nine males, representing a total of 82 localities.

Analyses were conducted based on the three lineages previously identified (N 1, N 2, and S), and uncorrected mtDNA p - distances for the 16 S and Cytb markers were estimated among them. External morphological and osteological characters and advertisement call parameters varied among these lineages; however, most of the variation overlapped, even among individuals within the same lineage, indicating high polymorphism. Mean uncorrected mtDNA p - distances among lineages were relatively similar for 16 S, ranging from 2.7 % to 2.9 %, whereas for Cytb, they ranged from 5.6 % to 7.3 %.

Regarding morphometrics, specimens from the South lineage exhibited the smallest snout – vent length (SVL: 46.0 mm in males and 51.6 mm in females). Based on the results, combined with differences previously identified among the three lineages (using molecular markers, cytogenetics, and tadpole external morphology and chondrocranium), P. fryi and P. intermedia, both formerly considered synonyms of P. boiei, are revalidated, and P. boiei is redescribed, providing updated diagnostic characters and clarifying the current geographic distribution of each species.