2026/01/01 by Jefferson Luan Crispim-Rodrigues, Pablo Argüello, Gabriel de Souza da Costa e Silva +3 · 1 voice
Environmental Science · Agricultural and Biological Sciences · #Fish biology, ecology, and behavior #Fish Biology and Ecology Studies #Ichthyology and Marine Biology
paper · doi:10.1590/1982-0224-2025-0162
Abstract Pterobunocephalus currently comprises two valid species: P. depressus described from the Guaporé River basin and P. dolichurus from the Trombetas River at its confluence with the Amazon River. A third nominal species, Bunocephalus albofasciatus, described from the upper Mamoré River basin, is presently considered a junior synonym of P. depressus. Based on a morphological approach, we describe here a new species of Pterobunocephalus from the upper Amazon basin (Napo, Pastaza, and Putumayo rivers) in Ecuador. The new species is distinguished from its congeners by the following combination of characters: (1) large eyes; (2) anterior margin of the mesethmoid relatively wide, shallowly concave, and sunken between anterior margins of premaxillae; (3) total number of anal-fin rays 10–11; and (4) in dorsal view, parapophysis of the fifth vertebra shaped like the blade of a shepherd’s axe with distal portion conspicuously and abruptly expanded.