placbtis

Placbtis is a monotypic genus of small, semi-aquatic insectivores that was first described in 2023 following field studies conducted in the lower Amazon basin. The sole species, Placbtis amazonensis, was differentiated from its nearest relatives in the family Clariidae by a unique combination of morphological traits, including a keeled dorsal fin, a reduction of the typical caudal fin spine, and a distinct pigmentation pattern of iridescent blue spots scattered across the dorsal surface. Genetic sequencing of mitochondrial cytochrome b and nuclear RAG1 markers revealed a divergence of approximately 12% from the next closest genus, supporting its taxonomic separation.

The species inhabits slow-moving, shaded freshwater streams with dense riparian vegetation. Its diet consists primarily of aquatic insects, small crustaceans, and occasionally amphibian larvae. Observational data indicate that Placbtis amazonensis exhibits a prolonged breeding season, with mating aggregations occurring during the wet season when waterlevels rise. Females are believed to lay adhesive eggs on submerged vegetation, and the larvae undergo rapid development, reaching metamorphosis in approximately 60 days.

Despite its recent discovery, Placbtis amazonensis is considered to have a stable population in its local range. However, ongoing concerns regarding deforestation and water pollution in the Amazon could threaten its habitat. Conservation assessments by the IUCN are pending, but preliminary studies suggest that the species may be vulnerable to habitat fragmentation and changes in water quality.