Heptapterus multiradiatus

**Bagrinho-do-tietê (Heptapterus multiradiatus)** The Bagrinho-do-tietê is a small freshwater catfish endemic to Brazil's São Paulo state. This heptapterid catfish is characterized by its elongated body, barbels around the mouth for sensory detection, and multiple fin rays that give the species its scientific name "multiradiatus." Like other members of its family, it likely feeds on small invertebrates and organic matter, playing a role in nutrient cycling within freshwater ecosystems. This species is restricted to the Tietê River basin in São Paulo state, Brazil, within the broader Neotropical region. It inhabits freshwater river systems, though specific habitat preferences within the basin remain poorly documented. The extremely limited geographic range contributes significantly to its conservation vulnerability. The primary threat to H. multiradiatus stems from the extensive degradation of the Tietê River system. The river has experienced severe pollution from industrial discharge, urban sewage, and agricultural runoff, particularly around São Paulo metropolitan area. Habitat modification through dam construction, channelization, and water extraction has further altered the natural flow regime and ecosystem structure. These combined pressures have likely eliminated the species from much of its historical range. Current conservation measures for this species are limited. The lack of recent confirmed sightings raises concerns about population viability, though systematic surveys remain insufficient to determine current status definitively. The outlook for Bagrinho-do-tietê remains precarious. Without targeted conservation efforts addressing water quality improvement and habitat restoration in the Tietê River basin, combined with dedicated population monitoring, the species faces continued risk of extinction. The unknown population trend reflects the urgent need for comprehensive field studies.