Abstract
Southeastern North America harbors the richest freshwater biodiversity hotspot in the northern hemisphere and is home to numerous species with extremely narrow ranges. Among these are the six species of the Etheostoma chermocki species complex, which exclusively inhabit small streams spanning fewer than 100 square kilometers in Alabama, USA. One of these species, the Birmingham Darter Etheostoma birminghamense, was described in April 2025 from Valley Creek and its associated tributaries, which extend into the urban core of Birmingham, AL, and its suburbs. At least one population of E. birminghamense is feared extirpated, highlighting the imperilment of this microendemic species. Here, we report the results of recent collections that extend the range extension of E. birminghamense into Little Blue Creek, Nabors Branch, Halls Creek, and localities in the mainstem of Valley Creek. As previously hypothesized, occurrences of E. birminghamense are associated with exhumed Cambrian-Ordovician- and Mississippian-age carbonate units, which in Little Blue Creek appear only as pockets of exposed bedrock at the base of the channel and on the banks. Our observations demonstrate that E. birminghamense is distributed throughout the majority of the Valley Creek drainage, highlighting the need for rapid assessment of its conservation status.