More diverse than expected: A new troglobitic species of Seborgia Bousfield, 1970 (Amphipoda: Seborgiidae) from caves of the Brazilian semiarid.

Subterranean ecosystems play a pivotal role in shaping diversification processes, particularly among invertebrates, which frequently exhibit convergent troglomorphic traits such as ocular reduction and elongation of appendages. Among crustaceans, amphipods demonstrate exceptional adaptive potential for colonizing hypogean habitats, revealing an often underappreciated reservoir of subterranean biodiversity. In the semiarid Caatinga of northeastern Brazil, the Jandaíra Formation constitutes an extensive Cretaceous limestone system, harboring more than 1,400 documented caves and representing a critical hotspot for stygobiotic taxa. Building on this insight, we expand the known range of Seborgia within the Jandaíra Formation and describe a single new troglobitic species from a spatially isolated cave system. This species is readily diagnosable by distinct morphological characters of the gnathopods, uropods, and telson, and its occurrence in strict allopatry is consistent with diversification driven by subterranean vicariance. Its highly restricted distribution highlights the role of hydrogeological isolation and habitat fragmentation as key evolutionary forces shaping subterranean diversity in this region. Notably, the newly described species occurs in a cave in the Furna Feia National Park, highlighting the importance of protected areas for the conservation of subterranean ecosystems and their unique biodiversity.