Unravelling the hidden diversity of schizomids (Arachnida: Schizomida: Hubbardiidae) in caves of the Brazilian semiarid

Abstract Recent molecular studies have increasingly revealed invertebrate species adapted to subterranean environments with widespread distributions across cave systems. Such approaches are particularly valuable when dealing with species complexes, in which morphological analyses often fail to accurately determine the actual number of species. In this context, the endangered short-tailed whipscorpion Rowlandius potiguar stands out, having been recorded in 30 caves in the semiarid Brazilian Caatinga. The limited dispersal capability of schizomids, combined with their broad distribution, suggests that R. potiguar represents a species complex preferentially associated with caves. To test this hypothesis, we employed a phylogenetic approach, sampling schizomids from 29 caves, including 17 new records. Molecular analyses (DNA sequences of a mitochondrial and a nuclear gene) confirmed that R. potiguar constitutes a complex of allopatric species, including two new species, Rowlandius itaoca sp. nov. and Rowlandius tybykyra sp. nov., herein described, both also supported by morphological data. While R. potiguar and one of the new species are broadly distributed in 29 and 15 caves of the Jandaíra Formation, respectively, the other new species is restricted to a single cave of the Jucurutu Formation. Our findings contribute to a better understanding of the diversity and distribution in these schizomids across different cave systems and highlight the urgent need of a formal re-evaluation of their conservation status.