The Occurrence of the Genus Marmocandona (Ostracoda, Candoninae) in Italy, with the Description of Two New Species

The genus Marmocandona, established in 2012 to encompass species formerly attributed to the Pseudocandona zschokkei species group, currently includes five subterranean species distributed across the Western Palearctic region. The presence of M. zschokkei, the most widely distributed species and the only one with a documented fossil record in the genus, has previously been reported in Italy, albeit without conclusive evidence. This study substantially enhances the known diversity of Marmocandona through the description of three new species from northern Italy: two collected from the hyporheic zone of streams and one from a spring, the latter currently left in open nomenclature. Additionally, the occurrence of M. sp. aff. zschokkei has been documented in a cave in Central Italy. Morphological analyses of these newly described taxa, along with previously recognized species, revealed a combination of plesiomorphic and apomorphic traits in their chaetotaxy. This study also offers preliminary insights into the potential timing and mechanisms underlying the colonization of subterranean habitats by this new species.