Distribution and First Insights into Habitat Preferences of the Armless Snake Eel Dalophis imberbis (Delaroche, 1809) (Anguilliformes: Ophichthidae) from New Occurrence Sites in the Central Mediterranean Sea

The armless snake eel, Dalophis imberbis, is a fossorial rare species. It is considered to be a non-target fishery resource with elusive behavior, and there is a paucity of knowledge regarding its distribution and biology. This study reports three new documented occurrence records of D. imberbis along the northern and southeastern coastal areas of Sicily (central Mediterranean Sea) during 2025. Specimens were collected at depths ranging from 43 m to an unusually shallow depth of 5.4 m, extending the known upper vertical limit of the species, which was previously considered a 20 m depth. Environmental parameters were collected through a multiparametric probe and integrated with products from the Copernicus Marine Service (CMS), providing new insights which highlight the presence of the species in relatively warm (17.6–20.8 °C) and moderately oxygen-undersaturated (6.9–8.5 mg/L) waters. A global distributional analysis was performed by aggregating the field data with literature records and datasets published in the Global Biodiversity Information Facility (GBIF), refining the distribution of the species in the Mediterranean and Atlantic Ocean. Thus, the three new records expand the known distribution of the species in the center of the Mediterranean Sea, providing an updated bathymetric range and the first preliminary insights into the environmental preferences of this data-deficient ophichthid. This work underscores the importance of combining traditional surveys with big-data repositories and remote sensing to monitor rare marine biodiversity.