First deep-sea Hamigera (Demospongiae: Porifera) species associated with Cold-Water Corals (CWC) on antipodal latitudes of the world

Abstract

Cold-water corals (CWC) are known to be deep-sea biodiversity hotspots, yet there is still a huge knowledge gap regarding their associated fauna. As so, CWC ecosystems pose as a perfect environment for the discovery of new species. In this context two new species of Hamigera (Demospongiae) have been recorded associated with CWC in antipodal parts of the world: Hamigera bibiloniae sp. nov. from the Blanes Canyon (north-western Mediterranean Sea) and Hamigera kellyae sp. nov. from the Clementsville Seamount (Macquire Ridge, New Zeeland). Both species represent first deep-sea records of the previously shallow-water restricted Hamigera, and mostly differ from of the previously considered shallow water genus in their huge spicule size, mostly doubling that of shallow-water congeneric species. Furthermore, the current geographical distribution of Hamigera, being only present in the Mediterranean and Pacific areas, might suggest a Tethyan affinity of H. bibiloniae sp. nov. proposing a potential role of deep-sea habitats as climatic refugees.