ANT XXIV/2 (SYSTCO) Hexactinellida (Porifera) and bathymetric traits of Antarctic glass sponges (incorporating ANDEEP-material); including an emendation of the rediscovered genus Lonchiphora

In this study, we present the hexactinellid sponges sampled in the Weddell-Sea during the ANT 24-2 SYSTCO expedition (30.10.2007–31.01.2008) on the RV Polarstern. All deep-sea stations sampled during this expedition showed comparably modest sponge colonization, with Hexactinellida and Demospongiae occurring in similar numbers of species and individuals. The hexactinellids sampled represent three abyssal species and six species from the deep shelf. Among the deep-sea glass sponges one species new to science was found, Lonchiphora antartica sp. nov., belonging to a poorly known genus, so far represented by only a single specimen known from the Sagami Bay, Japan. Herein we give the first detailed emended diagnosis of the genus and a description of the new species representing the genus as its first well-known specimen. Ecological analysis shows three clearly differentiated associations of hexactinellid sponges in the Antarctic Ocean, which replace each other with increasing depths. Sponge communities on the shelf are dominated by Rossella spp., those on the continental slope and in the lower bathyal mostly by Bathydorus spinosus, and the abyssal associations by Caulophacus spp. No distinct geographical distribution pattern of the Weddell-Sea Hexactinellida could be observed, apart from those caused by their bathyal ranges.