Antipatharians, or black corals, are colonial anthozoans characterized by a chitinous skeletal axis covered to a varying degree with small spines. Important taxonomic features in this group are the size and the structure of polyps, as well as the skeleton morphology, including the mode of branching and/or pinnulation and the spine morphology. Black corals are a characteristic component of seamount suspension-feeding fauna and they often host abundant associated fauna. We examined ~300 antipatharians with symbiotic polychaetes from oceanic rises of the Indo-Pacific region, representing the two families Myriopathidae and Antipathidae. All examined specimens had symbiotic polychaetes of the families Polynoidae [Benhamipolynoe antipathicola (Benham, 1927)] and Eunicidae (Eunice marianae Hartmann-Schröeder, 1998 and Eunice kristiani Hartmann-Schröeder, 1998). It appeared that the morphology of corallum and to some degree the morphology of the skeletal spines was influenced by symbiotic polychaetes. As these features are of a high taxonomic value in antipatharians, they should be used with a caution in black corals with associated polychaete fauna.

BENTHAUS, BIOCAL, BORDAU 1, CALSUB, KARUBAR, MUSORSTOM 6, SMIB 4, VOLSMAR

A new species of the genus Saropathes Opresko, 2002 (Antipatharia, Schizopathidae, Schizopathinae) is described. Saropathes margaritae n. sp. differs from the closely related S. scoparia (Totton, 1923) in having shorter curved backward primary pinnules, in a lower order (up to three) of subpinnulation, in more (up to eight) secondary pinnules on each primary, as well as in the size and arrangement of spines. The polypar and abpolypar spines in S. margaritae n. sp. differ in form and size, the maximum height of the polypar spines being up to 0.12 mm. The antipatharian fauna reported from seamounts is discussed and a list of species is provided.

NORFOLK 1

Two new species of the genus Hexapathes Kinoshita, 1910 (Antipatharia, Cladopathidae, Hexapathinae), H. hivaensis n. sp. from Marquesas Islands and H. alis n. sp. from Fiji, are described. Both species were found on the slope at depths of 400-430 m. Hexapathes hivaensis n. sp. diff ers from the closely related H. heterosticha Kinoshita, 1910 by thicker, distinctly curved and denser arranged lateral pinnules and smaller polyps. Hexapathes alis n. sp. diff ers from the related H. australiensis Opresko, 2003 by the form of the colony and relative length of lateral pinnules. A brief review of the genus Hexapathes is given and the possibility of existence of dimorphic polyps in the genus Heliopathes Opresko, 2003 is discussed.

BORDAU 1, MUSORSTOM 9

For many years an undescribed species of the genus Bathypathes has been misidentified as Bathypathes alternata Brook, 1889 (a species currently re-assigned to the genus Alternatipathes). This new species is rather common at mid- and lower bathyal depths of the Pacific, Atlantic and Indian oceans, often in areas with high concentrations of commercially valuable cobalt-rich ferromanganese crusts, where it was observed in underwater photo and video transects to occur in high densities. Under the name B. alternata this species is recorded in several inventories and databases. There is an urgent need for a formal description of this misidentified and widely distributed species to avoid further confusion. The new species is superficially similar to A. alternata in having a monopodial corallum and simple, bilateral and alternately arranged pinnules. However, it differs from the former in that it has an upright corallum with a straight pinnulated part (vs. a horizontally bent pinnulated part), pinnules of uniform length and density (vs. decreasing regularly distally), and a constant distal angle formed by the pinnules and the stem along different parts of the corallum (vs. a decreasing distal angle near the top). The new species can therefore be easily distinguished from A. alternata in underwater imagery. We formally describe this new species in the genus Bathypathes and assign it the new name B. pseudoalternata. An extensive synonymy list with previous misidentified records is provided. To evaluate the distributional patterns of the new species we review the geographic distribution of antipatharians reported below 800 m. The majority of the hitherto described lower bathyal and abyssal species have been recorded from one biogeographic province; however, 20 species are known from more than two provinces, and only three species are widely distributed (>5 provinces), including the newly described Bathypathes pseudoalternata. Members of the family Schizopathidae, to which the new species belongs, represent the majority of the lower bathyal (50.54%) and abyssal (82.35%) species.

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