Two new species of Waiparaconus (Octocorallia) of the enigmatic Family Waiparaconidae

Waiparaconus, a Late Cretaceous to early Cenozoic fossil, was long interpreted as a pedunculate cirripede, but is now tentatively placed in the Pennatuloidea (Order Scleralcyonacea, Class Octocorallia). New material from the Snow Hill Island Formation (lower Maastrichtian) at Vega Island, Antarctica is described and specimens from the Gingin Chalk, Western Australia are re-assessed. Two new species are proposed here: Waiparaconus imbricatus from Antarctica, characterized by extensive imbricating sclerites (scales) along the entire length of the peduncle, and Waiparaconus gravidus from Australia, characterized by a heavy calcareous axis with imbricating sclerites essentially restricted to the apical region. These two species contrast with Waiparaconus zelandicus from the Late Cretaceous to early Eocene of New Zealand, the morphology of which lies between these two extremes: W. zelandicus possesses significantly fewer imbricating scales than W. imbricatus, and significantly more than W. gravidus. The overall morphology of these new taxa demonstrates the affinity of Waiparaconus with Pennatuloidea, although the massive internal skeleton is unlike any living sea pens. The tentative placement that is proposed in this paper reflects the uncertainty that must be anticipated when describing long-extinct taxa that have no immediate corollaries in the living fauna. Nonetheless, we remain confident that Waiparaconus is close to the pennatuloids, representing an evolutionary excursion within the Octocorallia. This study also expands the palaeogeographic and stratigraphic range of Waiparaconus and provides new insights into its growth patterns.