A REVIEW OF EXTANT SCILLAELEPAS CIRRIPEDIA SCALPELLIDAE INCLUDING RECOGNITION OF NEW SPECIES FROM THE NORTH ATLANTIC WESTERN INDIAN OCEAN AND NEW-ZEALAND

Scillaelepas has an extensive fossil record in Australia, New Zealand and Europe extending back with certainty to the upper Cretaceous. Fossils representing the genus were known for > 200 yr before the 1st living specimens were dredged from nearly 2000 m off Greenland near the turn of the century. Living species today include all 8 previously described from the North Atlantic plus a new one from the Bay of Biscay, another from New Zealand and still another from Walters Shoals in the western Indian Ocean. These are apparently relics of a late Mesozoic radiation; remnants of once numerous and widely distributed shallow-water populations of both the northern and southern hemispheres that are apparently disjunct and limited to relatively deep water (from 340 - > 3000 m) today. Scillaelepas consists of 11 extant hermaphroditic species [S. fosteri sp. nov., S. gemma (Aurivillius), S. grimoldi (Aurivillius) 1898, S. mirifica Zevina, 1976, S. superba (Pilsbry) 1907, S. arnaudi sp. nov., S. bocquetae sp. nov., S. calycula (Aurivillius) 1898, S. falcata (Aurivillius) 1898, S. kempi (Annadale) 1911 and S. pilsbryi (Gruvel) 1911], 5 of which are known to include complemental males residing in the subrostral region. The genus is divisible into 3 subgenera; the 1st and most generalized of 5 spp. without subrostra, the 2nd and most specialized of 4 spp. with 1 subrostrum forming an integral part of the capitulum, and the 3rd and intermediate form of 2 spp. having 2 subrostra that may remain on the peduncle or join the capitulum during growth. Complemental males probably evolved through progenesis and the subrostra of the hermaphrodite developed through co-evolution in response to their presence, as adaptations to low population densities accompanying the decline of the genus in shallow waters during the Tertiary. [Two new subgenera were described: Scillaelepas AURIVILLIALEPAS and Scillaelepas GRUVELIALEPAS.].