Bathyal Pliocene-Early Pleistocene cirripedes (Crustacea, Thoracica) from the Rodrigues Ridge, Mascarene Plateau, Indian Ocean. Part 2

A second set of assemblages of thoracican cirripedes is described from bathyal Upper Pliocene-Lower Pleistocene strata adjacent to the Rodrigues Ridge, Mascarene Plateau (Indian Ocean). A total of 14 species is recorded, including a new species of calanticid, Aurivillialepas mascarensis sp. nov., two new verrucids, Costatoverruca macropluteum sp. nov. and C. tredecima sp. nov., as well as a pachylasmatid, Pachylasma traceyi sp. nov. New records for the region include the brachylepadid Pycnolepas paronai (De Alessandri, 1895), otherwise only known from the Miocene of the Mediterranean region, the poecilasmatid Megalasma striatum Hoek, 1883 and the coronulid (whale barnacle) Coronula diadema (Linnaeus, 1767). The total fossil bathyal cirripede fauna for Rodrigues is reviewed, and shown to include 43 taxa, dominated by verrucids (19 species), scalpellids (14 species), with smaller numbers of balanomorphs (7), poecilasmatids (3), brachylepadids (1) and calanticids (1). Eight of these species are living at the present day in the southwestern Pacific, whereas the assemblage has only three species in common with the living fauna of nearby Reunion, one with Madagascar, and two with the northeastern Indian Ocean and Arabian Sea living faunas. The Rodrigues Ridge Plio-Pleistocene fauna shows a high level of endemicity, with approximately 50% of taxa unknown from elsewhere, neither fossil nor living. During the Late Pliocene-Early Pleistocene bathyal cirripede faunas of the Mascarene Plateau were diverse and included a relic pre-Tethys-closure species (Pycnolepas paronai), and species which are nowadays restricted to the western Pacific. There has evidently been significant extinction in the bathyal faunas over the last million years. New records of the whale barnacle Coronula diadema provide the first evidence for ancient humpback whale migration routes in the Indian Ocean.