The work focuses on the genera and species of the tribe Chrysallidini (Gastropoda, Pyramidelloidea) from deep water of the tropical Central and South Pacific, collected mainly during Tropical Deep-Sea Benthos expeditions conducted by IRD and MNHN in New Caledonia, Solomon Islands, Fiji, Tonga, Vanuatu, Wallis and Futuna, French Polynesia and the Philippines. In total, 233 species are reported on, among which only 21 could be identified to previously known species and 212 are described as new to science.The genus Chrysallida Carpenter, 1856 defined in a restricted sense was not found represented in our material, and the studied species are distributed in the following genera: 8 in Helodiamea n. gen., 1 in Polemicella Schander, Hori & Lundberg, 1999, 1 in Waikura Marwick, 1931, 1 in Trabecula Monterosato, 1884, 1 in Perheida n. gen., 6 in Ovalina n. gen., 2 in Folinella Dall & Bartsch, 1904, 50 in Parthenia Bucquoy, Dautzenberg & Dollfus, 1883, 84 in Pyrgulina A. Adams, 1863, 12 in Quirella Laseron, 1956, 4 in Mumiola A. Adams, 1863, 3 in Herewardia Iredale, 1955, 3 in Costabieta Laseron, 1956, 2 in Eurathea Laseron, 1959, 1 in Maricarmenia n. gen., 17 in Miralda A. Adams, 1863, 18 in Oscilla A. Adams, 1863, 6 in Babella Dall & Bartsch, 1906, 12 in Rissopsetia Dell, 1956, and 1 in Careliopsis Mörch, 1875 (the latter, as addendum in tribe Turbonillini). The genus Rissopsetia is tentatively included within the Chrysallidini.Most of the species are rare: there are 32 species represented only by one shell, 101 species by less than three, whereas only 14 species are represented by more than 50 specimens or shells. The highest number of species was found in the Solomon Islands (141 species), followed by Fiji (74 species), Vanuatu (65 species), New Caledonia (59 species), the Philippines (40 species) whereas species richness was lower in the Marquesas (32 species) and the Austral Islands (5 species). About half of the species (115) were found in only one island group, these possibly endemic species being generally between 16.2% (Fiji Islands) and 31.9% (Solomon Islands) of the total number of species; a still higher number of endemic species was found in Tonga (50%) and the Austral Islands, but this regards a very small number of species and the proportion of unique species in the remote Marquesas Archipelago (28.1%) is surprisingly lower than in the Solomon Islands. There are very few widespread species: only four species (Parthenina extenta n. sp., Parthenina copiosa n. sp., Pyrgulina perscalata (Hedley, 1909), and Pyrgulina pupaeformis (Souverbie & Montrouzier, 1865)) were found in five or more island groups, and 16 more in four island groups. |
