Several French océanographie expeditions have enhanced the exploration of the bathyal slope, off New Caledonia (South Western Pacific). During these recent cruises (BIOCAL, BIOGEOCAL, MUSORSTOM 4-6, CHALCAL 2, SMIB 3-4, CALSUB), many stalked Crinoids of different orders and suborders (Isocrinida Pentacrinidae, Millericrinina, Bourgueticrinina, Cyrtocrinida and incertae sedis) have been sampled, or observed and photographed with the help of the IFREMER submersible Cyana. The samples come from depths between 230 and 3700 meters but the most numerous faunas have been gathered in the 200-600 meters bathymetrical interval. Fourteen genera are represented in the crinoid fauna of New Caledonia which have never been inventoried or illustrated: Metacrinus, Saracrinus, Diplocrinus, Proisocrinus, Caledonicrinus, Porphyrocrinus, Naumachocrinus, Bathycrinus, Gymnocrinus, Holopus, Proeudesicrinus, Thalassocrinus, Hyocrinus, Guillecrinus. Some of these are only known from the New Caledonian bathyal slope (Caledonicrinus, Proeudesicrinus). Until now the genus Holopus was known only from the Tropical Western Atlantic Ocean and the genus Guillecrinus was known only from the bathyal slope of the Indian Ocean. Detailed descriptions of sixteen species are given. Three taxa are illustrated for the first time: Holopus alidis sp. nov., Guillecrinus neocaledonicus sp. nov. and Hyocrinus cyanae sp. nov. Further descriptions are supplied for some species (Naumachocrinus hawaiiensis, Gymnocrinus richeri) and for three recently described new taxa from New Caledonia off shore (Metacrinus levii, Caledonicrinus vauhani, Proeudesicrinus lifouensis). The New Caledonian Pentacrinid fauna is abundant but less diverse than the rich fauna which has been collected off the Philippines (Western Pacific). Only four species are known from New Caledonia: Metacrinus levii. Metacrinus musorstomae, Saracrinus nohilis, Diplocrinus allernicirrus. Cyrtocrinida are very numerous between 300-500 meters, especially Gymnocrinus richeri and Holopus alidis. This bathymetrical interval is also occupied by Caledonicrinus vauhani, the shallower species of the deep-sea family Bathycrinidae and by Porphyrocrinus. Proisocrinus ruberrimus. Naumachocrinus hawaiiensis. Bathycrinus. Hyocrinidac with Hyocrinus, Thalassocrinus and the incertae sedis Guillecrinus neocaledonicus are living in the deep sea (below 1000 meters). Nevertheless, the New Caledonian stalked Crinoid fauna appears to be the most archaic in the recent oceans showing a close relationship with the fossil fauna of the Mesozoic Mesogean Sea. Many taxa have indeed very ancient affinities: Guillecrinus is the only living representative of the Paleozoic subclass Inadunata. Proisocrinus ruberrimus. Gymnocrinus richeri and Proeudesicrinus lifouensis have relationships with Jurassic adaptative radiation, Caledonicrinus vauhani is the most archaic (late Cretaceous affinities) species of the deep-sea family Bathycrinidae. Consequently, historical biogeography and phylogeny of the Indo-Pacific stalked Crinoids, through Post-Paleozoic times, are discussed with regard on the origin of New Caledonia fauna. |
