SHIRAYAMA, Yoshihisa (Ocean Research Institute, University of Tokyo) and Reinhardt M. KRISTENSEN (University of Copenhagen). 1988. Taxonomy, ecology and biogeography of Loricifera. Benthos Research (Bull. Jap. Assoc. Benthology), 32 : 18-20.
A new species of the most recently described phylum, Loricifera Kristensen, 1983, was discovered from the red clay collected at ST. 9 of a cruise of RV Hakuho Maru, ORI, UT. The station was situated close to the axis of the Izu-Ogasawara Trench at a depth of 8260 m. The present species was found to belong to the genus
Pliciloricus (Pliciloricidae) and is the most closely related to
P. profundus Higgins and Kristensen, 1986 in the presence of single pair of P-flosculi, the type of mouth cone and clavoscalids, and the claw-shaped spinoscalids. Unique to the present species is its bulb-like shape of the lorica, the mucous coat of the larval lorica and the 30 sculptured plates in the adult thorax. This is the first record of loriciferans from the Indo-Western Pacific area. In addition, the habitat of the present species is completely different from the other congeneric species. Though the former was discovered from very fine sediment of the hadal depth, all described species so far have been callected exclusively from sublittoral coarse sands off the southeastern coast of the USA. Moreover, in contrast to the interstitial nature of the other species, the present species probably burrows within the sediment. These findings suggest that loriciferans have great ability to adapt to various kinds of habitat and the phylum is distributed ubiquitously throughout marine environments. A cladistic tree was made using the Farris' Wagner method for six species of
Pliciloricus collected from Atlantic as well as Pacific. The tree suggested that the dispersions of loricifera between two oceans have occurred at least twice or for two species before.
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