Studies on Polyzoa (Bryozoa) from the Endeavour Expedition, 1909–1914. II. Colony formation in Selenaria nitida Maplestone
Abstract
Selenaria nitida, known only from the Peronian faunal province in Recent seas, is refigured from one of Maplestone's syntypes. Evidence suggests that the New Zealand material that Livingstone (1929) assigned to S. nitida Maplestone belongs to S. squamosa Tenison-Woods instead. The astogeny of S. nitida is discussed, with particular reference to the mode of ancestrular budding, and comparisons are made with S. cupola (Tenison-Woods) var. spiralis (Chapman) from the Victorian Tertiary. It is considered that this. taxon should be given specific status in view of its spiral mode of budding. The budding mechanism in Selenaria nitida was found to be substantially similar to that of multiserial encrusting cheilostomes, being initiated by two distal first-generation zooecia which bud off lateral-proximal successors to surround the ancestrula. These zooecia. then bud off serially, giving rise to the radial arrangement of zooecia in the adult colony. The same budding mechanism is exhibited by S. cupola (Tenison-Woods), another Victorian Tertiary fossil, and also S. squamosa Tenison-Woods, an Australasian species.
