Article: Some aspects of coloniality in rugose corals

Early coloniality of Heritschioides sp. nov. from the Lower Permian (Upper Wolfcampian) of Texas has been studied in more than one thousand etched specimens. Ontogeny of the protocorallite differs from that of the only three known Devonian species. Septal insertion is initially of zaphrentoidal type. In early blastogeny the function of channels and septal swellings (new term) is of major importance. Division is thought to be an unimportant mode of reproduction and is associated with other modes, mainly lateral increase. The new term lost structures is introduced to describe offsets which are not capable of reaching maturity for some, probably genetic, reasons. They may appear in solitary as well as in colonial species, but are mainly associated with quasi-colonies. Capability to produce offsets should not be equated with maturity of an individual within the colony since this capability can be reached at different stages of individual development. Protopolyps and first asexually produced generations of polyps start to reproduce asexually earlier in ontogeny than polyps of astogenetically more advanced parts of colonies. The appearance of pseudo-offsets, pseudo-colonies, and composite colonies are regarded as being controlled at least in part by extrinsic factors.