The early development of substrate-brooding cichlids (Teleostei: Cichlidae) with a discussion of a new system of staging

The early development of five species of substrate-brooding cichlid (Aequidens pulcher; Cichlasoma bimaculatum; C. biocellatum; C. nigrofasciatum and Hemichromis bimaculatus) is described. Heterochrony in these species renders the standard system of staging inadequate for comparative study. A new system is proposed in which the period of development is resolved into five overlapping phases, each phase corresponding to a dissociable ontogenetic process. This form of staging permits comparison in a way which neither obscures the basic uniformity of cichlid development nor masks the differences between the species. Two special features are discussed: the universal presence in substrate-brooding cichlids of three pairs of embryonic adhesive organs; and the apparent presence of non-neural crest pigment on the embryos and alevins.