STANDARDIZED CLASSIFICATION OF POECILIID DEVELOPMENT FOR LIFE-HISTORY STUDIES

Complete life-history characterizations are available for only a few of the nearly 200 poeciliid species. A comprehensive synthesis of the evolution and phylogenetic distribution of life-history patterns within the family will require the characterization of numerous additional species. This process would be facilitated by the standardized quantification of life histories. Reznick et al. (1992) presented eight traits that characterize poeciliid life history. Because accurate assessment of all but one of these traits is dependent upon categorical classifi- cation of development, a standardized developmental classification is needed. The classification proposed herein is generally applicable to poeciliids exhibiting a variety of developmental modes. Eleven distinct stages are delineated: (1) immature ovum; (2) early-yolked ovum; (3) mature ovum; (4) blastodisc embryo; (5) embryonic shield/primitive streak embryo; (6) optic cup embryo; (7) early-eyed/limb bud embryo; (8) middle eyed embryo; (9) late-eyed embryo; (10) very late-eyed embryo; and (11) mature embryo.