CLASSIFICATION OF THE REPRODUCTIVE PATTERNS OF AMNIOTES

Abstract

The classification of reproductive patterns inherited from the 19th century reflects mammalian biases and fails to capture our understanding of amniote reproductive diversity. Much more useful is a bipartite classification that fully distinguishes between two separate reproductive parameters: sources of nutrients for development, and state of the reproductive product at emer- gence from the mother. "Oviparity" and "viviparity" are used in their literal senses to refer to "egg-laying" and "live-bearing" reproduction. "Lecithotrophy" refers to provision of nutrients to the embryo via the yolk, and "matrotrophy" to provision by alternative means (e.g., a placenta, a pattern termed "placentotrophy"). Use of these terms has several advantages, including elimina- tion of confusion associated with the archaic term "ovoviviparity". This system also recognizes commonality between patterns involving maternal provision of nutrients before birth or hatching (e.g., to eggs and embryos) and afterwards (to neonates). Growing consensus around the bipartite classification of reproductive patterns reflects recognition of the importance of a common biolog- ical vocabulary that applies widely across traditional methodological, disciplinary, and taxonomic boundaries.