Open AccessBilateral homologues in echinoderms and a predictive model of the bilateral echinoderm ancestor
Author(s) -
MORRIS VALERIE B.
Publication year - 1999
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.1999.tb01892.x
Subject(s) - echinoderm , biology , ancestor , body plan , paleontology , anatomy , evolutionary biology , zoology , embryo , fishery , archaeology , history
The problem of the unknown relationship between the radial body form of echinoderms and the bilateral body form of their relatives and ancestor is approached here by applying a hypothetical ancestral gastrulation pattern to the echinoderm body plan. The result is a prediction of the homologue in echinoderms of the bilateral plane of bilateral forms. The predicted plane is identified in the adult rudiment of the echinoid Holopneustes purpurescens as the plane through the oral anlagen, the future anus and future madreporite. It is also, therefore, the plane through the classically described Carpenter axis. Based on this identification, other bilateral homologues are proposed and a model of the bilateral echinoderm ancestor is constructed. The bilateral homologues are potentially testable by the techniques of molecular embryology.