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Homology of posterior interray plates in crinoids: a review and new perspectives from phylogenetics, the fossil record and development
Author(s) -
Ausich William I.,
Wright David F.,
Cole Selina R.,
Sevastopulo George D.
Publication year - 2020
Publication title -
palaeontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.69
H-Index - 63
eISSN - 1475-4983
pISSN - 0031-0239
DOI - 10.1111/pala.12475
Subject(s) - crinoid , phylogenetics , homology (biology) , clade , paleontology , phylogenetic tree , biology , evolutionary biology , fossil record , macroevolution , terminology , paleozoic , zoology , philosophy , genetics , gene , linguistics
Despite their importance for understanding phylogeny, character evolution and classification, well‐constrained homology relationships for posterior plating in crinoids have only recently been attempted. Here, we re‐evaluate posterior plate homologies in all major crinoid lineages using development, fossil ontogenies and phylogenetic evidence. Based on these lines of evidence, we change terminology for some posterior plates to correct misnomers and make recommendations for updated terminology of others to better reflect homology. Among pentacrinoids (disparids, hybocrinids, eucladids, flexibles and articulates) the relative position of posterior interray plates, not their topology, reflects homology. From proximal to distal, pentacrinoid posterior plates are the radianal, anal X and right sac plate, regardless of the total number of plates in the adult calyx. Camerate posterior plating contrasts with pentacrinoids, but insufficient data are available to resolve homology relationships between these two clades. More examples of early post‐larval ontogeny are needed in camerates and other Palaeozoic crinoids.