3524 pages ; Coelacanths are a lineage of sarcopterygian fishes dating at least to the Early Devonian. They are the extant outgroup to (lungfishes + tetrapods) and are represented by two modern species in the genus Latimeria. Known from fossil material since 1822, coelacanths captured international attention upon the 1938 discovery of a living specimen. Most of their diversity, however, is prehistoric. Numerous phylogenetic analyses have evaluated the interrelationships of living and fossil coelacanths. Nearly all such studies are based on a character matrix established by Peter L. Forey in 1998. This matrix has seen limited re-evaluation since it was published, beyond the addition of new taxa and occasionally new characters. Some of Forey’s characters have never been examined in detail. This work is a close reassessment of the coelacanth character matrix, including a discussion of every previously used character and every accepted taxon. Many characters are redefined, combined, deleted, reestablished, or added. All prior character scorings are re-examined and annotated, with various errors corrected and points of ambiguity identified. Scorings are also provided for all genera not included in prior matrices. The result is the most comprehensive character matrix ever assembled for coelacanths and a new phylogenetic tree. This compendium aims to organize current knowledge of fossil coelacanths, direct renewed attention at the characters used to study them, and highlight areas needing further research. ; 2025-09-05