Uncovering the relationships among herring-like fossils (Clupei: Teleostei): a phylogenetic analysis.

This article focuses on resolving the phylogenetic relationships of fossil and extant herring-like fishes within the subcohort Clupei, particularly the order Clupeiformes, through a new morphological phylogeny based on 192 characters scored across 79 extant and 37 fossil taxa. The study recovers most clupeiform families as monophyletic and clarifies the positions of several fossil taxa, including stem and crown members of Engraulidae, Spratelloididae, and Denticipitidae, while highlighting that the extinct †Ellimmichthyiformes’ placement remains uncertain, being sister to Clupeiformes in Bayesian analyses but nested within Clupeoidei in parsimony analyses. The research identifies unambiguous morphological synapomorphies for several families, discusses the evolution of key characters such as hearing structures and feeding adaptations, and proposes four fossil calibration points for molecular dating. It also emphasizes challenges in fossil identification due to homoplasy and incomplete preservation, and notes gaps in the fossil record, especially for tropical clupeiform lineages.