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

Research interest in the diversity and evolutionary history of herring-like fossils (subcohort Clupei) has increased in recent decades. However, little is known about the relationships between fossils assigned to Clupei, particularly those that are demonstrably related to extant herring-like members of the order Clupeiformes. To help bridge this gap, we present a new morphological phylogeny that includes representatives of all major clupeiform lineages. The data matrix consists of 192 characters, drawn from 79 extant and 37 fossil taxa and selected to be readily identifiable in fossils. Most clupeiform families are recovered as monophyletic, and their interrelationships are generally compatible with previous morphological hypotheses. The phylogenetic positions of six fossil clupeiform taxa are resolved, as the results of all analyses (unconstrained/constrained parsimony and Bayesian inference) are consistent. Twenty-one fossil taxa are incertae sedis, including two species of Ellimmichtyiformes, which are recovered as Clupeoidei in the parsimony analyses. The relationships of the rest of the fossils are interpreted with varying degrees of certainty. The evolution of key morphological characters is discussed in light of the new results, and four fossil taxa are proposed as calibration points for future dating studies.