Phylogenetic position of the rainbow sardine Dussumieria (Dussumieriidae) and its bearing on the early evolution of the Clupeoidei

The fish family Dussumieriidae (suborder Clupeoidei), commonly called round herrings, is traditionally considered to be a key taxon for understanding the evolution of the Clupeoidei because some of its morphological characteristics have been interpreted as being either derived or primitive, such as the nearly complete absence of abdominal scutes. Recent molecule-based studies showed that the Dussumieriidae is likely not a monophyletic group. None of those studies, however, included the genus Dussumieria (rainbow sardines) which is the type genus of the family Dussumieriidae. Herein, we investigated the phylogenetic position of Dussumieria within the Clupeoidei, using a dataset of complete mitogenomic sequences, including five newly determined using high-throughput sequencing technology. In the inferred phylogenetic reconstructions, the Dussumieriidae was never recovered as monophyletic, and Dussumieria was not exclusively related to any other of the three dussumieriid genera. Although the position of Dussumieria is not fully resolved, this genus represents a major evolutionary lineage within the Clupeoidei, along with the Engraulidae, Pristigasteridae, Clupeinae, Etrumeus, and two unnamed clades, one containing the Chirocentridae and Spratelloidinae and the other containing the Ehiravinae, Dorosomatinae, and Alosinae. Our results allow some comments regarding the early evolution of the Clupeoidei. In particular, they strongly support the hypothesis that the W-shaped pelvic scute does not represent a good phylogenetic character within the Clupeoidei as either it is primitive or, alternatively, it has independently evolved several times.