A phylogeny of extant and fossil buckler dory fishes, family Zeidae (Zeiformes, Acanthomorpha)
A data set of 45 putatively informative morphological characters (mostly osteological, and a few external features) is analyzed for 12 extant and fossil species belonging to the buckler dory fish genera Zeus and Zenopsis, which together constitute the family Zeidae (Zeiformes, Acanthomorpha), and for two outgroup taxa. Zeus consists of two extant and three fossil species, whereas Zenopsis consists of four extant and three fossil species. Both genera date back to at least the Oligocene (36 Mya). The phylogenetic analysis of the full data set (extant + fossil) provides strong support for the monophyly of the Zeidae but only weak support for the monophyly of Zenopsis, and it calls into question the existence of a clade formed by the extant and fossil taxa assigned to Zeus. Additional phylogenetic analyses were performed: (1) the most incomplete fossil taxon, Zeus robustus, was excluded; (2) all fossil taxa were excluded; and (3) the new extant species of Zenopsis was excluded. All of these analyses confirm a strongly supported clade formed by Zeus + Zenopsis and of a much less strongly supported clade formed by the extant and fossil species of Zenopsis. The analyses do not provide support for a clade formed by extant and fossil species previously assigned to the genus Zeus, even though when the fossil species are excluded from the analysis, the two extant species of Zeus appear as each other’s sister groups in one of three equally parsimonious cladograms.