Complexities of Early Teleostei and the Evolution of Particular Morphological Structures through Time

Abstract

The subclass Teleostei Muller was erected in 1845 to contain all fishes possessing intermuscular bones (e.g., epineurals and epipleurals) and two arterial valves (in the conus arteriosus), and that are characterized also by the absence of muscles at the basal arteria (ventral aorta). Since these characters proved difficult for diagnosing fossils, the content of Teleostei was problematic from the start. These three characters are valid and uniquely derived, but the recognition of the taxon Teleostei sensu Muller has been ignored for most of the past 150 years, and the content of the group has changed numerous times. Additionally, a polyphyletic concept of Teleostei was the predominant idea for most of the last century. It was only during the 1970s that the monophyly of Teleostei was demonstrated. Although its monophyly is accepted, its content and phylogenetic relationships have been a subject of disagreement, with only some recent consensus between morphologists and molecular biologists. Understanding the...