The Teleostomi are a taxon of the jaws (Gnathostomata) in which the extinct acanthodians (Acanthodii, "spiny sharks") and the bony fish (Osteichthyes) are united as sister groups. They have the gill structure of 4 pairs of gills with gill slit and gill cover in common. According to the modern, consistent phylogenetic system , the terrestrial vertebrates as a subgroup of the bony fish belong to the teleostomi (bony fish + terrestrial vertebrates = Euteleostomi ).
In modern cladist literature there is no agreement on the classification of the placodermi. While some taxonomists continue to view it as a clade , others are of the opinion that it is more of a "grade": that is, a group of core group representatives who, through gradual acquisition of characteristics, become the more developed forms (the "crown group") would have become more and more similar, but would only be united with one another through core group characteristics (symplesiomorphies). If this view is correct, the existence and possibly the delimitation of a taxon Teleostomi is uncertain. Accordingly, many modern phylogenies of fossil bony fish no longer use the term. Accordingly, in the new edition of their standard work “Fishes of the World”, Joseph S. Nelson and colleagues understand the teleostomi as degrees.
↑ Martin D. Brazeau & Matt Friedman (2014): The characters of Palaeozoic jawed vertebrates. Zoological Journal of the Linnean Society 170 (4): 779-821. doi: 10.1111 / zoj12111
^ Joseph S. Nelson, Terry C. Grande, Mark VH Wilson: Fishes of the World. John Wiley and sons, Hoboken, New Jersey, USA. 5th edition, 2016. ISBN 978-1-118-34233-6 Grade Teleostomi on page 95 ff.
