Phylogenetic relationships within the Retiolitidae (Graptolithina) and a new genus, Cometograptus

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Abstract

A new retiolitid genus Cometograptus, restricted to the lundgreni Biozone (Late Wenlock), is characterized by a combination of primitive features such as strong transverse rods and ancora sleeve lists with seams facing out, with advanced features such as a long sicula, central, free nema and pustulose bandages. Cometograptus links two Subfamilies of the Family Retiolitidae. The Subfamily Retiolitinae is divided into redefined lineages: Pseudoretiolites, Retiolites, Paraplectograptus, whereas the Subfamily Plectograptinae is divisible into the Sokolovograptus (questionable), Gothograptus, Spinograptus, Plectograptus lineages, and Cometograptus. The Sokolovograptus group, the first retiolitids bearing ancora sleeve lists with seams facing out, did not survive the lundgreni crisis. The only survivors were Upper Wenlock retiolitids of the Gothograptus lineage. The new genus Cometograptus includes Cometograptus koreni n.gen. and n.sp., Cometograptus tomczyki n.gen. and n.sp., as well as the previously described Cometograptus nevadensis, Cometograptus marsupium and Cometograptus apoxys.

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