Trachynautilus [SEP] parent taxon
Trachynautilus
Trachynautilus is a member of the Tainoceratidae, named by Mojsisovics in 1902, with longitudial ridges on the flanks of its high-arched involute shell. "Phloiocedas" from the Upper Triassic of North America is similar except that its venter also has longitudinal ridges. "Trachynautilus" from the middle and Upper Triassic of Europe has a smooth venter.
References.
- Bernhard Kummerl, 1964. Nautiloidea-Nautilida. Treatise on Invertebrate Paleontology Part K. Geological Society of America and University of Kansas Press.
Taxon in disguise
In bacteriology, a taxon in disguise is a species, genus or higher unit of biological classification whose evolutionary history reveals has evolved from another unit of similar or lower rank, making the parent unit paraphyletic. This happens when rapid evolution makes a new species appear radically different from the ancestral group, so that it is not (initially) recognised as belonging to the parent phylogenetic group, leaving the latter an evolutionary grade.
While the term is from bacteriology, parallel examples are found throughout the tree of