Siberionautilidae [SEP] parent taxon
Siberionautilidae
Siberionautilidae is a family in the nautilid superfamily Clydonautiloidea that contains only the genus Siberionautilus, which comes from the Upper Triassic (Carnian) of Siberia, Russia.
The family, and genus, are characterized by an involute, globular shell covered by fine radial ribs, with flattened flanks that converge toward a rounded venter, distinct umbilicus with rounded shoulders, differentiated suture, and central siphuncle. The suture is goniatitic with the ventral or median saddle of the Clydonautilidae, subdivided so as to have a deep finger-like
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