Ptychagnostidae [SEP] parent taxon
Series 3 Epoch to the Paibian Age of the early Furongian Epoch in the Cambrian ( to million years ago). The earliest member of the family is "Ptychagnostus praecurrens" from the Burgess Shale fauna.
Taxonomy.
Ptychagnostidae is classified under the superfamily Agnostoidea of the suborder Agnostina, order Agnostida. The family was first established by the Japanese paleontologist Teiichi Kobayashi in 1939. Its name comes from the type genus, "Ptychagnostus", which is itself derived from Ancient Greek πτυχος ("ptychos", "folded"
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