The order Rodentia may be divided into suborders, infraorders, superfamilies and families. Recently lepidopterists have abandoned clades like suborders, and those between orders and superfamilies. The Neobatrachia suborder is further divided into the two superfamilies Hyloidea and Ranoidea. The Ensifera, Caelifera and all the superfamilies of grasshoppers except Pamphagoidea appear to be monophyletic. Molecular biology has shown that the nicotinic and muscarinic receptors belong to distinct protein superfamilies. According to TCDB, there are five evolutionarily independent superfamilies of porins. These are marine gastropod molluscs in the superfamilies Aplysioidea and Akeroidea. Znf motifs occur in several unrelated protein superfamilies, varying in both sequence and structure. Like the Ensifera, Caelifera and all of its superfamilies appear to be monophyletic. Proteins with similar structures are grouped into a hierarchy of protein families, superfamilies, and folds. These persist today as 9 of the superfamilies of Lepidoptera. Helicases are classified in 6 groups (superfamilies) based on their shared sequence motifs. The same geometric arrangement of triad residues occurs in over 20 separate enzyme superfamilies. While functionally similar, the two primase superfamilies evolved independently of each other. Protein families are more closely related than superfamilies.