Table 1.

Phylogenetic distribution of epidermal club cells in fishes.

Superclass	Class	Subclass	Infraclass/Division	Superorder	Order	Common Name	ECCs
Agnatha						Lamprey	Skein cells, which are distinct from club cells [31]
Gnathostoma	Chondrichthyes					Sharks, rays	Skein cells [32]
	Osteichthyes	Sarcopterygii				Coelacanth	Absent [33]
		Actinopterygii	Chondrostei		Polypteriformes	Reed fish	Present [34]
			Teleostei	Elopomorpha	Anguilliformes	Eels	Present [35]
				Ostariophysi	Gymnotiformes	Electric fishes	Secondary loss of ECCs due to electric sense [4,36]
					Gonorynchiformes	Milkfish	All possess ECCs [37]
					Siluriformes	Catfish	All possess ECCs [4,34,38,39,40,41,42,43,44,45,46]
					Characiformes	Characins	Most possess ECCs [4,47,48,49,50], absent in others [4]
					Cypriniformes	Minnows, zebrafish	All possess ECCs [4,24,41,51,52]
				Protacanthopterygii	Salmoniformes	Salmon, trout, charr	Possess ECCs [53], absent in others [24,54]
					Esociformes	Mudminnows, pike	Absent [55]
				Paracanthopterygii	Ophidiiformes	Pearlfish	Possess ECCs [44]
					Gadiformes	Cod	Possess ECCs [37]
				Protacanthopterygii *	Cyprinodontiformes	Pupfish, poolfish, mosquitofish	ECCs in low density [27,38], others lack them [56]
					Perciformes	Perch, walleye, darters, cichlids, sunfish	Some species have them, others lack them [25,50,55,57]
					Gasterosteiformes	Stickleback	Absent [4,58]
					Gobiiformes	Gobies	Some species have ECCs [59,60]
					Tetraodontiformes	Pufferfish	Some species have ECCs [61]

* Not all orders are listed to conserve space. Orders omitted from the table that do not have ECCs according to Pfeiffer [4]: Beloniformes (also [34]), Carangiformes, Anabantiformes, Blenniformes, Callionymiformes, Gobioesociformes, Labriformes, Mugiliformes, Ovalentaria, Pleuronectiformes, Scombriformes, Scorpaeniformes [62], Trachiniformes.