Clamp connection

It is used to maintain genetic variation within the hypha much like the mechanisms found in croziers (hooks) during the sexual reproduction of ascomycetes.

As the clamp continues to develop it uptakes one of the daughter (green circle) nuclei and separates it from its sister nucleus.

While this is occurring the remaining nuclei (orange circles) begin to migrate from one another to opposite ends of the cell.

[3][4] A fungal mycelium containing abundant clamp connections was found that dated to the Pennsylvanian era (298.9–323.2 Mya).

This fossil, classified in the form genus Palaeancistrus, has hyphae that compare with extant saprophytic basidiomycetes.