Mothur "list" file
See also
Making an OTU table (otutab command)
Mothur "shared" file
Mothur "names" file
1. Clustering identity given as fractional difference, e.g. 0.03 is 97%.
2. Number of OTUs.
3, 4, 5... Labels for each OTU. Labels for a given OTU are separated by commas.