diff --git a/modules/meryl/unionsum/meta.yml b/modules/meryl/unionsum/meta.yml
index 04dabac1..cea7f0f6 100644
--- a/modules/meryl/unionsum/meta.yml
+++ b/modules/meryl/unionsum/meta.yml
@@ -35,6 +35,7 @@ output:
   - meryl_db:
       type: directory
       description: A Meryl k-mer database that is the union sum of the input databases
+      pattern: "*.unionsum.meryldb"
 
 authors:
   - "@mahesh-panchal"