diff --git a/masque/utils/vertices.py b/masque/utils/vertices.py
index 176f0f5..f830696 100644
--- a/masque/utils/vertices.py
+++ b/masque/utils/vertices.py
@@ -43,7 +43,7 @@ def remove_colinear_vertices(vertices: ArrayLike, closed_path: bool = True) -> N
     Returns:
         `vertices` with colinear (superflous) vertices removed. May be a view into the original array.
     """
-    vertices = remove_duplicate_vertices(vertices)
+    vertices = remove_duplicate_vertices(vertices, closed_path=closed_path)
 
     # Check for dx0/dy0 == dx1/dy1