diff --git a/utilities.py b/utilities.py
index 884563a542d76b1f3b88f8d762b16ade6a85d221..808e33e3126f629b00a71f9272fadb9279bc0b66 100755
--- a/utilities.py
+++ b/utilities.py
@@ -158,7 +158,8 @@ def get_unique_species_dict_list(sp_dict_list):
 
     for sp in sp_dict_list:
         gspecies = get_gspecies_string_from_sp_dict(sp)
-        if gspecies not in unique_species_dict.keys() or sp[constants.ORG_PARAM_DESC][constants.ORG_PARAM_DESC_MAIN_SPECIES] == True :
+        if gspecies not in unique_species_dict.keys() or ( constants.ORG_PARAM_DESC_MAIN_SPECIES in sp[constants.ORG_PARAM_DESC].keys() and
+                                                           sp[constants.ORG_PARAM_DESC][constants.ORG_PARAM_DESC_MAIN_SPECIES] == True ) :
             unique_species_dict[gspecies] = sp
         else:
             continue