diff --git a/js/ActionIO.js b/js/ActionIO.js
index 4ec3c4c1..cb39c030 100644
--- a/js/ActionIO.js
+++ b/js/ActionIO.js
@@ -51,7 +51,8 @@ define( function( require ) {
     ActionIOImpl.documentation = 'Executes when an event occurs.';
     ActionIOImpl.events = [ 'emitted' ];
     ActionIOImpl.validator = ACTION_IO_VALIDATOR;
-    ActionIOImpl.typeName = `ActionIO.<${parameterTypes.map( param => param.typeName ).join( ', ' )}>`;
+    ActionIOImpl.typeName = `ActionIO<${parameterTypes.map( param => param.typeName ).join( ', ' )}>`;
+    ActionIOImpl.parameterTypes = parameterTypes;
     ObjectIO.validateSubtype( ActionIOImpl );
 
     return ActionIOImpl;
diff --git a/js/DerivedPropertyIO.js b/js/DerivedPropertyIO.js
index fe08ab0f..951d67d1 100644
--- a/js/DerivedPropertyIO.js
+++ b/js/DerivedPropertyIO.js
@@ -58,7 +58,7 @@ define( require => {
     DerivedPropertyIOImpl.documentation = 'Like PropertyIO, but not settable.  Instead it is derived from other DerivedPropertyIO or PropertyIO ' +
                                           'instances';
     DerivedPropertyIOImpl.validator = PROPERTY_IO_VALIDATOR;
-    DerivedPropertyIOImpl.typeName = `DerivedPropertyIO.<${parameterType.typeName}>`;
+    DerivedPropertyIOImpl.typeName = `DerivedPropertyIO<${parameterType.typeName}>`;
 
     // @public - allow type checking for DerivedPropertyIOImpl
     DerivedPropertyIOImpl.outerType = DerivedPropertyIO;
diff --git a/js/EmitterIO.js b/js/EmitterIO.js
index 37fe6734..d768d4f3 100644
--- a/js/EmitterIO.js
+++ b/js/EmitterIO.js
@@ -78,7 +78,7 @@ define( require => {
     EmitterIOImpl.documentation = 'Emits when an event occurs and calls added listeners.';
     EmitterIOImpl.parameterTypes = parameterTypes;
     EmitterIOImpl.validator = EMITTER_IO_VALIDATOR;
-    EmitterIOImpl.typeName = `EmitterIO.<${parameterTypes.map( param => param.typeName ).join( ', ' )}>`;
+    EmitterIOImpl.typeName = `EmitterIO<${parameterTypes.map( param => param.typeName ).join( ', ' )}>`;
     ObjectIO.validateSubtype( EmitterIOImpl );
 
     return EmitterIOImpl;
diff --git a/js/ObservableArrayIO.js b/js/ObservableArrayIO.js
index 4b810638..106b0ebb 100644
--- a/js/ObservableArrayIO.js
+++ b/js/ObservableArrayIO.js
@@ -118,8 +118,9 @@ define( require => {
     ObservableArrayIOImpl.documentation = 'An array that sends notifications when its values have changed.';
     ObservableArrayIOImpl.validator = OBSERVABLE_ARRAY_VALIDATOR;
     ObservableArrayIOImpl.events = [ 'itemAdded', 'itemRemoved' ];
-    ObservableArrayIOImpl.typeName = `ObservableArrayIO.<${parameterType.typeName}>`;
-    ObservableArrayIOImpl.parameterType = parameterType;
+    ObservableArrayIOImpl.typeName = `ObservableArrayIO<${parameterType.typeName}>`;
+    ObservableArrayIOImpl.parameterType = parameterType; // TODO: I hope we can get rid of this, https://github.com/phetsims/phet-io/issues/1371
+    ObservableArrayIOImpl.parameterTypes = [ parameterType];
     ObjectIO.validateSubtype( ObservableArrayIOImpl );
 
     return ObservableArrayIOImpl;
diff --git a/js/PropertyIO.js b/js/PropertyIO.js
index 588dbba6..146655ee 100644
--- a/js/PropertyIO.js
+++ b/js/PropertyIO.js
@@ -163,8 +163,9 @@ define( require => {
     PropertyIOImpl.methodOrder = [ 'link', 'lazyLink' ];
     PropertyIOImpl.validator = { valueType: Property };
     PropertyIOImpl.events = [ 'changed' ];
-    PropertyIOImpl.typeName = `PropertyIO.<${parameterType.typeName}>`;
-    PropertyIOImpl.parameterType = parameterType;
+    PropertyIOImpl.typeName = `PropertyIO<${parameterType.typeName}>`;
+    PropertyIOImpl.parameterType = parameterType; // TODO: I hope we can get rid of this, https://github.com/phetsims/phet-io/issues/1371
+    PropertyIOImpl.parameterTypes = [ parameterType];
     ObjectIO.validateSubtype( PropertyIOImpl );
 
     return PropertyIOImpl;