diff --git a/src/flib/pio_types.F90 b/src/flib/pio_types.F90
index b0bd4e05718..aeba6349b7a 100644
--- a/src/flib/pio_types.F90
+++ b/src/flib/pio_types.F90
@@ -1,7 +1,7 @@
 !>
 !! @file
 !! Derived datatypes and constants for PIO Fortran API.
-!!
+!! @author Jim Edwards
 !<
 !>
 !! @private
@@ -39,17 +39,13 @@
 !!  - PIO_real : 4-byte reals
 !!  - PIO_int :  4-byte integers
 !!  - PIO_char : character
-!<
 
 module pio_types
   use pio_kinds
   use iso_c_binding
   implicit none
   private
-  !-------------------------------------------
-  !  data structure to describe decomposition
-  !-------------------------------------------
-  type, public :: DecompMap_t
+  type, public :: DecompMap_t !< data structure to describe decomposition.
 #ifdef SEQUENCE
      sequence
 #endif
@@ -57,49 +53,29 @@ module pio_types
      integer(i4) :: length !< length
   end type DecompMap_t
 
-  !------------------------------------
-  !  a file descriptor data structure
-  !------------------------------------
   !>
   !! @struct iosystem_desc_t
-  !! @brief A defined PIO system descriptor created by @ref PIO_init (see pio_types)
-  !<
+  !! A defined PIO system descriptor created by @ref PIO_init (see
+  !! pio_types).
   type, public :: IOSystem_desc_t
      integer(kind=c_int) :: iosysid = -1 !< iosysid
   end type IOSystem_desc_t
 
-  !>
-  !! @private
-  !! @struct io_data_list
-  !! @brief Linked list of buffers for pnetcdf non-blocking interface
-  !>
-  !    type, public :: io_data_list
-  !       integer :: request
-  !       real(r4), pointer :: data_real(:) => null()
-  !       integer(i4), pointer :: data_int(:) => null()
-  !       real(r8), pointer :: data_double(:) => null()
-  !       type(io_data_list), pointer :: next => null()
-  !    end type io_data_list
-
-
   !>
   !! @public
   !! @struct file_desc_t
-  !! @brief File descriptor returned by \ref PIO_openfile or \ref PIO_createfile (see pio_types)
-  !!
-  !>
+  !! File descriptor returned by \ref PIO_openfile or \ref
+  !! PIO_createfile (see pio_types).
   type, public :: File_desc_t
      integer(kind=c_int) :: fh !< file handle
      type(iosystem_desc_t), pointer :: iosystem => null() !< iosystem
   end type File_desc_t
 
-
   !>
   !! @public
   !! @struct io_desc_t
-  !! @brief  An io descriptor handle that is generated in @ref PIO_initdecomp
+  !! An decomposition handle that is generated in @ref PIO_initdecomp.
   !! (see pio_types)
-  !<
   type, public :: io_desc_t
 #ifdef SEQUENCE
      sequence
@@ -110,8 +86,8 @@ module pio_types
   !>
   !! @public
   !! @struct var_desc_t
-  !! @brief A variable descriptor returned from @ref PIO_def_var (see pio_types)
-  !<
+  !! A variable descriptor returned from @ref PIO_def_var (see
+  !! pio_types).
   type, public :: Var_desc_t
 #ifdef SEQUENCE
      sequence
@@ -124,7 +100,7 @@ module pio_types
        PIO_iotype_pnetcdf = 1, &   !< parallel read/write of pNetCDF files
        PIO_iotype_netcdf  = 2, &   !< serial read/write of NetCDF file using 'base_node'
        PIO_iotype_netcdf4c = 3, &  !< netcdf4 (hdf5 format) file opened for compression (serial write access only)
-       PIO_iotype_netcdf4p = 4     !< netcdf4 (hdf5 format) file opened in parallel (all netcdf4 files for read will be opened this way)
+       PIO_iotype_netcdf4p = 4     !< netcdf4 (hdf5 format) file opened in parallel
 
 
   ! These are for backward compatability and should not be used or expanded upon
@@ -144,35 +120,17 @@ module pio_types
 
   !>
   !! @struct use_PIO_kinds
-  !! @brief The type of variable(s) associated with this iodesc.
+  !! The type of variable(s) associated with this iodesc.
   !! @copydoc PIO_kinds
-  !<
 
 #ifdef _PNETCDF
-#include <pnetcdf.inc>   /* _EXTERNAL */
-  integer, public, parameter :: PIO_global = nf_global       !< global atts
-  integer, public, parameter :: PIO_unlimited = nf_unlimited !< unlimited dimension
-  integer, public, parameter :: PIO_double = nf_double       !< double type
-  integer, public, parameter :: PIO_real   = nf_real         !< real type
-  integer, public, parameter :: PIO_int    = nf_int          !< int type
-  integer, public, parameter :: PIO_char   = nf_char         !< char type
-  integer, public, parameter :: PIO_noerr  = nf_noerr        !< no error
-  integer, public, parameter :: PIO_WRITE  = nf_write        !< read-write
-  integer, public, parameter :: PIO_nowrite  = nf_nowrite    !< read-only
-  integer, public, parameter :: PIO_CLOBBER = nf_clobber     !< clobber existing file
-  integer, public, parameter :: PIO_NOCLOBBER = nf_NOclobber !< do not clobber existing file
-  integer, public, parameter :: PIO_NOFILL = nf_nofill       !< do not use fill values
-  integer, public, parameter :: PIO_MAX_NAME = nf_max_name   !< max name len
-  integer, public, parameter :: PIO_MAX_VAR_DIMS = min(6,nf_max_var_dims) !< max dims for a var
-  integer, public, parameter :: PIO_64BIT_OFFSET = nf_64bit_offset        !< 64bit offset format
+#include <pnetcdf.inc>
   integer, public, parameter :: PIO_64BIT_DATA = nf_64bit_data            !< CDF5 format
-  integer, public, parameter :: PIO_FILL_INT = nf_fill_int;               !< int fill value
-  real, public, parameter :: PIO_FILL_FLOAT = nf_fill_float;              !< float fill value
-  double precision, public, parameter :: PIO_FILL_DOUBLE = nf_fill_double; !< double fill value
-
 #else
-#ifdef _NETCDF
-#include <netcdf.inc>   /* _EXTERNAL */
+#include <netcdf.inc>
+  integer, public, parameter :: PIO_64BIT_DATA = 0            !< CDF5 format
+#endif
+  integer, public, parameter :: PIO_num_OST =  16 !< num ost
   integer, public, parameter :: PIO_global = nf_global       !< global atts
   integer, public, parameter :: PIO_unlimited = nf_unlimited !< unlimited dimension
   integer, public, parameter :: PIO_double = nf_double       !< double type
@@ -181,38 +139,16 @@ module pio_types
   integer, public, parameter :: PIO_char   = nf_char         !< char type
   integer, public, parameter :: PIO_noerr  = nf_noerr        !< no error
   integer, public, parameter :: PIO_WRITE  = nf_write        !< read-write
-  integer, public, parameter :: PIO_nowrite = nf_nowrite     !< read-only
+  integer, public, parameter :: PIO_nowrite  = nf_nowrite    !< read-only
   integer, public, parameter :: PIO_CLOBBER = nf_clobber     !< clobber existing file
   integer, public, parameter :: PIO_NOCLOBBER = nf_NOclobber !< do not clobber existing file
   integer, public, parameter :: PIO_NOFILL = nf_nofill       !< do not use fill values
   integer, public, parameter :: PIO_MAX_NAME = nf_max_name   !< max name len
   integer, public, parameter :: PIO_MAX_VAR_DIMS = min(6,nf_max_var_dims) !< max dims for a var
   integer, public, parameter :: PIO_64BIT_OFFSET = nf_64bit_offset        !< 64bit offset format
-  integer, public, parameter :: PIO_64BIT_DATA = 0                        !< CDF5 format
   integer, public, parameter :: PIO_FILL_INT = nf_fill_int;               !< int fill value
   real, public, parameter :: PIO_FILL_FLOAT = nf_fill_float;              !< float fill value
   double precision, public, parameter :: PIO_FILL_DOUBLE = nf_fill_double; !< double fill value
-#else
-  integer, public, parameter :: PIO_global = 0  !< global atts
-  integer, public, parameter :: PIO_double = 6  !< double type
-  integer, public, parameter :: PIO_real   = 5  !< real type
-  integer, public, parameter :: PIO_int    = 4  !< int type
-  integer, public, parameter :: PIO_char   = 2  !< char type
-  integer, public, parameter :: PIO_noerr  = 0  !< no error
-  integer, public, parameter :: PIO_MAX_NAME = 25    !< max name len
-  integer, public, parameter :: PIO_MAX_VAR_DIMS = 6 !< max dims for a var
-  integer, public, parameter :: PIO_CLOBBER = 10     !< clobber existing file
-  integer, public, parameter :: PIO_NOCLOBBER = 11   !< do not clobber existing file
-  integer, public, parameter :: PIO_WRITE = 20       !< read-write
-  integer, public, parameter :: PIO_NOWRITE = 21     !< read-only
-  integer, public, parameter :: PIO_64BIT_OFFSET = 0 !< 64bit offset format
-  integer, public, parameter :: PIO_64BIT_DATA = 0   !< CDF5 format
-  integer, public, parameter :: PIO_FILL_INT = -2147483647;  !< int fill value
-  real, public, parameter :: PIO_FILL_FLOAT =  9.9692099683868690e+36; !< float fill value
-  double precision, public, parameter :: PIO_FILL_DOUBLE = 9.9692099683868690e+36; !< double fill value
-#endif
-#endif
-  integer, public, parameter :: PIO_num_OST =  16 !< num ost
 
   enum, bind(c)
      enumerator :: PIO_rearr_comm_p2p = 0
@@ -243,13 +179,12 @@ module pio_types
   !!                    number of requests use PIO_REARR_COMM_UNLIMITED_PEND_REQ)
   !!
   !! @defgroup PIO_rearr_options Rearranger Options
-  !! @brief Type that defines the PIO rearranger options
-  !! @details
+  !! Type that defines the PIO rearranger options.
+  !!
   !!  - comm_type : @copydoc PIO_rearr_comm_t
   !!  - fcd : @copydoc PIO_rearr_comm_dir
   !!  - comm_fc_opts_comp2io : @copydoc PIO_rearr_comm_fc_options
   !!  - comm_fc_opts_io2comp : @copydoc PIO_rearr_comm_fc_options
-  !>
   enum, bind(c)
      enumerator :: PIO_rearr_comm_fc_2d_enable = 0 !< COMM procs to IO procs and vice versa.
      enumerator :: PIO_rearr_comm_fc_1d_comp2io !< COMM procs to IO procs only.