Wouldnt you just query the data dictionary with your start/end ID's to map it back to the chunk ?
SQL> create table t as select * from dba_objects;
Table created.
SQL>
SQL> begin
2 dbms_parallel_execute.create_task (task_name => 'blah');
3 dbms_parallel_execute.create_chunks_by_rowid(
4 task_name => 'blah',
5 table_owner => user,
6 table_name => 'T',
7 by_row => true,
8 chunk_size => 20000);
9 end;
10 /
PL/SQL procedure successfully completed.
SQL>
SQL> select chunk_id, start_rowid, end_rowid
2 from user_parallel_execute_chunks
3 where task_name = 'blah'
4 order by chunk_id;
CHUNK_ID START_ROWID END_ROWID
---------- ------------------ ------------------
374201 AAAqsDAAGAAAs1oAAA AAAqsDAAGAAAs1vCcP
374202 AAAqsDAAGAAAs1wAAA AAAqsDAAGAAAs13CcP
374203 AAAqsDAAGAAAtOAAAA AAAqsDAAGAAAtOHCcP
374204 AAAqsDAAGAAAtOIAAA AAAqsDAAGAAAtOPCcP
374205 AAAqsDAAGAAAtOQAAA AAAqsDAAGAAAtOXCcP
374206 AAAqsDAAGAAAtOYAAA AAAqsDAAGAAAtOfCcP
374207 AAAqsDAAGAAAtOgAAA AAAqsDAAGAAAtOnCcP
374208 AAAqsDAAGAAAtOoAAA AAAqsDAAGAAAtOvCcP
374209 AAAqsDAAGAAAtOwAAA AAAqsDAAGAAAtO3CcP
374210 AAAqsDAAGAAAtO4AAA AAAqsDAAGAAAtO/CcP
374211 AAAqsDAAGAAAtPAAAA AAAqsDAAGAAAtPHCcP
374212 AAAqsDAAGAAAtPIAAA AAAqsDAAGAAAtPPCcP
374213 AAAqsDAAGAAAtPQAAA AAAqsDAAGAAAtPXCcP
374214 AAAqsDAAGAAAtPYAAA AAAqsDAAGAAAtPfCcP
374215 AAAqsDAAGAAAtPgAAA AAAqsDAAGAAAtPnCcP
374216 AAAqsDAAGAAAtPoAAA AAAqsDAAGAAAtPvCcP
374217 AAAqsDAAGAAAtQAAAA AAAqsDAAGAAAtR/CcP
374218 AAAqsDAAGAAAtSAAAA AAAqsDAAGAAAtT/CcP
374219 AAAqsDAAGAAAtUAAAA AAAqsDAAGAAAtV/CcP
374220 AAAqsDAAGAAAtWAAAA AAAqsDAAGAAAtX/CcP
374221 AAAqsDAAGAAAtYAAAA AAAqsDAAGAAAtZ/CcP
374222 AAAqsDAAGAAAtaAAAA AAAqsDAAGAAAtb/CcP
374223 AAAqsDAAGAAAtcAAAA AAAqsDAAGAAAtd/CcP
374224 AAAqsDAAGAAAteAAAA AAAqsDAAGAAAtf/CcP
374225 AAAqsDAAGAAAtgAAAA AAAqsDAAGAAAth/CcP
374226 AAAqsDAAGAAAtiAAAA AAAqsDAAGAAAtj/CcP
374227 AAAqsDAAGAAAtkAAAA AAAqsDAAGAAAtl/CcP
374228 AAAqsDAAGAAAtmAAAA AAAqsDAAGAAAtn/CcP
374229 AAAqsDAAGAAAtoAAAA AAAqsDAAGAAAtp/CcP
29 rows selected.
SQL>
So you would query user_parallel_execute_chunks.
Hope this helps