Como o segmento geralmente é nomeado como a tabela:
SELECT ut.table_name,
to_number(extractvalue(xmltype (dbms_xmlgen.getxml ('select count(*) c from ' ||ut.table_name)),'/ROWSET/ROW/C')) row_count,
db.blocks*8192/1024/1024 as MB,
db.tablespace_name
FROM user_tables ut
join dba_segments db on db.segment_name = ut.table_name
WHERE ut.table_name LIKE 'AUD_2012080%'
ORDER BY ut.table_name DESC
