From the time it first became known to science (in 1993) until 2007 or 2008, it was considered a subspecies of the
western red colobus (
Procolobus badius) and more recently
Pennant's colobus (
Procolobus pennantii), and its trinomial name was
Procolobus badius epieni or
Procolobus pennantii epieni.
Colin Groves recognized the Niger Delta red colobus as a full species in 2007, although Groves considered all the red colobus monkeys, including the Niger Delta red colobus to be in the genus
Piliocolobus, rather than
Procolobus (this nomenclature has been followed here). However, other authors consider
Piliocolobus to be a
subgenus of
Procolobus. ==Description==