Considering the species as a member of the
Callicebus moloch species group (Table 2), C. miltoni
differs from its closest geographically neighbor
C. bernhardi (Fig. 6) by the dark-ocher tone of the
sides of the face and throat, contrasting with the chest
and belly, rather than the brilliant orange of the latter
species; by the gray stripe on the forehead contrasting
with the darker gray on top of the head, not apparent
in C. bernhardi, and by the uniformly gray mid-dorsal
region, without the reddish tone of C. bernhardi.
Differs from its also closest geographically neighbor
C. cinerascens (Fig. 6) in all characters, including
the uniform gray pattern of the dorsal region, darkocher
sides of the face and light gray extremities,
rather than the general dark-gray pattern with reddish
mid-dorsum and darker extremities of C. cinerascens.
Differs from C. moloch by the dark-ocher sides of
the face rather than the brilliant orange, and by the
uniformly gray mid-dorsum, without the reddish
tone of C. moloch. Differs from C. vieirai in all
characters, including dark gray agouti forehead with
whitish stripe contrasting with the crown (white
or white-agouti in C. vieirai); dark ocher (orangebrown)
sideburns (white in C. vieirai); ocher neck,
orange-brown chest and light ocher (orange) belly
(uniformly light yellow to light orange underparts in
C. vieirai); and by the uniformly light ocher (orange)
tail (agouti with gray base, blackish middle and
whitish tip in C. vieirai). Differs from C. baptista by
the gray pattern of the dorsum, flanks and external
parts of members (dark gray in C. baptista), graywhite
member extremities and light-gray stripe of the