Titis, New World Monkeys
of the Genus Callicebus (Cebidae, Platyrrhini):
A Preliminary Taxonomic Review
Abstract
Tropical American titis. genus Callicebus (Ce-
bidae, Callicebinae), are described in terms of ex-
ternal, cranial, postcranial, dental, and cerebral
characters. Comparisons are made with other pla-
tyrrhines, including all other nonprehensile-tailed
cebids. As presently constituted, the genus consists
of 13 species and 16 included subspecies, each
described and defined here. The systematic ar-
rangement, in four species-groups roughly equiv-
alent to size groups from smallest to largest, is
based on trenchant morphological characters. The
modestus group consists of a single species which
appears to be the most primitive living cebid. The
donacophilus group, comprised of three species, is
nearer the moloch group, the latter with eight
species including dubius, and personatus, largest
of the genus. The geographic ranges of several
species of the moloch group overlap those of oth-
ers. The torquatus group contains a lone species
that differs grossly from all other cebids in its com-
bination of external, skeletal, and cytogenetic
characters.
I. Introduction
This is the sixth and last of a series of prelim-
inary and abridged taxonomic reviews of six gen-
era of the nonprehensile-tailed New World mon-
keys of the family Cebidae, comprising Volume 2
of Living New World Monkeys {Platyrrhini)
(Hershkovitz, in prep.). Preceding reviews by this
author were of Aotus (1983), Saimin (1984), Chi-
ropotes (1985), Cacajao (1987a) and Pithecia
(1987b). 1
Callicebus proves to be the most complex and
diversified genus of the platyrrhine group. In my
earlier review ( 1 963a), only three species were rec-
ognized; the number now is 13. The earlier study
was based on little more than 100 specimens, all
but a few in the collection of Field Museum of
Natural History. The present account results from
the study of nearly 1,200 specimens of Callicebus
preserved in 22 North American, South Ameri-
can, and European natural history collections. No
less important than the greater number of speci-
mens available for the present study was newly
gained cytological information, and insights into
evolutionary pathways in tegumentary coloration.
This preliminary report as in the case of the
earlier ones is intended to give advice of revised
taxonomic arrangements, descriptions of new
species and subspecies, and changes in scientific
nomenclature. Where appropriate, new ideas are
broached and controversial subjects explored. Be-
cause of limitations of time and space, the syn-
onymies are abridged and the taxonomic accounts
are reduced to the minimum required for accurate
identifications. A short article on titi behavior has
been published elsewhere (Hershkovitz, 1987c).
Studies on the origin, dispersal, and differentiation
of the species and subspecies of Callicebus have
been incorporated in an independent article
1 The dedication of Pithecia irrorata vanzolinii to Dr.
Paulo E. Vanzolini was inadvertently omitted from the
Pithecia revision (Hershkovitz, 1987). The naming is in
recognition of one of the most preeminent Brazilian sci-
entists, who has accorded unstinted attention and assis-
tance to me and every other scientist making use of the
natural history material preserved in the Universidade
de Sao Paulo Museu de Zoologia.
HERSHKOVITZ: CALLICEBUS TAXONOMY
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