Uacaries, new world monkeys of the genus Cacajao(Cebidae, Platyrrhini): A preliminary taxonomic review with the description of a new subspecies.

The two known species of uacaries, inhabitants of the upper Amazonian region, are the black head Cacajao melanocephalus with subspecies C. m. melanocephalus Humboldt and C.

The taxonomy of south American sakis, genus Pithecia (Cebidae, Platyrrhini): A preliminary report and critical review with the description of a new species and a new subspecies.

The report begins with a key based on external characters and a tabulation of diagnostic cranial characters for separating Pithecia from Chiropotes and Cacajao of the subfamily Pitheciinae. The description of Pithecia is based on external, cranial, dental, and certain postcranial characters with particular attention to limb proportions and the femoral third trochanter. The species of Pithecia are arranged in the Pithecia pithecia group with P.

Taxonomy of squirrel monkeys genus Saimiri (cebidae, platyrrhini): A preliminary report with description of a hitherto unnamed form.

Two groups of squirrel monkeys, genus Saimiri, are distinguished by external characters. The first, or Roman type, contains Saimiri boliviensis of upper Amazonia south of the Rio Marañón-Amazonas, with two subspecies of which S. boliviensis peruviensis is described as new.

More on the Homunculus Dpm and M and comparisons with Alouatta and Stirtonia (primates, platyrrhini, cebidae).

The little-worn deciduous fourth premolar and first molar of a mandibular fragment of Homunculus sp are compared with the cast of a previously described deciduous lower fourth premolar of Homunculus grandis and with lower molariform teeth of Alouatta and Stirtonia. Lower molars of Alouatta can be derived from those like Homunculus, but because of the fragmentary nature of the fossils, it cannot be demonstrated that Alouatta evolved from Homunculus or is even closely related. Comparison of mandibles and upper and lower molariform teeth of Alouatta with those of Stirtonia indicate wide divergence from some distant, possibly basic platyrrhine stock.

Two new species of night monkeys, genus Aotus (Cebidae, platyrrhini): A preliminary report on Aotus taxonomy.

The nine allopatric species of Aotus recognized represent two natural groups distinguished by karyotype, color, and pelage patterns. Correlated with these group characters are reported differences in serum proteins and degrees of susceptibility or immunity to experimental infection with malarial parasites. The primitive gray-neck species group of Aotus contains A.