A Taxonomic Review of the Titi Monkeys, Callicebus Thomas 1903 NEOTROPICAL PRIMATES: A Journal of the Neotropical Section of the IUCN/SSC Primate Specialist Group Volume 10 Supplement June 2002 Editors Anthony B. Rylands Ernesto Rodriguez-Luna [This supplement includes the work of artist/illustrator, Stephen Nash. His superb drawings and color rendering are a real prize. Included is a Nash poster "The Titi Monkeys." On the poster you will find his namesake Callicebus stephennashi. lj/wrprc] INTRODUCTION The titi monkeys of the genus Callicebus are a diverse group of Neotropical monkeys found mainly in the tropical forests of the Amazon and Orinoco basins, but also extending into the Atlantic forest region of Brazil, and the Chaco and dry forests of Paraguay and Bolivia as far south as the Rios Pilcomayo and Paraguay. They are small to medium in size, roughly between the tamarins and the pitheciines, weighing 1-2 kilograms, and ranging from 270-450 mm in headbody length (Hershkovitz, 1990). Locomotion consists mainly of quadrupedal walking, climbing and leaping. All modern revisions of this genus were by Hershkovitz, the first being in 1963, followed by two other major papers in 1988 and 1990. These were followed by a study by Kobayashi (1995) and the description of a new species from the Atlantic forest by Kobayashi and Langguth (1999). Once considered a moderately diverse Neotropical genus, Callicebus is now emerging as one of the most diverse of all primate genera, competing with Saguinus for the largest number of taxa in the New World. In Hershkovitz's (1963) revision, he recognized only two species from the Amazon and Orinoco river basins, Callicebus moloch with seven subspecies and Callicebus torquatus with three subspecies, including one, Callicebus torquatus medemi, described in that paper. He did not treat Atlantic forest Callicebus personatus in 1963, but indicated that the three subspecies there might be conspecific with Callicebus moloch. Consequently, the number of Callicebus taxa recognized as of 1963 was 13. In 1988, Hershkovitz published a more detailed revision of the Callicebus in which he divided the genus into four species groups (Callicebus modestus, Callicebus donacophilus, Callicebus moloch, and Callicebus torquatus), with 13 species and 24 taxa, nearly double what was recognized in 1963. This increase resulted mainly from the resurrection of a number of taxa described earlier in the 20th century by Thomas (1907, 1908, 1917, 1924, 1927) and Lonnberg (1939) (modestus, pallescens, olallae, oenanthe, cinerascens, baptista, lucifer, regulus, purinus), and one by Wagner (1842; caligatus), but also included the description of a new form, Callicebus dubius. In addition, four of the taxa recognized as subspecies of Callicebus moloch in Hershkovitz (1963) were elevated to full species status (donacophilus, hoffmannsi, brunneus, cupreus), whereas three others continued to be considered subspecies (baptista, discolor, ornatus). All taxa of Callicebus torquatus were treated as subspecies, including the three recognized in 1963 (torquatus, lugers, medemi) and the three resurrected from Thomas' earlier papers (lucifer, regulus, purinus). Hershkovitz appears to have decided whether a given taxon was a full species or just a subspecies based mainly on distributional evidence indicating partial sympatry. Finally, in 1990, Hershkovitz published his final contribution to Callicebus taxonomy, a full revision in which he recognized the same four species groups, 13 species and 24 taxa, but adding a new subspecies of Callicebus personatus, C. p. barbarabrownae, for a total of 25. Although a thorough review of the genus, this publication included only a handful of color illustrations and a number of black and white photographs of skins and live animals, the latter mostly by Mittermeier, many of them published again here in color along with many new color photographs. Given the importance of coloration in these animals, we believe it essential that color illustrations be provided for all taxa. This we have done here by providing both pencil drawings of every taxon and photographs of live animals wherever available. Since 1990, the only addition to our knowledge of Callicebus taxonomy has been a review by Kobayashi(1995) and a paper by Kobayashi and Langguth (1999), in which they described a new Callicebus from the state of Sergipe in northeastern Brazil, Callicebus coimbrai. In his 1995 paper, Kobayashi reviewed the taxonomy of the genus based mainly on cranial measurements, and made several modifications to Hershkovitz's earlier breakdown of species into clades. Groves (2001), although largely following Hershkovitz (1990), also made some decisions on Callicebus taxonomy. In particular, he decided that C. moloch and C. cinerascens are distinct; that C. brunneus, C. hoffmannsi hoffmannsi, C. hoffmannsi baptista, and C. moloch are four full species; that C. caligatus and C. cupreus cupreus are essentially the same; and that C. dubius is not distinct at all. We are in agreement with his first two observations, but disagree with the second two, continuing to recognize C. caligatus and C. dubius as distinct species. Like Hershkovitz (1990), he placed them in four species groups (C. modestus, C. donacophilus, C. moloch (including C. personatus), and C. torquatus), but increased the number of species to 15, while reducing the total number of taxa to 24. He recognized all members of the C. modestus and C. donacophilus groups and all members of his C. moloch group except for C. personatus as full species. With C. personatus, he recognized four of the five taxa as subspecies, but agreed with Kobayashi and Langguth (1999) that C. coimbrai is a distinct species. With the C. torquatus group, he elevated C. medemi to full species status, but continued to list the other five taxa as subspecies. In this paper, we provide a thorough reanalysis of the genus Callicebus, complete with distribution maps and color illustrations of each taxon. In addition, we describe two new species from central Brazilian Amazonia, Callicebus bernhardi and Callicebus stephennashi. Together with Kobayashi and Langguth's new taxon, Callicebus coimbrai, these new animals raise the total number of Callicebus to 28, second only to the 33 taxa of Saguinus (Rylands et al., 2000) among New World primate genera. Furthermore, since we increasingly find the concept of subspecies to be of minimal value in describing the diversity of Neotropical primates, we have elevated all Callicebus to full species status. To enable the reader to better comprehend the evolution of Callicebus taxonomy over the past 40 years, we also provide a comparative table listing the Callicebus taxa recognized by Hershkovitz in 1963, 1988 and 1990, Kobayashi in 1995 (including Kobayashi and Langguth, 1999), Groves in 2001, and in this paper (Table 1). WHERE TO ORDER Jill Lucena Conservation International 1919 M. St. NW, Suite 600 Washington, DC 20036 Telephone: (202)912-1000/1208 Toll-free (within the U.S.): (800) 406-2306 http://www.biodiversityscience.org/xp/CABS/home Book received: 9-04-02 Posted date: 9-12-02
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