Saguinus midas (Linnaeus)

VOSS, ROBERT S., LUNDE, DARRIN P. & SIMMONS, NANCY B., 2001, The Mammals Of Paracou, French Guiana: A Neotropical Lowland Rainforest Fauna Part 2. Nonvolant Species, Bulletin of the American Museum of Natural History 2001 (263), pp. 1-236 : 67-68

Saguinus midas (Linnaeus)

VOUCHER MATERIAL: AMNH 266481 , 266482 ; MNHN 1998.699 . Total = 3 specimens .

IDENTIFICATION: Our three vouchers correspond exactly with Husson’s (1978) detailed description of this species, which was based on topotypic material from Surinam. In particular, the diagnostic external markings of golden­handed tamarins—bright orange (sometimes reddish or yellow) hands and feet that contrast with the blackish limbs—are conspicuous in our vouchers as they are in all specimens referred to this taxon throughout the Guiana subregion of Amazonia (Hershkovitz, 1977). For comparison with published measurement data (Husson, 1957, 1978; Napier, 1976; Hershkovitz, 1977), selected external and craniodental dimensions (mm) of our two adult female vouchers are: head­and­body length 258, 285; length of tail 425, 440; length of hindfoot 77, 80; ear 36, 37; condylobasal length 38.9, 41.2; orbital breadth 28.7, 29.1; postorbital constriction 24.3, 25.6; zygomatic breadth 33.3, 34.8; maxillary toothrow (crown length C–M2) 12.8, 12.9.

The black­handed tamarins that occur south of the Amazon and east of the Xingu (including Ilha de Marajo´) were long considered to be a distinct species from the goldenhanded tamarins of the Guiana subregion (e.g., by Elliot, 1912; Cruz Lima, 1945; Hill, 1957; Cabrera, 1961). Hershkovitz ( 1977), however, treated golden­ and black­handed tamarins as no more than subspecifically distinct; according to this authority, the correct name for the golden­handed Guianan tamarins is Saguinus midas midas (Linnaeus) , whereas the black­handed tamarins of south­ eastern Amazonia should be called S. midas niger (E. Geoffroy) . Apparently, the only published justification for treating these unequivocally diagnosable taxa as conspecific is the following (Hershkovitz, 1977: 207):

The color of the cheiridia dictates the proffered hypothesis of racial differentiation. The pheomelanic or eumelanic cheiridia can be derived directly from the primitive agouti colored cheiridia... and either of the saturate patterns can switch to the other. Furthermore, presence of callitrichids on the Ilha de Marajó... discounts the probability of one race arising from the stock of another. It remains to be determined if tamarins with agouti cheiridia still persist on any of the innumerable islands of the lower Amazon.

Apparently, Hershkovitz judged the chromatic differences between midas (sensu stricto) and niger to be evolutionarily labile and predicted the existence of an extinct (or undiscovered) form that was (or is) intermediate in coloration and geography. However, the constancy of tamarin markings on opposite sides of the Amazon suggests that the character transformation in question is not evolutionarily labile, nor have populations with intermediate phenotypes yet been reported from any Amazonian islands.

According to Hershkovitz, only the coloration of the hands and feet distinguishes midas from niger , but his monograph contains no explicit comparison of these taxa in nonpelage characters. By contrast, subsequent research has shown that midas and niger have divergent dental measurements (Natori and Hanihara, 1992) and β 2 ­microglobulin DNA sequences (Canavez et al., 1999). Indeed, parsimony analysis of the β 2 ­microglobulin data provides compelling evidence that midas is more closely related to another species that occurs north of the Amazon, S. bicolor (Spix) , than it is to niger on the opposite bank (Canavez et al., 1999).

In view of (1) the diagnosability of golden­ and black­handed tamarins by bold and consistent pelage markings, (2) the existence of correlated divergence in nonpelage characters, and (3) clear indications from phylogenetic analysis that these taxa are not sister taxa, the currently accepted use of midas and niger as subspecies (Hershkovitz, 1977) or synonyms (Groves, 1993) is not defensible. Instead, we recognize the golden­handed tamarins of the Guiana subregion, Saguinus midas , as a species distinct from the blackhanded tamarins of southeastern Amazonia historically known by authors as S. niger , S. tamarin , or S. ursulus (see below).

REMARKS: Whereas most early authors used the epithets tamarin Link or ursulus Hoffmannsegg for the black­handed tamarin of southeastern Amazonia, Hershkovitz ( 1977) argued that the oldest applicable name for the zoological taxon in question is niger E. Geoffroy. Confusingly , the holotype of niger was clearly stated to have come from Cayenne (Geoffroy, 1803), far from the known range of black­handed tamarins. Although Hershkovitz reassigned the type locality to Belém, he did not examine Geoffroy’s specimen, the identity of which is obviously problematic. Unfortunately, the holotype of niger (No. XXIV in Geoffroy’s catalog) is lost: it was not listed in Rode’s (1938) catalog of MNHN primate types, and it is not part of the current Paris museum collection (M. Tranier, personal commun.). Whether the original specimen of Geoffroy’s niger was a melanistic individual of the golden­handed species collected at Cayenne or was a mislabelled example of the blackhanded species is now impossible to determine. Nevertheless, the black­handed species is now widely and consistently known by the epithet niger E. Geoffroy , a usage that should be preserved in the interest of taxonomic stability. For that purpose, we hereby designate as neotype of Sagouin niger E. Geoffroy, 1803 , an adult male specimen represented by a well­preserved skin and skull in the American Museum of Natural History, AMNH 96500, collected by A. M. Olalla on 2 November 1931 at Cametá on the Rio Tocantins, Para´, Brazil, from which locality a large series of topotypes is also available.

OTHER SPECIMENS EXAMINED: Guyana — Cuyuni ­Mazaruni, Kartabo (AMNH 65159, 142936).

FIELD OBSERVATIONS: This is the commonest primate species at Paracou. We saw groups of tamarins daily, in both swampy and well­drained primary forest and in roadside secondary growth. In primary forest, tamarins were invariably sighted in the canopy or subcanopy, but we often saw them descend to within a few meters of the ground in roadside secondary growth; occasionally, groups were seen crossing dirt roads on the ground when the gap between trees on either side was too wide to leap. Unlike other primate species at Paracou, tamarins did not noticeably decline in density from 1991 to 1994, probably because they are not locally hunted for meat.