The marmoset genus Mico comprises 14 species, 13 of which are endemic to Brazil (Rylands et al., 2009; Ferrari et al., 2010). Mico emiliae was described by Thomas (1920) based on two specimens collected by Emilia Snethlage in the Rio Curuá, a tributary of the Rio Iriri, that is an affluent of the Rio Xingu (Thomas, 1920; Vivo, 1985). Mico emiliae is restricted to the region between the Rio Curuá and Rio Iriri to the north, reaching the Rio Teles Pires to the west (Pimenta and Silva Jr., 2005; Fialho, 2010). The southern limit of the distribution remains unconfirmed but has been proposed by Roosmalen et al. (2000) to lie between the Xingú headwaters region and the eastern (or right) margin of the Upper Rio Teles Pires. Besides the aforementioned distribution, M. emiliae was believed to occur westwards, in the Madeira/Aripuanã interfluvium (Alperin, 1993; Ferrari and Lopes, 1992; Vivo, 1985, 1991). The form from this region, however, has now been described as a new species, M. rondoni (Ferrari et al., 2010). In this note, I report the first record of M. emiliae south of the Rio Teles Pires and Rio Iriri interfluvium, in the Xingú headwaters region, and provide an updated map of the known occurrence records of M. emiliae.

After reviewing the published records of M. emiliae and analyzing 12 museum specimens housed in the Museu de Zoologia da Universidade de São Paulo, São Paulo (MZUSP) and Museu Paraense Emílio Goeldi, Belém (MPEG) zoological collections, a total of seven locality records of M. emiliae were found (Figure 1). Pimenta and Silva Jr. (2005) cited the record from Vieira (1955) as distinct from Thomas (1920), but both publications refer to the type locality of M. emiliae. The new record is based on a stuffed skin, with separated skull and postcranial skeleton (field number PEV 1194–1195, voucher number MZUSP 35106), collected in the municipality of Cláudia (10°30′S, 54°53′ W, 345m) (Figure 1) by Marilia Kerr in 24.vii.1997. The determination of the species was based on diagnostic characters described in the literature (Vivo, 1991; Ferrari et al., 2010). According to the field notes made by the collector, the animal was run over by a vehicle while crossing the MT-423 highway (the label identifies it as “MT-427”, but since this road does not exist, and MT-423 passes through the municipality of Cláudia, I assume that the collector was referring to this highway) and was previously identified as Callithrix melanura. The collecting locality lies on a particular region, on the southeastern limit of the Brazilian Amazon Forest that can be classified phytogeographically as “Evergreen Seasonal Forest” (Ivanauskas et al., 2008).

Figure 1.

Map showing the known records of Mico emiliae. The grey area indicates the putative distribution of the species according to Ryhnds et al. (2009). 1. Cláudia (11°30′S, 54°53′W) (new record); *2. Fazenda São José, Peixoto de Azevedo (10°06′S, 55°31′W) (ÁvilaPires, 1986); 3. Alta Floresta (09°52′S, 56°05′W) (Ferrari et at., 2010); 4. Ourolândia, Alta Floresta (09°29′S, 56°22′W) (Ferrari et at., 2010); 5. Serra do Cachimbo (09°22′S, 55°00′W) (Pimenta and Silva Jr., 2005); **6. Rio São Benedito, left margin (09°03′S, 56°35′W) (Fialho, 2010, Fialho pers. comm.); 7. Maloca, Upper Rio Curuá (type locality) (07°55′S, 54°50′W) (Thomas, 1920). *Specimen housed in private collection; ^**Observational record

The observed characters agree with the analyzed series from Alta Floresta (MPEG 24595, 24596), Ourolândia, Alta Floresta (MPEG 24606, 24608, 24609, 24610, 24611), Serra do Cachimbo (MPEG 38104, 38105, 38106) and also with the paratype (MPEG 170). The specimen showed the typical black crown, white patch at the brow, unpigmented face, pigmented naked ears, light gray dorsum and black tail. The specimen differs slightly from the other analyzed specimens in its darker pelage (dark gray) of the dorsal sacral region and by having a tail with signs of annulations, caused by the presence of a dark brown basal band and a black distal band on the tail fur. The external measurements were taken from the label and are as follow: weight = 330 g, total body length = 539 mm, tail length = 333 mm, foot length = 65 mm, ear length = 25 mm.

This record confirms the occurrence of the species 165 km south of its previous southernmost locality, in the Xingú headwaters region, as predicted by Roosmalen et al. (2000) and is an important confirmation of the species' presence in the area. The possibility that the animal was kept in captivity by the local human population cannot be ruled out, as the collector did not state whether the single collected specimen belonged to a larger group of individuals or was found alone. As more specimens become available, a more comprehensive study about geographical variation in pelage among distinct populations of M. emiliae would be important for understanding whether the variation found within the species warrants its division into separate specific taxa or not.