Caluromys lanatus (Olfers, 1818)

PATTON, JAMES L., DA SILVA, MARIA NAZARETH F. & MALCOLM, JAY R., 2000, Mammals Of The Rio Juruá And The Evolutionary And Ecological Diversification Of Amazonia, Bulletin of the American Museum of Natural History 2000 (244), pp. 1-306 : 84-85

Caluromys lanatus (Olfers, 1818)

TYPE LOCALITY: ‘‘Paraguay’’; restricted to Caazapa´, Caazapá (Cabrera, 1916).

DESCRIPTION: A medium­sized arboreal opossum (range in body mass of adults from 350 to 520 g), this species is beautifully colored with long, lax, and wavy hair with a thickly furred tail above for its proximal half and below for one fifth its length. The dorsal color is a marked red­brown mixed with gray, particularly on the upper arms and hips, otherwise brightest over the shoulders, forearms, and lower hindlegs. The head is grayish, but the face has a prominent dark stripe down the center from between the ears to the nose. There is a reddish brown eye­ring extending as a dark streak from the corner of the eye to the nose. The nonfurred distal part of the tail is whitish­yellow mottled with brown spots. The feet are reddish­brown. The venter is yellowish white with a grayish midsection. Selected external and cranial measurements for eight adult individuals are given in table 18. Our samples are inadequate to determine the degree, if any, of sexual dimorphism or interlocality differences among adult individuals.

DISTRIBUTION AND HABITAT: This species is known from throughout the western Amazon, east of the Andes in Colombia, western Venezuela, Ecuador, Perú, and Bolivia, eastern Paraguay, northeastern Argentina, and western Brazil to east of Manaus and south to Estado do Minas Gerais. Known localities of sympatry between C. lanatus and C. philander include the region of Manaus (Malcolm, 1991b; Voss and Emmons, 1996) as well as Guyana and eastern Bolivia (L. H. Emmons, personal commun.). The two also occur in close proximity in Estado do Minas Gerais, Brazil (L. P. Costa and Y. R. Leite personal commun.). We collected all specimens in traps placed in trees at heights ranging from 5 to 15 m, with approximately equal numbers caught in terra firme and várzea forests.

REPRODUCTION: We obtained only two females with pouch young, one in November (Altamira, locality 9) and one in June (Vira­ Volta, locality 14), but caught postlactating females in October, February, and March These data, and the occurrence of very young individuals (age classes 1–2, calendar age about 4 months based on Didelphis , see Gardner, 1982) suggest that breeding takes place yearround, or nearly so, in C. lanatus Litter sizes are the smallest recorded for didelphid marsupials (review in Harder, 1992) ranging only from one to two young (n = 3) The related species C. philander has an average litter of four in French Guiana (Charles­Dominique et al., 1981; Atramentowicz, 1986).

KARYOTYPE: 2n = 14, FN = 24 (fig. 47F) The autosomal complement consists of four pairs of large biarmed and two pairs of medium­sized subtelocentric autosomes; the X­

chromosome is a small biarmed element and the Y­chromosome is very small but appears distinctly biarmed. This karyotype differs from those reported for the three recognized species of Caluromys (Reig et al., 1977) only in the morphology of the Y­chromosome. These authors note that the Y­chromosome of both C. derbianus and C. lanatus is uniarmed and that of C. philander is biarmed. This, however, appears to be a misprint as the illustrated karyotype of C. philander shows a clearly uniarmed element, and both C. derbianus and C. philander are listed as having a uniarmed Y in an accompanying table. We karyotyped two individuals, MNFS 584 and MNFS 796. The karyotype of C. lanatus from Bolivia reported by Palma and Yates (1996) also has a biarmed Y­chromosome.

COMMENTS: While morphological variation among samples of C. lanatus has never been examined, the species is remarkably uniform geographically in cytochrome­b sequence haplotypes. We have 396 bp of data for four specimens from three localities spanning the entire length of the Rio Juruá (Porongaba [locality 1], Altamira [9], and Vira­Volta [14]). These differ among themselves by a maximum of six substitutions (1.5%). One haplotype from Altamira is identical to that found in a single specimen from the upper Rio Urucu to the east in central Estado do Amazonas, Brazil, and none differ by more than four substitutions from a specimen from the Río Cenepa in northern Perú. The specimens from the upper Rio Urucu and Río Cenepa, two localities some 1600 km apart and spanning much of the known east­west distribution of the species, differ by only 1.5% in comparison of their entire cytochrome­b sequences (1200 bases; Patton et al., 1996b) .

SPECIMENS EXAMINED (n = 20): (1) 1f — MNFS 1331; (2) 1m — MNFS 1237; (a) 1f — MNFS 1106; (3) 5f — MNFS 1518, 1537–1538, 1553, 1660; (4) 2m, 2f — MNFS 1628, 1670, JUR 215, 231; (5) 1f — MNFS 584; (9) 1f — JUR 191; (10) 1f — MNFS 944; (12) 1m — MNFS 796; (13) 1m — JUR 306; (14) 1m, 2f — JUR 478, 486, 559.