Micoureus regina (Thomas, 1898)

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 : 74-77

Micoureus regina (Thomas, 1898)

TYPE LOCALITY: ‘‘West Cundinamarca (Bogotá Region),’’ Departamento de Cundinamarca, Colombia.

DESCRIPTION: Very similar to M. demerarae in overall body size, M. regina also has woolly dorsal fur and a black eye­ring. The dorsal pelage is slightly shorter than that of M. demerarae , averaging 10 mm along the middorsum. The overall color cast to the dorsal pelage is also richer, more orangish­graybrown. The ventral color is similarly richer with the cheeks, throat, thorax, abdomen, and inguinal regions ranging from Warm Buff to Antimony Yellow, or from Cream Buff to Chamois (Ridgway, 1912). In pattern, the purely buff­colored ventral region is contin­

uous from the chin to the genitals, typically widely separating the incursions of graybased lateral fur (fig. 54). The latter is found only in the lower thoracic and abdominal regions, never in the upper thorax or throat, in contrast to the pattern of M. demerarae . The purely colored ventral stripe separates the lateral gray­based bands by a width of at least 15 mm, and more typically as much as 25– 30 mm (measurements taken from skins). The skull is stout, as in M. demerarae , but with slightly wider interorbital region (particularly that behind the supraorbital processes). It is larger in most dimensions, on average, particularly when similar sized individuals are compared (see table 13 and fig. 56).

NONGEOGRAPHIC VARIATION: Our samples of M. regina come from a more limited region within the Rio Juruá than do those of M. demerarae . Over this area (Headwaters to Lower Central regions), geographic variation in mensural characters is nearly nonexistent, with only two cranial variables (CD and BB) exhibiting significant geographic differentiation (two­way ANOVA, p <0.05 or 0.01, respectively). Similarly, sexual dimorphism within localities is limited to a single variable (PW; p <0.05). However, when samples are pooled to increase size, sexual dimorphism characterizes most mensural variables in M. regina . Three of the four external measurements (TOL, TAL, and HF) and 13 of 15 cranial variables (CIL, ZB, BB, MB, OC, RL, NL, RW, C­M4, PL, PW, BOL, and CD) exhibit significant sexual dimorphism when all localities are pooled (p <0.05 or 0.01, one­way ANOVA). Samples are not sufficient to examine the combined effects of age and sex.

COMPARISONS: Morphological comparisons with M. demerarae are given above under that species, and in figs. 53–57; external and cranial measurements are compared in table 13. Divergence in cytochrome­b sequences within the Rio Juruá basin is illustrated in fig 50.

DISTRIBUTION AND HABITAT: We found M. regina at all but one of the 12 primary localities in the central and upper reaches of the Rio Jurua´, but at no locality in the Mouth Region. It also has not been taken by us, or others, from localities further to the east or north in Estado do Amazonas, Brazil. Consequently, the records from Jainu (locality 11) and Barro Vermelho (locality 12) represent the easternmost ones for the species within Amazonia to our knowledge.

For the most part, M. regina was the only species of woolly mouse opossums we took in true várzea forest along the river margins It was taken in all trap lines set within true várzea in the Upper and Lower Central regions of the Rio Juruá (localities 5 [Sacado] 8 [Nova Empresa], 9a [Boa Esperança], 10 [opposite Altamira], and 11 [Jainu]), and also in the two quasi­várzea localities in the Headwaters (localities 2 and 3). At the latter two it was sympatric with M. demerarae . We also took it in terra firme habitats at localities 6 (Condor), 7 (Penedo), and 12 (Barro Vermelho) with M. demerarae , and in near­equal numbers with that species at locality 7. All specimens were caught in canopy traps placed from 5 to 10 m off the ground, or were shot off perches more than 2 m high.

REPRODUCTION: We obtained reproductive females in the months of February, September, October, and November. As with M. demerarae , these data suggest the possibility of breeding in both dry and wet seasons. Fe­ males with attached young were taken at localities 5 (Sacado), 8 (Nova Empresa), and 10 (opposite Altamira); the number of pups varied from 6 to 8. Males of age classes 5 and 6 had testes larger than 9 mm; those of younger ages had testes 8 mm or less.

KARYOTYPE: 2n = 14, FN = 20 (fig. 47E). The chromosomal complement of M. regina is identical in gross features to that described above for M. demerarae .

COMMENTS: This species appears to be relatively uniform over its range. At least with regard to variation in cytochrome­b sequences, there is no difference between individual haplotypes from the Rio Juruá basin and those from northern Perú (Río Cenepa, Departamento de Amazonas). The true range of this species is not known at present and, given the rather slight morphological differences between it and M. demerarae , sequence analysis of samples from other localities within western Amazonia may be necessary to de­ fine that range. The designation of the type locality as ‘‘West Cundinamarca’’ lacks geographic precision, but since the western half of the Departamento de Cundinamarca consists of the humid lowlands of the Río Magdalena valley, the true type locality is thus probably within the trans­Andean region as defined by Haffer (1975). On biogeographic grounds, therefore, it is likely that the name regina is inappropriately applied to the western Amazonian taxon we characterize here Certainly, this Amazonian clade is quite distinct from all other sampled taxa of the genus, including M. alstoni from Panamá (fig 52), the closest locality that we have sampled to the type locality of regina . If M. regina proves to be a species distinct from that in the western Amazonian lowlands, the earliest name applicable to the latter is germana Thomas, 1904.

SPECIMENS EXAMINED (n = 55): (1) 2m, 2 — MNFS 1161, 1232, 1298, 1417; (2) 3m

1f — MNFS 1287, 1337, 1352, 1379; (3) 1m, 1f — MNFS 1530, 1673; (4) 1f — JUR 247; (5) 5m, 3f — MNFS 566–567, 608­611, 668, 678; (6) 1f — JLP 15703; (7) 4m, 3f — JLP 15358, 15496; MNFS 401, 426–428, 435; (8) 4m, 8f — JLP 15392, 15434–15437; MNFS 441­442, 486, 502–504, 509; (9a) 3m — JLP 16034–16035; JUR 198; (10) 4m, 2f — JLP 16031–16032; JUR 201; MNFS 902– 903, 935; (11) 2m, 3f — MNFS 717, 755– 756, 772–773; and (12) 2m — MNFS 728, 759.

MONODELPHIS BURNETT, 1830