Sciurus spadiceus 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 : 87-88

Sciurus spadiceus Olfers, 1818 Southern Amazonian red squirrel

TYPE LOCALITY: ‘‘ Brazil,’’ restricted by Hershkovitz (1959) to Cuyabá (= Cuiaba´) Estado do Mato Grosso.

DESCRIPTION: Similar in size and general color to S. igniventris (Patton, 1984; Lawrence, 1988; Emmons and Feer, 1997), S. spadiceus can be distinguished by its somewhat more grizzled overall dorsal coloration, lack of orange post­auricular patches, and distinctly orange dorsal surfaces mixed with black on both fore and hind feet. The thighs are a uniform rust, somewhat darker in tone than those of S. igniventris . The venter of all Rio Juruá specimens is sparsely covered with white hairs. The tail is similar to that of igniventris , but the hairs have only four alternating bands of black and orange. Cranially, S. spadiceus is readily distinguished from S. igniventris by its somewhat larger size, distinctly longer and narrower rostrum, longer diastema, and narrow­ er palate, among other dimensions (fig. 60, table 19, and Patton, 1984). The upper incisors also are distinctly more proodont in S. spadiceus , but more orthodont to opisthodont in S. igniventris .

DISTRIBUTION AND HABITAT: Emmons and Feer (1997) mapped the range of S. spadiceus to include the western Amazonia from southeastern Colombia south to northern Bolivia, east largely south of the Solimões­ Amazonas axis, and west of the Rio Tapajós to the northern Pantanal. This range includes the entire Río Ucayali, Rio Jurua´, Rio Madeira, and Rio Purus drainages. As with S. igniventris , we either collected or saw this species only in mature or disturbed terra firme forest, never in várzea.

REPRODUCTION: We caught scrotal males at Colocação Sabiá (locality f) in September and at Ocidente (locality b) in February. At the latter locality and time period, we also caught one lactating female with three placental scars, along with a subadult male and subadult female. As limited as these data are, it would appear that S. spadiceus breeds in both dry and wet seasons.

COMMENTS: Thomas (1926) described Sciurus pyrrhonotus juralis , with type locality of João Pessoa (= Eirunepe´), Rio Jurua´, and Vieira (1948) recorded additional specimens from Igarapé Grande, both situated on the Rio Juruá between our Upper and Lower Central regions (see comments and gazetteer in Patterson, 1992). Our specimens of S. spadiceus all come from localities upriver from Eirunepé (Upper Central or Headwaters regions, fig. 1), but we saw squirrels clearly belonging to the same taxon at Penedo (locality 7), also above Eirunepe´, and both Al­ tamira (9) and Barro Vermelho (12) downriver from that town (Lower Central Region) Our specimens cannot be distinguished by any cranial dimension from those from the Río Ucayali or upper Río Purus in eastern Peru´, which are clearly assignable to spadiceus (see Patton, 1984). Consequently, we agree with Hoffmann et al. (1993), who list­ ed both pyrrhonotus and juralis as synonyms of S. spadiceus .

SPECIMENS EXAMINED (n = 12): (b) 5m, 4 ­ MNFS 989–992, 1007, 1041–1042, 1050 1338; (f) 3m — JLP 15655, 15665–15666.