Dactylomys dactylinus (Desmarest, 1817)

Voss, Robert S., Fleck, David W. & Jansa, Sharon A., 2019, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 5. Rodents, Bulletin of the American Museum of Natural History 2024 (466), pp. 1-180 : 119

Dactylomys dactylinus (Desmarest, 1817)

Figure 48

VOUCHER MATERIAL (N = 16): Orosa (AMNH 73771–73786). In addition, Pavlinov (1994) reported a single ZMMU specimen from Jenaro Herrera that we have not seen.

UNVOUCHERED OBSERVATIONS: Río Yavarí ( Salovaara et al., 2003), Río Yavarí-Mirím ( Salovaara et al., 2003), San Pedro ( Valqui, 1999, 2001).

IDENTIFICATION: Dactylomys dactylinus is a large rat (600–700 g; Emmons, 1997) with soft fur and a long, macroscopically naked, and visibly scaly tail. The dorsal body pelage is blackish coarsely streaked with pale yellow, but the head is uniformly pale brown, and the backs of the thighs are bright rufous; the ventral coloration is self-white from chin to anus. Unlike any other arboreal rodent in our region, the digits of the manus are provided with blunt nails rather than sharp claws, and the two middle digits ( III and IV) are equal in length and much longer than the outer digits ( II and V). The cheekteeth are prismatic, and the upper toothrows are strongly convergent anteriorly. In these and other details—including external and craniodental measurements (table 36)—our specimens closely match the morphological descriptions of D. dactylinus provided by Patton et al. (2000) and Emmons et al. (2015b), who discussed unresolved taxonomic issues concerning the unknown type locality. We are aware of ongoing taxonomic research on bamboo rats (for which tissues have been taken from AMNH specimens for DNA sequencing), so we have not undertaken any further effort to identify our material .

ETHNOBIOLOGY: This species is not known to the Matses, who have no special name for it.

MATSES NATURAL HISTORY: No interviews were focused on this species.

REMARKS: Dactylomys dactylinus is typically, although not exclusively, found in the floodplains of white-water rivers, where the presence of this nocturnal, herbivorous species is conspicuous by its loud nocturnal barking from bamboo and canebrakes ( Emmons, 1981). The absence of Dactylomys from the vicinity of Nuevo San Juan can be inferred from the fact that the Matses there are unfamiliar with it, but multiple unvouchered observations suggest that bamboo rats may occur widely in riparian habitats elsewhere in our region. No habitat data accompany the Olalla’s series from Orosa, but their specimens were almost certainly collected in várzea, which extends inland for several kilometers from the right bank of the Amazon at this locality ( Wiley, 2010: 40).