Hylaeamys perenensis (Allen, 1901)

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 : 49-50

Hylaeamys perenensis (Allen, 1901)

Figures 19B, 19E

VOUCHER MATERIAL (N = 33): El Chino (UF 30508, 30509), Jenaro Herrera (MUSM 5450 [not seen], 16006–16010 [not seen]), Nuevo San Juan (AMNH 268261, 272688, 272713, 272718, 272826, 273065; MUSM 13326–13331, 15343–

15345), Orosa (AMNH 73829–73832, 74095– 74097), San Pedro (UF 30517–30519). Additional material that we have not examined was reported from Jenaro Herrera by Pavlinov (1994) and from Quebrada Betilia by Medina et al. (2015).

UNVOUCHERED OBSERVATIONS: None.

IDENTIFICATION: Hylaeamys perenensis (formerly Oryzomys perenensis ; Weksler et al., 2006) is a widespread western Amazonian species based on a type from Junín department, Peru. The name perenensis was treated as a junior subjective synonym of megacephalus Fischer, 1814 , by Musser et al. (1998), but H. perenensis and H. megacephalus are apparently not sister taxa ( Patton et al., 2000; Bonvicino and Moreira, 2001), and both are now treated as valid species based on molecular sequence divergence, karyotypes, and morphology ( Percequillo, 2015b). We follow the current taxonomy uncritically and have not attempted to evaluate the craniodental characters alleged to distinguish these very similar allopatric taxa.

Throughout western Amazonia Hylaeamys perenensis occurs sympatrically with another congener, H. yunganus (Thomas, 1902) . Although these species are externally similar and cannot be consistently distinguished in the field, many specimens of H. yunganus lack a hypothenar pad on the hind foot ( Musser et al., 1998: fig. 17), whereas a hypothenar pad is consistently present on the hind foot of H. perenensis . In effect, a specimen lacking a hypothenar pad is probably H. yunganus , but a specimen that has a hypothenar pad cannot be identified as either species. Fortunately, collected voucher material can be readily identified by dental characters ( Musser et al., 1998)—except for those with heavily worn molars that lack diagnostic occlusal details. Specimens of H. perenensis and H. yunganus identified by dental criteria have broadly overlapping measurements (table 11), although some univariate differences are statistically significant (tests not shown).

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: Of 13 specimens of Hylaeamys perenensis accompanied by ecological data from our region, 5 were taken in primary upland forest, 1 was taken in primary floodplain (seasonally inundated) forest, 3 were taken in swidden agricultural fields, and 4 were taken in secondary vegetation; all specimens were trapped on the ground.