Philander mcilhennyi Gardner and Patton, 1972

Voss, Robert S., Fleck, David W. & Jansa, Sharon A., 2019, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 3: Marsupials (Didelphimorphia), Bulletin of the American Museum of Natural History 2019 (432), pp. 1-89 : 54-56

Philander mcilhennyi Gardner and Patton, 1972

Figure 19

VOUCHER MATERIAL (TOTAL = 18): Nuevo

San Juan (AMNH 268223, 268224, 272818,

273039, 273040, 273054, 273055, 273089; MUSM 11068, 11070, 11071, 11073, 13299, 15319– 15323), Orosa (AMNH 74088).

OTHER INTERFLUVIAL RECORDS: Choncó ( Vriesendorp et al., 2006a), Divisor ( Vriesendorp et al., 2006b), Jenaro Herrera (as Philander andersoni ; Fleck and Harder, 1995).

IDENTIFICATION: Amazonian specimens of Philander with distinctly blackish middorsal fur belong to two strongly supported cytochrome b haplogroups ( Patton and da Silva, 1997; Patton et al., 2000; Voss et al., 2018). One haplogroup is represented by specimens collected north of the Amazon (in northern Loreto, eastern Ecuador, southeastern Colombia, southern Venezuela, and northwestern Brazil), but it also includes a sequence obtained from a paratype of P. andersoni ( Osgood, 1913) , which was collected south of the upper Amazon at Yurimaguas, in western Loreto department. The other haplogroup, represented by specimens collected south of the Amazon in Peru and western Brazil, includes specimens that closely resemble the type series of P. mcilhennyi (from Balta in Ucayali department). Both haplogroups are currently recognized as valid species ( Patton and da Silva, 2008), but Voss et al. (2018) noted that the material they referred to P. andersoni and P. mcilhennyi on the basis of cytochrome b sequences could not be consistently distinguished by morphological criteria.

Most specimens of Philander mcilhennyi (e.g., the type series from Balta, Peru, and material from western Brazil) are very dark: completely blackish middorsally with dark-grayish flanks and underparts. Although the lateral and ventral fur is frosted with gray, the tonal contrast with the middorsal fur is not abrupt. Additionally, the middorsal fur is much longer than the lateral fur, giving some skins a distinctly shaggy appearance. By contrast, typical material of P. andersoni has paler-grayish flanks, such that the black middorsal stripe is more obvious; additionally, the middorsal fur of andersoni is said to be shorter than that of mcilhennyi , and the ventral fur is either self-whitish or gray-based whitish (rather than dark gray). Lastly, P. andersoni is said to have a medial patch of pale fur at the base of the ear that is absent from the entirely blackish crown of P. mcilhennyi (see Patton and da Silva, 1997, 2008).

Patton et al. (2000) remarked that Philander andersoni and P. mcilhennyi might be sympatric on the “lower Río Javarí in northeastern Peru,” citing a personal communication with D.W.F., who had observed both phenotypes at Nuevo San Juan (on the Río Gálvez). In fact, our voucher material includes specimens that distinctly resemble P. mcilhennyi (e.g., AMNH 272818, MUSM 13299) and others that closely resemble P. andersoni (e.g., AMNH 273055; fig. 19). Cytochrome b sequences that we obtained from specimens of both phenotypes, however, all belong to the mcilhennyi haplogroup (Voss et al., 2018), so introgression rather than sympatry might be the more appropriate interpretation of pelage variation at this locality. Nevertheless, we maintain current binomial usage pending further genetic analysis of our material (Jansa and Voss, in prep.).

A curious aspect of intraspecific variation in both Philander mcilhennyi and P. andersoni is sexual dimorphism in the middorsal fur, which is significantly longer, on average, in females than in males (table 22). Same-sex comparisons, however, support Patton and da Silva’s (1997, 2008) description of P. mcilhennyi as longerfurred than P. andersoni , although there is species overlap in our measurements of fur length even when comparing males with males and females with females. To our knowledge, sexual dimorphism in fur length has not been reported from other didelphid species.

ETHNOBIOLOGY: The Matses do not distinguish this species from other “four-eyed” opossums (all known as cheka bëbëdi; see the generic account for Philander , above) and therefore have no particular beliefs about it.

MATSES NATURAL HISTORY: The Matses have no definite knowledge of this species.

REMARKS: Of the 17 specimens for which we have definite habitat data, seven (41%) were trapped or shot in primary forest (usually at well-drained sites, but once in the narrow floodplain of the Río Gálvez), another nine (53%) were taken in secondary forest (regenerating abandoned swiddens), and one was taken in an active swidden. Of the 14 specimens with recorded capture heights, 10 (71%) were trapped or shot on the ground, whereas four (29%) were shot or trapped on elevated substrates. Of the latter, one was trapped on a log 1 m above the ground, another was shot 3 m above the ground in a tree, and two others were shot at unrecorded heights in trees (one said to be “not very high” and the other “high up” [English translations from Matses field notes]).

OTHER SPECIMENS EXAMINED (TOTAL = 17): Brazil — Acre, Sena Madureira (USNM 546220– 546222), Sobral on left bank Rio Juruá (MVZ 190337). Peru — Loreto, Santa Elena on Río Samiria (FMNH 87125). Ucayali, Balta (LSUMZ 14014, 14015, 16393, 16394; MVZ 136379– 136381), 59 km SW Pucallpa (USNM 461133, 499003, 499005–499007) .

Figures

FIG. 19. Dorsal and ventral views of Philander skins from Nuevo San Juan (from left to right in each panel: MUSM 13299, AMNH 272818, AMNH 273089, AMNH 273055). Cytochrome b sequences obtained from all four specimens belong to the P. mcilhennyi haplogroup (Voss et al., 2018).