2004 
TABLE 13 
Records of Sympatry Among Bolivian 
Species of Marmosops 
(Based on material examined for this report) 

creightoni no 
impavidus no no 
noctivagus yes no yesb 
ocellatus yes¢ no no no 
bishopi _creightoni. impavidus noctivagus 

aMfarmosops bishopi and M. noctivagus were collected sym- 
patrically at localities 1, 5, and 11 (see appendix 2). 
bMarmosops impavidus and M. noctivagus were collected 
sympatrically at locality 21 (see appendix 2). 
¢Marmosops bishopi and M. ocellatus were collected sym- 
patrically at locality 28 (see appendix 2). 
predict that M. creightoni will eventually be 
found in wet montane forests from central 
Bolivia to southeastern Peru. Whether or not 
M. creightoni is really co-distributed with 
any of the taxa listed in table 12 remains to 
be demonstrated by more intensive collect- 
ing, but it is noteworthy that this assemblage 
of species is largely restricted to humid east- 
ern-Andean slopes with few convenient 
points of access for inventory fieldwork ex- 
cept along roads where colonization has al- 
ready caused extensive deforestation. There- 
fore, it may be a long time before significant 
range extensions of M. creightoni are report- 
ed. 
The material that we refer to Marmosops 
bishopi (a total of eight individuals from six 
localities) is an interesting exception to the 
ecogeographically restricted distributions of 
other Bolivian forms. Instead, specimens of 
M. bishopi have been taken in a diversity of 
landscapes, where they account for most of 
the known examples of sympatry document- 
ed by congeneric material examined for this 
report (table 13). Because strikingly different 
macrohabitats can sometimes occur in close 
proximity, we consulted field notes associ- 
ated with Bolivian specimens of M. bishopi 
seeking some common ecological circum- 
stance in which they might have been taken, 
but we found none: captures have been re- 
corded in primary lowland rainforest 
(UMMZ 156014, USNM 579249), lowland 
dry forest (LHE 1541), seasonally flooded 
evergreen gallery forest (LHE 1553, 1556), 
and cloud forest (CBF 7531). Either M. bish- 
VOSS ET AL.: BOLIVIAN MARMOSOPS 33 
opi 1s an unusually eurytopic species, or the 
material that we consider conspecific may 
consist of two or more morphologically 
cryptic taxa. 
Some of the obvious gaps in our distri- 
bution maps of Bolivian Marmosops are cer- 
tainly artifactual, but others are probably not. 
Despite considerable collecting effort in the 
seasonally flooded savannas and gallery for- 
ests of central and northern Beni, for exam- 
ple, no specimens of Marmosops have been 
collected there. The genus is likewise un- 
known from substantial collections made in 
the arid thorn-scrub of southern Santa Cruz, 
eastern Chuquisaca, and eastern Tarija, nor 
have we seen any material among the many 
hundreds of small mammals collected in the 
altiplano habitats of southwestern Bolivia. 
By contrast, the eastern-slope lower-montane 
forests of Chuquisaca and Tarija remain very 
poorly sampled by mammalogists, and it is 
possible that the genus is more widely dis- 
tributed there than current records suggest. 
ACKNOWLEDGMENTS 
We thank the curators and collection sup- 
port staffs that hosted our visits and pro- 
cessed the loans that made this study possi- 
ble, especially Paula Jenkins (BMNH); Julie- 
ta Vargas (CBF); Jorge Salazar-Bravo, Bill 
Gannon, and Joe Cook (MSB); Phil Myers 
and Steve Hinshaw (UMMZ); and Al Gard- 
ner, Linda Gordon, and Helen Kafka 
(USNM). Bolivian fieldwork was partially 
funded by a grant from the American Society 
of Mammalogists (to TT); and by the Na- 
tional Geographic Society, the Weeden Foun- 
dation, and BIOPAT (through grants to M. 
Kessler and S. Herzog). Logistical support in 
the Valle de Zongo was graciously provided 
by the Compafiia Boliviana de Energia Eléc- 
trica (COBEE). Cristian Olivo helped EY 
with fieldwork in the Saynani area. Permits 
to collect in Bolivia were issued by the Di- 
reccion General de Biodiversidad, Ministerio 
de Desarrollo Sostenible y Medio Ambiente. 
Louise Emmons provided useful observa- 
tions and digital images from her recent 
fieldwork in eastern Santa Cruz and allowed 
us to examine uncataloged material that she 
collected there. At the AMNH, Neil Duncan 
expertly extracted and cleaned skulls from 
