Material. Antioquia, Valdivia, 4500 ft. [-1370 m], M.A. Carriker leg., 1948 (USNM, holotype of Drymaeus rehderi). ?Cundinamarca, Bogota? (CMC C13893); Santa Fe de Bogota, ex Cuming (NHMUK n.c); Meta, Serrania de la Macarena, Rio Duda, Centro de Investigaciones Primatologicas La Macarena, Campamento Puerto Chamuza, Trail B1000, 350 m, E. Linares leg., x.1994 (ICNB 2841); Narino, Santa Rosa de Sucumbios, Rio San Miguel, Intendencia Putumayo, B. Malkin and P. Burchard leg., 2-25.X.1970 (FMNH 187568); Between Alpichague and San Antonio, Santa Rosa de los Cofanes, below San Antonio del Guamues, H. LeNestour, ii.1965 (FMNH 187569); Putumayo, Puerto Asis, Upper Rio Putumayo, F. Medem leg., 1958 (FMNH 114079). ?, Amazon River (ANSP, lectotype of D. e. vanattai). New Grenada (Colombia), ex Cuming (NHMUK n.c). Ecuador, Topo, ex Jackson (ANSP 306773, DMNH 142446); Rio Napo, ex Jackson (DMNH 147561); Santo Domingo de los Colourados, ex Jackson (DMNH 147570); Guarumos, ex Jackson (DMNH 150711); Nachiyacu, ex Jackson (DMNH 163667); Montalvo, Rio Bobonaza, 314 m, Ollala leg., (SMF, holotype of D. e. orcesi). ?, Ecuador, ex Sowerby (ZMUZ 511962); Ibidem, ex B. Wright (MHNN 35.49). Panama, Right bank of Chagres river, junction with Rio Chico, J. Zetek leg., 1921 (ANSP 155413); Rio Puerco, A. Olsson leg. (ANSP 140691 & 451781, types of D. e. balboa); Rio Puerco, Darien, Olsson leg. (FMNH 117079). Peru, Tarapoto (UMMZ 4516); Valle de Chanchamayo, 1100 m, J. Schunke leg. (USNM 601807).
Altitudinal range. The few precise locations from which altitudinal data can be ascertained range 230-1370 m, suggesting that this taxon occurs at low to moderate elevations.
Ecology. The species is known from different montane forests ecoregions in Colombia. The actual habitat is unknown.
Remarks. With the (quite limited) material at hand, we conclude that Drymaeus (D.) expansus is a very variable species, with a seemingly huge distribution from central Panama to central Peru. Within its range, several varieties and subspecies have been recognised, which we are unable to evaluate fully with the scant material available. Therefore, we have grouped them together as without implying formal synonymisation. This species complex will benefit from anatomical and molecular studies based on material from throughout its distribution range. Also the relationship between D. expansus and D. confluens, suggested above, needs further study.