Selected aspects of qualitative anatomy contrasted in the crania (dorsal view = A, ventral view = B) based on data of Neacomys marci sp. nov. (left; MECN 6232, holotype; Estación Fisher, Ecuador) and Neacomys tenuipes (right; UIS-MHN-M 1723; Finca La Bufalera, Colombia). The figure portrays differences between the characteristics of these species as follows: N. marci sp. nov. has the longest nasal (n) extending well beyond the plane of the lacrimals (la), larger molars (m), and a low sagittal ridge (sr). Figures are not to scale to facilitate comparisons.