In the dry season these frogs are readily found concentrated along streams on Costa Rica's Pacific slopes. Within any one population about 5% to 35% of E. stejnegarianus will have this mid-dorsal stripe pattern.
Two frogs from the same population. The frog on the right (SVL=31mm) has unusual green patches that are not commonly seen in this species. The frog on the left (SVL=42mm) shows the more typical sort of coloration. I suspect these are both females. Elevation = 1200m.