Salamanders nasolabial grooves

Brown, C. W., 1968, Additional observations on the liinetion of the nasolabial grooves of plethodontid salamanders, Copeia 1968 728-731. 

Figure 6.2. Nose-tapping by a plethodontid salamander. Salamanders from this family have nasolabial grooves that run from the nostril to the upper lip and deliver chemicals to the vomeronasal organ. Nose-taps may be directed toward the substrate, as pictured, or towards objects such as fecal pellets or the bodies of other salamanders.

Graves, B.M. 1994. The role of nasolabial grooves and the vomeronasal system in recognition of home area by red-backed salamanders. Anim. Behav. 47 1216-1219. 

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