Psychrophrynella wettsteini species without known major threats. Psychrophrynella wettsteini Psychrophrynella wettsteini is a species of frog in the family Craugastoridae. It is endemic to Bolivia and only known from the region of Unduavi in the Unduavi Valley, Sud Yungas Province, La Paz Department. Common name Wettstein's Andes frog has been coined for it. It is named for Otto von Wettstein, Austrian zoologist. "Psychrophrynella wettsteini" is a comparatively large species (maximum snout–vent length ) and has a robust body and long limbs. The snout is rounded. The tympanic membrane is absent, whereas the tympanic annulus is visible through the skin. Tips of the
Membrane stabilizing effect Membrane stabilizing effect Membrane stabilizing effects involve the inhibition or total abolishing of action potentials from being propagated across the membrane. This phenomenon is common in nerve tissues as they are the carrier of impulses from the periphery to the central nervous system. Membrane stabilization is the method through which local anesthetics work. They block the propagation of action potentials across nerve cells, thereby producing a nerve block. Some beta-blockers also possess what is referred to as membrane stabilizing activity (MSA). This effect is similar to the membrane stabilizing activity of sodium channel blockers that represent Class I antiarrhythmics. MSA