Atelopus petersi Atelopus petersi Atelopus petersi is a species of toads in the family Bufonidae. It is endemic to Ecuador and is known from the Cordillera Oriental in the Napo Province and more provisionally, in the Chimborazo Province. The specific name "petersi" honors James A. Peters, an American zoologist who collected the first specimens of this species in 1962 and provided a description under the name "Atelopus pachydermus". Common names Peters' stubfoot toad and Peters' jambato toad have been coined for it. Adult males measure and adult females in snout–vent length. The snout is acuminate. The tympanic membrane, annulus, and stapes are
Biological membrane fatty acid composition in accordance with differing temperatures. In animal cells, membrane fluidity is modulated by the inclusion of the sterol cholesterol. This molecule is present in especially large amounts in the plasma membrane, where it constitutes approximately 20% of the lipids in the membrane by weight. Because cholesterol molecules are short and rigid, they fill the spaces between neighboring phospholipid molecules left by the kinks in their unsaturated hydrocarbon tails. In this way, cholesterol tends to stiffen the bilayer, making it more rigid and less permeable. For all cells, membrane fluidity is important for many reasons. It enables membrane