While the focus is on amphibians, there are some cool insights about the general principles of the evolutionary biology of taste in this work.

I found it interesting that snakes, penguins, and dolphins/whales have lost most taste receptors because they swallow their food whole. It is obvious, but I hadn’t thought about that.

Other than dietary habits, foraging patterns may also affect the repertoires of Tas2r genes. Previous studies have indicated that cetaceans (0–1; Zhu et al., 2014; Feng et al., 2014), snakes (1–2; Zhong et al., 2017), and penguins (0; Zhao et al., 2015) possess a dramatic contraction in the number of functional Tas2r genes. Their behavior of swallowing food whole without mastication reduces the contact of the TRCs with bitter stimuli, resulting in less contact with poisonous foods.