The Montseny Brook Newt is native to the Montseny Massif in Northeast Spain. They primarily inhabit cold, fast-moving rivers with low nutrient levels, indicating they are strictly aquatic in nature. It was distinctively recognized as its own species, separate from the Pyrenean brook salamander, in 2005. 

Displaying a chocolate-colored back, this species has a flattened head, and its body is oval-shaped with minimal dorsoventral compression. If they feel threatened, these newts secret a white, sticky, highly odorous substance, likely intended to deter predators.  

Regrettably, the Montseny Brook newt is critically endangered, with fewer than 1,500 in the wild. Their survival is primarily challenged by the desiccation of their mountain stream habitats.

As the largest among the Siren family, the Greater Siren, found in North America's southeastern coastal plains, can measure up to 38 inches. It demonstrates paedomorphism, retaining external gills their entire life and lacking hindlimbs, pelvic girdle, and eyelids while sporting an unfused pectoral girdle. 

Greater sirens are nocturnal hunters, preferring invertebrates such as insects, crustaceans, molluscs, and small fish, thus taking a midlevel predator role in the aquatic food web. .