There are several species that are very much similar to Proteus anguinus with respect to body dimension, colour and even shape. Salamander is similar to Human fish as both live permanently under water and sustain throughout life with the help from filamentous gills along with caudal fins that are features of larvae. Both are found extensively in Europe particularly in Slovenia, Bosnia and Herzegovina and Montenegro. Both salamander and proteus anguinus tend to lack pigmentation and even have degenerated vision. The overall body structures are somewhat thin and have abridged toes that are present on forelimbs (three in number) and two that are situated on hind limbs. The toes are reasonably big reaching length of roughly 25 cm. On the other hand, Necturus is usually found in northern part of America and has standard pigmentation and differs from proteus anguinus who does not have any type of pigmentation. At the same time, Necturus has eyes and contains four toes on each foot whereas proteus anguinus has five scattered toes on forelimbs and hind limbs respectively. Inhabitants of the species Necturus are usually named as mudpuppies and even waterdogs. They live in rivers and lakes, where they tend to remain hidden underneath the rocks and fragments throughout the day and look for invertebrate quarry during at night.
It should be noted that mainly all the proteids are everlastingly aquatic larvae that have extended bodies, lengthy filamentous gills along with caudal fins as well. Proteids of European species proteus are known to be cavern inhabitants with de-pigmented covering and disintegrated eyes. On the other hand, American proteids of the species Necturus that include necturus lewisi, necturus maculosus, necturus beyeri, necturus alabamensis and necturus punctutus tend to have full-bodied structures that are typically dark brown or black on the dorsal exterior which habitually has a spotted exterior; 4 toes are located on stout forelimbs and even hind limbs also. Necturus lewisi tend to have oxidized brown dorsal surface with several big black pigments. The ventral surface is dark brown and is also pigmented. The nose is dense dorsally and shortened. The appendage is solid sideways and corrugated. Each hind limb has 4 four toes whereas Olm has 5 toes and their gills are dreary red and hairy. Sexually vigorous males tend to have soiled cloacae along with 2 engorged cloacal papillae on the back side. Males in Olm’s are not very sexually active when compared with necturus lewisi.
Mudpuppy or in other words necturus maculosus is a special breed of salamander that is attached to the genus, necturus. They survive in completely aquatic existence in the eastern region of North America in lakes, and ponds. Mudpuppies tend to go through paedomorphosis and preserve their peripheral gills. As exterior and lung respiration is not enough for gas swap over, they tend to depend on peripheral gills as their main method of gas liberation as in proteus anguinus. Necturus maculosus has typically corroded brown colour and has a standard length of 33 cm whereas Olm has 25 cm overall length.