I made this species (and reference sheet) about two years ago for my story, "Guilt," but I've since removed them from the story for simplification purposes.
I still really want to use these guys for something though because I like their design.

Portitoris (Singular is portitor.)
They are aquatic mammals based off of an odd mix between sea lion and crocodile.
The species is actually broken into two subspecies-- a freshwater portitor called a cumba, and a saltwater one known as a ponto.
The main difference between cumba and ponto is that the ponto is much larger. Ponto exhibit larger bodies, a longer snout, and a longer tail fin. In addition, they also present much larger, more numerous teeth. Their main set is hooked, to catch large sea fish.
Cumba, on the other hand, are much smaller with smaller snouts, and smaller tail fins. The only thing larger about them compared to the ponto is that their ears are slightly larger, and the spines on their backs are longer and more numerous. In colour, ponto tend to be more grey in colouration, while cumba are more often brown.
Both cumba and ponto eat all manner of fish and shellfish.

Though they are designed after crocodiles to a great extent, portitoris are not savage creatures. They are actually very friendly, or sometimes even skittish towards those that do not fit into their diet. Cumba are especially docile.
Within cities close to water, they are even used as beasts of burden. In exchange for food, they will allow humanoids to strap specialized harnesses around them to tug boats.

The colours here are all generally common with portitoris. The markings shown on both examples are also common visual elements for either species (ponto may have spots- cumba may not. Stripes and bars may be seen as well.)

Portitoris belong to me.
Drawn on SAI.