Hippo-saurids

Parallel evolution occurs when two unrelated species develop similar traits, be it physical or behavioral because they live in similar environments. As the Nile and Mississippi river deltas formed, two dinosaurs, an African igaunodont and an American hadrosaur, evolved to graze off water vegetation and use their size to deter predators (namely crocodilians). The Ammutasaura (named for the heart-eating demon from Egyptian myth) is more widespread and common in the Nile and Congo rivers, and defends its territory with a crude nose horn and powerful bite. The dorsal ridge supports thick muscles for the arms and legs, and even allows it to charge like a ceratopsian when threatened. The Mashenamak (named for a Native American river monster) has a thicker, tighter feather coat than the Ammutasaura (which only has feathers on its back) because of the colder Mississippi waters and because the beasts migrate through the river and Louisiana/Florida bayous for food and nesting grounds. Its crest is much smaller than its ancestors, so their calls don't travel the vast distances that they used to, but considering the amount of time they spend underwater it doesn't matter to them. They often stick to the shorelines and share the deltas with the aquatic Swamp Singers (velociraptor-king.deviantart.c…). Both individuals pictured here are males in their breeding plumage.

It's been a while since I made a modern dinosaur, and I got the idea when I read a book about Lurdusaurus, a Mid-Cretaceous iguanodont. It's name meant "Weighty Lizard," and the artist showed it in a swamp. My mind immediately said "hippo-saurus" and there you go. Also, since it's approaching Christmas time, I now have the song "I Want a Hippopotamus for Christmas" stuck in my head, and probably yours too. You're welcome. Let's all sing along!