Goblin shark

Although it is a shark and shares many anatomical features with them, the goblin shark is characterized by a few different features.

An excerpt from the article 19 facts about Goblin shark
They have short and rounded fins, anal and pectoral fins are larger than the dorsal fins. The caudal fin is heterocercal, with a significantly larger upper lobe and lacking a middle lobe. Heterocercal fin is an asymmetrical type, where the upper lobe is bigger than the lower one. Such a fin is characteristic for the phylogenetically oldest fish.