Ichthyosaurs, now extinct, were aquatic reptiles with dorsal fins and tails, similar to those of fish. their most recent ancestors were terrestrial reptiles that had neither dorsal fins nor aquatic tails. the dorsal fins and tails of ichthyosaurs and fish are ichthyosaurs

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.