Scientists say they have discovered the first fossil of a dinosaur in Angola, and that it's a new creature, heralding a research renaissance in a country slowly emerging from decades of war.

A paper published Wednesday in the Annals of the Brazilian Academy of Sciences describes a long-necked, plant-eating sauropod, among the largest creatures ever to have walked the earth. The international team that found and identified the fossilized forelimb bone say it is from a previously unknown dinosaur, citing unique skeletal characteristics.

The fossil was found along with fish and shark teeth in what would have been a sea bed 90 million years ago, leading its discoverers to believe the dinosaur might have been washed into the sea and torn apart by ancient sharks....