Plesiocidaris durandi is an extinct species of sea urchin

Sea urchin

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

. Including its spines, the creature was 13 cm (5 in) wide. Its remains have been found in Drâ el-Ahmar, near the Atlas Mountains

Atlas Mountains

The Atlas Mountains is a mountain range across a northern stretch of Africa extending about through Morocco, Algeria, and Tunisia. The highest peak is Toubkal, with an elevation of in southwestern Morocco. The Atlas ranges separate the Mediterranean and Atlantic coastlines from the Sahara Desert...

 in Oran

Oran

Oran is a major city on the northwestern Mediterranean coast of Algeria, and the second largest city of the country.It is the capital of the Oran Province . The city has a population of 759,645 , while the metropolitan area has a population of approximately 1,500,000, making it the second largest...

, Algeria

Algeria

Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...

. A Commander Durand found the fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s there in 1870 and sent them to French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 paleontologists

Paleontology

Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...

. The exact location of the find was not noted and hasn't been rediscovered since. The species name, durandi, refers to Commander Durand. Most Plesiocidaris fossils still have the spines attached, indicating they lived in calm water; the spines of dead sea urchins are easily detached by wave currents.