You have discovered a new coccoid-shaped microorganism with no nucleus, a rigid cell wall, and a diameter of 2 μm. chemical tests reveal that its cell wall does not contain peptidoglycan. the new microorganism is:

Archean  

Explanation:

The archea are the simple single-celled prokaryotic cells. They appear in various shapes. They posses no nucleus. There are various types of cell walls in archea. The cell wall lacks peptidoglycan which is a distinguishing feature between archea and bacteria. Their small size and rigid cell wall favors adaptation in extreme saline and heat conditions which further favors their survival and colonization.

Based on the given conditions, the microorganism mentioned in the given situation is an archean.