Pennales

The Pennales are an order of diatoms, which are microscopic algae found in all of Earth's waters. Diatoms are characterized by their silicified cell walls, called frustules, which are composed of overlapping halves with intricate patterns.12

Pennales diatoms are distinguished by their elongated shape and bilateral symmetry, featuring pinnate (featherlike) markings. They are capable of movement, exhibiting a gliding motion. In contrast, the other major order of diatoms, the Centrales, are typically round and have radial markings. Diatoms play a crucial role in aquatic ecosystems as a food source and are also utilized in various industrial applications, such as filters and insulation, due to the fossilized remains known as diatomaceous earth.12