How do megascleres differ from microscleres in animal sponges?

In the study of sponges, skeletal units known as spicules are categorized into two primary types based on their size and function: megascleres and microscleres.1

• Megascleres: These are the larger spicules that form the primary structural framework of the sponge's skeleton. In the class Demospongiae, megascleres exhibit a wide variety of forms, including monaxons (such as oxeas, styles, and strongyles), triacts, and tetracts (such as calthrops).12
• Microscleres: These are significantly smaller spicules that typically serve a protective role, often forming a dense armor around the sponge. They are generally derived from a polyaxon (many-axoned) spherical type, resulting in star-shaped forms known as asters, or specialized shapes such as sigmas, toxas, and chelas.1

While megascleres provide the main support for the sponge's body, microscleres are specialized, smaller elements that contribute to the organism's defense and structural integrity.1