How are members of the clade Clitellata distinguished from o

How are members of the clade Clitellata distinguished from other phyla?

Solution

Clitellata comes under phylum Annelida. Annelid consists of 3 classes: Polychaeta, Oligochaeta and Hirudinida. Oligochaeta and Hirudinida fall under Clitellata.

They form reproductive structure called clitellum.

The members of Clitellata are derived annelids that lack parapodia.

Young ones develop inside cocoon secreted by clitellum, and emerge as small worms.

They act as scavengers, i.e, they feed on decayed organic matter.

They have high calcium level in blood due to calcium in soil. Calciferous glands helps in reducing calcium concentration.

Food is stored in thin walled crop.

Muscular gizzard grinds food into small pieces.

Chloragogen around intestine synthesizes glycogen and fat.

Blood contains colorless ameboid cells and dissolved hemoglobin.

These members lack eyes but contain photoreceptors in epidermis.

Unlike Polychaeta, they have less developed heads and do not contain parapodia.