Flowers' Flatworm

Overview

Flowers' Flatworm (Pseudobiceros flowersi) is a striking marine flatworm widely distributed across the Indo-West Pacific region. Like other members of its genus, it is a hermaphroditic species known for its unique reproductive behaviors and vibrant, mottled appearance.

Appearance

This species features an oval-shaped body with a background color that varies from olive green to light brown, typically mottled with white. The entire dorsal surface is covered in evenly spaced brown and white dots, which often appear darker toward the center of the body. It possesses square, ruffled pseudotentacles at the anterior end and a round cerebral eyespot. The margins are wide and may be light olive green or orange-brown, often finished with a very narrow, interrupted rim.

Distribution & habitat

Pseudobiceros flowersi is found throughout the Indo-West Pacific, including areas such as Australia, Indonesia, Malaysia, the Philippines, and Papua New Guinea. It typically inhabits rocky reefs, rubble, and sandy bottoms, often seeking shelter under boulders or rubble on reef crests and slopes.

Feeding

This flatworm is a carnivore that feeds primarily on colonial ascidians (sea squirts), as well as various molluscs.

Biology & behavior

As a hermaphrodite, each individual possesses both male and female reproductive organs. When mating, these flatworms engage in a behavior known as "penis fencing," where they use their reproductive structures to attempt to inseminate one another. The individual that successfully delivers sperm to the other's skin becomes the "father," while the recipient takes on the role of the "mother."