---
title: Divided Flatworm (Pseudoceros dimidiatus)
scientific_name: Pseudoceros dimidiatus
common_name: Divided Flatworm
taxon: Flatworms

published: 2023-12-27T01:06:11.207Z
updated: 2025-11-25T13:58:09.000Z
tags: Divided Flatworm, Pseudoceros dimidiatus, Flatworms, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/worms/flatworms/divided-flatworm
---

# Divided Flatworm (*Pseudoceros dimidiatus*)

**Taxon:** Flatworms (*Pseudocerotidae*)  


Pseudoceros dimidiatus, also known as the divided flatworm or tiger flatworm, is a flatworm species belonging to the genus Pseudoceros and the family Pseudocerotidae.

These flatworms can reach a maximum length of 8 centimetres (3.1 in) and have an elongated, oval-shaped body. The dorsal surface is velvety in texture, while the ventral side is grey-black. The pseudo tentacles, formed by folds of the anterior margin, are relatively short.

Individuals of the divided flatworm exhibit a consistent color pattern, with a black body and an orange margin. Two wide longitudinal yellow-greenish stripes are typically present, separated by a narrow black median line. However, there is significant variation in color and pattern among this species, including the arrangement and width of transverse stripes and the width of the longitudinal stripes. It can display at least three different types of livery and possesses bilateral symmetry.

The vibrant and contrasting colors serve as a warning to predators, indicating that this species is inedible. Divided flatworms exclusively feed on colonial ascidians and are ectothermic.

The species is found across the Indian Ocean, ranging from the Red Sea to Australia, as well as in the Western Pacific Ocean.

Divided flatworms are capable of both asexual reproduction, through self-division, and sexual reproduction. As hermaphrodites, individuals possess both male and female reproductive organs. During mating, two flatworms engage in a battle to determine who will act as the male and who will be fertilized. The winner fertilizes the other.

These flatworms inhabit coral reefs in tropical waters.

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/worms/flatworms/divided-flatworm)*
*Updated: November 25, 2025*