---
title: Flatworms (Pseudocerotidae)
scientific_name: Pseudocerotidae
common_name: Flatworms
rank: Family
published: 2024-11-19T18:41:51.573Z
updated: 2026-08-03T21:26:15.261Z
tags: Flatworms, Pseudocerotidae, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/worms/flatworms
---

# Flatworms (*Pseudocerotidae*)

## Quick facts

- **Rank:** Family
- **Scientific name:** Pseudocerotidae
- **Body shape:** Flattened - Pressed flat top-to-bottom, lies on the bottom - rays, flounders, crocodilefishes.
- **Species listed here:** 2

## How to recognise this group

- broad, flattened, oval body
- small size, typically 1 to 10 cm long
- prominent sensory folds (pseudotentacles) on anterior margin

Members of the family Pseudocerotidae are marine flatworms, typically measuring 1 to 10 cm (0.4 to 4 in) in length. They possess broad, dorsally flattened, oval or leaf-like bodies. Most species exhibit prominent pseudotentacles, which are sensory folds located along the anterior margin of the body. Many species display bright coloration, often with intricate patterns of contrasting stripes, spots, or marginal bands.

These flatworms inhabit shallow reef environments, typically found from 1 to 30 m (3 to 100 ft) deep. They are commonly observed on hard substrates such as coral rubble, beneath rocks, or occasionally on various soft corals. Pseudocerotidae are carnivorous, feeding on sessile invertebrates including sponges and tunicates. They move by gliding across surfaces using ventral cilia and can swim short distances through undulating their body margins when disturbed. Their often conspicuous and intricate patterns make them readily noticeable to divers.


## Species (2)

- [Divided Flatworm (Pseudoceros dimidiatus)](https://redseacreatures.com/taxon/invertebrate/worms/flatworms/divided-flatworm)
- [Pseudoceros sp (Pseudoceros sp)](https://redseacreatures.com/taxon/invertebrate/worms/flatworms/pseudoceros-sp)

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/worms/flatworms)*
*Updated: August 3, 2026*