---
title: Striped Flatworm (Pseudobiceros gratus)
scientific_name: Pseudobiceros gratus
common_name: Striped Flatworm
taxon: Flatworms
published: 2026-08-10T21:29:09.346Z
updated: 2026-08-11T06:41:21.552Z
tags: Striped Flatworm, Pseudobiceros gratus, Flatworms, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/worms/flatworms/striped-flatworm
---

# Striped Flatworm (*Pseudobiceros gratus*)

## Quick facts

- **Group:** Flatworms (*Pseudocerotidae*)
- **Size:** up to 5 cm
- **Depth:** 1-20 m
- **Diet:** Carnivore
- **Activity:** Nocturnal
- **Rarity:** Uncommon
- **Habitat:** Rubble and sheltered reef, often under stones by day
- **Reproduction:** Egg layer, Simultaneous hermaphrodite
- **Hazard:** Poisonous

## How to recognise it

- translucent brownish body with three or four dark lengthwise stripes
- dark margin running the full outline
- up to 5 cm, thin enough to show what it has eaten
- usually under a stone by day

A translucent brownish sheet up to 5 cm (2 in) long, marked with three or four dark stripes running its length and finished with a dark margin. Thin enough that a recent meal shows through as a shadow in the branching gut, which is the closest thing to an internal organ this animal displays.

Days are spent under a stone or in the shade of rubble, nights out in the open. Prey is soft and stationary - sea squirts, bryozoans, small colonial animals - located by chemical trail rather than sight, since the eyes are clusters of simple spots that register light and little else.

A flatworm's most useful trick is regeneration. Cut in half, many polyclads rebuild the missing end, and a fragment with the right tissue can regrow a whole worm. That capacity is why this group has spent a century in laboratories as a model for how bodies rebuild themselves, and why the animal on the reef can survive a bite that would end most others.

## Also known as

- **Russian:** Плоский червь полосатый

## Scientific synonyms

- *Eurylepta striata* Schmarda, 1859
- *Proceros striatus* (Schmarda, 1859)
- *Pseudobiceros strigosus* (Marcus, 1950)
- *Pseudoceros gratus* Kato, 1937
- *Pseudoceros striatus* (Schmarda, 1859)
- *Pseudoceros strigosus* Marcus, 1950

## Range

Australia, Papua New Guinea

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/worms/flatworms/striped-flatworm)*
*Updated: August 11, 2026*