---
title: Sheep's Foot Ascidian (Polycarpa mytiligera)
scientific_name: Polycarpa mytiligera
common_name: Sheep's Foot Ascidian
taxon: Sea squirts
published: 2024-04-15T09:50:02.651Z
updated: 2026-08-24T13:58:59.379Z
tags: Sheep's Foot Ascidian, Polycarpa mytiligera, Sea squirts, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/tunicates/sea-squirts/sheeps-foot-ascidian
---

# Sheep's Foot Ascidian (*Polycarpa mytiligera*)

## Quick facts

- **Group:** Sea squirts (*Ascidiacea*)
- **Size:** up to 15 cm
- **Depth:** 3-30 m
- **Diet:** Filter feeder
- **Activity:** Cathemeral
- **Rarity:** Common
- **Habitat:** Hard reef bottom, undercuts and shaded rock
- **Reproduction:** Broadcast spawner, Simultaneous hermaphrodite

## How to recognise it

- solitary leathery bag on rock, not a shared colony
- two siphons set close together at the top
- black and white pattern inside the siphon openings
- outside almost always overgrown with sponge, algae and silt
- up to 15 cm

Cut this animal into three pieces and a month later there are three animals.

The work was done here, on sea squirts taken off Eilat at the northern tip of the Red Sea. Individuals were cut along and across the body, and every fragment rebuilt what it was missing, went back to filtering and responded to touch. Whole-body regeneration was known from colonial sea squirts, which grow by budding anyway; a solitary one that cannot bud doing it was new. There is a second trick. Squeeze this species and it fires most of its digestive tract out through the intake siphon within seconds, then grows a replacement in about twelve days.

What you are looking at is one animal, not a colony of tiny ones sharing a coat. It is a leathery bag up to 15 cm tall, cemented to hard bottom, and it is normally so overgrown with sponge, algae and silt that it reads as another lump of reef. Two openings sit close together at the top. Water is drawn in through one, strained through a sheet of mucus stretched across an internal basket, and pushed out through the other. With the outside overgrown, the black and white pattern inside the two siphons is the most reliable mark on it.

It grows on rock: reef framework, undercuts, the shaded flanks of coral heads, the walls of small caves, from a few meters down. Once it is there it does not move again.

It moved once, and that is the strangest part. The egg hatches into a swimming larva shaped like a tadpole, with a stiff rod running the length of its tail. That rod is a notochord, the structure our own backbone is built around. The larva swims for a few hours, finds a surface, lands head first, glues itself down, and then reabsorbs its own tail and most of its nervous system. Everything it needed in order to choose a place is dismantled once the place is chosen.

Each adult makes both eggs and sperm and releases them into open water.

## Also known as

- **French:** Ascidie noire tropicale

## Scientific synonyms

- *Cynthia mytiligera* Savigny, 1816
- *Pandocia seychellensis* Michaelsen, 1912
- *Polycarpa seychellensis* (Michaelsen, 1912)

## Range

Djibouti, Mozambique, Red Sea, South Pacific Ocean, Tanzania, Yemen

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/tunicates/sea-squirts/sheeps-foot-ascidian)*
*Updated: August 24, 2026*