---
title: Mammillated Sea Star (Pentaceraster mammillatus)
scientific_name: Pentaceraster mammillatus
common_name: Mammillated Sea Star
taxon: Starfish
published: 2026-08-06T16:37:23.098Z
updated: 2026-08-29T12:11:30.329Z
tags: Mammillated Sea Star, Pentaceraster mammillatus, Starfish, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/echinoderms/starfish/mammillated-sea-star
---

# Mammillated Sea Star (*Pentaceraster mammillatus*)

## Quick facts

- **Group:** Starfish (*Asteroidea*)
- **Size:** up to 30 cm
- **Depth:** 4-15 m
- **Diet:** Omnivore
- **Activity:** Cathemeral
- **Rarity:** Uncommon
- **Habitat:** sand and seagrass beside reef
- **Reproduction:** Broadcast spawner, Gonochoric

## How to recognise it

- heavy body, arms thick and triangular, broad at the base
- rows of blunt conical tubercles, usually darker than the body
- five larger cones near the disc
- orange to brown here, gray-blue in some populations
- up to 30 cm across

Watch one long enough on the sand and nothing appears to happen, because the eating is done invisibly and outside the body. The star pushes its stomach out through the mouth on its underside, lays it over the sand surface or a crust of encrusting growth, digests the film of microorganisms and small attached animals in place, and pulls the stomach back in. There is no biting and no swallowing.

It is the heavy one. The arms are thick and triangular in section and broad where they meet the disc, and the whole upper surface carries rows of blunt conical tubercles, with five larger cones set near the disc. Most animals here are orange to brown with darker tubercles, but color is not reliable across the range: the Persian Gulf population was described in 2025 as gray-blue with red or navy tubercles. Across the arm tips it reaches about 30 cm (12 in).

Underneath, five grooves run out along the arms, each packed with tube feet. Every foot is a small hydraulic cylinder that extends, grips and releases, and they work in relays, so the animal crosses a sand patch as a rolling wave of hundreds of separate grips. Seawater enters that system through the madreporite, the perforated plate visible on the upper surface, which is the intake for the entire water vascular system.

It lives on soft bottoms in sheltered places, sand and seagrass beside reef, mostly between about 4 and 15 m (13 and 50 ft). It turns up as scattered single animals rather than groups, and on open sand its bulk makes it visible from a long way off. It is harmless to handle, though it should be left where it lies.

Audouin described it in 1826 from material gathered by the French expedition to Egypt, which puts it among the earliest animals ever named from this coast.

## Also known as

- **English:** Multicolored Knobbed Sea Star, Multicolored Knobbed Starfish, Beaded Starfish
- **Italian:** Stella di mare nodosa
- **Czech:** hvězdice strukovitá
- **Russian:** Бугорчатая звезда
- **TH:** ดาวแดง

## Scientific synonyms

- *Asterias mammillata* Audouin, 1826
- *Oreaster mammillatus* (Audouin, 1826)
- *Oreaster verrucosus* Müller & Troschel, 1842
- *Pentaceros mammillatus* (Audouin, 1826)
- *Pentaceros verrucosus* (Muller & Troschel, 1842)

## Range

Eastern Africa & Madagascar, Egyptian Exclusive Economic Zone, Federal Republic of Somalia, Madagascar, Mozambique, Red Sea, Republic of Mauritius, South Africa, Tanzania

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/echinoderms/starfish/mammillated-sea-star)*
*Updated: August 29, 2026*