---
title: Collector Urchin (Tripneustes gratilla)
scientific_name: Tripneustes gratilla
common_name: Collector Urchin
taxon: Sea urchin
published: 2024-01-09T06:57:16.960Z
updated: 2026-08-12T13:12:48.456Z
tags: Collector Urchin, Tripneustes gratilla, Sea urchin, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/echinoderms/sea-urchin/collector-urchin
---

# Collector Urchin (*Tripneustes gratilla*)

## Quick facts

- **Group:** Sea urchin (*Echinoidea*)
- **Size:** up to 15 cm across
- **Depth:** 1-30 m
- **Diet:** Herbivore
- **Activity:** Cathemeral
- **Rarity:** Common
- **Habitat:** Seagrass beds, rubble and reef flats
- **Reproduction:** Broadcast spawner, Gonochoric
- **Hazard:** Dangerous, Venomous

## How to recognise it

- short blunt white to purple spines over a dark test, never long needles
- usually carrying seagrass blades, shells and rubbish on its back
- bands of tube feet visible between the spines
- up to 15 cm across

A round urchin to 15 cm (6 in) with short blunt spines, almost always wearing something: seagrass blades, shell fragments, bits of rubble held over the back by its tube feet. The habit is what the name records, and the animal collects continuously.

Why it does it is not fully settled. The load shades the urchin from ultraviolet light, breaks up its outline, and may weigh it down against surge; individuals in bright shallow water carry more than those in the shade, which supports the sunshade explanation over the others.

The spines are short and hollow and carry mild venom, along with small pincer organs between them that grip and inject anything soft that lands on the test. Stepping on one is unpleasant rather than dangerous, but the spine tips break off in the skin.

It is one of the most important grazers on any reef flat. Where these urchins are removed, algae take over the seagrass and rubble within months, and they are farmed and released as a biological control on algae in several countries - an animal whose main value is that it eats constantly and indiscriminately.

## Also known as

- **English:** Bischofsmützenseeigel, collector urchin, Parson's hat sea urchin
- **French:** Oursin-bonnet de prêtre
- **Italian:** riccio collezionista
- **German:** Gift-Seeigel, Pfaffenhut-Seeigel
- **Portuguese:** Ouriço-do-mar-decorador
- **Czech:** ježovka křehká
- **Japanese:** シラヒゲウニ
- **Chinese:** 白棘三列海膽 (花膽 馬糞海膽), 白棘三列海膽, 馬糞海膽
- **Russian:** Трипнеустес
- **KO:** 흰수염성게
- **TH:** เม่นแต่งตัว

## Scientific synonyms

- *Cidaris angulosa* Leske, 1778
- *Cidaris variegata* Leske, 1778
- *Echinus (Tripneustes) sardica* auct.
- *Echinus fasciatus* Lamarck, 1816
- *Echinus gratilla* Linnaeus, 1758
- *Echinus inflatus* Blainville, 1825
- *Echinus pentagonus* Lamarck, 1816
- *Echinus peronii* Blainville, 1825
- *Echinus subcaeruleus* Lamarck, 1816
- *Echinus variegatus* (Leske, 1778)
- *Echinus virgatus* Des Moulins, 1837
- *Hipponoe nigricans* A. Agassiz, 1863
- *Hipponoe sardica* (L. Agassiz in L. Agassiz & Desor, 1846)
- *Hipponoe variegata* (Leske, 1778)
- *Hipponoe variegata var. alba* Tenison-Woods, 1883
- *Hipponoe violacea* A. Agassiz, 1863
- *Tripneustes (Hipponoe) variegasta* (Leske, 1778)
- *Tripneustes angulosus* (Leske, 1778)
- *Tripneustes bicolor* Perrier, 1869
- *Tripneustes fuscus* Michelin, 1862
- *Tripneustes garatilla*
- *Tripneustes grabella*
- *Tripneustes lorioli* Lambert & Thiéry, 1914
- *Tripneustes pentagonus* (Lamarck, 1816)
- *Tripneustes sardicus* L. Agassiz in L. Agassiz & Desor, 1846

## Range

Cape Howe, Eastern Africa & Madagascar, Egypt, Federal Republic of Somalia, Indian Ocean, Kenya, Madagascar, Maldives, Mozambique, New Zealand, Northeastern New Zealand, Philippines, Red Sea, Republic of Mauritius, Seychelles, South Africa, Tanzania, Western Indian Ocean

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/echinoderms/sea-urchin/collector-urchin)*
*Updated: August 12, 2026*