Bischofsmützenseeigel

Tripneustes gratilla

Other invertebrates
IUCN: Not evaluated

Usual depth2–18 m
Water temperature18–30 °C
Best monthsJanuary, April, and May
How commonOccasional

Photo credit: (c) Philippe Bourjon, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist

About this species

Tripneustes gratilla, the collector urchin or halloween urchin, is a species of sea urchin. Collector urchins are found at depths of 2 to 30 metres in the waters of the Indo-Pacific, Hawaii, the Red Sea, and The Bahamas. They can reach 10 to 15 centimetres in size.

Text from the Wikipedia article “Tripneustes gratilla”, licensed CC BY-SA 4.0. Read the article

Where and when

Where it has been recorded

Worldwide

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Best months

Worldwide (open data)

January: 611 records
February: 332 records
March: 327 records
April: 424 records
May: 436 records
June: 297 records
July: 417 records
August: 356 records
September: 385 records
October: 391 records
November: 424 records
December: 385 records

Depth and water temperature

Depth

Mostly recorded at 2–18 m · Deepest record: 814 m

0–10 m: 313 records
10–20 m: 305 records
20–30 m: 7 records
30–40 m: 24 records
40–50 m: 15 records
50–60 m: 15 records
60–70 m: 1 records
70–80 m: 0 records
80–90 m: 0 records
90–100 m: 0 records
100–110 m: 0 records
110+ m: 1 records

Water temperature

Recorded in surface water of 18–30 °C

16–18 °C: 4 records
18–20 °C: 2 records
20–22 °C: 63 records
22–24 °C: 17 records
24–26 °C: 36 records
26–28 °C: 94 records
28–30 °C: 94 records

Photos

(c) Philippe Bourjon, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
(c) Jacek Pietruszewski, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Franz Anthony, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Nick T., some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
no rights reserved · CC0 1.0 · iNaturalist
(c) Алёна Осипова, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Jay Pruett, some rights reserved (CC BY) · CC BY · iNaturalist

Names and classification

English: Bischofsmützenseeigel, Collector urchin, Parson's hat sea urchin, Cake Urchin, collector urchin, Short-spined Urchin

Names in 6 more languages

German: Gift-Seeigel, Pfaffenhut-Seeigel
French: Oursin-bonnet de prêtre
Japanese: シラヒゲウニ
Korean: 흰수염성게
Thai: เม่นแต่งตัว
Simplified Chinese: 白棘三列海膽, 白棘三列海膽 (花膽馬糞海膽), 馬糞海膽

Other scientific names: Cidaris angulosa, Cidaris variegata, Echinus (Tripneustes) sardica, Echinus fasciatus, Echinus gratilla, Echinus inflatus, Echinus pentagonus, Echinus peronii, Echinus subcaeruleus, Echinus variegatus, Echinus virgatus, Hipponoe nigricans, Hipponoe sardica, Hipponoe variegata, Hipponoe violacea, Tripneustes (Hipponoe) variegasta, Tripneustes angulosus, Tripneustes bicolor, Tripneustes fuscus, Tripneustes garatilla, Tripneustes grabella, Tripneustes lorioli, Tripneustes pentagonus, Tripneustes sardicus, Tripneustes subcaeruleus, Tripneustes variegatus, Tripneustes zigzag

Similar species

Toxopneustes pileolus
Warty Sand Urchin
Nudechinus verruculatus
Stained Collector Urchin
Pseudoboletia maculata

Sources and credits

Names and taxonomy: WoRMS (CC BY 4.0) and the GBIF Backbone (CC BY 4.0). Photos: iNaturalist observers, each under the licence shown (CC0, CC BY or CC BY-SA).

Depth, temperature, months and maps: records from OBIS and GBIF under CC0 or CC BY.
Descriptions: Wikipedia, licensed CC BY-SA, each linked to its article.
Conservation status as published by GBIF (IUCN Red List).
2,084 open-data records from 1758 to 2023.
Species data updated October 26, 2026.

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