Robust Sea Squirt

Atriolum robustum

Other invertebrates
IUCN: Not evaluated

Usual depth10–52 m
Water temperature19–28 °C
Best monthsApril
How commonRare

Photo credit: no rights reserved · CC0 1.0 · iNaturalist

About this species

Atriolum robustum is a colonial tunicate or sea squirt in the family Didemnidae. It is native to the western and central Indo-Pacific where it is usually found anchored to a hard surface in shallow water.

Text from the Wikipedia article “Atriolum robustum”, 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: 0 records
February: 1 records
March: 1 records
April: 6 records
May: 2 records
June: 2 records
July: 0 records
August: 1 records
September: 1 records
October: 1 records
November: 1 records
December: 1 records

Depth and water temperature

Depth

Mostly recorded at 10–52 m · Deepest record: 225 m

0–10 m: 3 records
10–20 m: 5 records
20–30 m: 1 records
30–40 m: 0 records
40–50 m: 1 records
50–60 m: 1 records
60–70 m: 0 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 19–28 °C

18–20 °C: 2 records
20–22 °C: 1 records
22–24 °C: 0 records
24–26 °C: 3 records
26–28 °C: 3 records
28–30 °C: 7 records

Names and classification

English: Robust Sea Squirt, Urn Tunicate

Names in 1 more languages

French: Synascidie pomme de pin

Other scientific names: Atriolum robostum

Similar species

Green Barrel Sea Squirt
Didemnum molle
Gray encrusting compound tunicate
Diplosoma listerianum
Moseley's Ascidian
Didemnum moseleyi
Colonial tunicate
Didemnum perlucidum
Diplosoma virens
White crust
Didemnum candidum

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).
34 open-data records from 1964 to 2015.
Species data updated October 26, 2026.

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