Diamond-mask Sap-sucker

About this species

Costasiella kuroshimae is a species of sacoglossan sea slug. Costasiella kuroshimae are shell-less marine opisthobranch gastropod mollusks in the family Costasiellidae. Despite being animals, they perform photosynthesis, via kleptoplasty.

Text from the Wikipedia article “Costasiella kuroshimae”, 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: 23 records
February: 31 records
March: 49 records
April: 51 records
May: 76 records
June: 36 records
July: 48 records
August: 54 records
September: 24 records
October: 30 records
November: 26 records
December: 32 records

Depth and water temperature

Depth

Mostly recorded at 4–18 m · Deepest record: 25 m

0–10 m: 29 records
10–20 m: 19 records
20–30 m: 3 records

Water temperature

Recorded in surface water of 22–29 °C

22–24 °C: 9 records
24–26 °C: 45 records
26–28 °C: 10 records
28–30 °C: 43 records

Photos

(c) Gregor Bailar, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Heine Jensen, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Pierre Pericard, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Pierre Pericard, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Thomas Irvine, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Georgina Jones, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
(c) rashidchan, some rights reserved (CC BY) · CC BY · iNaturalist

Names and classification

English: Diamond-mask Sap-sucker, Leaf Sheep, Leaf Slug, little leaf-sheep, Little Leaf Sheep, Salty Ocean Caterpillar, Shaun the Sheep

Names in 3 more languages

French: Mouton des mers
Japanese: テングモウミウシ
Simplified Chinese: 黑島天兔海蛞蝓

Similar species

Costasiella paweli
Rabbit Sapsucking Slug
Costasiella usagi

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).
150 open-data records from 2002 to 2026.
Species data updated October 26, 2026.