Willey’s Nudibranch

About this species

Halgerda willeyi is a species of sea slug. It is a dorid nudibranch, a shell-less marine gastropod mollusk in the family Discodorididae.

Text from the Wikipedia article “Halgerda willeyi”, 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: 49 records
February: 49 records
March: 58 records
April: 60 records
May: 88 records
June: 73 records
July: 81 records
August: 72 records
September: 67 records
October: 57 records
November: 56 records
December: 50 records

Depth and water temperature

Depth

Mostly recorded at 6–43 m · Deepest record: 149.5 m

0–10 m: 41 records
10–20 m: 69 records
20–30 m: 20 records
30–40 m: 1 records
40–50 m: 4 records
50–60 m: 3 records
60–70 m: 2 records
70–80 m: 1 records
80–90 m: 2 records
90–100 m: 0 records
100–110 m: 1 records
110+ m: 3 records

Water temperature

Recorded in surface water of 20–29 °C

18–20 °C: 1 records
20–22 °C: 22 records
22–24 °C: 34 records
24–26 °C: 84 records
26–28 °C: 24 records
28–30 °C: 67 records

Photos

(c) Ewout Knoester, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
(c) Susan Prior, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Bernard Picton, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Georgina Jones, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
(c) Bernard Picton, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Dan Schofield, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Georgina Jones, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist

Names and classification

English: Willey’s Nudibranch

Names in 3 more languages

French: Halgerda de Willey
Japanese: エレガントヒオドシウミウシ, パイナップルウミウシ
Simplified Chinese: 威利瘤背海牛, 威氏瘤背海蛞蝓, 威氏瘤背盤海牛

Other scientific names: Doris incii, Halgerda elegans

Similar species

Batangas Halgerda
Halgerda batangas
Halgerda carlsoni
Golden Waffle Dorid
Halgerda dalanghita
Starry Waffle Dorid
Halgerda indotessellata
Halgerda mango
Halgerda scripta

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).
281 open-data records from 1903 to 2026.
Species data updated October 26, 2026.