Common names can overlap
Names such as polka dot, black and white or pyjama can describe more than one animal.
Common names vary between dive guides, countries and websites. Scientific names give divers and photographers a shared language for nudibranchs and sea slugs.
How a scientific name works
Chromodoris willani
Genus
Chromodoris
The broader group. Think of it as the family name.
Species
willani
The individual species within that group.
Scientific names travel well
A scientific name can be understood by divers, photographers and researchers around the world.
Photos still matter
Correct identification also depends on body shape, colour pattern, rhinophores, gills and location.
Common Name vs Scientific Name
Shaun the Sheep
Costasiella species
Chamberlain's Nembrotha
Nembrotha chamberlaini
Spanish Dancer
Hexabranchus sanguineus
Why Sea Slug Classification Can Feel Complicated
Most divers only need to understand genus and species to make sense of scientific names. With sea slugs, however, the wider classification can become complicated very quickly. That is why MacroDivers keeps the database simple enough to use, while still trying to use correct taxonomic terminology.
A familiar animal: black rat
A black rat has a relatively familiar classification structure:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Rodentia
- Family: Muridae
- Genus: Rattus
- Species: Rattus rattus
A sea slug example: Armina magna
A sea slug such as Armina magna can sit within a much deeper classification structure:
- Kingdom: Animalia
- Phylum: Mollusca
- Class: Gastropoda
- Subclass: Heterobranchia
- Infraclass: Euthyneura
- Subterclass: Ringipleura
- Superorder: Nudipleura
- Order: Nudibranchia
- Suborder: Arminina
- Superfamily: Arminoidea
- Family: Arminidae
- Genus: Armina
- Species: Armina magna
How MacroDivers Uses Order and Type
We have tried to keep MacroDivers useful for interested divers rather than turning it into a scientific database. At the same time, we want to use the correct terminology wherever we can.
If you are trying to identify a sea slug you have seen or photographed, and you already know the genus, the shortlist of possible species may be manageable. If you do not know the genus, you need another way to reduce the options.
For that reason, the MacroDivers database includes Order and Type.
Order
Order is the formal taxonomic order used for the animal at the time the page or database entry was reviewed. For nudibranchs, this will normally be Nudibranchia, but sea slugs also include animals outside Nudibranchia.
Type
Type is our practical identification grouping. Where possible, Type follows the official suborder. In some cases, however, another taxonomic level or practical grouping may be more useful for identification. That is why we call it Type rather than presenting it as an official scientific rank.
Why Names and Groups Sometimes Change
Sea slug taxonomy is not fixed forever. As scientists study anatomy, DNA, relationships between species and older descriptions, animals can be moved between groups, renamed, split into separate species or combined with others.
That means a name or classification that was accepted when a page was written may later change. We do our best to keep MacroDivers accurate and up to date, but changes do happen and we may not always spot them straight away.
If you notice a possible error, please contact us and let us know. Corrections from experienced divers, photographers and sea slug enthusiasts help make the site better for everyone.
Report a possible ID or taxonomy errorScientific Names FAQ
Why do sea slugs have scientific names?
Scientific names give each species a more precise identity than common names. Common names can vary between countries, dive guides and websites, but scientific names help divers, photographers and researchers talk about the same animal more clearly.
What is the difference between genus and species?
The genus is the broader group, and the species identifies the individual animal within that group. In Armina magna, Armina is the genus and Armina magna is the species name.
Why does MacroDivers use Order and Type in the database?
Order gives the formal broad taxonomic group. Type is a practical MacroDivers grouping to help narrow down identification. Where possible it follows the official suborder, but in some cases another grouping is more useful for divers trying to identify a sea slug from a photograph.
Is Type an official taxonomic rank?
No. Type is not an official taxonomic rank on MacroDivers. It is a practical identification field designed to make the database easier to search and understand.
Why do sea slug names and classifications change?
Taxonomy changes as scientists learn more. New research, DNA studies and closer examination of older records can move species into different groups, change names, or reveal that animals once thought to be one species are actually several.
What should I do if I think MacroDivers has a wrong name or classification?
Please contact us and tell us what you think is wrong. Include the page, species name, photo or database entry, and any source you are using. We are happy to review corrections and update the site where needed.
Back to Nudibranchs
Return to the Nudibranchs Academy section to explore anatomy, behaviour, identification, life cycles, food sources and hotspots.
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