Dear Sylvia,

The example name you used is spelt Bullina lineata and only the first name begins with a capital letter. This is the species' scientific name and as you will see on the Fact Sheet about 'common names' it is the only name worth using if you want to be understood worldwide.

All animals have two words in their scientific name and we call this a binomial system - [bi = two; nomen = name]. The first word Bullina is the genus name - the genus being a group of closely related animals. If you look in the species list you will see that first names often repeat themselves. All the species with the same first name are closely realted to each other. The second name, in this case lineata is what we call the species epithet.  It shouldn't be called the species name because we don't go round talking about 'I found a 'lineata' yesterday' - or if we do we shouldn't - because lineata is used for many species and just means 'lined'. The animal's 'species name' is Bullina lineata which we usually write in italics. We can shorten it to B. lineata if its clear we are talking about a species of Bullina, but we shouldn't use such shorthand if the 'B' could be confused with all the other genera, such as Bulla or Bothryembrion, which start with B.

It's a system that works quite well because it means every species has a unique name. By including the genus name as well it means we can link related species together, much like many human cultures use surnames or family names.

Best wishes,
Bill Rudman

Dear Maria,

The short answer is that it doesn't have a common name. Have a look at the Fact Sheet I have on the use of common names

Best wishes,
Bill Rudman

Dear Dave,

As you might know from reading various replies, I am not a big fan of common names. The main problem is that these names are used non-uniformly around the world, and may apply to different species. White lined, this and that, tells us nothing, and can lead to miss-communications. Ali and I put many in the book, but hope readers will use the scientific nomenclature in the end. Hence no Index of Common Names. The scientific names are not that hard to learn, and force you to group similar species within genera and family. See Bill's comments on common names

Hope you understand,
Dave Behrens

Dear Brendan,
This sounds like a question a teacher has given the class. Rostanga pulchra is the scientific name of a nudibranch. It doesn't have a meaning. I guess you would be puzzled if someone asked you what 'brendan' meant in English, just as I would if someone asked me what 'bill' meant. It doesn't mean anything - it's our names!

We give animals and plants scientific names so that everyone in the world uses the same name for the same animal. For example, there must be a 1000 names for a lion in different languages around the world, but when biologists call it by its scientific name, Panthera leo, they all know what they are talking about. Under a set of international rules, scientific names are made either from Ancient Greek or Latin words, or if words from modern languages are used, they have to be 'latinised'. Scientific names can be made from existing words, or they can just be made up. I am not sure whether Rostanga is a made up word. Sometimes names of ancient gods and mythical characters are used. However, pulchra is from a Latin word meaning pretty. I named another species of Rostanga, Rostanga bassia, because it came from a place called Bass Strait, and there is another species called Rostanga arbutus, because arbuta refers to the cherry, and the species is cherry red. However this doesn't mean that Rostanga arbutus means the 'cherry red Rostanga' or that Rostanga bassia means the 'Bass Strait Rostanga'. It just shows how scientists make up new names.

Some books have English 'translations' alongside scientific names. These are silly, and often don't make sense and are certainly NOT the meaning of the scientific names. They don't need a meaning - they are names. I hope you have an interesting class discussion at school.
Best wishes,
Bill Rudman

Dear Danna,
I am afraid most species don't have common names in any language. Have a look at my views on common names. Also look at other postings on this topic which are attached below. There are plenty of photobooks in English which have invented 'common' names to please their editors or publishers. This is quite absurd in itself. If you were to translate these 'common names' into French it would just be taking the absurdity to a higher level.
Best wishes,
Bill Rudman

Dear Marina,
Congratulations on your site. Concerning the word 'Sea Slug'. I guess its the continuing problem with common names. I suspect whoever is giving you advice doesn't really know what they are talking about. 'Sea Slug' is a very broad term encompassing all opisthobranch molluscs and unfortunately sometimes some non-mollusc animals such as Holothurians. My feeling was that 'limace de mer' had the same wide meaning in French as 'Sea Slug' has in English so I did a quick web search in google.com and quickly confirmed this view. Although 'limace de mer' is used for nudibranchs, as in English, it is also used for Sea Hares [also = Lièvre de mer, Aplysie, Pisse-Vinaigre] and sacoglossans.

For example, on the website of The Natural History Museum, Paris, 'Limace de mer' is used as a synonym of 'l'aplysie' [http://www.mnhn.fr/expo/cerveaux/sommaire.htm].
And on another site about the pest alga Caulerpa taxifolia in the Mediterranean, 'limace de mer' is used for the sacoglossan Elysia. [http://www.ifrance.com/asame/francais/exocetus1999/article4/exocetusarticle4.htm].

My advice is to use limace de mer = sea slug = Opisthobranchia. People who tell you otherwise are just wrong.
Best wishes,
Bill Rudman

Dear Jeff,
If you look at the my general comments on using common names, and at the other messages on this page you will see that I don't think common names are a very good idea for sea slugs. I don't know of any species which is commonly called the Striped Pajama Nudibranch. I did a quick web search for 'Pajama Nudibranch' and came up with three sites all referring to animals from the Red Sea. One did not identify the slug, and the others referred to two quite different nudibranchs - Nembrotha megalocera and Chromodoris quadricolor.

I don't know if you have more than the common name to start with but I really can't help more unless I have a photo or further information on what you are calling the Striped Pajama Nudibranch.

Dear Kathe,
Thanks for a wonderful story,
Bill Rudman

Dear Jun,
Don't worry too much about how you pronounce scientific names. My European colleagues often laugh at my pronunciation of some scientific names and I must admit that I find the pronunciation of some of our American colleagues quite incomprehensible. But it doesn't take long for us to sort out the few words we don't understand. So my advice is do your best and if you meet someone who pronounces a word differently from you just remember that no one really knows how the Romans pronounced their words.
Best wishes,
Bill Rudman

Dear Jun,
An interesting question. I have often wondered if there was some organisation which controlled or supervised the system of 'Japanese names' which has developed in Japan. As far as I know Japan is the only country that has developed this custom of giving a 'Japanese name' to species when they are first described.

In general, there are two types of common names which can be called 'Real' common names and 'Artificial' common names:
• Real Common Names are names that local people have used for an animal which is part of their local environment - something they eat, use for decoration, see all the time, etc. These names may have existed long before scientific names were invented. While such names are useful locally they can cause major problems nationally and worldwide. Fish are an excellent example of this. In Australia there may be 20 different common names used in different places for the same species of fish, and sometimes the same common name is used in different parts of Australia for different species of fish. So no-one knows what they are talking about when they buy & sell fish throughout the country. And the problems are even greater when Australians export fish to Europe, because many Australian names are derived from English names for quite different species of fish.
This is why scientific names are so useful. An animal can have only one scientific name and it has worldwide currency. As well as being a 'name' it also gives us a short summary of the evolutionary history of the animal as well. In animals like opisthobranchs there are very few true 'common names' anywhere in the world. Apart from 'Sea Hare' (Aplysia spp) and 'Spanish Dancer' (Hexabranchus sanguineus) there are not many names in common daily use for opisthobranchs.
• Artificial Common Names
When you look at an identification guide book you will usually find there are 'common names' for all species. These are nonsense names - often no more than a bad translation of the scientific name. Why publishers and authors do this I have no idea - I guess they think their readers will be more comfortable with 'English names' but I think this is insulting to their readers who are quite capable of learning scientific names. I don't know if dinosaurs are popular with kids in Japan, but certainly in Australia most kids can tell you the long scientific names of their favourite dinosaurs. So if kids have no problem with these names why should adults?

I hope I haven't moved too far from your question, but I think manufactured common names are confusing and unnecessary. I would be interested to know whether it is a problem to write scientific names in the Japanese alphabet? If so perhaps this would explain the tradition of 'Japanese names'.
Best wishes,
Bill Rudman

Dear Valda,
Common names are a problem because they are seldom in common use. As you suspect they are often made up by authors often under pressure from publishers. The whole point of scientific names, and the Rules that govern their formation and use, was to overcome the problem of common names, and provide a universal dictionary of species names.

Because I am often commenting on the use of 'common names' I have made a special page for any discussion on common names.

Best wishes,
Bill Rudman.