Seaslug species numbers

Many species of nudibranchs and their relatives have not yet been scientifically described and named. When referencing an unnamed or unknown species, authors usually use numbers to represent them, such as Goniobranchus sp. 1 if the genus is known or perhaps Dendrodorididae sp. 3 if the animal can be identified only to family. Confusion may arise when different authors, or sometimes even the same authors, use different species numbers to refer to the same species. For example, Gymnodoris sp. 51 in Gosliner et al (2018) is called Gymnodoris sp. 6 in Debelius & Kuiter (2007), Gymnodoris sp. 2 on the Sea Slug Forum and Gymnodoris sp. 12 in Gosliner et al (2008).

We have taken a different approach. We assign each different species we find in a particular geographic location a separate 3-digit number and prefix it with a letter to indicate the location: e for the Marshall Islands (I started my numbering at Enewetak Atoll and subsequently included all the Marshall Islands under this category), h for Hawaii, b for Bali, a for Anilao (Philippines), l for Lembeh Strait (Indonesia), p for Pohnpei (Caroline Islands), s for the Solomons, c for California and sc for Mexico's Sea of Cortez. So b163 is the 163rd seaslug species we saw in Bali. Our species numbers are a bit more awkward, but are not likely to be confused with different species in different references. Where confusion could arise is when we use different numbers for the same species from different areas, for example Tenellia sp. b065 from Bali and Tenellia sp. a025 from Anilao.

As long as we are on the subject of species names, you may notice that we often use the letters "cf" between the genus and species names. The cf is an abbreviated form of the Latin "confer" meaning "compare." What we mean by Jorunna cf ramicola, for example, is that this is a species of Jorunna and we think it could be the species ramicola, but it it really needs to be verified by comparing it with the real species.

In fact, we use "cf" too often. Some of our cf references should probaby be changed to "aff," which means this species is related to or has an affinity to, but is not identical to, the species with the binomial name that follows. For example, we could say Platydoris sp. aff. P. pulchra if our animals are similar to Platydoris pulchra but we do not really think they are that species.

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