Tag Archives: Holotype

The Neotype – Why, When and How

Since my last piece was rather short I thought I would write another on a totally different topic. In past posts I have mentioned Neotype’s on several occasions and defined it as more or less as a replacement, or new type for a species.

In the glossary of the Code the Neotype is defined as: “The single specimen designated as the name-bearing type of a nominal species or subspecies when there is a need to define the nominal taxon objectively and no name-bearing type is believed to be extant.”

It has the same function as the Holotype in that it is now the name bearing type of the species. My reasons for doing a post on this is that in my recent description I set one for the turtle species Elseya branderhorsti, or Branderhorst’s Snapping Turtle, pictured above is the Neotype prior to fixation. I have also seen, or at least heard about this being done the wrong way and for the wrong reasons. I would suggest for people who do not understand this to download my recent paper and look at the Elseya branderhorsti section.

First up, and I want to state this very clearly, if there is an existing Holotype (or Lectotype or Syntype) for a species you cannot set a Neotype for that species. If for some reason one is required in this situation then a Case to do so must be submitted to the ICZN for consideration and only they can set the Neotype. An example of this is Case 3628 where Ehret et al (2013) have requested a Neotype be set to replace a poor quality and essentially unusable Holotype for the fossil species Terrapene putnami. They have had to outline their reasons and provide details of a suitable specimen as the Neotype.

Under the Code there are, however, occasions where you can set a Neotype and this needs to be done in a peer reviewed journal, a high quality one that is used to publishing taxonomic or nomenclatural paper is preferred. It must be done for the right reasons and if you look at the relevant Article (75) of the Code one thing I hope is apparent is that it’s actually more difficult to set a Neotype than it is a Holotype (in the original description), and so it should be. There are good reasons for this and one such reason is one practice I have heard of which is setting a Neotype for a species essentially making it a Nomen Novum (new name) which would place it in synonymy with another species. In simple terms someone has found an old name without a type that has been found to apply to an otherwise undescribed species. They set a Neotype to destroy the old name so they can name the now un-named species.

To avoid the above scenario occurring either deliberately or accidently there are many conditions a Neotype must meet. Apart from the point that there must be no existing type you also cannot do it for no other reason than there is no type. The Mata mata (Chelus fimbriatus) has no type, never did, yet there is no justification for setting a Neotype. It is a monotypic genus with no confusion as to which species it is. Hence no justification for a Neotype. If it is demonstrated to be more than one species maybe that could change, but until then it is not justified under Article 75.2 of the Code.

Article 75.3 (1-7) are the qualifying conditions for a Neotype designation. I would suggest people look through them on the ICZN website. Basically you must demonstrate why you need to do this, that there are no other types, describe your Neotype, declare it, and ensure it is in a Museum or similar. One of our difficulties in the Elseya branderhorsti case was determining exactly where the original, lost, Holotype had been collected. We went into a detailed reconstruction of the original collectors travels through southern New Guinea and then used this to restrict the type locality (that is define it better) and then collected our Neotype from this area.

In the paper the entire section on Elseya branderhorsti was about setting up our objective of setting a Neotype for this species, the original was lost, we published photos of the Neotype, measurements, placed it in a Museum (Papua New Guinea National Museum), declared it represented the same species as the original description and importantly presented reasons for setting the Neotype. Our reasons were that Elseya branderhorsti overlapped in range with another species that was new to science that we were describing in the same paper. So it was a clarification of which taxa was which by having name bearing types for both in a region and genus that had seen some very confusing taxonomic and nomenclatural issues.

Despite the point that I have tried to show that setting a Neotype is difficult I have tried to point out why. I hope that people understand that they are, however, very important and can go a long way to clarifying nomenclatural issues. When genuinely needed they should be set and there are many reasons for this. It is generally older names that need this, ie they never had a type or its been lost but there are some newer names where the types have been lost or destroyed by accident.

How names are attached to animals, the importance of the type.

I wanted to write about this one because there are a lot of misconceptions about how this is actually done. It is important to understand the process, by understanding a process we can understand why we would do something. So in this case by understanding the connection between nomenclature and taxonomy we can understand why I will recommend certain names be used.

When a species is described the actual published description is attached, or based, on a single specimen called the holotype. This specimen is a representative of a wild population. As a taxonomist I see types as so important I go to great lengths to ensure that any species I name is actually represented correctly and with useable material. There is nothing worse than have holotypes of different species that are effectively not comparable, for example, one species being represented by an adult and another by a juvenile. There are many changes in the morphology between juvenile and adult due to growth and maturity, likewise there can also be differences between the sexes.

Although not required I have come to the decision, over time, to only set adult females as Holotypes. I also set a Paratype which is an adult male and declare it the Allotype. A Paratype is one or more individual specimens examined at the same time as the holotype and declared as such in the original description, an Allotype is a specimen of opposite sex to the holotype, also declared at the same time as the Holotype. As I said the way I do this is not required, I can in fact set any specimen that is representative of the species I am describing as the Holotype and I do not have to set a Paratype or an Allotype. I do not think taxonomists working on other species should follow my view on this. My reasons for adult females are two fold, first by choosing one or the other and following it I have taken sexual dimorphism out of the issue when comparing types, second I choose females because they are somewhat easier to catch in turtles, they bask more, come out of the water more, go into traps easier, hence it is a little more likely that anyone comparing freshwater turtle species will be looking at females. An equally valid argument can be made in snakes, for example, to set males as holotypes since hemipene morphology is an important diagnostic character. But this is all preference, entirely up to the person working on the group. The only compulsory part under the ICZN Code is that a holotype is set.

The name for the taxon is attached to this holotype so whatever that holotype turns out to be that is where the name goes. As I discussed in the Chelodina oblonga article a misidentified holotype is generally a difficult issue, often requiring the intervention of the ICZN. It will often mean that a name, well used and understood, is going to be moved to another species. All the previously published literature on that species will now be using the wrong name. This can create a lot of confusion, and believe it or not anger. It also in vertebrates such as reptiles creates legal issues, as many are protected by various local and international laws and agreements.

The part of all this that attaches the name to the holotype and determines if that name is available for use is nomenclature, and is governed by the ICZN Code. The term available has a very specific meaning in Nomenclature. It means that the name has been published in accordance with the ICZN Code and has sufficient details in the description to meet Articles 10 to 20 of the Code. So put simply this would mean the original description identifies a type specimen, provides diagnostic characters that claim to differentiate the taxon and is not an identical name to another species in the same genus. There are several other minor rules also and readers can look at Articles 10 to 20 of the code for themselves to see what a description needs to have. Feel free to ask me questions on this.

So if the name is available the next part is the taxonomy. The population represented by the holotype is demonstrated by acceptable means to be diagnosable different to other populations. This can be done with morphology, molecular work and statistics. I personally prefer to see all three. Now that is taxonomy, this is where the two connect through that holotype which is a part of the taxonomic analysis, and of course is attached to the name. Taxonomy and Nomenclature are separate fields, but are also intrinsically entwined in their practice. The taxonomy will produce, among other things, a synonymy and this is a list of the available names in order of Priority, that is, in order of usage by date of publication. The oldest name, is the one to be used for the taxon. Or a new one is proposed if there was none, and that leads back to nomenclature.

The Holotype is, therefore, the most important specimen of any species. If you go to a museum to examine specimens of a species you are working on you will soon see this. The way Holotypes are stored, and who has access to them, and the fact that they generally cannot be loaned out shows the higher level of importance placed on them. Many older names have problematic types. Many do not have one at all, or they may have a type series, called syntypes. This is because the concept of types came into zoology some 100 years after Linnaeus so early descriptions do not have them actually set. This is fine under the Code; it’s not fair to hold someone’s work to a set of rules that came into being over 100 years after they wrote the paper. However, it is important to try and identify which specimens were used in the description and this is one of the causes of confusion in nomenclature with older names.

If there is a series of syntypes and there is potential for confusion, eg more than one species represented by the syntypes (eg Chelodina expansa, Emydura victoriae are both in this position) a lectotype is often set. A lectotype is a specimen from the type series that has been determined to be the name-bearing type, that is, the one the name is actually attached to. This is done by a later author who is reviewing the issues. If a holotype is absent altogether and there is good reason to expect confusion, a neotype can be set. This is again a name-bearing type that is equivalent to a holotype and will now represent the name. Again this must be justified and done by a later author who is reviewing the problem at hand.

The one thing I will emphasize above all else, examination of the types.  If you want to publish a work naming a new species, or rearranging them significantly, you must examine all the relevant types. Many specimens in museums are misidentified, this is not their fault they have the label that the museum was given when they got them, this could be 50 or 100 years ago, even older. If you do not examine the types you cannot guarantee that a name is attached to the correct species.  The two examples I mentioned before; Chelodina expansa has two syntypes, one is a C. expansa, one is a C. longicollis; Emydura victoriae has two syntypes, one is an E. victoriae, one is an E. macquarii. In the end seriously, examine the types, after all do you want to be remembered for the species you named, or the mess you made?