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.