Triturus ivanbureschi, sort-of new species

[FrogEyes]

For some time, three species-level groups have been known by the name Triturus karelinii. The western was named T.arntzeni, the central T.karelinii, and the eastern unnamed [trusting my memory here]. The present paper treats the type specimens of T.arntzeni as T.macedonicus, although other populations remain undescribed members of the T.karelinii group. The type locality of T.karelinii is actually in the eastern region, resulting in that population retaining the name. As the central and western groups are related, they are treated as a single species under the new name T.ivanbureschi. The present authors have previously ignored the name T.arntzeni in their studies, and this is now explained by their referal of type specimens to T.macedonicus.

The paper is open-access:
http://www.mapress.com/zootaxa/2013/f/zt03682p453.pdf

B. WIELSTRA, S.N. LITVINCHUK, B. NAUMOV, N. TZANKOV, & J.W. ARNTZEN, 2013. A revised taxonomy of crested newts in the Triturus karelinii group (Amphibia: Caudata: Salamandridae), with the description of a new species. Zootaxa 3682 (3): 441–453.

Abstract

We present a taxonomic revision of the crested newt Triturus karelinii sensu lato. Based on the presence of discrete nuclear DNA gene pools, deep genetic divergence of mitochondrial and nuclear DNA, and no indication of gene flow, we interpret this taxon as comprising two species: one covering the southern Caspian Sea shore, the Caucasus and the Crimea, i.e. the eastern part of the total range and another covering northern Asiatic Turkey and western Asiatic Turkey plus the southeastern Balkan Peninsula, i.e. the central and western part of the total range. We acknowledge that the central/western species should likely be further subdivided into a central and a western taxon, but we prefer to await a more detailed genetic analysis of the putative contact zone, positioned in northwestern Asiatic Turkey. The name T. karelinii (Strauch, 1870) applies to the eastern species as the type locality is positioned along the coast of the Gulf of Gorgan, Iran. The name T.arntzeni has been applied to the central/western species with Vrtovaæ, Serbia as the type locality. We show that not T. karelinii sensu lato but T. macedonicus occurs at Vrtovaæ. Hence, the name T. arntzeni Litvinchuk, Borkin, Džukiæ and Kaleziæ, 1999 (in Litvinchuk et al., 1999) is a junior synonym of T. macedonicus (Karaman, 1922) and should not be used for the central/western species. We propose the name T. ivanbureschi sp. nov. for the central/western species and provide a formal species description.

 

[otolith]

The splitting makes sense given how isolated the populations are, but it seems kind of useless without photos of each described species. A lot of these papers build upon incredibly esoteric knowledge/papers, how does one describe a new species without providing any photographs (3 pictures of a long preserved specimen don't cut it)? All of the papers describe the merits of splitting based on mitochondrial DNA etc. but can't manage a few photographs of individual animals from the various type localities. I feel like there have been a lot of seemingly arbitrary taxonomic revisions lately and without locality data for our animals (which in many cases is not possible) what do we do? From the hobbyist perspective it makes it difficult to know what we keep, and what to call it. If we keep "T karelinii" what do we call them? The few photos of T. macedonicus I've seen don't look anything like T. arntzeni, and the three specimen photos (of the same animal) of T. ivanbureschi look more like T. cristatus than T. karelinii.

While I don't doubt the validity of splitting the T. karelinii species complex I do find the disconnect between the value of photographic vs. mitochondrial/nuclear DNA charts incredibly frustrating.

 

[FrogEyes]

In my experience, photographs are misleading in many instances. People are under the mistaken belief that general "look"of an animal is sufficient to identify it, when that is frequently not the case. This paper provides detailed morphological descriptions of the species concerned, and comparison to those details will serve you better than 'it sorta looks like that picture'. They do note that at present, there are no traits to distinguish T.ivanbureschi from T.karelinii, but that the two species do not overlap or interbreed and are genetically distinct.

Case in point:

and the three specimen photos (of the same animal) of T. ivanbureschi look more like T. cristatus than T. karelinii.

Physical differences are not a requirement for speciation - lack of interbreeding is. Given sufficient generations and population size, any two populations which have ceased to interbreed are likely to randomly accumulate visible, audible, habitat, or behavior differences by random chance. There is no requirement though, that this happen. Consequently, organisms may appear identical yet be distinct and non-interbreeding species.

Hyla chrysoscelis and H.versicolor are a decent example: they look identical, have largely overlapping ranges and habitats, and voices which are very similar below 16C. One can get a fair impression of which is which from where they occur and what they look like, but since they breed in the same ponds and all color variants occur in both species, you can only really tell by comparing calls above 16C, examining the chromosomes, or looking at cells under a microscope. Nonetheless, they are distinct species which favor different habitats and which are unable to interbreed because of their different chromosome counts. In fact, they're not truly even sibling species, as H.versicolor seems to be derived from hybridization of three OTHER species which are apparently now extinct.

As for animals not looking like T.macedonicus, that's covered in both the abstract and in my summary above: the type specimens of T.arntzeni and those from the type locality are T.macedonicus. That makes the name T.arntzeni a synonym of T.macedonicus. Captive populations of "T.arntzeni" probably did not come from the type locality, which means they are not T.macedonicus, but also means they are unnamed. They now take the name T.ivanbureschi, which IS based on animals belonging to that species. Basically, all "T.arntzeni", plus [for the moment] all central "T.karelinii", except those from the type locality of the former, take the new name T.ivanbureschi.

 

[otolith]

Just because photographs can be misleading does not mean they do not have value. It seems there are over a dozen described Asian caudate species that seemingly no one knows what they look like except for a physical description in a translated paper. A physical description will always be more helpful when accompanied by a photographic example of a "typical" specimen.

I understand the tenets of speciation, I take no issue with the contents of the paper. The "what do I have?" question was more of a rhetorical one. I am simply trying to make the point that papers like this continue to be more or less useless to the average hobbyist without the addition of more accessible forms of data.

 

[FrogEyes]

Just because photographs can be misleading does not mean they do not have value.

I agree. I just feel that among hobbyists, they can do more harm than good sometimes.

It seems there are over a dozen described Asian caudate species that seemingly no one knows what they look like except for a physical description in a translated paper.

As my current projects have not yet dealt with hynobiids in detail, I don't know what species you refer to. All salamandrids from Asia have photos available, either in the describing paper or in subsequent sources. Many people would probably misidentify several of those species if they depended on photos for identification. Tylototriton yangi, T.pseudoverrucosus, T.pulcherrima, and Yaotriton lizhenchangi were published without illustrations, but color photos were posted online and reposted shortly thereafter, and then more were included in a book. Y.ziegleri appeared in print prior to its description. All Pachytriton and Paramesotriton appeared with photos, but Pachytriton are almost impossible to ID without a ruler and calculator.

A physical description will always be more helpful when accompanied by a photographic example of a "typical" specimen.

I'd LIKE to agree, but can't. On more than one occasion I've been more confused by photos, because they don't quite show a diagnostic trait in the most meaningful way, or because they show [or don't show] traits which don't seem to line up with the description. Still, I'd rather HAVE a set of good images than lack them, especially if the description is in Chinese or is poorly translated!

I understand the tenets of speciation, I take no issue with the contents of the paper. The "what do I have?" question was more of a rhetorical one. I am simply trying to make the point that papers like this continue to be more or less useless to the average hobbyist without the addition of more accessible forms of data.

Understood. In the context of the present thread:
T.karelinii/T.arntzeni from the type locality of the latter = T.macedonicus
T.karelinii from eastern populations = T.karelinii
T.karelinii/T.arntzeni from anywhere else (ie western or central) = T.ivanbureschi
T.karelinii/T.ivanbureschi from central populations may be described as another species later.

T.macedonicus can be morphologically distinguished.
Anything in the T.karelinii complex will ID as T.karelinii, and you'll need locality data