Vipera ammodytes (Linnaeus, 1758)

Wüster, Wolfgang, Böhme, Wolfgang, Denzer, Wolfgang & Kaiser, Hinrich, 2025, Nomenclatural historians are kindly requested to respect the intent of the Code: “ Nomenclatural parsimony ” and the case of the Nose-horned Viper, Vipera ammodytes (Linnaeus, 1758), Zootaxa 5696 (3), pp. 385-397 : 387-392

The case of the Nose-horned Viper ( Vipera ammodytes )

Overview of the Vipera ammodytes complex. As generally conceived, the widespread, iconic, and medically significant European Nose-horned Viper, Vipera ammodytes ( Linnaeus, 1758) , is distributed from northeastern Italy and southern Austria south and east to Greece, northern Anatolia, and Georgia. This species is iconic because of the protrusion on its snout, it is well-known to the general public, of conservation concern in several range countries ( Happ et al. 1999; Happ & Wieser 2008; Plasinger et al. 2016; Tudor 2010), of public health importance due to the frequency of snakebites ( Di Nicola et al. 2021; Dobaja Borak et al. 2023; Radonić et al. 1997) and therefore listed as a Category 1 species (Highest Medical Importance) for most range countries by the World Health Organization (2013), and it is the subject of a considerable body of toxinological literature ( Georgieva et al. 2008; Križaj 2011; Osipov & Utkin 2023).

Vipera ammodytes was described by Linnaeus with “Habitat in Oriente” as the sole locality indication. For a long time, the type locality had been assumed to lie within the northwestern part of its range, namely the western Balkans , but it remained curiously ill-defined in the older literature (e.g., Boulenger 1896). Nevertheless , the northwestern populations have consistently been assigned to the nominate form, V. a. ammodytes , while three additional subspecies have been widely recognised since their descriptions: V. a. meridionalis Boulenger, 1903 , from Greece and adjoining regions); V. a. montandoni Boulenger, 1904, from SE Romania, eastern Bulgaria, European Türkiye; and V. a. transcaucasiana Boulenger, 1913 , from northern Anatolia and Georgia). This taxonomic arrangement has remained largely stable since Boulenger’s descriptions ( David & Ineich 1999; Di Nicola et al. 2021; Geniez 2018; Heckes et al. 2005; Klemmer 1963).

Further taxonomic refinements. Points of instability have revolved around science-driven rather than process-driven questions, including whether V. a. montandoni should be recognised as distinct from V. a. meridionalis ( Golay et al. 1993; Heckes et al. 2005; Thanou et al. 2023; Tomović 2006), and whether V. a. transcaucasiana constitutes a distinct species ( Nilson et al. 1999) or a subspecies of V. ammodytes ( Geniez 2018; Ursenbacher et al. 2008). In addition, several colour variants in the northwestern parts of the range were recognised as additional subspecies: V. a. gregorwallneri Sochurek, 1974, V. a. illyrica Laurenti, 1768 , and V. a. ruffoi Bruno, 1968. However, their recognition has remained an uncommon minority view in the literature that largely ceased after Tomović (2006) and Ursenbacher et al. (2008) demonstrated the cohesiveness of the northwestern populations (extending from southernmost Dalmatia to northeastern Italy).

Crucially, all previous revisions of the taxonomy of V. ammodytes neglected the fundamental step of exhaustively examining historical specimens and establishing the geographical origin of the Linnaean types for the species. Several authors attempted to restrict the type locality, and different options were retained by different subsequent authors. Mertens & Müller (1928) restricted the type locality to “Illyria” (i.e., the western Balkans ), whereas Schwarz (1936) restricted it to Zara (now Zadar), Croatia, both without providing detailed reasoning and without legal basis ( Dunn & Stuart 1951). Bruno (1968) stated that Linnaeus’s physical specimen, UPSZTY 95, in the Uppsala collection, had been collected by Edvardo Carlesonio from below the walls of Castello Nuovo di Duino, Trieste, effectively selecting it as the lectotype of V. ammodytes , but he did not provide a source. None of these authors critically examined the Linnaean type. As a result, the attempted restrictions of the type locality of V. ammodytes to the northwestern parts of the range remained unchallenged and allowed Vipera a. ammodytes to become universally accepted as the trinomen for the northwestern populations.

To understand the usage pattern of these long-standing trinomina, we searched Google Scholar, as well as available books and other older sources, for all references containing the string “ Vipera ammodytes ammodytes ”, and the terms Vipera , ammodytes , and meridionalis , and Vipera , ammodytes , and montandoni, verifying in each case that the names meridionalis and montandoni were indeed used as subspecific epithets for the relevant populations of V. ammodytes . As of 25 June 2025, this search has yielded 608 uses of the combination Vipera ammodytes ammodytes , 192 of Vipera ammodytes montandoni , and 346 of Vipera ammodytes meridionalis , all in the traditional sense outlined above ( Table 1 ). Since the name transcaucasiana is not affected by any nomenclatural uncertainty, it was not included in this bibliographic analysis.

For the sake of clarity against a background of confusing proposals for nomenclatural changes, we will in the following paragraphs refer to the traditional concepts of V. a. ammodytes , V. a. meridionalis , V. a. montandoni, and V. a. transcaucasiana as the Northwestern, Southern, Eastern, and Trans-Caucasian Nose-horned Viper, respectively.

Science-based changes: Thanou et al. (2023). Recently, Thanou et al. (2023) analysed the genetic structure of the V. ammodytes complex using ddRADSeq-derived genome-wide single nucleotide polymorphisms (SNPs) and found a deep split between northwestern populations, from central Albania and Serbia northwestward, termed the North Balkan Clade (NBC), and a South Balkan Clade (SBC), which included the remaining populations from Greece and southeastern Romania to the Caucasus. The NBC corresponds to the previous concept of V. a. ammodytes , whereas the SBC regroups V. a. meridionalis , V. a. montandoni, and V. a. transcaucasiana . Additional genomic structure was uncovered within the SBC, but Thanou et al. drew no taxonomic conclusions (but see Cattaneo 2021 and Roussos 2015). Given the absence of admixture between the NBC and the SBC, Thanou et al. suggested that they should be considered as separate species, the NBC becoming V. ammodytes and the SBC V. meridionalis . Thanou et al. (2023) did not explicitly recommend for or against the recognition of subspecies, but noted that recognition of the traditional subspecies meridionalis , montandoni, and transcaucasiana as subspecies of meridionalis would be most compatible with their results. Dufresnes et al. (2024) adopted recognition of V. meridionalis as a species and V. m. transcaucasiana as its subspecies but did not mention the taxon montandoni. At the time of writing, they appear to be the only authors to have implemented the proposal of Thanou et al. On its own, the proposal of Thanou et al. (2023) would have limited implications for the nomenclature of the V. ammodytes complex and pose few problems for information retrieval: all recognised taxa would retain their key identifying specific or subspecific epithets, albeit as subspecies of V. meridionalis rather than V. ammodytes in the case of montandoni and transcaucasiana .

Process-based changes: an impactful type reassessment by Krecsák et al. (2024). In a remarkable and fascinating piece of historical sleuthing, Krecsák et al. (2024) upended this status quo when they determined that the origin of the Linnaean type of V. ammodytes (UPSZTY 95) lies in Belgrad Forest (Belgrad Ormanı), on the northwestern outskirts of Istanbul, Türkiye, rather than in the northwestern part of the range of the species. A morphological reanalysis of its taxonomic affinities confirmed its association with the Eastern Nose-horned Viper , hitherto called V. a. montandoni. As a result, under the provisions of the Code , the name V. a. ammodytes would be transferred from the Northwestern Nose-horned Viper to the eastern population (previously V. a. montandoni) ( Figure 1 ), whereas what was V. a. ammodytes would become V. a. illyrica Laurenti, 1768 , for which Krecsák et al. (2025a,b) proposed a neotype. If the Southern Nose-horned Viper ( meridionalis ) is considered distinct from the eastern taxon (formerly montandoni, now ammodytes ), its name would remain unchanged as V. a. meridionalis ; if the southern and eastern taxa are considered synonymous, V. a. meridionalis would become V. a. ammodytes , losing the epithet meridionalis that has received prominent use in the literature ( Table 1 ). Implementation of the proposals of Thanou et al. (2023) together with those of Krecsák et al. (2024) would lead to the Northwestern Nose-horned Viper becoming V. illyrica , thereby losing all nomenclatural connection with the name ammodytes .

The combined nomenclatural impact of the proposals by Krecsák et al. (2024, 2025a,b) and Thanou et al. (2023) is dramatic, complex, and destabilising. A major source of uncertainty is the recognition or non-recognition of the eastern and southern taxa as distinct subspecies ( Table 1 ). Given that the prior nomenclature would no longer map directly onto the new nomenclature proposed by Krecsák et al. (2024), hundreds of existing uses would be affected by the changes ( Table 1 ). Contrasting with the upending of the nomenclature caused by the proposals of Krecsák et al., the name illyrica has, to the best of our knowledge, been used as valid only eleven times since the beginning of the 20 th century (excluding Krecsák et al. 2024, 2025a,b), and always in addition to the simultaneous use of V. a. ammodytes in the same publication.

Seeds of nomenclatural confusion in toxinology. Implementing the proposals of Krecsák et al. (2024) would clearly have a profound impact on how the literature on the V. ammodytes complex is interpreted and sow the seeds of confusion for many years to come. In fact, these changes would make the scientific names used in at least 69% of the existing literature on the V. ammodytes complex outdated ( Table 1 ). Moreover, the transfer of the name V. a. ammodytes from the Northwestern Nose-horned Viper that originally bore it to what was previously V. a. montandoni will cause grave difficulties for future workers seeking to compile and compare information on these taxa. Worse still, if the Eastern and Southern Nose-horned Vipers are deemed part of the same subspecies, which would be V. a. ammodytes , the entirety of the literature would be affected. In this context it is important to emphasise that the Code (Appendix B, Recommendation 1) explicitly states that “it is of especial importance that a name should not be transferred to a taxon distinct from that to which it is generally applied”.

This confusion would be especially strongly felt in the toxinological literature, where the Nose-horned Vipers, particularly the northwestern and southern populations, are of considerable importance. These taxa differ profoundly in aspects of their venom composition: the dominant neurotoxin in the venom of the Northwestern Nose-horned Viper is the presynaptic monomeric phospholipase A 2 (PLA 2) ammodytoxin ( Križaj 2011), whereas that of the Southern Nose-horned Viper is the postsynaptically active PLA 2 dimer vipoxin ( Georgieva et al. 2008; Osipov & Utkin 2023). Both these taxa and their toxins have accumulated an extensive body of literature, with ammodytoxin in particular serving as a model reference toxin in the study of viperid phospholipases A 2 ( Križaj 2011). Transferring the applicability of the combination V. a. ammodytes to the Southern and Eastern Nose-horned Vipers would represent a major source of confusion and impede communication and information retrieval for many years to come. Moreover, the toxinological literature has a long track record of being slow to adopt taxonomic innovation ( Wüster & McCarthy 1996). It can therefore be anticipated that a confusing application of parallel systems of nomenclature would persist for many years.

This nomenclatural confusion could also confound antivenom distribution and purchases. Currently, multiple European antivenoms directed at V. ammodytes envenomations are available for the treatment of bitten patients ( Lamb et al. 2017). There is no clinical or pre-clinical evidence of significant problems with a lack of cross-neutralisation across the subspecies of V. ammodytes ( García-Arredondo et al. 2019) , so a change in the nomenclature at subspecific level would have no consequences on treatment effectiveness. However, labelling of vials and changes of the medication package insert (summary of product characteristics) would become necessary should V. illyrica be recognised as a species in its own right, although this would also apply if the southern populations were recognised as V. meridionalis . Asynchronous changes in the use of nomenclature between producers and purchasers, such as national health ministries, could cause confusion when selecting antivenoms for national distribution in range countries.

Forestalling Nomenclatural Chaos

Author responsibilities and a case for the Commission. The reassessment of the geographical origin and affinities of the Linnaean name-bearing type of Vipera ammodytes (UPSZTY 95), its nomenclatural consequences, and the impact of those consequences on the wider community of users of scientific names represent a prime example of the need of authors of research into nomenclatural history to be mindful of the consequences of their actions. Article 75.6 is very clear and explicit in recommending that authors discovering “that the existing name-bearing type of a nominal species-group taxon is not in taxonomic accord with the prevailing usage of names and stability or universality is threatened thereby […] should maintain prevailing usage [Art. 82] and request the Commission to set aside under its plenary power [Art. 81] the existing name-bearing type and designate a neotype ” [our emphasis]. Applying this to the case of the type of V. ammodytes , the Code thus clearly places the onus of action to maintain stability on Krecsák et al. (2024). Unfortunately, these authors did not follow this recommendation and instead invited other scientists concerned about the nomenclatural impact to go through the necessary steps.

In our view, the extent of prevailing usage of all three affected names in numerous fields outside the specialised systematic literature ( Dubois 2010), and the disruption threatened by the new proposals, constitute an overwhelming case for the Commission to use its plenary power for the sake of nomenclatural stability. We are therefore in the process of petitioning the International Commission on Zoological Nomenclature to set aside the Linnaean holotype of Coluber Ammodytes , specimen UPSZTY 95, and to designate specimen NHMW 25274:6, from Trieste, Italy, as a neotype for the species. This specimen was described by Krecsák et al. (2025a,b), who designated it as the neotype of Vipera Illyrica Laurenti, 1768 . Designation of the same specimen as neotype of V. ammodytes would have the effect of anchoring the name ammodytes to the Northwestern Nose-horned Viper, thus preserving prevailing usage, and V. illyrica would become an objective junior synonym of V. ammodytes . A request to set aside an extant Linnaean type is highly unusual, but not unprecedented (e.g., ICZN Case 3703: Nikolaeva et al. 2017; Opinion 2426: International Commission on Zoological Nomenclature, 2018). We strongly believe that there is an overwhelming case for this course of action to stabilise the nomenclature of this iconic, heavily studied, and widely discussed species.

While this Case is before the Commission, authors should follow Article 82.1 of the Code and maintain prevailing usage. The period during which a case to the Commission is officially under consideration (Article 82.1) only starts when receipt of the case is published in the Bulletin of Zoological Nomenclature ( BZN) (Article 82.2). However, we here take the liberty of anticipating this process: the high volume of publications on the V. ammodytes complex creates the very real possibility of confusion if some but not all authors implement the nomenclatural consequences of Krecsák et al. (2024) prior to acknowledgement of receipt of the case.

Process-driven changes in nomenclature and the status and reputation of taxonomy. The case of the typification of the V. ammodytes complex illustrates the profound consequences that process-driven nomenclatural changes resulting from historical nomenclatural research can have on long-established scientific nomenclature. Here, a very thorough and historically fascinating piece of research threatens to destabilise the nomenclature of an iconic and much-discussed species complex of public health importance without adding anything to our knowledge of the biology of the species.

Most users of scientific names greatly value nomenclatural stability and ease of information retrieval and communication ( Hillis 2019; Jiménez-Mejías et al. 2024; Mayr et al. 1971; Vences et al. 2013). This will certainly be the case for the large user community of toxinologists, for whom the V. ammodytes complex continues to be a rich source of material and research questions ( Ferquel et al. 2007; Križaj 2011; Petrova et al. 2012). The excitement taxonomic historians may feel at the discovery of a type misidentification and its nomenclatural consequences is unlikely to be shared by those outside the taxonomic silo, who simply want stable labels for their study organisms. Changes to the nomenclature that do not reflect advances in knowledge are likely to be perceived as impediments rather than as helpful, leading to reputational damage to the entire discipline of taxonomy.

By describing, delimiting, and cataloguing the world’s biodiversity, the science of taxonomy provides the essential underpinnings for all further research. Yet, the under-resourcing and undervaluation of taxonomy is a long-running issue ( Ebach et al. 2011; Giangrande 2003; Löbl et al. 2023; Singh 2025). Faced with criticism over perceived taxonomic “anarchy” ( Garnett & Christidis 2017), taxonomists have been emphatic in defending their science as a fully-fledged, rigorous scientific discipline with rich conceptual and theoretical underpinnings ( Garnett et al. 2020; Thomson et al. 2018), rather than a service industry generating scientific names on demand ( De Carvalho et al. 2005; Jackson et al. 2017).

However, this emphasis on taxonomy as a modern, hypothesis-driven and relevant scientific discipline is undermined by scenarios such as the one explored here, where the reassessment of an 18 th century specimen, coupled with the seemingly arcane rules of the Code, disrupts the entire knowledge base of a medically, scientifically, and societally important group of animals.While taxonomy is indeed not an on-demand name factory, taxonomists would do well to remember that the esteem of their discipline is affected by its visible outputs, which for those outside taxonomy consist primarily of the scientific names of organisms. Actions have consequences: where process-driven changes to long-established nomenclature impede information retrieval and sow confusion without the benefit of conveying new biological insights, it is highly likely that the entire discipline will suffer reputational damage. It is virtually inevitable that this will ultimately affect its support and resourcing for taxonomy. We therefore argue that those researching the history of nomenclature have a responsibility to strive for the maximum possible economy of nomenclatural change, not only out of consideration for other users of nomenclature, but also out of self-interest, for the preservation of their own discipline.

Towards greater nomenclatural parsimony: making it easier to Do The Right Thing

While it is clearly essential for taxonomists to enact the principle of nomenclatural parsimony, it also behooves our discipline to consider ways of making Doing The Right Thing easier. While the Code exhorts taxonomists to petition the Commission to use its plenary powers to preserve prevailing usage, for instance in Article 75.6, the unfortunate reality is that this is a long-winded and complex process. Petitions to the Commission must be written, submitted to the BZN, and published there. Time is then required to receive and publish comments in subsequent issues, followed by another round of comments. Finally, the Commission must reach and publish its opinion in the BZN. This multistage process generally takes several years.

The do-it-yourself option. The Commission set a precedent for a more streamlined approach through the introduction of Article 23.9 in the 4 th Edition of the Code in 1999. This allows a Do-It-Yourself approach, without recourse to the Commission, to the designation of nomina oblita if they have demonstrably remained unused since 1899 but threaten the status of a name widely used since 1900. Avella et al. (2025) suggested the introduction of similar rules for their concepts of acta and facta oblita, forgotten acts or facts, which, when rediscovered, threaten the stability of established names. The unexpected origin of the name-bearing type of Vipera ammodytes , reconstructed by Krecsák et al. (2024), would constitute one such factum oblitum. A provision analogous to Article 23.9, allowing the setting aside of types and the designation of neotypes without the need for a Commission opinion under certain clearly defined conditions, could reduce the procedural impediment to following the recommendations of Article 75.6. While the precise wordings and conditions of such provisions in a future edition of the Code require careful consideration and deliberation, it is our belief that they would significantly streamline the fulfilment of the aims of the Code.

Clearly, not all cases are suitable for such a fast-track process, and many will continue to require Commission intervention. However, here again, there is a need for simplifying and accelerating this process. In particular, we argue that streamlining the publication of cases, comments on cases, and Commission opinions would incentivise taxonomists to engage actively with the Code and the Commission, instead of allowing the Code -mandated default to perturb nomenclatural stability against the Code ’s own recommendations.

The need for speed. The current process of publication of cases, comments, and opinions is lamentably slow. In most recent years, only a single issue of the BZN has appeared per annum. While the BZN unfortunately does not provide the dates of receipt and acceptance of submitted cases or comments, at least some of these must logically have waited a year or more from acceptance to publication. It also means that each case must wait at least one year for relevant comments to be published, and possibly another year or more for further comments or comments on comments, and another year, and sometimes much longer, for the Commission’s Opinion to be published (7.5 years in the case of Case 3601; International Commission on Zoological Nomenclature 2021). In some cases, this delay has led to new realities becoming established and acquiring a momentum of their own, to the detriment of the universal acceptance of the Code ( Wüster et al. 2021). In the 2020s, it seems anachronistic for accepted cases and comments on matters of acute current concern to be delayed by up to a year or more until publication. Changing the publication model of the BZN from one complete issue per year to a series of numbered individual articles, published online as soon as they have been accepted, would greatly accelerate the publication of cases without imposing restrictions on the crucial step of public scrutiny and commentary on such proposals.

Figures

FIGURE 1. A problematic name change: under the proposals of (Krecsák et al. 2024), the name Vipera ammodytes ammodytes would pass from the Northwestern Nose-horned Viper (left – an individual from near Sarajevo, Bosnia and Hercegovina; Photo W. Wüster) to the Eastern Nose-horned Viper, hitherto widely known as V. a. montandoni (right – an individual from near Greci, Dobrogea, Romania; Photo A. Strugariu), causing many hundreds of past uses to become outdated and subject to confusion.