Bufo Garsault, 1764

Dubois, Alain & Bour, Roger, 2010, The nomenclatural status of the nomina of amphibians and reptiles created by Garsault (1764), with a parsimonious solution to an old nomenclatural problem regarding the genus Bufo (Amphibia, Anura), comments on the taxonomy of this genus, and comments on some nomina created by Laurenti (1768), Zootaxa 2447, pp. 1-52 : 12-25

Bufo Garsault, 1764

The nominal genus Bufo was created by Garsault (1764) in the lower half of his plate 672, which shows a specimen of toad (“ Crapaud ”) clearly resembling the “common toad” Bufo bufo ( Linnaeus, 1758) from France. No origin was given for this specimen in the text of Garsault (1765, 1767). The generic nomen Bufo may have been derived from the specific nomen Rana bufo Linnaeus, 1758 or from any of the numerous non- Linnaean uses of the same term as uninomen. In agreement with the figure in his plate 672, we hereby designate the nominal species Rana bufo Linnaeus, 1758 as nucleospecies (type-species) of Bufo Garsault, 1764 .

This finding has an important, unexpected and happy consequence: it allows solving for the best the problem of the nucleospecies of the genus Bufo . This genus has been universally considered a valid generic nomen of anurans since its “second creation” by Laurenti (1768), who clearly had used the same etymology as Garsault. For the reason explained above, the nomen Bufo Laurenti, 1768 must be considered a distinct nomen, invalid junior homonym of Bufo Garsault, 1764 , and the nomenclatural status of which must be established independently. In particular, its nucleospecies must be clarified, a point that has been controversial until now, and that we therefore examine in detail here, in the light of the discovery of Garsault’s works.

In his new genus Bufo, Laurenti (1768) included 13 nominal species, none of which was designated as “ type ”. Presumably because he did not accept tautonymy, he did not mention anywhere in his book the nominal species Rana bufo Linnaeus, 1758 , but he redescribed this species under the nomen Bufo vulgaris .

Had he mentioned the nomen Rana bufo as its senior synonym, this latter nomen would have been the nucleospecies of Bufo Laurenti, 1768 by absolute tautonymy (Article 68.4 of the Code). As he did not, the nucleospecies must have been fixed by subsequent designation, and only the 13 species originally listed in this genus are eligible for this designation, which excludes the nominal species Rana bufo . Therefore, Stejneger (1936: 134) was in error when he stated that the latter species was the “type-species” of Bufo Laurenti, 1768 by absolute tautonymy simply because Bufo vulgaris was a synonym of it. This error was first pointed out by Leviton & Anderson (1970: 38) and recognized as such by Dubois (1984: 14, 19). The nucleospecies designation for this genus must therefore be traced in the literature subsequent to Laurenti (1768), which is problematic.

Fleming (1822: 305) wrote: “ The common toad (which the ignorant and the prejudiced persecute, though harmless), is the type of the genus.” Unfortunately, Fleming (1822) used only vernacular nomina in his book and nowhere mentioned the nomen Bufo vulgaris Laurenti, 1768 . Throughout his work, he referred to the book of Pennant (1769), who mentioned Latin nomina, but used for this species the nomen Rana bufo , which is not eligible for nucleospecies fixation of Bufo Laurenti, 1768 . For these reasons, Dubois (1992: 342) considered this designation as invalid.

The next author to consider here is Tschudi (1838: 50), who wrote: “ Von ältern [sic] Naturforschern immer mit Rana verbunden, trennte Laurenti das Genus Bufo , dessen Typus in Europa, Bufo vulgaris , auch in Japan vorkömmt, und von der europäischen nur in der Schädelform abweicht ” [“Still referred to Rana by the older naturalists, it is Laurenti who separated the genus Bufo , whose type in Europe Bufo vulgaris is found also in Japan, and which differs from the European only by the shape of the skull”]. The mention of a “ type in Europe” cannot qualify as a valid nucleospecies designation under the Code, which states: “ The term ‘designation’ in relation to fixation of a type species (…) must be rigidly construed; the following are not designations under the Code: (…) 67.5.3. one made in an ambiguous or conditional manner ” (Article 67.5). A nucleospecies for a genus only makes sense if it applies fully to the whole genus. It cannot be restrictive. It is not acceptable to have a single genus with several nucleospecies, one in Europe, one in Africa, one in America, or one in ponds, one in rivers, or one in spring, one in summer, etc. A survey of the whole volume of Tschudi (1838) shows that the term “ Typus ” does not appear anywhere else than in the sentence above, suggesting that his author did not have a concept of “type-species”. In our opinion, “ type in Europe” does not refer to the concept of “type-species” of a genus, but means “typical form among the European species”, leaving open the possibility that other species may be considered “typical” of the genus in other parts of the world. Tschudi’s (1838) statement is unclear and ambiguous, and as such does not qualify as a valid nucleospecies designation. Nevertheless, it has been accepted as valid by a few authors ( Frost 1985: 34; Dubois 1992: 342). The reason why they did so is that if this was not accepted as valid, one had to accept the next designation, which is formally correct but raises another problem.

As a matter of fact, in a work which contains hundreds of valid formal nucleospecies designations (using the term “ Typus ”) for new or older generic nomina, Fitzinger (1843: 32) designated Bufo viridis as “typespecies” of Bufo . Fitzinger (1843) was one of the first authors (after Oken 1816) to place the nominal species Bufo viridis and Bufo vulgaris in different genera, restraining the use of the nomen Bufo to the group containing the former and using Oken’s (1816) nomen Phryne for the group including the latter. The species Bufo viridis being part of those originally included by Laurenti (1768) in his new genus Bufo , it is eligible for nucleospecies fixation in this genus, as accepted by Leviton & Anderson (1970: 38) and Dubois (1984: 14, 19), although not by Mertens (1971 b). For 163 years, this designation did not create any problem, as both the species Rana bufo Linnaeus, 1758 and Bufo viridis Laurenti, 1768 were referred to a single genus Bufo , without subgenera. But this situation changed with the publication of Frost et al. ’s (2006) work.

From 1768 to 2006, the genus Bufo has been considered a world-distributed genus of the family BUFONIDAE Gray, 1825 , with about 250 species ( Dubois 2004 b). This genus, although long known to include various subunits or “species groups” ( Blair 1972), had only very rarely been divided into formally named subgenera, let alone split into several taxa. Frost et al. (2006), on the basis of preliminary molecular data, decided to split this genus into no less than 14 genera, while leaving 27 species unallocated to genera. Given the highly incomplete coverage of their taxonomic sampling and the preliminary nature of their molecular data, this action appeared premature to some (e.g., Vences 2007; Lescure 2008; Pauly et al. 2009), inasmuch as some of these species had been known for about 200 years or more under the generic nomen Bufo . However, this reason alone is not sufficient to reject this proposal: taxonomy is a science in permanent progress, and it is normal to implement changes in the nomina of taxa when new data are obtained ( Dubois 1998). But this must be done with caution.

Changing the generic allocation of well-known species may of course be fully justified if based on robust phylogenetic and solid biological information, but is premature if there is a strong possibility that a reversal to the original situation might result from further analyses. This indeed happened in the case of Frost et al. ’s (2006) work, as emphasized by the quasi-immediate lumping by Chaparro et al. (2007) of Frost et al.’s (2006) bufonid genera Chaunus Wagler, 1828 , Rhamphophryne Trueb, 1971 and Rhinella Fitzinger, 1826 in a single genus Rhinella : in this case, some of the many new combinations in the genus Chaunus listed in Frost et al. (2006: 364) had a life span of one year only. Other instabilities resulted from an incomplete or incorrect nomenclatural survey prior to creating new combinations, as exemplified by the saga of the generic nomina Cranopsis Cope, 1876 , Ollotis Cope, 1876 and Incilius Cope, 1863 , all used successively for the same genus in no more than 3 years by the same research team (see Frost et al., 2009 a). But other, more serious, problems are also met if Frost et al.’s (2006) purely “cladistic” generic concept is considered, as discussed below.

There are many reasons why cladistic trees should be considered with caution when it comes to using them to build supraspecific taxonomies. Dubois & Raffaëlli (2009: 8–9) listed some of them, and Frost et al. (2009 b: 141) stressed another one, the incompleteness of our inventory of species, a problem which will not be solved soon ( Gónzalez-Oreja 2008). This taxonomic gap (Dubois 2010 b-c) is particularly relevant in amphibians: “ in the 1970’s (…) the number of species known was less that half that known today ” ( Frost et al. 2009 b: 141). For these reasons, when basing a taxonomy on a tree, Dubois & Raffaëlli (2009: 9) suggested “ recognizing taxonomically all the robust specific clusters, but some only of the nodes of the trees obtained, those that appear constant in all analyses ”. This is particularly relevant if these different analyses used different sets of characters and different methods of analyses for the building of the trees, and if the support values for the nodes are high.

Furthermore, even if some of the taxa erected after their analysis appear warranted in view of the data presented, a basic question arises concerning the “genus concept” used by Frost et al. (2006). Not all sets of species supposed or shown to be holophyletic (monophyletic sensu Hennig 1950) should be given the rank genus, otherwise any two pair of sister-species should be given the rank genus, adding a third external species would require erecting a new genus for it, etc. The topology of a tree alone does not provide a taxonomy. Some criteria, or at least guidelines, are needed to decide which “clades” should be given the rank genus instead of species-group, subgenus, subtribe, tribe, subfamily, etc. This problem is complex ( Dubois 2007 b; Dubois & Raffaëlli 2009) and cannot be discussed in detail here.

In our opinion, the proposal by Dubois (1981 a-b, 1982, 1983, 1988 a-b, 2004 c) to use hybridization data as a help for the recognition of genera, although it until now rose interest only from few authors (e.g., Böhme & Köhler 2005), should be considered seriously. This proposal is simple: whenever two species are liable to produce, either in natural or in artificial conditions, viable adult hybrids (either fertile or sterile), these should never be included in different genera, although they can be placed in different subgenera of the same genus. The reverse is not true of course, for reasons explained in detail by Dubois (1988 a-b): two species may belong in the same genus even if they cannot hybridize successfully.

Applying this criterion to the traditional genus Bufo definitely precludes to split it in as many genera as suggested by Frost et al. (2006), as fully viable hybrid adults are known to be sometimes produced between species placed by these authors in different genera. Dubois & Dinesh (2007) provided references to works where such successful hybridization has been reported between Frost et al.’s (2006, 2009 b) “genera” Anaxyrus Tschudi, 1845 and Bufo , Anaxyrus and Incilius , Bufo and Pseudepidalea Frost et al., 2006 , and Epidalea Cope, 1864 and Pseudepidalea (for details, see the legends of our figures 4–6). According to Dubois’s (2004 c) guidelines, in order to apply the crossability criterion and in order not to recognize paraphyletic genera, the two species of any hybridizable pair must be included in a single genus, and this genus must be expanded so as to include all the other species necessary to make this genus holophyletic. This may in some cases require to include in the genus several “subclades” that may show rather strong phenotypic differentiation. It is however possible, if one wishes to recognize taxonomically these “subclades” as taxa, to give them the status of subgenera. Strangely enough, although this rank is widely used in the taxonomy of many animal groups, e.g. in entomology, it has been little used in the amphibians and reptiles, presumably as a result of Dunn’ (1943) personal opinion on this matter (see also Duellman 1977 b), but this point of view is fully questionable: for example, recently, Smith & Chiszar (2006) and Wallach et al. (2009) gave good arguments for a more frequent use of the rank subgenus in taxonomy.

In the case of the genus Bufo , despite the multiplication of recent molecular phylogenetic works, no consensus exists among them (e.g., Graybeal & Cannatella 1995; Graybeal 1997; Pauly et al. 2004, 2009; Frost et al. 2006, 2009 b; Pramuk 2006; Chaparro et al. 2007; Pramuk et al. 2008; Van Bocxlaer et al. 2009). The most recent of these studies ( Van Bocxlaer et al. 2009) no doubt presents a much better set of data than all of the previous ones in this group: the tree presented by these authors (see our figure 6) is well resolved and based on a comprehensive set of nuclear and mitochondrial genes, equivalent to data sets that have recently produced well-supported phylogenies in many other amphibian groups. However, the sample of species sequenced is small, compared to the whole family, and many groups are not represented. It is predictable that when more species and nuclear genes are added, the topology of this tree will change, at least in some of its “details”, but these “details” may have important taxonomic consequences, for example if sister-taxa relationships between species and groups change.

In such a situation, a prudent, conservative attitude is warranted, and it is not warranted to recognize as many genera as in Frost et al. (2006). Several clusters of “genera”, as recognized by Frost et al. (2006) or other recent authors, seem well established as they appear to constitute exclusive holophyletic groups according to all the recent analyses that dealt with them. A first step at this stage, which would not result in the recognition of any paraphyletic group, might be to recognize them as provisional taxa, e.g. genera (here presented by alphabetic, not phylogenetic, order), including two or more subgenera: (1) Anaxyrus , with the subgenera Anaxyrus and Incilius ; (2) Bufo Garsault, 1764 , with the subgenera Bufo (including Torrentophryne Yang in Yang et al., 1996) and Epidalea ; (3) Leptophryne Fitzinger, 1843 , with the subgenera Ingerophrynus Frost et al., 2006 and Leptophryne ; (4) Sclerophrys Tschudi, 1838 1, with the subgenera Capensibufo Grandison, 1980 and Sclerophrys (including Amietophrynus Frost et al., 2006 , Mertensophryne Tihen, 1960 , Stephopaedes Channing, 1979 and Vandijkophrynus Frost et al., 2006 ); (5) Nectophryne Buchholz & Peters in Peters, 1875 with the subgenera Nectophryne , Werneria Poche, 1903 and Wolterstorffina Mertens, 1939 ; and (6) Nectophrynoides Noble, 1926 , with the subgenera Churamiti Channing & Stanley, 2002 and Nectophrynoides .

But this is not enough. If we consider the data from successful hybridization until the adult stage, we realize, first, that they are on the whole very congruent with the phylogenetic data, but, second, that they suggest recognition of slightly more inclusive genera.

First of all, Bufo and Pseudepidalea , between which successful hybridizations have been reported, should be kept as subgenera of a single genus Bufo . The same applies to Epidalea and Pseudepidalea , which requires to include also Epidalea in Bufo , and to Anaxyrus and Incilius , which implementation of the crossability criterion demands to place in a single genus Anaxyrus . However, as explained and illustrated in detail by Dubois (2004 c), this is not enough, as use of this criterion must remain compatible with cladistic data. Whenever two groups are united in a genus because of this criterion, in order for this genus to remain holophyletic it often needs to be expanded to include several other groups as well. In the case of the genus Bufo , the final extension of this genus will depend on the phylogeny finally considered robust for the whole bufonids. Several incompatible cladistic hypotheses have been published in the recent years, and the last published one is still liable to change. On the basis of such provisional data, no straightforward decision is possible.

1. Reexamination of the holophoront (holotype) of Sclerophrys capensis Tschudi, 1838 , still kept in the Paris Museum collection (MNHN 742; Guibé 1950), shows that it is a young male (43 mm in snout-vent length) that belongs in this group. More details on this question will be provided elsewhere.

For example, if the tree of Frost et al. (2006) was accepted, then the genus Bufo would correspond to the grey rectangle in fig. 4, with the following subgenera: Bufo , Peltophryne Fitzinger, 1843 (including Duttaphrynus Frost et al., 2006 , Peltophryne , Pseudepidalea and Schismaderma Smith, 1849 in fig. 4), Rhinella (including Anaxyrus , Chaunus and Incilius in fig. 4) and Sclerophrys (including Amietophrynus , Capensibufo , Mertensophryne , Stephopaedes and Vandijkophrynus in fig. 4). But then, the subgenera listed above in these groups should be downgraded to the rank of species-groups or supraspecies, simply because the Code does not accept additional ranks below subgenus, like infragenus of hypogenus ( Dubois 2006 b; Dubois & Raffaëlli 2009). This latter limitation does not have any theoretical justification and is only a nuisance for the development of a modern phylogenetic taxonomy at low levels (between genus and species) in zoology ( Dubois 2006 b, d, 2007 b; Dubois & Raffaëlli 2009), so let us hope that the ICZN will soon consider its abrogation.

If the alternative tree of Pramuk et al. (2008) was adopted (fig. 5), the genus Bufo , as limited by the data on successful hybridization, would not need to include the genus Sclerophrys, and could be slightly less inclusive.

Finally, if the tree of Van Bocxlaer et al. (2009) was accepted (fig. 6), in order to remain holophyletic the genus Bufo would have to correspond to almost the whole family BUFONIDAE . It would contain many other “genera”, including the ADENOMINAE Cope, 1861 as recognized by Van Bocxlaer et al. (2009), and it would exclude only the genus Rhaebo Cope, 1862 and a few other South American genera, formerly known as the ATELOPODIDAE Fitzinger, 1843 or ATELOPODINAE. At any rate, even if the crossability criterion is not implemented, but the phylogeny of these authors adopted, their taxonomy is not acceptable, as it recognizes a subfamily (ADEMONINAE) whose sister-group includes two genera ( Ansonia Stoliczka, 1870 and Pelophryne Barbour, 1938 ) but is not recognized as a subfamily, and as no further subfamily is recognized for all the other genera of the family. It would be unacceptable to group all these genera in a subfamily BUFONINAE, as the latter would be paraphyletic relative to the ADENOMINAE. If taxonomy is to reflect the hypothesized cladistic relationships between taxa, a basic requirement is that sister-taxa be always afforded the same rank, and that any optional subordinate rank like subfamily be used only if at least two sister-taxa are given this rank (for details, see Dubois 2007 a, 2008 d).

A troubling fact is the report ( Blair 1972: 420) of a single case of adult male hybrid obtained between a male Bufo bufo and a female Anaxyrus woodhousii ( Girard, 1854) . This unique case needs confirmation, in order to be sure that the adult reported was a true diploid hybrid with one genome of each parental species, and not a gynogenetic or triploid specimen (for more details, see Dubois 1988 a-b). If the possibility of successful (until adult stage) hybridization between some species, at least, of Bufo and Anaxyrus , was confirmed, this would require, for those who wish to implement the crossability criterion, to downgrade both these groups to the rank of subgenera of a single genus Bufo , as shown in the lighter grey rectangles of our figures 4–6. If this possibility was refuted, this would have no consequence on the limits of the genus Bufo in our figure 4. However, in our figures 5 and 6, Rhinella could remain as a genus distinct from Bufo and from Anaxyrus (which would include two subgenera Anaxyrus and Incilius ).

Even if we ignore at this stage the case of the American species, uncertainties remain. Several species of the genus Pseudepidalea , erected by Frost et al. (2006) for Bufo viridis and its close allies, are well known to hybridize successfully among them in nature, sometimes giving birth to stable polyploid hybrid species ( Stöck et al. 1999, 2001 c, 2002, 2005, 2009; Stöck & Grosse 2003), but also to produce not rarely adult hybrids with species of the genera Bufo and Epidalea . This requires to include also Pseudepidalea as a third subgenus of the genus Bufo , along with Bufo and Epidalea , but for the time being it is impossible to know where this genus should “stop” until we have a robust phylogeny of the whole family. Just considering the successful hybridization between Bufo and Pseudepidalea (and ignoring the case of Anaxyrus ), the content of Bufo would be very different according to the tree adopted as phylogenetic hypothesis for the bufonids.

Considering all these uncertainties, we think the situation is not ripe for a robust generic taxonomy of the BUFONIDAE . More work must be done, in three directions at least: (1) rapidly increasing our survey, discovery and description of the species of this group in all parts of the world, before they are extinct ( Dubois 2009 b); (2) ascertaining better the cladistic relationships of all identified groups and subgroups of species of this family at least, if not of all known species; and (3) obtaining more reliable data on interspecific hybridization within this huge assemblage of species. The latter work had been remarkably started by Blair (1972) and his co-workers, but has unfortunately largely been abandoned nowadays, in our “ all-cladistic age ” ( Dubois & Raffaëlli 2009: 13). As stressed by Dubois (1988 a-b), the advantage of the hybridization data used at genus level as a nonarbitrary criterion for taxonomic inclusion ( Simpson 1961: 115) is that, if the original works are methodologically good (ascertaining that the adult obtained were true biparental diploid hybrids), their conclusions are not liable to be changed later on. In zoological groups of biparental species, this can be a strong factor for stabilizing generic taxonomy, a goal that many authors claim to pursue (e.g., Pauly et al. 2009; Frost et al. 2009 b). For this reason, we think that at least two groups of “genera” as recognized by Frost et al. (2006) should be considered as single genera, namely Anaxyrus-Incilius and Bufo-Epidalea- Pseudepidalea . These two groups might further have to be aggregated as a single genus, and most probably other groups, considered by Frost et al. (2006) as distinct genera, should also join them.

In what follows, we only consider the nomenclatural status of the three later nomina, in the light of the rediscovery of the book of Garsault (1764). The discussion above suggests that the Palaearctic species of Bufo should be referred to three distinct subgenera, including respectively B. bufo , B. calamita and B. viridis . With such an arrangement, crediting the nomen Bufo to Laurenti (1768) and its valid nucleospecies designation to Fitzinger (1843), would result in having the species B. viridis in the nominative subgenus Bufo , and in having to refer the species B. bufo to another subgenus, for which the nomen that has priority would be either Palaeophrynos Tschudi, 1838 or Pegaeus Gistel, 1868, according to the subgeneric allocation of † Bufo gessneri ( Tschudi, 1838) (see below). Although nomenclaturally formally correct, this situation would be strange and likely to be confusing for many zoologists.

Contrary to what some seem to believe or to wish (see e.g. Jennings et al. 1994; Webb et al. 1994; Bour et al. 2009; Takahashi et al. 2009), zoological nomenclature is not, cannot and should not be, regulated by “usage”, “consensus”, “majority”, “poll”, “lobbying” or by a “principle of authority” ( Dubois 2010 c), but must be so by an international system of stringent and automatic Rules, accepting only very few exceptions, in really exceptional cases. Misunderstanding this opens the door to problems of various kinds, and is not doing a service to taxonomy at the time of the biodiversity crisis and of the taxonomic impediment (for details, see Dubois 2010 c). Even if most zoologists would certainly agree that it would be “better” to apply the subgeneric nomen Bufo to the group including the species B. bufo , this cannot be obtained by simply ignoring the Rules, as suggested by Mertens (1971 b), or, in another recent case, by Swingland (2009). If some zootaxonomists decided to “consider valid” Tschudi’s (1838) “designation” of nucleospecies for Bufo , and to ignore Fitzinger’s (1843) valid designation, others would certainly be entitled not to accept this and to continue to consider Bufo viridis as the nucleospecies of Bufo , which would open a period of instability and confusion in the use of these well-known nomina. As Tschudi’s (1838) sentence is ambiguous, clarifying definitively its meaning cannot result from discussing his text at length, but could only be obtained by a Ruling of the ICZN using its Plenary-Powers. This is why, after the publication of Frost et al.’s (2006) work, one of us had planned to apply to the ICZN for a Ruling on this matter. The fortunate discovery of Garsault’s publications allows to disentangle this situation, and such an action by the ICZN is not necessary any more.

The nomen Bufo Garsault, 1764 , nucleospecies by present designation Rana bufo Linnaeus, 1758 , is now the valid nomen for the subgenus including Bufo bufo (“true toads”). It has six junior invalid synonyms (see below). It accommodates about 20 species (including a fossil one) and eight non-hyponymous (nonnominotypical) subspecies currently recognized at least by some authors, but no consensus exists among taxonomists regarding either the species or the subspecies (see e.g. Speybroeck & Crochet 2007). This subgenus is in bad need of taxonomic revision based on a large sampling of Palaearctic populations and on morphological, caryological, molecular, bioacoustic and etho-ecological data.

The earliest synonym of Bufo Garsault, 1764 is Phryne Oken, 1816 , which deserves a short discussion. This nomen is a junior homonym of Phryne Meigen, 1800 (Diptera) , published in a work which was suppressed by the ICZN (Anonymous 1963). Phryne Oken, 1816 itself was made nomenclaturally unavailable for having been published in a book also suppressed by the ICZN ( Hemming 1956 b). Oken (1816: 210–213) applied both this nomen and the nomen Bufo to a genus in which he mentioned 16 nominal species. However, his nomen Phryne cannot be considered a neonym for Bufo , as in page 207 he also mentioned Bufo as a “synonym” of his genus Bombina : the most logical interpretation seems to be that he split the former genus Bufo in two genera, one for which he provided the nomen Bombina (which included, among others, the species Bufo viridis Laurenti, 1768 ) and one for which he provided the nomen Phryne . Fitzinger (1843: 32) used the nomen Phryne , which he expressly credited to Oken, and for which he designated Bufo vulgaris Laurenti, 1768 as nucleospecies. As this species was one of the 16 originally included species of Phryne , this designation is valid, but as the work where the nomen Phryne Oken, 1816 was published was invalidated by the ICZN, the latter cannot be the valid nomen of a genus.

The nomen Bufo Garsault, 1764 still has five other junior synonyms, including two based on fossil material, and which do not require special discussion (see the synonymy of this generic nomen below).

The nomen Epidalea Cope, 1864 applies to the single species Bufo calamita Laurenti, 1768 (“natterjack”). As discussed below, the species Bufo raddei Strauch, 1876 , and possibly also the American † Bufo alienus Tihen, 1962 , might have to join this subgenus when more data are available. The generic nomen Epidalea has at least two senior synonyms. The first one is “ Calamitus ” Rafinesque, 1815 (a nomen overlooked by all authors until now), which is a gymnonym (nomen nudum), as it appeared without any diagnostic character nor included nominal species. In order to fix its place in synonymies, we hereby designate Bufo calamita Laurenti, 1768 (on which specific nomen it was clearly based) as its nucleospecies. The second senior synonym of Epidalea Cope, 1864 is Calamita Oken, 1816 , but the latter nomen is twice invalid: first, as noted by Frost et al. (2006: 359), for having being published in a book suppressed for nomenclatural purposes by the ICZN ( Hemming 1956 b), but also for being a junior homonym of Calamita Schneider, 1799 , a junior doxisonym (subjective synonym) of Hyla Laurenti, 1768 (see e.g. Dubois & Ohler 2009). Three other possible senior synonyms of Epidalea , based on fossil material, are Palaeophrynos Tschudi, 1838 and its two neonyms Palaeophryne Fitzinger, 1843 and Troglobates Gistel, 1848 (a nomen overlooked by all authors until now). According to Sanchíz (1998: 77), the nucleospecies of the genus Palaeophrynos, † Bufo gessneri ( Tschudi, 1838) , is similar to Bufo calamita , but differs from it and all other European species of Bufo by several characters. The possibility exists that this species be in fact a member of the subgenus including B. calamita , which should therefore take the nomen Palaeophrynos. Unless or until this point is clarified, for the time being it is better, for the sake of nomenclatural stability, to leave † Bufo gessneri , as well as its close relative † Bufo priscus Špinar, Klembara & Meszároš, 1993 , as an incertae sedis at subgeneric level in the genus Bufo .

The third subgenus, accommodating Bufo viridis (“green toads”), contains about 15 species (including a doubtful fossil one) and four non-hyponymous subspecies. Despite several important revisionary works recently devoted to this complex and interesting group ( Stöck et al. 2001 b, 2006, 2008 b), the status of some taxa (species, subspecies or synonyms) is still controversial (see e.g. Speybroeck & Crochet 2007). Five nomina apply to this subgenus. The first available one is Bufo Laurenti, 1768 , type-species Bufo viridis Laurenti, 1768 by subsequent designation of Fitzinger (1843). This nomen is however invalid for being a junior homonym of Bufo Garsault, 1764 . Three neonyms were subsequently published for Bufo Laurenti, 1768 : Buffo de la Cepède, 1788 a,c; Batrachus Rafinesque-Schmaltz, 1814 ; and Bufotes Rafinesque, 1815: 78 . Let us consider them successively.

De la Cepède (1788 a-c) adopted the genus Bufo , which he clearly credited to Laurenti (1768), as he mentioned his work on many occasions, but never the works of Garsault (1764, 1765, 1767). In the text in the first part of his work, de la Cepède (1788 a: 568, 620; 1788 b: 22) used for all species of the genus the spelling Bufo . However, in the Synopsis Methodica which provides a table of Latin nomina at the end of this work (de la Cepède 1788 a: tab.; 1788 c: 460), he used the orthography Buffo , which was clearly intentional and based on the patronym of the Comte de Buffon, and was therefore an autoneonym for Bufo Laurenti, 1768 (see David et al. 2002: 24; Dubois & Ohler 2009: 8). However, the nomen Buffo cannot be resurrected for the subgenus including B. viridis , because it was published in a book recently invalidated by the ICZN (Anonymous 2005) despite its having been used as a reference for valid nomina in thousands of publications for two centuries.

The next nomen proposed to replace Bufo Laurenti, 1768 was Batrachus Rafinesque-Schmaltz, 1814 . This is without any possible doubt an alloneonym, as Rafinesque-Schmaltz (1814: 102) wrote: “ Hò cambiato il nome generico di Bufo in Batrachus , il primo nome essendo compreso in Buffonia ” [“I have changed the generic name Bufo in Batrachus , the former name being comprised in Buffonia ”]. Rafinesque-Schmaltz (1814) did not mention the author of the nomen Bufo . In his paper, he did not mention anywhere the work of Laurenti (1768), but several other sources, and especially on many occasions the book of Daudin (1803), which he credited (incorrectly) with authorship of most amphibian nomina, including the species of the genus Bufo . In this book, Laurenti’s book was often quoted, but never the works of Garsault (1764, 1765, 1767). Batrachus Rafinesque-Schmaltz, 1814 is therefore a neonym for Bufo Laurenti, 1768 . However, it cannot be the valid nomen for the taxon at stake here, as it is a junior homonym of three available generic nomina, all proposed for “fishes”: Batrachus Schaeffer, 1760 ; Batrachus Walbaum, 1792 ; and Batrachus Schneider, 1801 .

Shortly after the publication just discussed, Rafinesque (1815) proposed a second neonym for Bufo . He wrote: “G. 4. Bufotes R. Bufo Daud. ”. This mode of writing is similar to that he used to introduce many neonyms in the same work, for example Triturus for Triton Laurenti, 1768 , a case discussed in detail by Dubois & Raffaëlli (2009: 27–29). In all his publications, and particularly in his 1815 work, Rafinesque rigorously used a very precise way of proposing his new generic nomina, followed by the letter ‘‘R.’’, which means that he claimed authorship for them. Some of these new nomina were immediately followed by another generic nomen. This mode of notation, very common in taxonomic works at the beginning of the 19th century, means that the new nomen was proposed as a neonym for the following one. Thus, Rafinesque (1815) expressly presented his new nomen Bufotes as a replacement nomen for “ Bufo Daud. ”, so it is in fact a neonym for Bufo Laurenti, 1768 . The nomen Bufotes is the first one available and not preoccupied applying to the taxon here discussed, so it is the valid nomen of this subgenus.

Finally, Pseudepidalea Frost et al., 2006 , which has the same nucleospecies by original designation as Bufotes Rafinesque, 1815 , is its junior isonym (objective synonym) and should be abandoned.

In conclusion, we recommend maintaining the species B. bufo , B. calamita and B. viridis in three distinct subgenera of a single genus Bufo (which most probably should include other subgenera, not discussed here). Their synonymies are given below. They also apply if, following Frost et al. (2006), these three groups are recognized as genera. We also provide tentative lists of their species and subspecies, although this is still a controversial matter, as mentioned above. It should be stressed that because all taxa described in the past in the genus Bufo Laurenti, 1768 are now transferred into the genus Bufo Garsault, 1764 , their authors and dates now appear between parentheses.

A final note of interest is warranted. In genera that include several subgenera, the subgeneric nomen does not have to be mentioned every time the species is cited, especially in non-taxonomic works (Dubois 1988 ab). Citing the most important combination, including the generic substantive and the specific epithet, is often enough. Furthermore, an often overlooked advantage of the rank subgenus is that it is optional. Whenever, for lack of data, some species cannot be allocated to one of the subgenera of the genus, they can be left “outside” of them, being just referred to the genus. For the time being, this applies at least to two species of Palaearctic toads, Bufo raddei Strauch, 1876 and Bufo brongersmai Hoogmoed, 1972 . As for B. raddei , the bioacoustic data of Stöck et al. (2001 a) pointed to mating calls (MCs) similarities between this species and B. calamita , that distinguish them from the species of the B. viridis group. They wrote: “ we consider the resemblance of the B. calamita and B. raddei MCs to be caused by synapomorphic anatomic and functional structures which are not only phenetic similarities ” (p. 222). However, the molecular results of Stöck et al. (2006), although confirming that both these species are not closely related to the other green toads, also suggested that they are not closely related to each other. They seem to be relicts of early radiations previous to that of the green toads. For the time being, we refrain from formally referring B. raddei to the subgenus Epidalea . This question will have to be explored further. As for B. brongersmai , both Stöck et al. (2006) and Van Bocxlaer et al. (2009) suggested that it does not belong in the green toads radiation, but its position is still controversial, so here also more work should be done before its allocation to a subgenus. A third species, † Bufo alienus Tihen, 1962 , is here referred to Bufo as incertae sedis at subgeneric level: according to Sanchíz (1998: 76), although its ilium resembles that of B. calamita , “ more material would be necessary to demonstrate the presence of this Old World group in the North American Miocene ”. Finally, we already mentioned above the cases of the species † Bufo gessneri ( Tschudi, 1838) and † Bufo priscus Špinar, Klembara & Meszároš, 1993 .

Genus Bufo Garsault, 1764

(1) Subgenus Bufo Garsault, 1764

Bufo Garsault, 1764 : pl. 672, list of plates p. 19 [nec Bufo Laurenti, 1768: 25 ]. – Nucleospecies, by present designation, Rana bufo Linnaeus, 1758: 210 .

Phryne Oken, 1816: 210 [nec Phryne Meigen, 1800: 16 , exoplonym (see Anonymous 1963); nec Phryne Herrich- Schäffer, 1843: 90]. – Exoplonym, as having been published in a book placed on the Official Index of Rejected and Invalid Works in Zoological Nomenclature ( Hemming 1956 b). – Nucleospecies, by subsequent designation of Fitzinger (1843: 32), Bufo vulgaris Laurenti, 1768: 28 . – New invalid junior doxisonym.

Pegaeus Gistel, 1868: 161. – Nucleospecies, by original monophory, Rana bufo Linnaeus, 1758: 210 . – New invalid junior isonym.

Platosphus de l’Isle, 1877: 472. – Nucleospecies, by original monophory, † Platosphus gervaisii de l’Isle, 1877: 472, junior doxisonym of Rana bufo Linnaeus, 1758: 210 according to Sanchíz (1998: 121). – New invalid junior doxisonym.

Bufavus Portis, 1885: 1182. – Nucleospecies, by original monophory, † Bufavus meneghinii Portis, 1885: 1182, junior doxisonym of Rana bufo Linnaeus, 1758: 210 according to Sanchíz (1998: 125). – New invalid junior doxisonym.

“ Torrentophryne ” Rao & Yang, 1994: 142. – Anoplonym, as having been published with two included nominal species but without designation of a nucleospecies. – Nucleospecies, by present designation, Torrentophryne aspinia Rao & Yang, 1994: 142 . – New invalid junior doxisonym. – Comment: see Dubois et al. (2005: 32).

Torrentophryne Yang in Yang, Liu & Rao, 1996: 353. – Nucleospecies, by original designation, Torrentophryne aspinia Rao & Yang, 1994: 142 . – New invalid junior doxisonym. – Comment: see Dubois et al. (2005: 32) and Frost et al. (2006: 215, 220).

Content. Bufo (Bufo) ailaoanus ( Kou, 1984) ; Bufo (Bufo) aspinius ( Rao & Yang, 1994) ; Bufo (Bufo) bankorensis ( Barbour, 1908) ; Bufo (Bufo) bufo ( Linnaeus, 1758) , including Bufo (Bufo) bufo bufo ( Linnaeus, 1758) , Bufo (Bufo) bufo gredosicola ( Müller & Hellmich, 1935) and Bufo (Bufo) bufo spinosus ( Daudin, 1802) ; Bufo (Bufo) cryptotympanicus ( Liu & Hu, 1962) ; Bufo (Bufo) eichwaldi ( Litvinchuk, Borkin, Skorinov & Rosanov, 2008) ; Bufo (Bufo) gargarizans ( Cantor, 1842) , including Bufo (Bufo) gargarizans andrewsi ( Schmidt, 1925) , Bufo (Bufo) gargarizans gargarizans ( Cantor, 1842) , Bufo (Bufo) gargarizans miyakonis ( Okada, 1931) and Bufo (Bufo) gargarizans popei ( Matsui, 1986) ; Bufo (Bufo) japonicus ( Temminck & Schlegel, 1838) , including Bufo (Bufo) japonicus formosus ( Boulenger, 1883) and Bufo (Bufo) japonicus japonicus ( Temminck & Schlegel, 1838) ; Bufo (Bufo) kabischi ( Herrmann & Kühnel, 1997) ; † Bufo (Bufo) linquensis ( Yang, 1977) ; Bufo (Bufo) luchunnicus ( Yang & Rao, 2008) ; Bufo (Bufo) menglianus (Yang in Yang & Rao, 2008); Bufo (Bufo) minshanicus ( Stejneger, 1926) ; Bufo (Bufo) pageoti ( Bourret, 1937) ; Bufo (Bufo) tibetanus (Carevskij, 1926) ; Bufo (Bufo) torrenticola ( Matsui, 1976) ; Bufo (Bufo) tuberculatus (Carevskij, 1926) ; Bufo (Bufo) tuberospinius (Yang & Liu in Yang, Liu & Rao, 1996); Bufo (Bufo) verrucosissimus ( Pallas, 1814) , including Bufo (Bufo) verrucosissimus circassicus ( Orlova & Tuniyev, 1989) , Bufo (Bufo) verrucosissimus turowi ( Krasovsky, 1933) and Bufo (Bufo) verrucosissimus verrucosissimus ( Pallas, 1814) ; Bufo (Bufo) wolongensis ( Herrmann & Kühnel, 1997) .

(2) Subgenus Bufotes Rafinesque, 1815

Bufo Laurenti, 1768: 25 [nec Bufo Garsault, 1764 : pl. 672, list of plates p. 19]. – Nucleospecies, by subsequent designation of Fitzinger (1843: 32), Bufo viridis Laurenti, 1768: 27 . – New invalid senior isonym. – Comment: see text above.

Buffo de la Cepède, 1788 a: tab.; 1788 c: 460. – Exoplonym, as having been published in a book placed on the Official Index of Rejected and Invalid Works in Zoological Nomenclature (Anonymous 2005). – Autoneonym of Bufo Laurenti, 1768: 25 . – New invalid senior isonym. – Comment: see text above.

Batrachus Rafinesque-Schmaltz, 1814: 26 [nec Batrachus Schaeffer, 1760: 20 ; nec Batrachus Walbaum, 1792: 580 ; nec Batrachus Schneider, 1801 : xxvi]. – Alloneonym of Bufo Laurenti, 1768: 25 . – New invalid senior isonym. – Comment: see text above.

Bufotes Rafinesque, 1815: 78 . – Autoneonym of Bufo Laurenti, 1768: 25 . – Comment: see text above.

Pseudepidalea Frost, Grant, Faivovich, Bazin, Haas, Haddad , de Sá, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green & Wheeler, 2006: 10, 219. – Nucleospecies, by original designation, Bufo viridis Laurenti, 1768: 27 . – New invalid junior isonym.

Content. Bufo (Bufotes) balearicus ( Boettger, 1880) ; Bufo (Bufotes) boulengeri ( Lataste, 1879) ; Bufo (Bufotes) latastii ( Boulenger, 1882) ; Bufo (Bufotes) luristanicus ( Schmidt, 1952) ; Bufo (Bufotes) oblongus ( Nikolsky, 1896) , including Bufo (Bufotes) oblongus danatensis ( Pisanets, 1978) and Bufo (Bufotes) oblongus oblongus ( Nikolsky, 1896) ; Bufo (Bufotes) pewzowi ( Bedriaga, 1898) ; Bufo (Bufotes) pseudoraddei ( Mertens, 1971 a) , including Bufo (Bufotes) pseudoraddei baturae ( Stöck, Schmid, Steinlein & Grosse, 1999) and Bufo (Bufotes) pseudoraddei pseudoraddei ( Mertens, 1971 a) ; Bufo (Bufotes) siculus ( Stöck, Sicilia, Belfiore, Buckley, Lo Brutto, Lo Valvo & Arculeo, 2008) ; † Bufo (Bufotes) stranensis ( Nĕmec, 1972) ; Bufo (Bufotes) surdus ( Boulenger, 1891) including Bufo (Bufotes) surdus annulatus ( Schmidtler & Schmidtler, 1969) and Bufo (Bufotes) surdus surdus ( Boulenger, 1891) ; Bufo (Bufotes) turanensis ( Hemmer, Schmidtler & Böhme, 1978) ; Bufo (Bufotes) variabilis ( Pallas, 1769) , including Bufo (Bufotes) variabilis kermanensis ( Eiselt & Schmidtler, 1971) and Bufo (Bufotes) variabilis variabilis ( Pallas, 1769) ; Bufo (Bufotes) viridis ( Laurenti, 1768) ; Bufo (Bufotes) zamdaensis (Fei, Ye & Huang in Fei et al., 1999); Bufo (Bufotes) zugmayeri ( Eiselt & Schmidtler, 1973) .

(3) Subgenus Epidalea Cope, 1864

“Calamitus” Rafinesque, 1815: 78. – Anoplonym (gymnonym), as having been published without a description or diagnosis and without any included nominal species. – Nucleospecies, by present designation: Bufo calamita Laurenti, 1768: 27 . – New invalid senior doxisonym.

Calamita Oken, 1816 : v, 209 [nec Calamita Schneider, 1799 : i, 151]. – Exoplonym, as having been published in a book placed on the Official Index of Rejected and Invalid Works in Zoological Nomenclature ( Hemming 1956 b). – Nucleospecies, by absolute tautonymy, Bufo calamita Laurenti, 1768: 27 . – Comment: see text above. Epidalea Cope, 1864: 181 . – Nucleospecies, by original monophory, Bufo calamita Laurenti, 1768: 27 .

Content. Bufo (Epidalea) calamita ( Laurenti, 1768) .

(4) Incertae sedis at subgeneric level

(a) Genus-series nomina:

Palaeophrynos Tschudi, 1838: 52. – Nucleospecies, by original monophory, † Palaeophrynos gessneri

Tschudi, 1838: 89. – Comment: see text above.

Palaeophryne Fitzinger, 1843: 32. – Autoneonym of Palaeophrynos Tschudi, 1838: 52. Troglobates Gistel, 1848: xi. – Alloneonym of Palaeophrynos Tschudi, 1838: 52.

(b) Species-series nomina:

† Bufo alienus ( Tihen, 1962) .

Bufo brongersmai ( Hoogmoed, 1972) . † Bufo gessneri ( Tschudi, 1838) .

† Bufo priscus ( Špinar, Klembara & Meszároš, 1993) . Bufo raddei ( Strauch, 1876) .