Replacement names and nomenclatural comments for problematic species-group names in Europe's Neogene freshwater Gastropoda. Part 2

Abstract In the course of a new database project on Miocene to Recent freshwater gastropods of Europe, a great many of primary and secondary homonyms were revealed. Such nomenclatural issues need clarification in order to avoid misunderstandings and wrong statements about geographical distributions and temporal ranges. The following 16 new names are introduced to replace existing homonyms: Theodoxus militaris jurisicpolsakae nom. n., Viviparus stevanovici nom. n., Melanopsis haueri ripanjensis nom. n., Melanopsis wolfgangfischeri nom. n., Micromelania ramacanensis nom. n., Pseudamnicola welterschultesi nom. n., Muellerpalia haszprunari nom. n., Muellerpalia pseudovalvatoides nom. n., Lithoglyphus gozhiki nom. n., Valvata heidemariae willmanni nom. n., Radix macaleti nom. n., Gyraulus okrugljakensis nom. n., Gyraulus rasseri nom. n., Gyraulus vrapceanus nom. n., Planorbarius halavatsi nom. n., and Segmentina mosbachensis nom. n. Additionally, six cases of homonyms are discussed that are not replaced by new names, because they are considered junior synonyms.

Etymology. In honor of Zlata Jurišić-Polšak (Croatian Natural History Museum), who contributed to our knowledge of Neogene Neritidae. Type locality. Malino, Croatia. Age. Late Pliocene to Early Pleistocene ("Paludina Beds"). Syntypes. Croatian Natural History Museum, coll. no. 9454. Discussion. Handmann (1887, p. 9) described and figured Neritina leobersdorfensis var. oblonga from the Late Miocene of the Vienna Basin and made it thus available as species-group name (published before 1961, see ICZN 1999, Articles 45 and 57.1). The subspecific status was maintained by Papp (1953, p. 99), who recombined the species with Theodoxus. Although Jurišić-Polšak (1979) mentioned that species and cited both works in her study about Miocene and Pliocene neritids from Croatia, she established the name oblongus for a different species-group taxon in Theodoxus. Thereby she referred to a determination by Spiridion Brusina, who had established the name "Neritina militaris var. oblonga" for material in the collection but never published it. Jurišić-Polšak accepted this "in schedis"-determination and formally described the subspecies, obviously unaware of the fact that this would create a secondary homonym. It can be separated from the nominal species by the more elevated spire and the fewer axial ribs. Cox, 1960 Order unassigned Superfamily Viviparoidea Gray, 1847 Family Viviparidae Gray, 1847 Subfamily Viviparinae Gray, 1847 Genus Viviparus Montfort, 1810 Type species. Viviparus fluviorum Montfort, 1810 [currently considered as a synonym of Viviparus viviparus (Linnaeus, 1758)]. Recent, Northern Eurasia, Europe, Anatolia and Northern America. Type by original designation (Welter-Schultes 2012, p. 31).

Discussion.
Obviously unaware of the fact that also subspecific or variety names can constitute homonyms, Brusina (1902) introduced M. austriaca serbica from the Early Pannonian of Serbia, although this name was already preoccupied by another species described by himself, M. serbica Brusina, 1893 (p. 50). The latter species was also described from the Early Pannonian of Serbia (locality Begaljica, c. 15 km E Ripanj), but clearly represents a different taxon as evident from Brusina's descriptions and illustrations. Here we follow the taxonomic decision of Wenz (1929a), who synonymized M. austriaca Handmann, 1882with M. haueri Handmann, 1882 (both from the Kottingbrunn, Austria) and consequently ranked the here discussed taxon as subspecies of M. haueri. Melanopsis haueri serbica can be distinguished from M. haueri haueri in its distinctly stronger spruce-like outline.
Etymology. In honor of Wolfgang Fischer (Vienna), who greatly contributed to nomenclature and taxonomy of fossil and Recent melanopsids.
Type locality. Wittmannsdorf near Leobersdorf, Austria (Fischer 1996). Age. Late Miocene (Early Pannonian, Slavonian; Papp 1951). Type material. Geological Survey Austria, Vienna, no number indicated (Fischer 1996). Discussion. This taxon is a primary homonym of Melanopsis rugosa Matheron, 1842 (p. 293, pl. 37, fig. 11), a fossil species from SE France. Melanopsis rugosa Handmann, 1887 is a member of the complexly evolving M. impressa-species lineage in the Late Miocene Lake Pannon (Geary 1990, Geary et al. 2012, Neubauer et al. 2013a). The morphological variability in this group resulted in the description of many names, most of which are today synonymized. While Wenz (1929a, p. 2719) regarded rugosa Handmann as synonym of M. fossilis (which is the accepted name of "M. martiniana"), Papp (1953), Lueger (1980) and Fischer (1996) treated it as separate species. As implied by Neubauer et al. (2013a) the validity in a biological sense of this and other species-group taxa is doubtful. Nevertheless, since many authors clearly referred to it as a separable unit, a replacement name is inevitable.
Additionally, there exists another primary homonym of M. rugosa, i.e. M. lanzaeana rugosa Brusina, 1897 from the Middle Miocene deposits of the Sinj Basin. It was synonymized with M. lanzaeana by Neubauer et al. (2011, p. 205), who treated it as a mere morphotype and already mentioned the problem of homonymy. We therefore avoid introducing another name for this Croatian taxon, which is not used anymore.
Etymology. In honor of Francisco W. Welter-Schultes (University of Göttingen), a great expert for the living non-marine mollusks of Europe.
Discussion. This species is a primary homonym of Valvata minima Hislop, 1859 (p. 170, pl. 5, fig. 13) from the Tertiary of East India (see also Haszprunar 2014, p. 69) and needs a replacement name. Based on general shape and the lack of striae on the protoconch typical of Valvata, Willmann (1981) combined this species with Pseudamnicola, what is followed herein. Jekelius (1944), Stevanović (1951) and Bartha (1955) and several other authors also documented this taxon from various localities of the early Late Miocene of Lake Pannon. Given the stratigraphical and biogeographical gaps, these records probably represent different species.
Etymology. In honor of Gerhard Haszprunar (Bavarian State Collection of Zoology Munich and Ludwig Maximilians University Munich), who summarized all existing names of living and fossil valvatids in a comprehensive nomenclator (Haszprunar 2014).
Type material. According to the inventory books of the Natural History Museum Vienna the material should be stored there, but despite great effort it could not be located.
Discussion. This species is a primary homonym of the extant taxon Valvata tricarinata var. simplex Gould, 1841 (p. 226) from Massachusetts, USA. The American taxon was elevated to species level by Fluck (1932). As the European species was combined with various genera since its first description and several subspecies have been described, a summary of its history is given below.

Muellerpalia pseudovalvatoides nom. n.
Valvata carinata Fuchs, 1870  Type material. According to the inventory books of the Natural History Museum Vienna the material should be stored there, but despite great effort it could not be located.
Discussion. Up to now it has been overlooked by several authors, including ourselves (Neubauer et al. 2014), that this species is a primary homonym of V. carinata Sowerby, 1834 (see also Haszprunar 2014, p. 28). According to Bandel (2010, p. 104) this species should be classified within the new hydrobiid genus Muellerpalia, particularly because of its strongly different protoconch sculpture. This systematic concept is followed herein. For a more detailed discussion about the involved taxa and the species confusions in Bandel (2010)  Discussion. A classic case of a primary homonym. Probably as a result of prolonged publication times, Gozhik had no chance to become aware of this problem. However, the taxonomic status of L. maeoticus Papaianopol, 2006 from the Early Maeotian of the Dacian Basin is doubtful. It greatly resembles and might be a synonym of the Dacian species L. acutus Cobălcescu, 1883 (p. 145, pl. 14, fig. 10; see also Wenz 1942, p. 48, pl. 15, figs 195-198).

Clade Heterobranchia Informal Group Lower Heterobranchia Superfamily Valvatoidea Gray, 1840
Family Valvatidae Gray, 1840 Note. The here applied suprageneric systematics of Valvata follows Bouchet et al. (2005). Discussion. This species is a secondary homonym of Limnaea socialis von Zieten, 1832, of which the presently accepted and widely used combination is Radix socialis (e.g., Wenz 1923b, Gall 1972, Kókay 2006. Macaleț (2000) omitted the "sp. nov." in the heading of the description, which he indicated for all other species newly introduced by him in this paper, but gave it in the figure captions and the text and he designated a holotype. Radix macaleti is one of several similar species newly introduced by Macaleț (2000). Although the Lymnaeinae of the Dacian Basin are not well represented in the older literature, several of these new taxa may actually represent synonyms of one another, given the extreme variability of this clade (see, e.g., Glöer 2002, Welter-Schultes 2012. A revision of the entire group in the Dacian Basin would be necessary to clarify this issue.  lan et al. 1974, p. 117).

Genus
Discussion. This species represents a primary homonym of Planorbis (Helisoma) clathratus Sandberger, 1880 from the Pleistocene of West Runton, Norfolk, United Kingdom. We follow Wenz (1923c), who placed Brusina's species within Gyraulus. The classification of the British species within Helisoma by Sandberger is rather doubtful. This North American genus was artificially introduced to Europe, wherefore an occurrence in the Pleistocene of the British Isles is unlikely. The morphology as depicted in Sandberger (1880) suggests an attribution to Planorbarius.
Discussion. The name Planorbis discoideus as established by Pavlović (1903) represents a primary homonym of P. discoideus Hilgendorf, 1867. The latter species is a member of the Gyraulus species flock in the Middle Miocene Lake Steinheim and is presently considered a junior synonym of G. sulcatus by Rasser (2013). From the rather character-poor shell it is impossible to reliably attribute Pavlović's species to Planorbis or Gyraulus. Here we follow the taxonomic decision of Wenz (1923c) to place it in Gyraulus.

Gyraulus vrapceanus nom. n.
Planorbis dubius Gorjanović-Kramberger, 1890: 156, pl. 6, fig. 6  Discussion. The name Planorbis dubius was first used by Hartmann (1821, p. 254) for an extant species from Zurich region in Switzerland. The name is not available from this publication, since Hartmann did not give a description or indication (see also AnimalBase project 2005-2014). He first described and thus formally introduced it in Hartmann (1844, p. 111). Today its status is disputed. Glöer (2002, p. 253) ranked it as forma within P. carinatus Müller, 1774. Later, Glöer and Pešić (2010) stated that Hartmann's material contained two different taxa, i.e. P. planorbis and P. carinatus, making P. dubius a junior synonym of both. Finally, Kantor et al. (2010) listed it as accepted species in their catalogue of Russian continental mollusks. In summary, although the status of the extant species is doubtful, the name is available. This makes Planorbis dubius Gorjanović-Kramberger, 1890 a primary homonym of Planorbis dubius Hartmann, 1844. Here follow Wenz (1923c) (Boda 1964, p. 130).
Discussion. As both taxa were introduced within Planorbis, the species described by Halaváts is a primary homonym. Both are today unambiguously assigned to the genus Planorbarius (for the Pannonian species see, e.g., Sauerzopf 1953, Harzhauser andTempfer 2004) Lőrenthey (1902, p. 190) knew about the identical naming and discussed the differences between both taxa, but did not take appropriate steps to clarify this problem. Fuchs' species was first described from the Pannonian of Rădmănești in Romania and has been recombined with Gyraulus by Wenz (1923cWenz ( , p. 1562; see also Harzhauser et al. 2002, p. 106).

Discussions
In the following, we present six cases of primary and secondary homonyms that seem not to be in use anymore (e.g., are unambiguously considered junior synonyms). We were unable to find any recommendation in the Code regarding the necessity of replacement names for disused junior homonyms. Following the intent expressed in Article 23.9.5, which seems to discourage the proposal of unnecessary replacement names, we choose not to introduce new names for these cases. In addition, the statuses of two taxa apparently constituting homonyms are discussed.
Still we refrain from introducing a replacement name, because the taxonomic status of this subspecies is highly doubtful. It greatly resembles the nominal species V. lomejkoi Pavlović, 1932 from Crmljan and Orahovac (like the type locality Gjurakovc in the Metohia Basin). The only difference is the stronger degree of whorl stepping, which is not documented by Pavlović's original description and illustrations. This is regarded to fall into intraspecific variability, why we suggest synonymizing V. lomejkoi brevis with V. lomejkoi. If, however, another author keeps both forms separate, a replacement name has to be introduced.

Viviparus berbestiensis grandis Lubenescu & Zazuleac, 1985 non Neumayr in Herbich & Neumayr, 1875
Viviparus berbestiensis grandis Lubenescu & Zazuleac, 1985: 109, pl. 28, figs 15-17, pl. 29, fig. 1 Herbich and Neumayr (1875, p. 413) and many other authors of this time, is an incorrect subsequent spelling of Viviparus Montfort, 1810 (Melville andSmith 1987, p. 185). The species-group name grandis in combination with Viviparus, as introduced for a new species by Lubenescu and Zazuleac (1985), therefore is a primary homonym of Viviparus grandis (Neumayr in Herbich & Neumayr 1875) and would require a replacement name (see also Wenz 1928aWenz , p. 2323. We refrain from introducing a nomen novum because of the highly doubtful taxonomic status of this subspecies. The only criterion for Lubenescu and Zazuleac (1985, p. 110) to separate this form from the nominal species was the additional whorl and thus bigger size (therefore the name grandis). Apart from that it completely corresponds to V. berbestiensis Lubenescu & Zazuleac, 1985. Consequently, we regard V. berbestiensis grandis as junior synonym of V. berbestiensis. Papaianopol and Marinescu (1995) ranked V. berbestiensis grandis as subspecies of V. cucestiensis Lubenescu & Zazuleac, 1985, but without explanation and only in the figure captions. Here we follow the original authors to avoid additional confusion.

Melanopsis pygmaea inflata Sauerzopf, 1952 non Handmann, 1882
Melanopsis pygmaea inflata Sauerzopf, 1952: 13, pl. 2, fig. 4  Discussion. There are several issues with the name Melanopsis inflata. First, the name introduced by Sauerzopf definitely constitutes a primary homonym of M. pygmaea inflata Handmann, 1882. Sauerzopf (1952 explicitly introduced it as new taxon, although the combination is identical to that established by Handmann. Both taxa were obviously erected for different morphologies: while Sauerzopf's form is elongated conical, Handmann's subspecies is rather globular. Handmann's taxon is meanwhile considered as junior synonym of M. pygmaea Hörnes, 1856(Wenz 1929a, p. 2813. M. pygmaea inflata Sauerzopf, 1952, in turn, highly resembles M. fuchsi Handmann, 1882 concerning its size, the regular conical outline and the slightly inflated last whorl. Exactly these last two criteria were for both authors the reason to separate their forms from M. pygmaea (see Handmann 1887, p. 13;Sauerzopf 1952, p. 13). Therefore we consider both synonymous and refrain from introducing a replacement name.
The second problem regards the availability of Melanopsis inflata Handmann, 1882. This name was already introduced as subordinate taxon by Férussac (1823) within M. buccinoidea. Whether it is available as species-group name, however, cannot easily be determined, given the chaotic system in Férussac's work (see also discussion of M. elongata below) and the fact that it is not found to be used as species-group name attributed to Férussac in the literature, which would have made it available via ICZN 1999, Article 45.6.4.1. If Férussac's name is accepted as species-group name, Handmann's taxon would become a primary homonym. Since this is apparently not the case and Handmann's subspecies was synonymized anyway, the introduction of a replacement name would be inexpedient.

Melanopsis elongata auctores
In the biological and palaeontological literature several species-group taxa were introduced as "Melanopsis elongata". The first mention traces back to Férussac (1823, p. 150), who described a subordinate taxon within M. buccinoidea, which he described two pages above, from Épernay, France. From Férussac's remarks it is not clear, if elongata has subspecific or infrasubspecific rank. Moreover, the inconsistent formatting in this work leaves doubts about what is intended to be a taxon's name and what a descriptive term. Usually it is important to find out the exact rank of a taxon, since infrasubspecific taxa are not governed by the Code. In this case, however, we follow ICZN (1999, Article 45.6.4.1), stating that an infrasubspecific taxon is deemed to be subspecific from its original publication if, before 1985, it was adopted as the valid name of a species or subspecies. This criterion is at least fulfilled by the publication of Pallary (1916).
Probably the problems we are presently aware of are only several of many invalidly erected taxa named "Melanopsis elongata".
The names introduced by Locard, Jooss and Gillet and Marinescu have not yet undergone nomenclatural revision. Although primary homonyms are invalid, it is, however, not expedient to introduce new names for taxa that are not used anymore. This particularly regards Melanopsis narzolina elongata Locard, 1878 from the Late Miocene of Tersanne, which was apparently not used at all by subsequent authors and synonymized by Wenz (1929a) with M. narzolina narzolina. If later authors regard this taxon as distinct from M. narzolina, a new name will have to be introduced.
A more complicated case in terms of synonymy is presented by Melanopsis callosa elongata Jooss, 1911 from the Aquitanian of the Mainz Basin. Wenz (1929aWenz ( , p. 2729 cited the record of M. callosa from Jooss (1911) in the synonymy list for M. fritzei Thomä, 1845, both of which he considered synonymous, but either overlooked that Jooss had introduced a new variety or forgot to state it in the catalogus. The synonymization by Wenz is preliminarily accepted here, so as not to introduce yet another, probably superfluous name. A more thorough taxonomic revision is needed to clarify the taxonomic status of this subspecies and whether a new name is needed.
The remaining two homonyms are still in usage and thus require a more detailed assessment.
Age. Middle to Late Burdigalian ("Helvetian"). Type material. Paleontological Institute and Museum, University of Zurich, no number indicated.
Discussion. Unlike the case of M. narzolina elongata Locard, 1878, this taxon was not synonymized by Wenz (1929aWenz ( , p. 2693. Despite separating it from M. citharella, Wenz noted that this form is probably indistinguishable from the nominal species. After review of Locard's description and illustrations we fully agree with Wenz, and draw the taxonomic conclusion to synonymize M. citharella elongata with M. citharella. Hence, although it is a primary homonym, we avoid introducing another superfluous name.
Holotype. Gillet and Marinescu (1971) designated the specimen illustrated by Fuchs (1870a, pl. 14, fig. 79) as holotype. According to the inventory books of the Natural History Museum Vienna the material should be stored there, but despite great effort it could not be located.
Discussion. This case represents another primary homonym of M. elongata Férussac, 1823. Here some specific notes are necessary to elucidate the history of this taxon. Gillet and Marinescu (1971) erroneously linked the holotype of M. defensa to the variety trochiformis Fuchs, 1870(Fuchs 1870a, who explicitly separated these two specimens from the typical form (Fuchs 1870a, p. 354). Since Fuchs did not denote a holotype, all material studied by him, except the two specimens determined as trochiformis, are syntypes of M. defensa defensa. It was unwise, though nomenclaturally correct as the nominal subspecies was still based on several (not illustrated) syntypes, to assign the new name elongata to the remaining figure of M. defensa in Fuchs (1870a, pl. 14, fig.  79). If, however, a lectotype would be designated from Fuchs's original material and one would choose the figured specimen (pl. 14, fig. 79) as such, M. defensa elongata would become an objective synonym of M. defensa defensa. In conclusion, we avoid introducing a replacement name because of the obvious misapprehension of Gillet and Marinescu (1971) and synonymize M. defensa elongata with M. defensa defensa.
A part of the material of M. defensa defensa in Gillet and Marinescu (1971, pl. 23, fig. 10) was later separated as the new species M. lebedai by Lueger (1980, p. 104 Kantor et al. 2010).
Discussion. This tricky case requires a careful assessment of the original literature. Penecke (1886, p. 35) introduced a new species, Hydrobia tenuis, from the Paludina beds of Malino and Sibinj in Croatia. Later, Wenz (1913) described a different new taxon as Hydrobia obtusa tenuis from the Frankfurt area. Despite the identical naming, Wenz' taxon is no primary homonym. Since Wenz clearly introduced this taxon as "mutation" it is not available as species-group name (ICZN 1999, Articles 45.5 and 45.6), although he erroneously cited it as "variety" when referring to his own work in the Fossilium Catalogus (Wenz 1926). The latter record is in fact a nomen nudum (as is true for the mutations aperta, distorta, incrassata, and umbilicata). We are not aware of any work making Hydrobia obtusa tenuis available by treatment as valid species or subspecies (ICZN 1999, Article 45.6.4.1).
Discussion. Both involved taxa were originally combined with different genera, but have been attributed to Pseudamnicola in the second half of the 20 th century. Lőrenthey's species was recombined with Amnicola by Wenz (1926), based on overall shell morphology. Because an attribution of a European species to this North American genus is relatively doubtful (Paulucci 1878, Wenz 1938-1944, Papp (1953) recombined this species with Pseudamnicola. Valvata minima Fuchs, 1877, described from the Pliocene of Megara (Fuchs 1877, p. 14, pl. 1, figs 25-27), was recombined with Pseudamnicola by Willmann (1981, p. 212). This would make Pseudamnicola minima (Lőrenthey, 1893) a secondary homonym of Pseudamnicola minima (Fuchs, 1877). However, as pointed out by Haszprunar (2014), Valvata minima Fuchs, 1877 is a primary homonym of V. minima Hislop, 1859 from the Tertiary of East India and is thus not available (for replacement name see above). Lőrenthey's species consequently is no secondary homonym and needs no replacement name. Anyway, the generic classification of neither species appears to be settled. Several species of the Miocene of Central and Southeastern Europe previously attributed to Pseudamnicola have been shown lately not to belong to this genus (Neubauer et al. 2013b, c).