Taxonomic vandalism in malacology: comments on molluscan taxa recently described by N. N. Thach and colleagues (2014–2019)

a Vietnamese malacologist Nguyen Ngoc Thach described 235 land snail species and subspecies from Southeast Asia with co-authors; further 11 species were described by an Austrian malacologist Franz Huber in Thach’s publications (2014–2019). Nearly all taxa were described in self-published books and non-peer-reviewed journals. The low quality of the published photographs, imprecise locality data, deficient literature surveys, and the lack of examination of type specimens raise reasonable doubts concerning the validity of these taxa. In this paper we list all land snails described by Thach and colleagues, and comment on approximately half of his taxa based on examination of the literature and type specimens. As a result, 102 of their taxa are moved to the synonymies of previously described taxa. Three additional taxa, described by other authors, are also considered synonyms of known species here: Helix (Ganesella?) lamyi Dautzenberg et Fischer, 1905, Helix (Plectotropis?) chaudroni Bavay et Dautzenberg, 1909, Amphidromus xiengkhaungensis Inkhavilay et Panha, 2017. Further, nine species are moved to other genera: Pearsonia huberi Thach 2016 to Spiraculum, Streptartemon huberi Thach 2016 to Indoartemon, Tropidophora huberi Thach, 2018 to Leptopoma, Microstele huberi Thach, 2018 to Apoecus, Camaena khamducensis Thach et Huber, 2018 to Hemiplecta, Camaena abbasi Thach, 2016 to Asperitas, Mysticarion huberi Thach, 2016 to Megaustenia, Helixarion annhiae Thach et Huber, 2017 to Megaustenia, and Lamprellia huberi Thach, 2018 to Trichochloritis. Chloritis bifoveata vinhensis Thach et Huber, 2018 is elevated to species level. Oospira naggsi callosa Páll-Gergely, nom. nov. is established as a replacement name for Hemiphaedusa huberi Thach, 2016, non Oospira huberi Thach, 2016. Trichochloritis mussonena Páll-Gergely, nom. nov. is established for Mussonena huberi Thach, 2018, non Trichochloritis huberi (Thach, 2018).


INTRODUCTION
The description of Southeast Asian land snails began in the late 18th century when European travellers returned with large and conspicuous specimens. The most active period was the mid-late 19th and early 20th centuries when colonial European naturalists travelled the world to document its biodiversity. Therefore, most specimens examined during the descriptions of these species are housed in European museums. The majority of land snail genera have yet to be properly revised and many species described over a century ago have not yet been illustrated in scientific literature. And, even when illustrated, these early descriptions do not necessarily demonstrate what we now consider as critical morphologi-cal characters by which to differentiate species. The description of new Southeast Asian land snail species, as well as their revision, generally requires the examination of all type specimens. This work is often challenging as some museums do not loan type specimens so researchers must visit those collections to properly examine these types.
Vietnamese malacologist nGuyen nGoc tHacH, at times with colleagues, published three non-peer reviewed, self-published books (tHacH 2016a(tHacH , 2018a and several papers (tHacH & HuBer 2014, tHacH 2015a, b, c, 2016b, c, d, e, f, g, h, 2017b, c, d, e, f, 2018b, c, 2019a, b, c, d, e, f, g, h, tHacH & aBBas 2017a. Most taxa in the publications were described solely by Nguyen Ngoc Thach, but occasionally with others, such as the Austrian malacologist, Franz Huber. The lack of peer-review, low quality of the published photographs, imprecise locality data, deficient literature surveys, and the lack of examination or even mention of type specimens of other species that should have been examined, raise reasonable doubts concerning the validity of these taxa. A few species have already been synonymised (Páll-GerGely & Hunyadi 2018, inKHavilay et al. 2019.
The high number of new species and subspecies, assigned to 63 genera, makes it impossible to properly deal with them in a single contribution. Most of the groups require extensive systematic revision that may take several years each. Therefore, in this paper we comment only on those taxa that are obvious synonyms, those that have been reviewed earlier, or on those we are currently working.

MATERIALS AND METHODS
All scientific names of tHacH mentioned in this study are validly introduced according to the ICZN Code, and thus, are available, validly introduced names. The terms "valid species", "valid taxon" and "validity" in the following refers to scientifically acceptable taxa (i.e. not synonyms).
We examined the published photographs of specimens or the actual type specimens described by tHacH and his colleagues, and compared them with specimens from other sources and figures published in the literature.

GENERAL REMARKS
Altogether tHacH and his colleagues (see: Introduction) described 246 land snail species and subspecies from Southeast Asia (Cambodia: 5 taxa, Indonesia: 36 taxa, Laos: 51 taxa, Myanmar: 2 taxa, the Philippines: 1 taxon, Thailand: 11 taxa, Vietnam: 140 taxa). Eleven of these were authored by Franz HuBer ("Huber in Thach") in tHacH's books (tHacH 2016a(tHacH , 2018a, and one species was described by F. HuBer in a paper authored only by him . Besides these, tHacH described a species from Spain (Helicella candoni Thach in tHacH 2018a: 72), and one from Madagascar (Kalidos huberi Thach in tHacH 2018a: 43), and 88 marine and one freshwater species were described, which are not treated here. Appendix 1 summarises all terrestrial species.
The general shortcomings of these publications are: 1. In most cases it is obvious that the authors have not examined type specimens of similar species or their illustrations/photographs. Instead, they compared their specimens with images posted on shell dealer websites and other online sources (https:// www.conchology.be/, http://www.bagniliggia.it, Wikipedia, etc.) and popular science books (e.g. aBBott's [1989] Compendium of Landshells). 2. Their general understanding of basic intraspecific variability in some genera differs from ours and that of recently active malacologists working in the same geographic areas. As a result, minor differences in shell morphology and colouration observed between individuals are interpreted as characters by which to distinguish species. This has resulted in an unrealistic increase in species numbers, especially in the genus Amphidromus, which often differ in colour and colour pattern even within populations. 3. They have placed new species in genera and families that have not been recorded from Southeast Asia, but are known from the Neotropics (Streptartemon Kobelt, 1905, Helminthoglypta Ancey, 1887, Obeliscus Beck, 1837, Australia (Mysticarion Iredale, 1941, Lamprellia Stanisic, 2010, Megalacron I. Rensch, 1934, Mussonena Iredale, 1938, and Madagascar (Tropidophora Troschel, 1847, Cyclotopsis W. T. Blanford, 1864), a clear sign of their lack of knowledge of evolutionary convergence and biogeography. A vast majority of land snail taxa are known to have limited dispersal abilities, and most have clear geographically definable distributions. They are far more likely to be related to taxa that occur in the same geographical area instead of those inhabiting different areas of the world. Furthermore, tHacH and his coauthors often place new species in inappropriate families, most conspicuously the Camaenidae versus Ariophantidae/Dyakiidae/ Helicarionidae. 4. Very poor locality data of the new taxa are often provided, making the collection of additional specimens to investigate intraspecific variability unlikely. 5. In many cases these new species belong in genera and families that have never been revised, or not in the past few decades. For example, hundreds of species have been described in the family Camaenidae over the last two centuries. These are often very similar in shell morphology yet no comprehensive revision has been published, even at the genus level. Generic boundaries are not well defined, species' ranges of variation and distributions are largely unknown, and many of the species have never been illustrated. The description of a camaenid species without a comparison of it to pertinent species has a great risk of creating a synonym. 6. The types or illustrated specimens are often immature, juvenile, or so weathered that further taxonomic work on the species will be greatly impeded (see: Appendix 1). the discretion of the author(s). However, we find it unadvisable to give the same specific epithet to many species, particularly in areas where species boundaries are unclear or unknown. Among the species described by N. N. tHacH, 43 are named huberi, 9 as franzhuberi, and 7 as abbasi and F. HuBer named 10 species as thachi (in tHacH 2017a, 2018a, and HuBer 2015). These patronyms greatly increase the possibility of secondary homonyms when the generic assignments are changed (e.g. Páll-GerGely & Hunyadi 2018 and this study). Furthermore, homonyms occur even within the same publication, as well as multiple original spellings (e.g. Páll-GerGely 2019).
The inadequate description of tHacH's taxa comes from a general lack of knowledge of the groups and/ or faunas made apparent by: 1) lack of comparison (LC) or mention of previously described species, to which they are similar or identical, and 2) the use of minor shell characters (MC) that are known to be of little or no use by which to distinguish species. These two types are listed in Appendix 1 after each taxon.  Panha et Patamakanthin, 2001 by the ovate, not triangular, aperture, "spire whorls much broader" and dorsal side of body whorl concave (convex in A. somnueki). Firstly, the aperture is "ovate" because the holotype of A. huberi is a subadult specimen.

TAXONOMY AND SYSTEMATICS
It is clear that the aperture of the holotype of A. huberi is not continuous, as the peristome is not yet developed in the parietal area. In only one alycaeid species (the Japanese Cipangocharax okamurai (Azuma, 1980)) does it appear that the aperture is discontinuous, but even in that case the parietal callus is developed, just thin and blunt, represented as a slight, thin calcareous layer. The aperture is continuous in all other alycaeid species (we have examined most types of all the ca. 380 alycaeid taxa recently). Therefore, the not fully expanded peristome of the subadult holotype of A. huberi causes it to appear different than that of A. somnueki. Secondly, we cannot concur that the body whorl of A. huberi is broader than that of A. somnueki (at least we believe this is what the author meant by "spire whorls"). Thirdly, it is unclear what tHacH (2018a) meant by the concave-convex difference of the dorsal body whorl, and we see no difference between the two taxa. Additionally, the type locality of A. huberi "Aouluc, South Thailand" is the same as that of A. somnueki "Ao Luk limestone areas, Krabi Province, (...) Thailand". Therefore, we consider A. huberi as a junior synonym of A. somnueki.

Family Cyclophoridae Gray, 1847 Genus Cyclophorus Montfort, 1810
Cyclophorus montfort 1808-1810, vol. 2 (1810): 290. Remarks. The genus Cyclophorus Montfort, 1810 contains hundreds of names and it is clear that the infra-and intra-variability of almost all species are very poorly understood. Revision and description of new species of Cyclophorus requires morphometric analysis of large series of specimens and perhaps molecular phylogeny to reveal species boundaries (e.g. nantarat et al. 2019). Although the description of new species during the 19th and 20th centuries from a few specimens with imprecise collection data was normal, it is very unwise to do so now. We find it nearly impossible to decide whether the new taxa introduced by tHacH and his colleagues are valid and is beyond the scope of this paper. Unfortunately, the thorough paper of nantarat et al. (2014)  Remarks. According to the original description C. huberi Thach, 2018 is characterised by a "deep groove at periphery". However, it is clear from photos of the holotype that the deep groove is of teratological origin. The specimen had stopped growing about half a whorl behind the peristome, when the snail probably estivated for some time. The groove on the last half whorl was developed probably due to an injured mantle. The groove cannot be ascribed to any breathing functions known in several terrestrial caenogastropod genera (Páll-GerGely et al. 2016), because it would require the presence of a passage between the operculum and the peristome to allow gas exchange. This species was compared with the Vietnamese C. lubricus (Dautzenberg et Fischer, 1908), which has a short snorkel near its peristome, and C. micron Pilsbry, 1900(in PilsBry 1900b. The latter species, now assigned to Nakadaella Ancey, 1904, is ca. 1 mm in diameter while the holotype of C. huberi is 21.2 mm in diameter. This species could be valid because the only species known from Laos (C. porrec tus Möllendorff, 1898) is clearly not conspecific (see:   According to the original description, P. nicoi Thach, 2018 differs from P. crossei by having "subsutural bands", "short axial ribs below suture", and an operculum with red-brown lines. The meaning of "subsutural bands" is unclear, because the illustrated specimens show no distinct bands below the suture. Short axial ribs below suture are visible on P. crossei specimens examined by KonGim et al. (2013). The stripes on the operculum cannot be used to distinguish species, as no evidence is provided on the intra-and interspecific variability of this trait, and the latest revisions (KonGim et al. 2013(KonGim et al. , minton et al. 2017 did not use operculum colour as an important trait for species recognition and delimitation. As a consequence, P. nicoi is assigned a junior synonym of P. crossei, which was synonymised with P. rochebruni by    Fig. 8). Remarks. We cannot find notable differences between P. anceyi and P. huberi Thach, 2018 (Figs 6-7), so the latter is here considered a synonym of the former. In the superfamily Achatinoidea, most species have undetermined growth so overall size and number of whorls are not critical for species discrimination. Therefore, we regard O. owengriffithsi as a junior synonym of P. excellens.  new synonym Remarks. The holotype of I. huberi Thach, 2018 is stated to differ from O. bulbulus (Morelet, 1862) by the absence of a blunt basal denticle. However, a slight thickening is visible behind the basal lip, and it would have developed further if the animal lived longer. Due to the identical shell shape we consider I. huberi a junior synonym of O. bulbulus.

Perrottetia gregoi Thach, 2018
Perrottetia gregoi tHacH 2018a: 39, figs 534-536. Remarks. This species is very similar to Oophana diplo don (Möllendorff, 1900) (described in möllendorff 1900a, see: photo in ZilcH 1961), but we did not have the opportunity to compare the two species in detail. Thus, the validity of P. gregoi requires further revision.  Dautzenberg, 1912, so we have no reservation in treating the former as a synonym of the latter. The type specimen of A. macrostoma figured in the original description has fine, vertical, brown stripes on its shell. The shell photographed by inKHavilay et al. (2019) also has these stripes, but they are very pale, probably because it is a dead-collected specimen. The holotype of M. huberi lacks any radial stripes due to its weathered condition.

Hemiplecta khamducensis (Thach et Huber, 2018) new combination
Camaena khamducensis Thach et Huber in tHacH 2018a: 67, figs 886-888. Remarks. C. khamducensis Thach et Huber, 2018 is clearly a member of the Ariophantidae, and not a camaenid. Although the assignment of the species to the genus Hemiplecta is provisional, it is very similar in shell morphology to better-known members of Hemiplecta (see: photos of Hemiplecta species in inKHavilay et al. 2019). Its validity will be determined upon a systematic revision. , the species inhabits an extensive area in Southeast Asia, and the differences between the two taxa mentioned by tHacH (2017a) (weaker keel and stronger sculpture of H. huberi) do not seem correct based on the presented photos. Therefore, we assign H. huberi as a junior synonym of H. pluto.

Family Camaenidae Pilsbry, 1893
Genus Amphidromus Albers, 1850 Bulimus (Amphidromus) alBers 1850: 138. Remarks. molluscaBase (2019) lists 187 species of Amphidromus, 92 species described by tHacH and HuBer. Only 95 species have been described by all other authors (molluscaBase 2019). It is highly unlikely that doubling the number of species in the genus is warranted. Many Amphidromus species have highly variable colour forms, and in some cases, minor aspects of shell morphology are also variable. This has been noted by multiple, competent malacologists over the last two centuries. With the availability of many more specimens due to increased collecting activity over the last few decades, recent studies have clearly demonstrated that this variability exists and many Amphidromus species are some of the most variable of all land snails (sutcHarit & PanHa 2006, inKHavilay et al. 2017).
The Amphidromus of West Timor are extremely variable in shell colour and pattern. This variability was extensively studied by Haniel (1921) and was even mentioned in the original description (scHePman 1892) of A. reflexilabris. Yet, tHacH (2017a, d, e, f, 2018a and tHacH & aBBas (2017a, b) described nine new species from the island, all of which we synonymise with A. reflexilabris below.
Additionally, solem (1965) studied 500 shells (91 samples), and reported that 9 valid taxa inhabit Thailand. Thach and his colleagues describe three new species from Thailand while only examining 18 specimens (3 samples).
Here we synonymise the Amphidromus species of Thach and co-authors that we believe identical with previously described taxa, or whose shell morphologies and colour patterns fall well within the known variability of those species.  , Fig. 14); Süd-Annam, 120 km von der Küste, auf dem Wege zum Plateau von Lang-Bian, zw. 600-1,000 m a.s.l., SMF 7762 (holotype of asper Fig.  15); NHMUK 1910.12.30.98 (lectotype of buelowi); "CNHM 72436" = FMNH 72436 (paralectotype of buelowi, Fig. 16). Remarks. tHacH (2016a) compared A. franzhuberi Thach, 2016 only with A. buelowi Fruhstorfer, 1905, which is indeed a different species. However, the holotype of A. franzhuberi is identical to that of A. as per (although the latter shell is weathered). Therefore, A. franzhuberi is a junior synonym of A. asper. tHacH (2017a: 37) later stated that A. asper (referring to it as "the new species") and A. franzhuberi are similar, but noted that the anterior extremity of the aperture is rounded in A. asper and pointed in A. franz huberi, and that A. asper lacks a canal. This is correct for the figured specimen of A. asper (tHacH 2017a: figs 432-433) (although we find this insufficient to distinguish species), but inaccurate when compared with the holotype of A. asper. Namely, A. montesdeocai is pale with greenish colouration on the body whorl, whereas A. schileykoi possesses a pinkish last whorl, and typical A. cambojiensis has faint, brownish radial stripes on the teleoconch. However, the very similar shell and aperture shape, the pink aperture, and the overall simple colour pattern suggest that they all belong to the same species. Therefore, we treat them as junior synonyms of A. cambojiensis. A. cambojiensis was originally described from Cambodia, whereas the other two forms are known from neighbouring southern Vietnam. The shell and aperture shape, the colour of the aperture and the shell colouration of A. lamdongensis agrees with that of A. cambojiensis, therefore we consider that species also as a synonym of A. cambojiensis.

Amphidromus comes (L. Pfeiffer, 1861)
Bulimus comes L. According to the original description of A. naggsi, it differs from A. ingens by the wrinkled shell surface and the presence of 2-3 broad spiral channels on the body whorl instead of a single spiral channel, the latter being incorrect. However, both possess two elevated spiral ridges on the body whorl, although it is a bit more marked in A. naggsi. The difference in the shell surface also does not seem to be supported by the presented photographs. For example, the shell of A. naggsi (tHacH & HuBer 2014: fig. 5) appears smoother than the one presented as A. ingens (tHacH & HuBer 2014: fig. 14). Since shell sculpture appears to be variable, we consider this character insufficient to differentiate species. Therefore, we allocate A. naggsi as a junior synonym of A. ingens.  (1892) mentioned in the original description of A. reflexilabris, that "this species varies very much in size and colour, no two specimens being alike...". Haniel (1921) extensively studied the radula, genital and shell variability of Amphidromus from West Timor. Apparently the Amphidromus taxa of West Timor are among the most variable of land snails in terms of shell morphology and colour. The synonymised nine Amphidromus taxa described by Thach and by Thach & Abbas can be easily placed in the morphological continuum presented by Haniel (1921) as follows: A. beschau eri Thach, 2018 (Haniel 1921: fig. 17), A. calvinab basi Thach, 2017 (Haniel 1921:  The corpulent shell, white and/or reddish line along the suture, and the yellow-greenish stipes are characteristic of A. roseolabiatus, and therefore, we treat them as synonyms of that species.

Amphidromus mirandus Bavay et Dautzenberg, 1912
A. koonpoi Thach et Huber, 2018 (see: note on multiple original spellings in Páll-GerGely 2019) is slightly more slender than typical A. roseolabiatus, which is not sufficient for species-level distinction from A. roseolabiatus, which is a common species in central Laos, near Takhek Huber, 2018, A. salzmanni Thach et Huber, 2017, all described from central and southern Vietnam, agree with each other with respect to shell shape and the uniformly coloured shell (or the apical whorls have a slightly different colour than the body whorl) with a slender sutural band, and some darker colouration on the callus and/or on the peristome and should be classified within the same species. They also largely match A. ventrosulus, and are therefore handled as synonyms here. Moreover, A. hassi ngoanmucensis nearly matches the paralectotype of A. ventrosulus in all important characters (see: sutcHarit et al. 2015).

Genus Camaena Albers, 1850
Helix ( Remarks. C. lacthuyensis Thach, 2016 agrees with C. duporti in shell shape and size, and although the latter has several brownish spiral bands, both agree in the presence of a white band just below the middle line of the body whorl. We interpret the slight colour pattern differences as intraspecific variability, and handle C. lacthuyensis as a junior synonym of C. duporti. Remarks. C. anhi Thach, 2017 is identical to C. ga briellae, therefore we designate it a junior synonym of the latter. Camaena binhgiaensis Thach, 2016 differs from typical C. gabriellae only by the more strongly pronounced reddish spiral bands, which we believe to be insufficient for species-level distinction. Therefore, it is also regarded as a junior synonym of C. gabriellae.  15°47'18.0"N, 107°46'33.4"E, leg. Hunyadi, 16.02.2019, coll. HA. Remarks. C. franzhuberi Thach, 2018, C. franzhuberi laosianus Thach, 2018and C. suprafusca Möllendorff, 1898 do not differ from C. pachychila in important shell characters such as shell and aperture shape, and sculpture, therefore, we consider the three taxa above as junior synonyms of C. pachychila.

Genus Ganesella Blanford, 1863
Helix ( Brazier, 1878), which is endemic to eastern Australia, and was only compared with a Lamprellia species (L. angulata Stanisic, 2010). However, there are a number of similar species described from Cambodia, Vietnam, and Laos in more appropriate genera. This species is very similar to the type spe-cies of Trichochloritis (Helix breviseta L. Pfeiffer, 1862) in terms of general shell and aperture shape, but differs from it by the angled body whorl, which is rounded in T. breviseta. Therefore, it is transferred here to Trichochloritis.

DISCUSSION
wHeeler (2014: 371) summarised the specific traits of a taxonomist as follows: "If the focus of your work is to make as many species of a clade known as possible, to carefully interpret and analyse the transformational history of as many of its homologous characters as possible, to study and master all taxonomic literature on a group since 1753, to apply informative names, and to ultimately build a phylogenetic classification summarizing all that is known of a taxon, then you are unquestionably a taxonomist." Unfortunately, the authors discussed here have not followed these guidelines in their mostly non-peer-reviewed descriptions of more than three hundred species and subspecies over the last 5 years (2014-2019). Ideally, the purpose to describe an unknown species or subspecies is to contribute to the knowledge of the biodiversity of our planet. However, these descriptions must be presented to the scientific community in a consistent and accepted manner, i.e. a peer-reviewed journals and books. Why do some authors choose not to adhere to the accepted formats, i.e. present new taxa in non-peer-reviewed publications, even when they have interest in biodiversity?
Time and effort are surely factors. Some authors simply do not want to take the time or apply the effort necessary to complete the peer-review process. They may also believe that review is unnecessary because no one knows more about the subject so why should it be reviewed? Also, some degree of fame and respect comes with the introduction of new taxa and this increases as the number of taxa described increases. This is a well-known phenomenon already described as nomenclatural mihilism (duBois 2008) and "Mihi itch" (evenHuis 2008). And, finally, some invertebrate groups such as molluscs, butterflies, beetles, corals, etc. are widely collected by enthusiasts worldwide. These are traded, bought, and sold and this has become a huge industry in many parts of the world. Specimens with attractive colours and colour patterns are particularly sought after and supply and demand forces values up (and profits). Value is also greatly determined by rarity. So, new taxa described, particularly those with attractive colour patterns and small distributions, drive interest and desire in enthusiasts to enhance their collections with species that no other collector possesses. For the seller, new names create more taxa to inventory and sell, even when the taxa represent nothing but intra-specific variation. Some authors retain or give type specimens to the collector instead of depositing them in recognised institutions. These specimens have much higher value than non-typical material if sold. Some collectors, but surely not all, that provide specimens to those that may describe them as new taxa are sometimes motivated by two purposes: 1) potential future financial gain, and 2) the naming of patronyms. The latter has certainly occurred.
For whatever reasons, Nguyen Ngoc Thach and his colleagues described over three hundred species over the last five years, mostly land snails from Southeast Asia, almost all without peer review. Our estimate is that ca. 30-40 species of their terrestrial taxa are valid (less than 15% of all of the newly described taxa!), although we are unable to judge in many cases with the general lack of generic revisions. Similar to the activity of the Australian "herpetologist" R. Hoser (Kaiser et al. 2013, denZer et al. 2016) and some other pseudo-taxonomists (see e.g. moore et al. 2014), the hundreds of taxon names introduced by these authors simply must be considered unacceptable and marked as taxonomic vandalism. Although the community of taxonomists rejects the concept of more bureaucracy over taxonomy (Garnett & cHristidis 2017, tHomson et al. 2018, it seems inevitable to require peer-review for the description of new taxa and other taxonomic decisions to be acceptable as valid (e.g. Kaiser et al. 2013, scHutZe et al. 2017