Commented checklist of European Gelechiidae (Lepidoptera)

Abstract The checklist of European Gelechiidae covers 865 species, belonging to 109 genera, with three species records which require confirmation. Further, it is the first checklist to include a complete coverage of proved synonyms of species and at generic level. The following taxonomic changes are introduced: Pseudosophronia constanti (Nel, 1998) syn. nov. of Pseudosophronia exustellus (Zeller, 1847), Metzneria expositoi Vives, 2001 syn. nov. of Metzneria aestivella (Zeller, 1839); Sophronia ascalis Gozmány, 1951 syn. nov. of Sophronia grandii Hering, 1933, Aproaerema incognitana (Gozmány, 1957) comb. nov., Aproaerema cinctelloides (Nel & Varenne, 2012) comb. nov., Aproaerema azosterella (Herrich-Schäffer, 1854) comb. nov., Aproaerema montanata (Gozmány, 1957) comb. nov., Aproaerema cincticulella (Bruand, 1851) comb. nov., Aproaerema buvati (Nel, 1995) comb. nov., Aproaerema linella (Chrétien, 1904) comb. nov., Aproaerema captivella (Herrich-Schäffer, 1854) comb. nov., Aproaerema semicostella (Staudinger, 1871) comb. nov., Aproaerema steppicola (Junnilainen, 2010) comb. nov., Aproaerema cottienella (Nel, 2012) comb. nov., Ptocheuusa cinerella (Chrétien, 1908) comb. nov., Pragmatodes melagonella (Constant, 1895) comb. nov., Pragmatodes albagonella (Varenne & Nel, 2010) comb. nov., Pragmatodes parvulata (Gozmány, 1953) comb. nov., Oxypteryx nigromaculella (Millière, 1872) comb. nov., Oxypteryx wilkella (Linnaeus, 1758) comb. nov., Oxypteryx ochricapilla (Rebel, 1903) comb. nov., Oxypteryx superbella (Zeller, 1839) comb. nov., Oxypteryx mirusella (Huemer & Karsholt, 2013) comb. nov., Oxypteryx baldizzonei (Karsholt & Huemer, 2013) comb. nov., Oxypteryx occidentella (Huemer & Karsholt, 2011) comb. nov., Oxypteryx libertinella (Zeller, 1872) comb. nov., Oxypteryx gemerensis (Elsner, 2013) comb. nov., Oxypteryx deserta (Piskunov, 1990) comb. nov., Oxypteryx unicolorella (Duponchel, 1843) comb. nov., Oxypteryx nigritella (Zeller, 1847) comb. nov., Oxypteryx plumbella (Heinemann, 1870) comb. nov., Oxypteryx isostacta (Meyrick, 1926) comb. nov., Oxypteryx helotella (Staudinger, 1859) comb. nov., Oxypteryx parahelotella (Nel, 1995) comb. nov., Oxypteryx graecatella (Šumpich & Skyva, 2012) comb. nov.; Aproaerema genistae (Walsingham, 1908) comb. rev., Aproaerema thaumalea (Walsingham, 1905) comb. rev.; Dichomeris neatodes Meyrick, 1923 sp. rev.; Caryocolum horoscopa (Meyrick, 1926) stat. rev.; Ivanauskiella occitanica (Nel & Varenne, 2013) sp. rev.; Apodia martinii Petry, 1911 sp. rev.; Caulastrocecis cryptoxena (Gozmány, 1952) sp. rev. Following Article 23.9.2 ICZN we propose Caryocolum blandella (Douglas, 1852) (Gelechia) nom. protectum and Caryocolum signatella (Eversmann, 1844) (Lita) nom. oblitum.


Introduction
Lepidoptera, butterflies and moths, are among the best-known insects, and due to a long tradition of studying Lepidoptera in Europe our knowledge of European Lepidoptera is more comprehensive compared to other parts of the world. Even though Lepidoptera is a well-defined group they exhibit a huge diversity in size, colour and wing markings. Whereas everybody can recognize a butterfly the vast majority of Lepidoptera are small and often dull coloured insects. One such group is the family Gelechiidae. They have for a long time been rather neglected by most lepidopterists mainly due to their external similarity and lack of resources for their identification. Over the last couple of decades, the latter problem has partly been addressed, e.g., Elsner et al. (1999), Karsholt (1999, 2010), and at the same time there has been an increasing research interest in the Gelechiidae, resulting in a number of smaller and larger taxonomic reviews and faunistic publications (see reference list) dealing with these moths. However, what was becoming increasingly a hindrance for ongoing research was the lack of an updated checklist of European Gelechiidae. In particular, when planning an extensive DNA barcoding project for the family (Huemer et al. 2020), this deficit became obvious and therefore the authors decided to compile such a checklist for this and future requirements.
A checklist is the most basic taxonomic work on a group of organisms. It can be alphabetical or systematic, viz. trying to reflect the current knowledge of the relationship of the included taxa. This checklist is in systematic order, and it moreover includes synonyms and annotations. Its aim is to present an updated overview of the Gelechiidae known from Europe. This is highly appropriate as nearly a quarter of the currently known species have been described since 1990 (Huemer et al. 2020).
This checklist of European Gelechiidae is the first one to include all known synonyms of genera and species of Europaean Gelechiidae. It is mainly based on data published in Fauna Europaea (Karsholt 2004(Karsholt -2019 but supplemented with numerous published and unpublished additions and corrections from the last few years. It covers all currently accepted species known from the European fauna and their synonyms. Subspecies are not given separate entries, but listed among synonyms, though marked as subspecies. Subgenera are listed among generic synonyms. The considerable number of likely undescribed species (Huemer et al. 2020) are not included in the list.
Taxonomically critical genera and species, especially possible cases of cryptic diversity ( Fig. 1) manifested by divergent DNA barcodes, are commented on in detail (see also Huemer et al. 2020).

Geographic restriction
For the purpose of the present checklist we define Europe in a broad sense, which includes the Ural Mountains, Russian parts of the Caucasus, the 'European' part of Kazakhstan, the Mediterranean islands and the Macaronesian Islands (except Cape Verde) (Fig. 2).
The inclusion of the Russian parts of the Caucasus only added four species to the list (Acompsia caucasella Huemer & Karsholt, Neofriseria caucasicella Sattler, Chionodes caucasiella Huemer & Sattler and Scrobipalpa caucasica (Povolný)), which is surprising. One would expect a richer gelechiid fauna to occur in this vast and diverse mountain system. However, most likely the species inventory is simply underestimated as only few lepidopterists have done field research in this area so far.

Content and structure of the checklist
The checklist is restricted to described nominal taxa. Potentially undescribed species (Huemer et al. 2020) are not included. Species introduced from other parts of the World are only included if they are known to have been naturalized within the area described above. Doubtful, though possible, records of occurrence are considered in the checklist and marked with an asterisk *, whereas confirmed incorrect records and doubtful species (taxa incertae sedis) are not listed. Names applied to misidentified taxa are listed only in cases where the incorrect taxonomy has been widely used or where the misidentification can easily cause misunderstandings. These are marked with auct. (= of authors).

Systematic arrangement
The higher classification follows the molecular study of Karsholt et al. (2013), whereas the listed order of genera and species is largely according to published revisions and data from Huemer et al. (2020).

Synonymy
Although our knowledge of European Gelechiidae has increased much over the last years, there are still available species-group names in the family which have not yet been associated with known species. Very few of these are likely to represent additional taxa, whereas most cases will be synonyms. Furthermore, several of the published synonyms need taxonomic re-assessment. We have not made special efforts to search for type specimens of such taxa for the purpose of the present checklist, and they should be considered in connection with taxonomic revisions within the Gelechiidae.

Gender agreement
Many species-group names of European Gelechiidae have been combined in different genera since they were first made available. Following article 31.2 of the International Code of Zoological Nomenclature (ICZN 1999) these names require gender agreement between specific and generic names. However, we follow the widely accepted proposals by Sommerer (2002) in Lepidoptera and keep the original spelling of species names to avoid unnecessary instability (van Nieukerken et al. 2019).

Molecular species delimitation
DNA barcodes have been sequenced for a significant number of the species included in the inventory (741 nominal species with sequences > 500 bp). These supported the compilation of the checklist and helped identify and fix yet unpublished synonyms and the systematic position of some species. Details to species and specimens are available on BOLD (Ratnasingham 2018) in the public dataset "Lepidoptera (Gelechiidae) of Europe" under the DOI: https://doi.org/10.5883/DS-GELECHEU (see also Huemer et al 2020).
We tested the congruence of morphologically based species determinations and COI sequence data with the Barcode Index Number (BIN), a methodology recently proposed by Ratnasingham and Hebert (2013). This system clusters sequences into Operational Taxonomic Units (OTUs) regardless of their previous taxonomic assignment. It is based on a two-stage algorithm that groups the sequences in a cluster and automatically assigns new sequences. All high-quality sequences > 500 bp are recorded independently of the project origin and assigned to a BIN. Though BINs reflect classical Linnean taxonomy to a high level they were not used uncontested (Huemer et al 2020). We found 114 morphologically delimited species with multiple BINs that are potential cases of cryptic diversity, particularly cases with BIN distances > 3%, and these are therefore discussed in the comments. However, there is clear evidence that no species delimiting threshold values exist in Lepidoptera (Kekkonen et al. 2015) and therefore all cases of barcode divergence require further and integrative analysis in the future. Such work was largely outside the scope of this paper which principally followed current taxonomy and only exceptionally considered obvious taxonomic issues. An in-depth taxonomical analysis will also be necessary for 65 clusters with a unique BIN which remained unidentified to species level from morphology and which are not considered in the checklist itself, and for 55 cases of BIN-sharing (see also Huemer et al. (2020)).

Comments on the checklist
Approximately 200 comments on systematic problems, taxonomic changes and particularly potential cryptic diversity, are mainly derived from molecular data and are cross-referenced in the checklist: [1] - [202].
[1] Anacampsidae Bruand d'Uzelle, 1851 has priority over Gelechiidae Stainton 1854. The former name has hardly been used (Sattler 1973) and the use of the older synonym would threaten stability. Following Art. 23.9.3 (ICZN) the case should therefore be referred to the Commission for a ruling under the plenary power. The year of description of Anacampsidae is according to Viette (1977).
Stomopteryx. This genus is in need of a taxonomic revision and includes several probable cases of cryptic diversity, and equally probably cases of over-splitting.
Stomopteryx nugatricella / S. mongolica / S. lineolella. The taxonomy of these species is unresolved and should be checked in upcoming revisionary work. Junnilainen et al. (2010) separated S. mongolica and S. lineolella on morphological differences they observed in male genitalia but at the same time stated that European specimens of S. mongolica differ from typical Mongolian vouchers (Note: They did not compare S. mongolica from southern Russia with the externally similar S. nugatricella from Spain). DNA barcodes do not support species status of all these taxa which cluster with very low divergences in the same BIN. We therefore believe that taxonomic over-splitting cannot be excluded and would be a reasonable explanation for the current species concept, although barcode sharing between some taxa cannot be excluded.
Stomopteryx deverrae. We have barcoded only North African specimens so far, including a syntype from Algeria, and the material from Spain should be sequenced in future to prove the occurrence in Europe.

[5]
Stomopterayx flavoclavella. European samples from Spain slightly differ from a sequenced syntype from Morocco and cluster in a separate BIN. The suspected conspecificity will be addressed in an upcoming revision.
Stomopteryx remissella. This species represents an unresolved species complex. DNA barcodes show an extraordinarily high and largely geographic variation, reflected by eight different BINs and differences in phenotype. Aproaerema cinctella. This species clusters into two weakly separated DNA barcode clusters with max. distance of 1.86%, probably reflecting intraspecific variation.
[10] Aproaerema linella. A unicolorous, dissected male from Montenegro largely corresponds with the lectotype figured by Nel et al. (1996) in the male genitalia. However, the original description of A. linella as well as bred samples from the type area characterize S. linella as a species with a distinct yellow-orange subterminal fascia or costal and tornal spots and a further yellow spot in the middle of the forewing. A female from northern Italy clustering in a separate BIN matches these phenotypical characters better and also largely agrees in the genitalia. However, in the absence of molecular data from the type-locality, identification of both specimens remains uncertain and we only tentatively assign the name A. linella to the former specimen and leave the latter as an unidentified cluster.
[11] Aproaerema suecicella. Two strongly divergent BINs (4.33% min. distance) show a geographic pattern and need to be tested for potential cryptic diversity.
[13] Aproaerema anthyllidella. The moderate DNA barcode variation with three BINs may reflect cryptic diversity, as e.g., suspected for the current synonym A. natrixella (Schmid pers. comm.) and some of the other five current synonyms, but has to be carefully checked with an integrative taxonomic approach.
[14] Iwaruna. Species in this genus share their BINs and partially overlap in DNA barcodes (I. biguttella and I. klimeschi) but differ in morphology. DNA barcodes of I. heringi, a species requiring taxonomic re-assessment, are unknown.
[15] Anacampsis populella / A. blattariella. A population from western Austria (Vorarlberg) shares its BIN with a unique specimen of A. populella from Finland though matching A. blattariella in morphology. This is most likely a case of a so far unrecognized introgression in these two species, though the weakly deviating DNA barcode may require further studies. All other sequenced specimens of both species group in separate BINs.
[16] Anacampsis scintillella. Two specimens from Spain cluster in a separate BIN.
[17] Anacampsis obscurella. Our limited data indicates geographically separated species with three BINs but requires additional revisionary work.
[18] Mesophleps. The genus was recently revised by Li and Sattler (2012). Two strongly deviating DNA barcode clusters (and BINs) from Spain and Greece probably represent undescribed species.
[19] Nothris. The sequence of species follows the revision by Karsholt and Šumpich (2015 Huemer et al. (2013). Currently this variation is considered as an intraspecific divergence.