Toward a revised checklist of the Western Palearctic butterflies, hyperlinked to the original descriptions at species, genus and family level (Lepidoptera, Papilionoidea)
Part V: Rationale and framework for the Lycaenidae (part II)
Submitted: 10.vi.2026 | Accepted: 23.vi.2026 | Published online: 30.vi.2026.
DOI: 10.5281/zenodo.20759567

Michel Taymans¹ | Sylvain Cuvelier²
0
¹ Clos du Moulin Royal 2 bte 02, B-6900 Marche-en-Famenne, Belgium. michel.taymans@hotmail.com
² Diamantstraat 4, B-8900 Ieper, Belgium. sylvain.cuvelier@telenet.be

Abstract
This second review of taxonomic and nomenclatural issues in Lycaenidae examines the status of family-group names in the light of the International Code of Zoological Nomenclature (ICZN), historical classification schemes, recent phylogenetic evidence, and current usage. Emphasis is placed on the classification of subfamilies and tribes, for which conflicts among older names, synonymies, and prevailing usage have required rigorous assessment under the Code.
The classification of all species within the genera and subgenera of the subfamily Polyommatinae, excluding the tribe Polyommatini (which will be addressed in a future contribution), is critically reviewed and justified. Particular emphasis is placed on the generic classification of the tribe Scolitantidini, for which alternative taxonomic arrangements have been proposed and remain contentious.

Key words
Taxonomy — Checklist — Papilionoidea — Lycaenidae — Lycaeninae — Theclinae — Polyommatinae — Polyommatini — Lampidini — Celastrinini — Scolitantidini — Everini — Zizeerini — Azanini (tribe proposed) — Phengarina (subtribe proposed) — Palaeophilotina (subtribe proposed) — Leptotes — Cyclyrius — Azanus — Lampides — Cacyreus — Celastrina — Tarucus — Phengaris — Maculinea — Pseudophengaris (genus proposed) —Turanana — Pseudophilotes — Palaeophilotes — Scolitantides — Iolana — Glaucopsyche — Zizeeria — Zizina — Cupido — ESU — Cigaritis estherae — Lycaena heracleana — Satyrium vandalusica — Western Palearctic.

Introduction

The present article aims to clarify and justify the classification adopted in the checklist for the subfamily Polyommatinae of the family Lycaenidae, with the exception of the tribe Polyommatini, which will be treated in a subsequent paper. Despite extensive taxonomic and phylogenetic research, the internal classification of Lycaenidae remains only partially resolved. In particular, the rank and delimitation of the major lineages traditionally recognised as subfamilies have been interpreted differently by various authors, reflecting differences in the morphological, molecular, and combined datasets on which their conclusions are based. As a result, alternative classifications continue to coexist in the literature, and some aspects of the higher-level taxonomy of the family remain subjects of ongoing debate.
Over the past decades, numerous phylogenetic studies have advanced competing hypotheses concerning the relationships among these groups. Analyses based on morphological characters, molecular data, or combinations of both have yielded alternative arrangements of the major clades and have often assigned them different taxonomic ranks, recognising them either as subfamilies or as tribes within more inclusive classifications. As a consequence, no single classification has gained universal acceptance, and the circumscription, placement, and relationships of several groups remain subjects of ongoing debate.In addition, some recent phylogenetic studies have proposed generic delimitations based primarily on molecular evidence, with limited consideration of morphological, ecological, biogeographical, or nomenclatural criteria. Although such approaches have provided valuable insights into evolutionary relationships, they may also contribute to nomenclatural instability when taxonomic changes are introduced without sufficient integration of other lines of evidence.

1. Classification of of tribes, subtribes, genera and subgenera within the subfamily Polyommatinae

1.1. Introduction - Taxonomic approach adopted in the present work
Recent phylogenetic studies have considerably improved our understanding of evolutionary relationships within the subfamily Polyommatinae. However, the translation of phylogenetic hypotheses into a practical and stable taxonomic classification remains a matter of debate. In several instances, the strict application of monophyly as the primary criterion for generic delimitation has led to the synonymisation of long-established genera or to the transfer of numerous species between genera. While such changes may reflect inferred evolutionary relationships more accurately, they can also result in substantial nomenclatural instability and reduce the continuity and practical utility of traditional classifications.
The classification adopted herein is guided by three complementary objectives: (1) the recognition of monophyletic taxa, (2) the explicit representation of the principal evolutionary lineages recovered by recent phylogenetic studies, and (3) the preservation of nomenclatural stability whenever compatible with the preceding objectives. The aim is to achieve a classification that reflects current knowledge of phylogenetic relationships while maintaining a practical and stable taxonomic framework.
In some cases, the recognition of previously unnamed monophyletic clades may require the establishment of new suprageneric taxa. However, such changes are generally limited in scope and have a considerably smaller impact on nomenclatural stability than the widespread synonymisation of genera. Another potential drawback of extensive generic synonymisation is the loss of diagnosability. Although the resulting genera may satisfy the criterion of monophyly, they may become morphologically heterogeneous and difficult to characterise using traditional taxonomic characters. In some instances, no clear diagnostic features remain other than those derived from molecular data, and species exhibiting markedly different external morphology, genital structures, or biological traits may be placed within the same genus. While such classifications may accurately reflect phylogenetic relationships, they can reduce the practical and descriptive value of generic taxa for taxonomists, ecologists, and conservation biologists.
The advantages of this approach are illustrated by two well-known cases within the subfamily Polyommatinae. The synonymisation of Maculinea under Phengaris and the placement of Palaeophilotes within Pseudophilotes have resulted in substantial nomenclatural changes, despite the recognition of clearly distinct evolutionary lineages. By making fuller use of intermediate taxonomic ranks, particularly tribes and subtribes, and, where appropriate, subgenera, it becomes possible to accommodate phylogenetic evidence without unnecessarily suppressing long-established generic names.
The classification proposed in the present work should therefore be regarded as a compromise between phylogenetic accuracy and nomenclatural stability. Its primary objective is not merely to assign names to clades but to provide a hierarchical framework that remains both informative and practical for future taxonomic, faunistic, and conservation studies.
It should be emphasised that the classification proposed herein is intended as a provisional framework based on currently available phylogenetic evidence. Ongoing phylogenomic initiatives and future large-scale studies will undoubtedly provide a more detailed understanding of relationships within the subfamily Polyommatinae and may necessitate the revision of some of the taxonomic arrangements adopted in the present work.
In particular, initiatives such as the Lepidoptera Tree of Life project (PSYCHE), which aim to generate extensive genomic datasets across the diversity of Lepidoptera, are expected to clarify relationships among several currently unresolved lineages. Consequently, the classification proposed herein should not be regarded as definitive, but rather as a practical and phylogenetically informed working hypothesis that can be readily updated as new evidence becomes available.

1.2. Historical and taxonomic context
The suprageneric classification of the Polyommatinae has undergone substantial changes over the past decades, reflecting the transition from morphology-based systems to phylogenetic hypotheses inferred from molecular data.
In his influential classification of the Lycaenidae, Eliot (1973) recognised four tribes within the Polyommatinae: Candalidini, Lycaenesthini, Niphandini, and Polyommatini. The first three tribes include relatively few genera and species and are not represented in the West Palaearctic fauna. In contrast, Polyommatini comprises a large number of genera and species, most of which occur in the Palaearctic region. To facilitate their classification, Eliot subdivided Polyommatini into several informal sections corresponding to limited groups of genera, which may be regarded as equivalent to subtribes. These sections were primarily defined on the basis of morphological characters, including wing venation, external morphology, and genital structures.
Restricting his study to the European and North African fauna, Higgins (1975) proposed a different arrangement, dividing the Polyommatinae into six tribes. The genera were distributed as follows:
Lampidini: Tarucus, Syntarucus (=Leptotes), Cyclyrius, Lampides.
Everini: Azanus, Cupido, Everes.
Zizeerini: Zizeeria.
Scolitantidini: Pseudophilotes, Scolitantides, Glaucopsyche, Maculinea, Iolana, Turanana.
Celastrini: Celastrina.
Subsequent catalogues largely followed Higgins’s arrangement, with only minor modifications. Vives Moreno (1994) placed Cacyreus, a genus not yet established in the European fauna at the time of Higgins’s work, within Lampidini and recognised a separate tribe, Tarucini, for Tarucus. Leraut (1997), on the other hand, transferred Celastrina to Everini.
Since then, numerous phylogenetic studies have investigated the relationships among Polyommatinae genera, leading to several alternative classifications. Two recent large-scale phylogenetic analyses, one focused on the European fauna (Wiemers et al. 2020) and the other based on worldwide sampling of Papilionoidea (Kawahara et al. 2023), provide particularly useful frameworks for evaluating the suprageneric classification of the group.
Wiemers et al. (2020) presented a comprehensive phylogenetic hypothesis for the European butterfly fauna. Although the authors did not propose a formal tribal classification within Polyommatinae, their phylogenetic tree reveals several well-supported lineages corresponding to the following assemblages:

A:	Azanus
B:	Zizeeria, Tarucus Celastrina, Lampides, Cacyreus Phengaris Scolithantides, Praephilotes, Iolana, Glaucopsyche Turanana, Pseudophilotes
C:	Leptodes, Cyclyrius
D:	Tongeia, Cupido
E:	Polyommatina

In contrast, Kawahara et al. (2023), based on a much broader worldwide sampling, recognised three tribes within the Polyommatinae: Lycaenesthini, Niphandini, and Polyommatini. The first two tribes contain only a limited number of genera and are absent from the West Palaearctic fauna. The large tribe Polyommatini includes the majority of West Palaearctic taxa and is structured as follows:

A:	Azanus
B:	Cupido, Tongeia, Luthrodes
C:	Polyommatina
D:	Leptodes, Cyclyrius, Cacyreus, Lampides
E:	Pseudophilotes, Turanana Phengaris Scolithantides Iolana, Glaucopsyche
F:	Celastrina
G:	Zizina, Zizeeria Tarucus

1.3. Conclusion
As higher taxonomic ranks are intended to reflect different levels of relationship within a phylogenetic framework, the subfamily Polyommatinae is herein subdivided into several tribes. The alternative approach, consisting of recognising only three tribes, with Lycaenesthini and Niphandini containing relatively few species and Polyommatini encompassing the vast majority of taxa, greatly limits the ability of expressing phylogenetic relationships through lower-ranking subdivisions. Such a classification fails to adequately reflect several well-supported lineages revealed by both morphological and molecular studies.
Based on the phylogenetic evidence currently available, it remains premature to propose a definitive suprageneric classification of the subfamily Polyommatinae. Nevertheless, several recurring patterns emerge from the studies discussed above and provide a basis for the following provisional arrangement.
Azanus consistently appears as part of a distinct lineage associated with several non-West Palaearctic genera. As no currently available tribal name appears suitable for this group, the genus is provisionally assigned to Azanini (proposed tribe).
Cupido and Tongeia are closely related genera and are therefore placed in Everini. Although their precise position within the subfamily remains uncertain, both recent phylogenetic studies recover them near the core Polyommatini lineage. To maintain monophyletic groups, Luthrodes is provisionally excluded from Everini and treated together with Polyommatini; its placement will be discussed in a subsequent paper.
Leptotes and Cyclyrius on the one hand, and Cacyreus and Lampides on the other, form two closely related pairs of genera. Wiemers et al. (2020) recovered these pairs as relatively distant lineages, whereas Kawahara et al. (2023) placed them within a common clade. Pending further phylogenomic studies, these four genera are provisionally grouped within Lampidini.
All recent phylogenetic studies consistently recover Pseudophilotes, Turanana, Phengaris, Scolitantides, Iolana and Glaucopsyche as closely related genera. They are therefore assigned to Scolitantidini.
The position of Celastrina remains particularly uncertain. Wiemers et al. (2020) recovered the genus close to Lampides, whereas Kawahara et al. (2023) placed it within a distinct clade together with numerous non-Palaearctic taxa. Pending further studies, Celastrina is provisionally retained within a separate tribe, Celastrinini.
Finally, Zizina, Zizeeria and Tarucus form a well-supported lineage and are consequently grouped within Zizeeriini.
The classification proposed herein, recognising a relatively large number of tribes within the Polyommatinae, is fully compatible with the principle of monophyly as inferred from the phylogenetic hypothesis of Kawahara et al. (2023). It also provides a practical framework for recognising subtribes grouping closely related genera.
A limitation of several recent classifications is the synonymisation of numerous traditionally recognised genera, which are consequently reduced to subgeneric rank. The broader use of the intermediate rank of subtribe, as adopted herein, makes it possible to retain these genera while simultaneously preserving monophyletic suprageneric groups. As demonstrated in the following chapters, this approach reduces unnecessary nomenclatural changes and contributes to a more stable and informative classification.

1.4. Proposed tribe Azanini
This tribe-level lineage corresponds to the clade recovered in the phylogenomic tree A Time-Calibrated Global Phylogeny of Butterflies by Kawahara et al. (2023), between:
BN003936_KD94S033_Lycaenidae_Polyommatinae_Polyommatini_Neolucia_agricola
and
BN007150_DL18S337_Lycaenidae_Polyommatinae_Polyommatini_Danis_danis
The limits and diagnosis of this lineage remain provisional and should be refined by future phylogenomic studies before any formal nomenclatural action is undertaken.
Type genus: Azanus Moore, 1881.
Currently included genera: Neolucia, Sahulana, Theclinesthes, Azanus, Petrelaea, Pseudonacaduba, Orthomiella, Una, Ionolyce, etc.

1.5. References
Eliot J.1973. The higher classification of the Lycaenidae (Lepidoptera): a tentative arrangement. — Bulletin of the British Museum (Natural History) Entomology 28(6): 371-505, fig. (url)

Higgins L. G. 1975. — The classification of european butterflies. Collins (Ed.). p. 1-320.

Leraut, P. 1997. — Liste systématique et synonymique des Lépidoptères de France, Belgique et Corse. Deuxième édition. (Supplément à Alexanor). p. 1-526.

Kawahara A., Storer C., Carvalho A., Plotkin D., Condamine F., Braga M., Ellis E., St Laurent R., Li X., Barve V., Cai L., Earl C., Frandsen B., Owens H., Valencia-Montoya W., Aduse-Poku K., Toussaint E., Dexter K., Doleck T., Markee A., Messcher R., Nguyen Y., Badon J., Benítez H., Braby M., Buenavente P., Chan W., Collins S., Rabideau Childers R., Dankowicz E., Eastwood R., Fric Z., Gott R., Hall J., Hallwachs W., Hardy N., Hawkins Sipe R., Heath A., Hinolan J., Homziak N., Hsu Y., Inayoshi Y, Itliong M., Janzen D., Kitching I., Kunte K., Lamas G., Landis M., Larsen E., Larsen T., Leong J.,
Lukhtanov V., Maier C., Martinez J., Martins D., Maruyama K., Maunsell S., Mega N., Monastyrskii A., Morais A., Müller C., Naive M., Nielsen G., Padrón P., Peggie D., Romanowski H., Sáfián S., Saito M., Schröder S., Shirey V., Soltis D., Soltis P., Sourakov A., Talavera G., Vila R., Vlasanek P., Wang H., Warren A., Willmott K., Yago M., Jetz W., Jarzyna M., Breinholt J., Espeland M., Ries L., Guralnick R., Pierce N. & Lohman D. 2023. A global phylogeny of butterflies reveals their evolutionary history, ancestral hosts and biogeographic origins. — Nature Ecology & Evolution 7: 903-913. Article: https://doi.org/10.1038/s41559-023-02041-9 . Supplementary Materials: (url).

Taymans M. & Cuvelier S. 2025. A dynamic checklist of the Western Palearctic butterflies hyperlinked to the original descriptions at species, genus and family level (Lepidoptera, Papilionoidea). — Archives of Western Palearctic Lepidoptera 2025(1): 1-70. https://doi.org/10.5281/zenodo.14733224

Taymans M. & Cuvelier S. 2026. Toward a revised checklist of the Western Palearctic butterflies, hyperlinked to the original descriptions at species, genus and family level (Lepidoptera, Papilionoidea) Part IV: Rationale and framework for the Riodinidae and Lycaenidae (part I) — Archives of Western Palearctic Lepidoptera 2026(1): 1-70. https://zenodo.org/records/18985843

Vives Moreno A. 1994. — Catálogo sistemático y sinonímico de los lepidopteros de la Península Ibérica y Baleares (Insecta : Lepidoptera) (Segunda parte). Madrid: Ministerio de Agricultura, pesca y Alimentación (Ed.). p. 1-775.

2. Phengaris Doherty, 1891 and Maculinea Eecke, 1915 (Lycaenidae): nomenclatural and taxonomic considerations

2.1. Historical Taxonomic Framework and Phylogenetic Evidence
Prior to 2007, all Palaearctic species of this group, including alcon, nausithous, teleius, arion and related taxa, were traditionally assigned to the genus Maculinea. This genus was characterised by a relatively homogeneous external morphology, notably the predominantly blue coloration of the male upperside and the characteristic arrangement of markings on the brownish underside. In contrast, the Oriental and eastern Palaearctic species, including daitozana, atroguttata and albida, were assigned to the genus Phengaris, whose species share a distinct habitus characterised by a pale to whitish dorsal surface and a characteristic arrangement of ventral markings on a whitish underside.
In a phylogenetic study of the group, Fric et al. (2007) concluded that Maculinea and Phengaris should be treated as a single genus. Their proposal was based primarily on the principle of monophyly. Molecular analyses indicated that the species traditionally assigned to Maculinea did not form a lineage distinct from Phengaris but rather were embedded within the same evolutionary clade. The resulting phylogenetic hypothesis can be summarised as follows:
A + (B + C)
where:

Under this hypothesis, the recognition of Maculinea and Phengaris as separate genera would render one of the genera paraphyletic.
The phylogenetic study of Ugelvig et al. (2011) produced a somewhat different topology. In this analysis, the species traditionally assigned to Maculinea formed a more homogeneous lineage and were not intermingled with the species assigned to Phengaris. Furthermore, the genus Caerulea was recovered as part of the same broader clade, according to the following structure:In contrast, Kawahara et al. (2023), based on a much broader worldwide sampling, recognised three tribes within the Polyommatinae: Lycaenesthini, Niphandini, and Polyommatini. The first two tribes contain only a limited number of genera and are absent from the West Palaearctic fauna. The large tribe Polyommatini includes the majority of West Palaearctic taxa and is structured as follows:
A + (B + (C + (D + E)))
where:

A =	Azanus
B =	Cupido, Tongeia, Luthrodes
C =	Polyommatina
D =	Leptodes, Cyclyrius, Cacyreus, Lampides
E =	Pseudophilotes, Turanana Phengaris Scolithantides Iolana, Glaucopsyche
F =	Celastrina
G =	Zizina, Zizeeria Tarucus

2.2. Taxonomic Interpretation and Provisional Classification
Pending the availability of such data, and following the principles outlined in the previous chapter, Maculinea is provisionally retained as a distinct genus in the present checklist. Together with Phengaris and Caerulea, it is assigned to the new subtribe Phengarina (subtribe proposed) within the tribe Scolitantidini.
Under the phylogenetic hypothesis proposed by Ugelvig et al. (2011), the maintenance of monophyletic genera would nevertheless require the recognition of an additional generic entity corresponding to clade B. Should this topology be confirmed by future studies, the resulting classification would comprise four genera arranged as follows:
A = Caerulea ; B = Pseudophengaris (genus proposed) ; C = Phengaris ; D+E = Maculinea.
Such an arrangement would preserve both the monophyly of all recognised genera and the long-established usage of the generic name Maculinea, while minimising nomenclatural changes within the group.

2.3. Proposed subtribe Phengarina
This subtribe-level lineage corresponds to the clade recovered in the phylogenomic tree A Time-Calibrated Global Phylogeny of Butterflies of Kawahara et al. (2023), defined as extending from:
BN004046_FH05M001_Lycaenidae_Polyommatinae_Polyommatini_Caerulea_coeligena
and
BN006335_AD00P068_Lycaenidae_Polyommatinae_Polyommatini_Phengaris_nausithous

This lineage belongs to the tribe Scolitantidini, which in the same phylogeny corresponds to the clade spanning rom:
BN003925_AS92Z401_Lycaenidae_Polyommatinae_Polyommatini_Euphilotes_enoptes
to
BN002858_LEP31611_Lycaenidae_Polyommatinae_Polyommatini_Glaucopsyche_lygdamus
The limits and diagnosis of this lineage remain provisional and should be refined by future phylogenomic studies before any formal nomenclatural action is undertaken.

Type genus: Phengaris Doherty, 1891. Currently included genera: Caerulea, Phengaris, Maculinea, etc.

Currently included genera: Caerulea, Phengaris, Maculinea, etc.

The subtribal groupings proposed herein are intended as provisional classificatory units that reflect current phylogenetic hypotheses. Their circumscription and diagnostic characters remain incompletely resolved, and the descriptions provided should not be interpreted as formal diagnoses. Additional phylogenetic, morphological, and biological evidence will be required to establish stable limits and comprehensive diagnoses for these lineages. Consequently, the proposed subtribal names are introduced only as provisional frameworks for discussing evolutionary relationships and remain subject to revision as new data become available.

2.4. Proposed genus Pseudophengaris
This genus lineage corresponds to the clade recovered in the phylogenomic tree of Ugelvig et al. (2011) for the species Phengaris daitozana Wileman, 1908.

Type species: Phengaris daitozana Wileman, 1908.

Currently included species: Phengaris daitozana Wileman, 1908.

The genus-group classifications proposed herein are intended as provisional units to facilitate interpretation of currently available phylogenetic hypotheses. They do not constitute formal diagnoses under the International Code of Zoological Nomenclature (ICZN). The limits, composition, and diagnostic characters of several lineages remain insufficiently resolved and will require further phylogenetic, morphological, and biological study before robust diagnoses can be established. Accordingly, the proposed genus-group names are provided as practical tools for discussing phylogenetic relationships and should be regarded as provisional pending future systematic revision.

2.5. References
Bálint Z. 2013. Comments on the proposed precedence of Maculinea van Eecke, 1915 over Phengaris Doherty, 1891 (Lepidoptera, LYCAENIDAE). Bulletin of Zoological Nomenclature 70: 250-251. (url)

Balletto E., Bonelli S., Settele J., Thomas J. A., Verovnik R. & Wahlberg N. 2010. Case 3508: Maculinea Van Eecke, 1915 (Lepidoptera: LYCAENIDAE): proposed precedence over Phengaris Doherty, 1891. — Bulletin of Zoological Nomenclature 67: 129-132. (url)

Fric Z., Wahlberg N., Pech P. & Zrzavy J. 2007. Phylogeny and classification of the Phengaris–Maculinea clade (Lepidoptera: Lycaenidae): total evidence and phylogenetic species concepts. —
Systematic Entomology 32: 558-567.

Fric Z., Kudrna O., Pech P., Wiemers M. & Zrzavy J. 2010. Comment on the proposed precedence of Maculinea van Eecke, 1915 over Phengaris. — Bulletin of Zoological Nomenclature 67: 315-319. (url)

Kalashian M. Y. 2010. Comments on the proposed precedence of Maculinea Van Eecke, 1915 over Phengaris Doherty, 1891 (Lepidoptera, LYCAENIDAE) — Bulletin of Zoological Nomenclature 67: 245. (url)

Korb S. K. 2015. Comments on the proposed precedence of Maculinea van Eecke, 1915 over Phengaris Doherty, 1891 (Lepidoptera, LYCAENIDAE). Bulletin of Zoological Nomenclature 72(2): 154-155. (url)

Morris M.G., Barclay M.V.L. & Agassiz D. 2011. Comments on the proposed precedence of Maculinea van Eecke, 1915 over Phengaris Doherty, 1891 (Lepidoptera, LYCAENIDAE). Bulletin of Zoological Nomenclature 68: 292-293. (url)

Paclt J. 2013. Comments on the proposed precedence of Maculinea van Eecke, 1915 over Phengaris Doherty, 1891 (Lepidoptera, LYCAENIDAE). Bulletin of Zoological Nomenclature 70: 52-53. (url)

Taymans M. & Cuvelier S. A dynamic checklist of the Western Palearctic butterflies hyperlinked to the original descriptions at species, genus and family level (Lepidoptera, Papilionoidea). — Archives of Western Palearctic Lepidoptera 2025(1): 1-70. https://doi.org/10.5281/zenodo.14733224

3. Pseudophilotes Beuret, 1958 and Palaeophilotes Forster, 1938 (Lycaenidae): nomenclatural and taxonomic considerations

3.1. Phylogenetic context and taxonomic conflict
Zhang et al. (2023) conducted a detailed phylogenetic study of the tribe Scolitantidini. Their results revealed a very low genetic divergence (approximately 2.1%) between Palaeophilotes triphysina, the type species of Palaeophilotes Forster, 1938, and Pseudophilotes baton, the type species of Pseudophilotes Beuret, 1958. In contrast, bavius, traditionally assigned to the subgenus Rubrapterus, was recovered as a more distinct lineage within the same complex.
Based on these results, Zhang et al. (2023) concluded that the taxa traditionally treated as Palaeophilotes and Pseudophilotes should be regarded as congeneric. However, in view of the relatively rapid evolution of the nuclear genome and the phylogenetic structure recovered in their analyses, the authors proposed retaining Pseudophilotes and Rubrapterus as subgenera within Palaeophilotes rather than placing them in complete synonymy.
Although phylogenetically consistent, this solution would result in substantial nomenclatural changes, particularly through the replacement of the well-established generic name Pseudophilotes by Palaeophilotes for a number of widely known species.
An alternative approach is proposed herein. Rather than modifying the generic nomenclature, phylogenetic relationships may be expressed through the use of suprageneric ranks, particularly subtribes. Such an approach is difficult to implement in classifications recognising only a single West Palaearctic tribe, Polyommatini, because the extensive use of subtribes within such a broad taxonomic unit rapidly becomes impractical. However, the multi-tribal classification adopted in the present work provides a more suitable framework for the recognition of phylogenetically meaningful subtribes.

3.2. Nomenclatural Implications and Alternative Interpretations
An alternative approach is proposed herein. Rather than modifying the generic nomenclature, phylogenetic relationships may be expressed through the use of suprageneric ranks, particularly subtribes. Such an approach is difficult to implement in classifications recognising only a single West Palaearctic tribe, Polyommatini, because the extensive use of subtribes within such a broad taxonomic unit rapidly becomes impractical. However, the multi-tribal classification adopted in the present work provides a more suitable framework for the recognition of phylogenetically meaningful subtribes.
Furthermore, additional molecular studies are still required. Several taxa closely related to this complex have not yet been adequately sampled, and their inclusion may significantly modify the inferred relationships. The phylogenomic tree published by Kawahara et al. (2023) already suggests that other genera may belong to the same evolutionary lineage. The phylogenetic placement of the genera Euphilotes and Philotiella remains uncertain. While Zhang et al. (2023) recovered these genera within the Palaeophilotes–Pseudophilotes clade in the mitochondrial tree, they appear as a distinct lineage in both the nuclear and chromosomal trees. Pending further investigations, this apparent incongruence should be regarded as unresolved and may have implications for the future classification of the group.
Pending the availability of more comprehensive phylogenetic data, Palaeophilotes, Pseudophilotes, Rubrapterus and Turanana are provisionally retained as distinct genera and placed within the new subtribe Palaeophilotina (proposed subtribe) of the tribe Scolitantidini.
The resulting phylogenetic structure may be summarised as follows:
A + (B + (C + D))
where:

This arrangement preserves the monophyly of the group while minimising nomenclatural disruption and maintaining the long-established generic names currently used in the taxonomic literature. It also provides a flexible framework that can readily accommodate future phylogenetic results without requiring major changes to generic nomenclature.

3.3. Proposed subtribe Palaeophilotina
This subtribe-level lineage corresponds to the clade recovered in the phylogenomic tree A Time-Calibrated Global Phylogeny of Butterflies of Kawahara et al. (2023), defined as extending between:
BN001321_LEP50916_Lycaenidae_Polyommatinae_Polyommatini_Scolitantides_vicrama [= Pseudophilotes vicrama]
and
BN005598_RI18W078_Lycaenidae_Polyommatinae_Polyommatini_Micropsyche_ariana
This lineage is assigned to the tribe Scolitantidini, which in the same phylogeny corresponds to the clade spanning from:
BN003925_AS92Z401_Lycaenidae_Polyommatinae_Polyommatini_Euphilotes_enoptes
to
BN002858_LEP31611_Lycaenidae_Polyommatinae_Polyommatini_Glaucopsyche_lygdamus
The limits and diagnosis of this lineage remain provisional and should be refined by future phylogenomic studies prior to any formal nomenclatural action.

Type genus: Palaeophilotes Forster, 1938.

Currently included genera: Turanana, Rubrapterus, Palaeophilotes, Pseudophilotes, etc.

The subtribal groupings proposed herein are intended as provisional classificatory units designed to facilitate the interpretation of currently available phylogenetic hypotheses. They should not be regarded as formal diagnoses under the International Code of Zoological Nomenclature (ICZN). In particular, the limits, composition, and diagnostic characters of several lineages remain insufficiently resolved and will require further phylogenetic, morphological, and biological study before robust diagnoses can be established. Accordingly, the proposed subtribal names are introduced solely as practical tools for discussing phylogenetic relationships and are to be regarded as provisional pending future systematic revision.

3.4. References
Kawahara A., Storer C., Carvalho A., Plotkin D., Condamine F., Braga M., Ellis E., St Laurent R., Li X., Barve V., Cai L., Earl C., Frandsen B., Owens H., Valencia-Montoya W., Aduse-Poku K.,
Toussaint E., Dexter K., Doleck T., Markee A., Messcher R., Nguyen Y., Badon J., Benítez H., Braby M., Buenavente P., Chan W., Collins S., Rabideau Childers R., Dankowicz E., Eastwood R., Fric Z.,
Gott R., Hall J., Hallwachs W., Hardy N., Hawkins Sipe R., Heath A., Hinolan J., Homziak N., Hsu Y., Inayoshi Y, Itliong M., Janzen D., Kitching I., Kunte K., Lamas G., Landis M., Larsen E., Larsen T., Leong J., Lukhtanov V., Maier C., Martinez J., Martins D., Maruyama K., Maunsell S., Mega N., Monastyrskii A., Morais A., Müller C., Naive M., Nielsen G., Padrón P., Peggie D., Romanowski H., Sáfián S., Saito M., Schröder S., Shirey V., Soltis D., Soltis P., Sourakov A., Talavera G., Vila R., Vlasanek P., Wang H., Warren A., Willmott K., Yago M., Jetz W., Jarzyna M., Breinholt J., Espeland M., Ries L., Guralnick R., Pierce N. & Lohman D. 2023. A global phylogeny of butterflies reveals their evolutionary history, ancestral hosts and biogeographic origins. — Nature Ecology & Evolution 7: 903-913. Article: https://doi.org/10.1038/s41559-023-02041-9 . Supplementary Materials: (url).

4. Addition of Evolutionarily Significant Units (ESU) to the Checklist

4.1. ESU Cigaritis estherae Brévignon, 1985
Pending a more comprehensive integrative study of the entire group, Cigaritis estherae is provisionally regarded herein as an Evolutionarily Significant Unit (ESU), following the detailed study by Tarrier et al. (2026), which supported its recognition as a distinct species on the basis of biogeographical, biological, and mitochondrial genetic evidence, while also noting that the observed genetic divergence was relatively limited and subject to alternative interpretation.

Reference
Tarrier M., Brévignon C. & Gauthier J., 2026. Un nouveau statut pour une espèce endémique du Maroc : Cigaritis estherae Brévignon, 1984, n. stat. (Lepidoptera Papilionoidea : Lycaenidae : Aphnaeinae). — Lépidoptères, revue des lépidoptéristes de France 35(88): 3-12, fig. (url not available)

4.2. ESU Lycaena heracleana (Blachier, 1908)
Pending further integrative taxonomic studies, the Moroccan populations currently assigned to Lycaena alciphron heracleana are provisionally regarded as a distinct Evolutionarily Significant Unit (ESU). This treatment is based on their mitochondrial genetic divergence (Dapporto et al., 2022: 139, figs 255–256; Wiemers, 2003: 48, fig. 34) and their marked geographic isolation from other L. alciphron populations, separated by more than 500 km.

References
Dapporto L., Menchetti M., Vodă R., Corbella C., Cuvelier S., Djemadi I., Gascoigne-Pees M., Hinojosa J., Lam N., Serracanta M., Talavera G., Dincă V. & Vila. R. 2022. The Atlas of mitochondrial genetic diversity for Western Palearctic butterflies. — Global Ecology and Biogeography. 00, 1–7. doi.org/10.1111/geb.13579 (url Atlas appendix S1)

Wiemers M. 2003. Chromosome differentiation and the radiation of the butterfly subgenus Agrodiaetus (Lepidoptera: Lycaenidae: Polyommatus) – a molecular phylogenetic approach. — Dissertation Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn. 204 pp. (url)

4.3. ESU Satyrium vandalusica (Lederer, 1853)
The taxon vandalusica is here regarded as a potential Evolutionarily Significant Unit (ESU), based on the marked genetic divergence identified by Dapporto et al. (2022) within S. spini, between Spanish populations and those occurring elsewhere in Europe.
However, confirmation of this status will require further integrative research combining ecological and morphological evidence with higher-resolution genomic approaches, preferably based on whole-genome data.

Reference
Dapporto L., Menchetti M., Vodă R., Corbella C., Cuvelier S., Djemadi I., Gascoigne-Pees M., Hinojosa J., Lam N., Serracanta M., Talavera G., Dincă V. & Vila. R. 2022. The Atlas of mitochondrial genetic diversity for Western Palearctic butterflies. — Global Ecology and Biogeography. 00, 1–7. doi.org/10.1111/geb.13579 (url Atlas appendix S1)

Author contribution
Michel Taymans: conceptualisation, analysis, visualisation, writing - original draft, writing – review and editing.
Sylvain Cuvelier: analysis, validation, visualisation, writing – review and editing.

Acknowledgements
We are sincerely grateful to Theo Garrevoet for his careful and thorough review of the final draft, and we wish to acknowledge Bénédicte Jonckers for her invaluable administrative support as production editor.