Tharsalea Scudder, 1876

Zhang, Jing, Cong, Qian, Shen, Jinhui, Opler, Paul A. & Grishin, Nick V., 2020, Genomic evidence suggests further changes of butterfly names, The Taxonomic Report of the International Lepidoptera Survey 8 (7), pp. 1-41 : 10-12

Tharsalea Scudder, 1876 , Helleia Verity, 1943 , Apangea Zhdanko, 1995 and Boldenaria Zhdanko, 1995 are genera distinct from Lycaena [Fabricius], 1807

Discovering non-monophyly of Lycaena [Fabricius], 1807 (type species Papilio phlaeas Linnaeus, 1760 ) in a pioneering DNA-based phylogenetic analysis ( van Dorp 2004) but stopping short of imminent taxonomic lumps or splits, de Jong and van Dorp (2006) concluded: "we propose that first the interrelationships as suggested by the present study are confirmed by further genetic markers." We accepted this challenge and used not some further markers, but all protein-coding genes in 34 Lycaeninae species, including the type species of 22 out of 28 available genus-group names (two of which share valid name of the type species with another genus-group name). The results confirm that Lycaena is not monophyletic ( Fig. 5). Notably, Iophanus Draudt, 1920 (type and the only species Chrysophanus (?) pyrrhias Godman & Salvin, 1887 ) originates within Lycaena and is sister to most other American species with strong support. This placement is unexpected due to the prominent phenotypic similarities between Iophanus and Melanolycaena Sibatani, 1974 (type species Melanolycaena altimontana Sibatani, 1974 ). Even using genitalic morphology, Iophanus pyrrhias (type locality Guatemala) was associated with the (largely) Palearctic clade ( Fig. 5 blue) by Klots (1936) who wrote: " pyrrhias ... relation-ship is undoubtedly with the Palaearctic rather than with the Nearctic series, and is possibly rather ancient." As the genomic tree suggests, Klots was incorrect on both counts: I. pyrrhias is a relatively recent offshoot of the (largely) Nearctic clade ( Fig. 5 red). To the contrary, Melanolycaena is sister to Lycaena boldenarum White, 1862 (type locality New Zealand) and they form a clade that is sister to all other Lycaeninae we have sequenced, including Heliophorus Geyer, [1832] (type species Heliophorus belenus Geyer, [1832] , considered to be a junior subjective synonym of Polyommatus epicles Godart, [1824] ). Thus, we were impressed by the intuition of Sibatani (1974) who stated in the last sentence of his work: "the possibility is not completely ruled out that the New Guinean Melanolycaena and the coppers of New Zealand are monphyletic [sic!]." Indeed, Melanolycaena is sister to Boldenaria Zhdanko, 1995 (type species Lycaena boldenarum White, 1862 ) from New Zealand ( Fig. 5), despite phenotypic dissimilarities. For these reasons, genomic phylogeny implies that the division of Lycaeninae into two sections ( Lycaena and Heliophorus ) as suggested by Eliot (1973) was indeed tentative and needs to be revised because these sections are not monophyletic. Here, armed with genomic data for ~80% of the available genus-group names, we attempt such a revision. One solution to restore monophyly is to treat the whole subfamily as a single genus Lycaena that subsumes Melanolycaena and Heliophorus among others. This super-lumping solution may be in agreement with relatively low genetic diversification among all these species. Indeed, Lycaeninae experienced some of the slowest evolutionary rates among Lycaenidae as revealed by relatively shorter branches within the Lycaeninae clade compared to others ( Zhang et al. 2019d). The difference in COI barcodes between distantly related Lycaeninae species ranges from about only 5% (35 bp, L. boldenarum and L. phlaeas , a difference common for closely related congeners) to about 8% (53 bp, Heliophorus sena Kollar, 1844 and Lycaena pang Oberthür, 1886 , a difference typical for distantly related congeners). This high similarity in COI underscores the idea that it is meaningless to impose a strict cutoff on divergence values due to the differences in evolutionary rates in different lineages. However, even American species of Lycaena are estimated to have diverged over 20 million years ago ( Zhang et al. 2019d), which is larger than for a typical diverse genus; i.e., it is larger than the divergence between Anthocharis and Euchloe Hübner, [1819] ( Pieridae ) and about the same as between Vanessa [Fabricius], 1807 and Nymphalis Kluk, 1780 ( Nymphalidae ). Furthermore, Heliophorus has been traditionally maintained as a genus-level taxon. Therefore, we reject the super-lumping solution of a monotypic subfamily Lycaeninae .

The opposite extreme would be to find a meaningful level closest to the leaves of the tree that defines genera. Ideally, there would be situations in the tree where many lineages diverge at about the same level (i.e. at the same distance from the root, meaning at about the same time in the past) and then stay as single lineages for some time (i.e. form longer branches). This rapid diversification immediately followed by a relative lack of further diversification creates a level in the classification, i.e. the tree looks more like a bush or a comb than a bifurcating tree at that point. Taking the (largely) Nearctic group ( Fig. 5 red), we see exactly this situation: at its base, this group diversifies into five prominent clades, and then two of these clades diversify further, also at approximately the same time point in the past. These five clades form a level in the tree and can be used as genera, offering the splitting solution. Notably, every one of these clades already has a genus-group name ( Pelham 2008), including Palearctic Hyrcanana Bethune-Baker, 1914 (type species Polyommatus caspius Lederer, 1870 ). Apparently, these clades were also obvious from phenotypes: that is how they were defined and named to begin with ( Scudder 1876; Klots 1936; Miller and Brown 1979). This level of classification can be propagated to other parts of the tree, although they are currently poorly covered by species. It is a meaningful level that can be chosen to define genera, but a significant number of such genera will be monotypic (e.g. two out of five in the Nearctic clade), and excepting knowledgeable aficionados of this group, such genera carry little information about their interrelationships. Hence, we looked for a compromise between the splitting and lumping solutions.

Inspection of the tree reveals a rapid diversification point between its root and the diversification of the red clade ( Fig. 5): i.e. orange-brown, cyan, magenta, blue and red + green clades diverged at approximately the same time in the past. This divergence is followed by the lack of immediate further divergence, creating long and prominent branches in the tree and resulting in a meaningful level for classification. We have chosen to take this intermediate level to suggest division of Lycaeninae into genera. Most of these genera are unambiguously apparent from the tree: black, purple, orange-brown, cyan, magenta, blue and red clades stand for seven genera, all of which have previously proposed names. Two instances require further elaboration. First, Heliophorus sena (Kollar, [1844]) stands out from the rest in the genus ( Fig. 5 orange). The type species of subgenus Nesa Zhdanko, 1995 , it may be a genus-level taxon. However, it is monophyletic with Heliophorus and we leave it there as a subgenus to emphasize this relationship, awaiting further studies. Second, Iophanus ( Fig. 5 green) is at about the same divergence from the rest of Nearctic species ( Fig. 5 red) as H. sena from other Heliophorus . For now, we decided to keep this monotypic genus, because it is currently treated as such, and because its earlier divergence time sets it apart from the rapid diversification of the red clade. The name for the red clade is Tharsalea Scudder, 1876 (type species Polyommatus arota Boisduval, 1852 ), as chosen by Klots (1936), probably because this name was proposed before others in the paper ( Scudder 1876).

In summary, we refrain from partitioning Lycaeninae into tribes and revise the status of the following names treating them as genera: Tharsalea Scudder, 1876 , Helleia Verity, 1943 (type species Papilio helle Denis & Schiffermüller, 1775 ), Apangea Zhdanko, 1995 (type species Chrysophanus pang Oberthür, 1886 ) and Boldenaria Zhdanko, 1995 . Furthermore, in agreement with previous studies ( Sibatani 1974; van Dorp 2004; de Jong and van Dorp 2006), we conclude that the endemic South African species currently placed in Lycaena represent the 9th genus of Lycaeninae that is named next. We are looking forward to testing this hypothesis with genomic data.