Tomares nogelii (Herrich-Schaffer, 1851)

Krupitsky, Anatoly V, Shapoval, Nazar A, Schepetov, Dmitry M, Ekimova, Irina A & Lukhtanov, Vladimir A, 2022, Phylogeny, species delimitation and biogeography of the endemic Palaearctic tribe Tomarini (Lepidoptera: Lycaenidae), Zoological Journal of the Linnean Society 196 (2), pp. 630-646 : 639-641

PHYLOGENY, SYSTEMATICS AND PHYLOGEOGRAPHY OF THE T. NOGELII CLADE

Neither T. nogelii nor T. nesimachus is recovered as a monophyletic entity in our analysis. Species delimitation analysis suggests the species status for the whole T. nogelii clade, and the haplotype network analysis reveals no phylogeographical structure within the clade.

Summarizing the results of the previous research ( Hesselbarth & Schurian, 1984; Hesselbarth et al. 1995; Van Oorschot & Wagener, 2000; Nazari & Ten Hagen, 2020), we can conclude that T. nogelii is presented by three phenotypes, all with intermediates between them: T. nogelii monotona Schwingenschuss, 1939 (wings dark brown dorsally, without red patches), T. nogelii nogelii (wings red, with wide, dark border dorsally) and T. nogelii nesimachus (wings red, with narrow, dark marginal border dorsally). Intermediate specimens were described as T. nogelii obscura Rühl, 1893 , T. nogelii cesa Koçak, Kemal & Seven, 2000 and T. nogelii aurantiaca Staudinger, 1871 . These phenotypes, or colour morphs, and intermediate specimens differ in distribution but may co-occur. It was noted that adults of dark phenotypes (T. n. nogelii and T. n. monotona) tend to appear ~1 month later than those of T. n. nesimachus and/or inhabit higher elevations ( Larsen, 1974; Hesselbarth et al., 1995). According to the literature, the north of the T. nogelii range (southern Ukraine and Crimea) is inhabited by the phenotypes T. n. nogelii and T. n. monotona ( Tshikolovets, 2011), Turkey is inhabited by all three colour morphs ( Hesselbarth et al., 1995), both T. n. nogelii and T. n. nesimachus are known from Lebanon and Syria ( Larsen, 1974), and the southernmost part of the range, in Israel and Jordan, is inhabited by T. n. nesimachus ( Larsen & Nakamura, 1983; Tshikolovets, 2011). Specimens of T. n. nesimachus from Israel, Jordan and Syria differ from those in Turkey in their well-developed red discal field, narrow, dark marginal border on the dorsal side of the wings and large size. They could be considered a distinct subspecies, but such treatment is not supported by phylogenetic and haplotype network analyses because these specimens do not form a clade.

The results of our analysis do not support the opinion of Nazari & Ten Hagen (2020) that T. nogelii and T. nesimachus are distinct sister species. Taking our results into account, in addition to the absence of morphological diagnostic characters delimiting these taxa, broadly shared distribution ranges and absence of clear reproductive barriers ( Van Oorschot & Wagener, 2000; Nazari & Ten Hagen, 2020), considering all mentioned phenotypes a single species T. nogelii is most reasonable. We consider T. n. nesimachus (syn. nov.) a synonym of T. n. nogelii to obtain taxonomic stability and solve nearly a century and a half of confusion and attempts to discriminate these two taxa.

Apart from the nominotypical subspecies of T. nogelii inhabiting Turkey, Syria, Lebanon, Israel, Jordan and, according to old, unconfirmed data, Azerbaijan ( Tshikolovets & Nekrutenko, 2012), separation of a northern subspecies, T. n. dobrogensis , from south-eastern Romania, Moldova, southern Ukraine and Crimea, is reasonable, but the specimens of T. n. dobrogensis do not form a monophyletic entity in our phylogenetic reconstruction. In the haplotype network analysis, they are represented by five unique haplotypes, three related ones, from Crimea (H15 and H17) and Kherson Oblast in Ukraine (H16), and two unconnected haplotypes, from Donetsk Oblast (H8) and Zaporizhzhia (H9) in Ukraine. At least some of them should be attributed to T. n. dobrogensis . We hope that the addition of specimens from Moldova and Romania to the analysis will refine the taxonomic status of these populations. Until then, we follow Nazari & Ten Hagen (2020) and provisionally consider T. n. dobrogensis as a subspecies of T. nogelii from the northern Pontic region. The specimens from Turkey previously attributed to T. n. dobrogensis by Nazari & Ten Hagen (2020) share the second widespread haplotype (H2) with T. nogelii and ‘ nesimachus ’.

Tomares romanovi is also not recovered as a species in species delimitation analyses, but it clearly differs from parapatrically distributed T. nogelii in morphological characters, overlapping with a small part of the range of the latter in its easternmost part. Several populations morphologically intermediate between T. nogelii and T. romanovi , including T.n. obscura from eastern Turkey and populations from Georgia and Azerbaijan, known as T. r. cachetinus , and specimens with shared haplotypes were detected in an overlapping zone of their ranges ( Hesselbarth et al. 1995; Van Oorschot & Wagener, 2000; Nazari & Ten Hagen, 2020). Phylogenetic analysis reveals that samples of T. romanovi from Armenia, Azerbaijan and Georgia form a clade within the T. nogelii group corresponding to the nominotypical subspecies of T.romanovi , but this clade is not united with specimens of T. romanovi from Turkey, Iran and Turkmenistan, which appear on an unresolved branch comprising samples of T. nogelii from Syria, Turkey and Jordan.

In the phylogeographical analysis, the majority of the T. romanovi specimens share haplotypes with T. nogelii (H1, H13 and H20), and five haplotypes from Iran, Georgia and Azerbaijan (H14, H18, H19, H21 and H22) are unique for the species, differing from the haplotype H 1 in only one or two nucleotide substitutions. The overall haplotype network structure ( Fig. 3 ) shows a common haplotype (H1) shared by many specimens from different localities and a starlike pattern of its sister haplotypes. This might indicate that the hypothetical ancestral populations underwent a significant reduction in effective population size and that a bottleneck event occurred in the recent historical past. At the same time, the large number of closely related haplotypes combined into a cluster with a dominant haplotype indicates that T. romanovi populations are currently undergoing exponential growth ( Avise, 2000).

The taxonomic status of the populations of T. nogelii and T. romanovi with shared haplotypes needs further examination. This pattern can be the result of hybridization leading to mitochondrial introgression or incomplete lineage sorting, which occurs occasionally in Lycaenidae ( Talavera et al., 2013b; Lukhtanov et al., 2015a, b). Another possible explanation of the shared haplotypes within the T. nogelii group is an influence of Wolbachia Hertig, 1936 , an intracellular rickettsial bacterium that infects arthropods and filarial nematodes. As an endosymbiont associated with mitochondria and thus maternally inherited, Wolbachia can cause selective sweeps in mitochondrial haplotypes owing to genetic hitchhiking ( Whitworth et al., 2007). Wolbachia infection can lead to mitochondrial introgression and reduce mitochondrial diversity, but can also mimic the speciation process, causing a deep divergence in mitochondrial phylogenies ( Ritter et al., 2013). It is possible that both species, T. nogelii and T. romanovi , share the same Wolbachia strain owing to hybridization in the common parts of their distribution ranges in Eastern Turkey, which has resulted in the observed star-like structure of the haplotype network obtained. In the Lycaenidae , a case of Wolbachia and mitochondrial DNA interference was found recently in the Pseudophilotes baton (Bergsträsser, 1779) species complex ( Bartoňová et al., 2021). Their phylogeographical analysis also resulted in a star-like network structure, but in contrast to our case, it mirrored the geographical pattern of the revealed haplotypes and Wolbachia infection.

Given the distinct morphological characters ( Weidenhoffer & Bozano, 2007; Nazari & Ten Hagen, 2020) and differences in ecology and distribution ( Hesselbarth et al. 1995; Van Oorschot & Wagener, 2000), T. romanovi is best regarded as a distinct species until additional molecular studies are conducted.

Figures

Figure 3. A, result of the statistical parsimony network analysis illustrating relationships of the 25 cytochrome c oxidase subunit I haplotypes of the Tomares nogelii species group. Colours of circles correspond to origins of samples. B, result of the statistical parsimony network analysis illustrating relationships of the 25 cytochrome c oxidase subunit I haplotypes of the T. nogelii species group. Colours of circles correspond to species previously considered within the group (Weidenhoffer & Bozano, 2007).