Tracing the radiation of Maniola (Nymphalidae) butterflies: new insights from phylogeography hint at one single incompletely differentiated species complex

The use of DNA sequence data often leads to the recognition of cryptic species
within putatively well-known taxa. The opposite case, detecting less diversity
than originally described, has, however, far more rarely been documented.
Maniola jurtina , the Meadow Brown butterfly, occurs all over Europe, whereas
all other six species in the genus Maniola are restricted to the Mediterranean
area. Among them, three are island endemics on Sardinia, Cyprus, and Chios,
respectively.
Maniola species are almost indistinguishable morphologically, and
hybridization seems to occur occasionally. To clarify species boundaries and
diversification history of the genus, we reconstructed the phylogeography and
phylogeny of all seven species within Maniola analyzing 138 individuals from
across its range using mitochondrial and nuclear genetic markers. Examination
of variation in mitochondrial and nuclear DNA surprisingly revealed a case of
taxonomic “oversplitting”. The topology of the recovered phylogenetic tree is
not consistent with accepted taxonomy, but rather reveals haplotype clades that
are incongruent with nominal species boundaries: instead of seven species, we
recognized only two major, yet incompletely segregated, lineages. Our results
are consistent with the hypothesis that Maniola originated in Africa. We suggest
that one lineage dispersed over the Strait of Gibraltar and the Iberian Peninsula
to the west of Europe, while the other lineage spreads eastward through Asia
Minor and over the Bosporus to Eastern Europe.