Phylogeography of the micro-endemicPedicia staryigroup (Insecta: Diptera): evidence of relict biodiversity in the Carpathians

Abstract

The Carpathian region is recognized as one of the most important hotspots for aquatic biodiversity in Europe. In the present study, 658-bp long nucleotide sequences from the mitochondrial cytochrome c oxidase subunit I (mtCOI) gene were used to study the phylogeographical patterns of the Carpathian endemic dipteran species belonging to the Pedicia staryi group. Molecular data support the taxon status of the allopatric sibling pairs of the morphologically highly similar Pedicia apusenica, Pedicia staryi, and Pedicia lobifera. This pattern is most likely the result of long-term isolation in so-called cumulative microrefugia in the Carpathians, caused by aridification and forest fragmentation in the Miocene-Pliocene period, in combination with the specific habitat requirements of these species (i.e. the wet and humid environments of forested headwater springs). Furthermore, molecular data reveal an important cryptic diversity in the case of the most wide-spread Carpathian P. staryi, as represented by highly divergent, allopatric populations from distant mountainous ranges, already recognized as important centres of endemism for aquatic insects. In addition, an unexpectedly high genetic diversity was identified in populations from the Rodnei Mountains, where the northern and southern slopes harbour highly divergent genetic lineages. This highlights the importance of this mountain range in the preservation of autochthonous diversity in the Carpathians. The present study provides important new evidence regarding the persistence of relic species in spring habitats in the Carpathians, with ancient divergence events that predate Quaternary glaciations and confirm their continuous presence during the Last Glacial Maximum in multiple isolated refugia, leading finally to a high genetic complexity in these particular aquatic ecosystems.

Survival in northern microrefugia in an endemic Carpathian gammarid (Crustacea: Amphipoda)

“…However, most of the direct evidence surprisingly comes from the more northerly located Western Carpathians and consists of fossil remains of plants (Willis & Van Andel, ), mammals (Sommer & Nadachowski, ), molluscs (Harl, Duda, Kruckenhauser, Sattmann, & Haring, ; Juřičková, Horáčková, & Ložek, ) and pollen deposits (Mitka, Bąba, & Szczepanek, ). Furthermore, indirect molecular evidence supports the view that the Western Carpathians (Copilas¸‐Ciocianu, Rutová, Pařil, & Petrusek, ; Fehér, Major, & Krízsik, ; Kotlík & Berrebi, ; Neumann et al., ; Vörös, Mikulíček, Major, Recuero, & Arntzen, ) and especially the southern half of the Carpathian arc served as refugia for a wide range of aquatic and terrestrial taxa (Antal et al., ; Berchi et al., ; Dénes, Kolcsár, Török, & Keresztes, ; Drees et al., ; Harl, Páll‐Gergely, et al., ; Homburg et al., ; Jablonski et al., ; Korábek, Petrusek, & Juřičková, ; Kotlík et al., ; Wielstra, Babik, & Arntzen, ). It appears that these species survived in relatively small, isolated refugial areas scattered throughout the Carpathians (Mráz & Ronikier, ), a pattern consistent with the microrefugia model.…”

Biogeography of the Carpathians: evolutionary and spatial facets of biodiversity

“…This range provides important habitat islands where populations of high‐mountain organisms persist, such as the herb Ranunculus glacialis (Ranunculaceae), represented here by a rare and strongly divergent plastid DNA lineage (Ronikier et al ., ). The importance of the area is further highlighted in a study of the aquatic dipteran Pedicia staryi ( Dénes et al ., 2016 ), which revealed the presence of two divergent lineages. Dénes et al .…”

“…Dénes et al . ( 2016 ) suggest that these populations persisted in isolated long‐term refugia and were subject to microspeciation processes and divergence events significantly predating the last glaciation. On the other hand, Lendvay et al .…”

“…Three papers present phylogeographical/phylogenetic case studies either focused on the Carpathians ( Dénes et al . , 2016 ; Lendvay et al . , 2016 ) or placing Carpathian populations in a wider context ( Daneck , Fér & Marhold , 2016 ) and using molecular tools to explore historical processes and present‐day biodiversity.…”

“…Another example of a microspeciation pattern leading to taxonomically relevant entities, in this case in flies, is explored by Dénes et al . ( 2016 ). On the other hand, the endemic status of several traditionally delimited taxa has not been supported by detailed molecular analyses (Schönswetter et al ., ; Španiel et al ., ; Băcilă et al ., ; Frajman et al ., ).…”