The new species belongs to the subgenus Mediotipula, a cranefly group restricted to the western Palearctic area, with the majority of taxa (eight out of twelve) having a range-restricted distribution in the Mediterranean area and the Caucasus. Mediotipula has a rather isolated phylogenetic position among the western Palearctic Tipulidae, sharing a combination of synapomorphies that is unique for this subgenus (De Jong 1995), and present also in T. (M.) gjippensis, such as the relatively small discoidal cell, the entirely fused, plate-like posterior apodemes of the sperm pump and a laterally compressed projection on the posterolateral corner of the gonocoxite in males. Additionally, females have the hypogynal valves fused for approx. one-half to two thirds of the length, in comparison with the totally separated (up to their bases) hypogynal valves in females of other Tipula (for more details see De Jong 1995).

The new species is most similar to T. (M.) stigmatella, having the inner gonostylus of the male terminalia approx. two times as high as inner gonostyli of other species of Mediotipula (Figs 3D, 6B, G). However, the new species can be easily distinguished from the latter species, because in the males the posterior margin of tergite IX–X has a medial spiny extension with a wide base that gradually narrows towards the tip (Figure 2C), instead of the narrowed and rounded medial spinous extensions seen in T. (M.) stigmatella (Figure 5A, C). The medial spiny extension is relatively small (Figure 2E) in comparison with the similar structure in T. (M.) stigmatella (Figure 5B). In T. (M.) gjipeensis the lateral corner of the posterior margin of tergite IX–X is mostly rounded (Figure 2C) instead of pointed, as in T. (M.) stigmatella (Figure 5A, C) and the ventral surface of the posterior margin of tergite IX–X is flat (Figure 2E), while T. (M.) stigmatella has two triangular protuberances (Figure 5B). In T. (M.) gjipeensis males a narrow medial longitudinal suture is present on the medial part of the disk of tergite IX–X (Figure 2C), with a reduced whitish area close to the posterior margin, instead of the long light stripe in the middle part found in T. (M.) stigmatella (Figure 5A, C). In T. (M.) gjippensis males, the posterior margin of sternite VIII ends straight (Figure 2D), instead of having two lateral projections as in T. (M.) stigmatella (Figure 5E). The outer gonostylus widens gradually to tip, ending obliquely towards the dorsal margin (Figure 2E), while in T. (M.) stigmatella, the anterior and posterior edges of the outer gonostylus run more or less parallel, ending straight or rounded toward dorsal margin (Figure 5F, G). The posterior arm of the inner gonostylus has its dorsal margin in the posterior half with a concentration of strong thorn-like setae directed anteriorly, anterior part bare, ending with a thorn-like process (Figure 3A–C). while in T. (M.) stigmatella a concentration of strong setae covers the entire dorsal margin of the posterior arm of the inner gonostylus, with the anterior corner rounded, but a conspicuous subterminal acute process directed ventrally is present (Figure 6A, C–E, F, H). In M. gjipeensis, the posterior part of the inner gonostylus has a small triangular posterolateral extension present in the middle (Figure 3D), differing from the long thorn-like process displayed in T. (M.) stigmatella (Figure 6B, G) and T. (M.) sarajevensis, while in all other members of Mediotipula such processes are absent. Parameres in the new species are small and triangular (Figure 2B), similar to T. (M.) stigmatella, but not lobe-like and spiny, as in T. (M.) siebkei (De Jong 1995). The females of the new species are clearly distinct from all other Mediotipula in having a bulbous base of the hypogynal valve (Figure 4A), rather than the gradually narrowed base found in all other species except T. (M.) stigmatella. However, T. (M.) gjipeensis is also distinct from T. (M.) stigmatella in having the bulbous base of the hypogynal valve rounded, instead of angular (Figure 4B).

Figure 5. 

Photographs of the morphological structures of the male genital structures of individuals of Tipula (Mediotipula) stigmatella Schummel, 1833. Specimen from Kavala (Greece) A, B, D, E, F Specimen from Kulata (Bulgaria) G; Specimen from Lunca Bradului (Romania) (C) A, C tergite IX dorsal view B tergite IX distal view D aedeagus complex lateral view E sternite VIII ventral view F, G outer gonostylus, lateral view.

Figure 6. 

Photographs of the morphological structures of the male genital structures of individuals of Tipula (Mediotipula) stigmatella Schummel, 1833. Specimen from Kavala (Greece) A, B, C Specimen from Lunca Bradului (Romania) D, E; Specimen form Kulata (Bulgaria) (F, G, H) A, F inner gonostylus outer lateral view B, G inner gonostylus ventral view C, H inner gonostylus inner lateral view D gonostyli outer lateral view E gonostyli inner lateral view.

During our investigation, morphological differences were detected between allopatric populations of T. (M.) stigmatella in the Carpathian-Balkan area. Most important divergences were detected in the shape of the posterior margin of the tergite IX–X between populations from the Carpathians (Figure 5C) and the Balkans (Figure 5A), but no important differences in the general shape of the outer and inner gonostylus were found between populations from Lunca Bradului (the Carpathians) (Figure 6D, E) and Kavala (Greece) (Figs 5F, 6A–C). However, a series of important structures were detected between more proximal populations from Kavala (Greece) together with individuals from Vevchani (FY of Macedonia) and Kulata (Bulgaria), mostly on the width of the outer gonostylus (Figure 5F, G), and on the apex of the posterior arm of the inner gonostylus (Figure 6A–C, F–H). The triangular-like apex of the posterior side of the posterior arm of the inner gonostylus of the specimens from Kavala (Greece) and Vevchani (FY of Macedonia) is shorter, with a broader base (Figure 6B), while in specimens collected from Kulata (Bulgaria) such similar structure is longer, with a narrowed base (Figure 6G). Without having a clear geographic pattern of the detected morphological divergences in the studied population, and with only a limited number of individuals, more data is required, covering the whole of the species distribution area, in order to evaluate the taxonomic importance of the detected differences.

Current systematic and phylogeographical studies of the Mediterranean terrestrial fauna (Oosterbroek and Arntzen 1992, De Jong 1998, Sloan et al. 2014) reveals complex origins and evolutionary histories of temperate taxa in relation with the complex paleoecological history of the area. High levels of species diversity are related to ancient events (Paleocene-Miocene) and also to more recent events (Pliocene-Pleistocene) followed by active speciation and even explosive radiations, leading finally to the emergence of the so-called “Mediterranean Sanctuary” of diversity, the second largest hotspot in the world and the largest of the world’s five Mediterranean-climatic regions (Grabowski et al. 2017, Vargas et al. 2018). Albania belongs to the Eastern Mediterranean chorotype of the fauna, as proposed by Taglianti et al. (1999) including the NE-Mediterranean, Palestino-Cyprioto-Taurian, Palestino-Taurian, and Aegean distribution patterns of different animal species.

The eastern Mediterranean area, where the new member of the subgenus Mediotipula was collected, is recognised as an important centre of endemism, but no range-restricted Mediotipula species were detected in the area to date. Tipula (M.) gjipeensis sp. n. was identified by us only in a small, humid limestone gorge in Albania. We hypothesised a restricted distribution of the species, most probably as a result of the presently isolated distribution of humid ecosystems in the Mediterranean area. Several aquatic and semi-aquatic organisms have similarly restricted or fragmented distributions in the Mediterranean area, which most probably followed the general decline of humid ecosystems during the late Cainozoic and simultaneous retreat in highly-fragmented local populations (sometimes highly-divergent evolutionary significant units, or in many cases distinct species) (Fernandez-Mazuecos et al. 2014, Godunko et al. 2017, Neubauer et al. 2016).

However, a number of case studies on plant species (Allegrucci et al. 2017, Crowl et al. 2015) hypothesise an evolutionary process in lineages that are adapted to pre-Mediterranean (pre-Pliocene) conditions in relatively small, xeric areas. Later, they became strongly competitive and expanded as the Mediterranean climate became dominant (Pliocene-Quaternary) across the Mediterranean Basin, and most probably also began to penetrate into the northern parts of Europe. Similar patterns were detected in the case of the Lacerta viridis complex (Cassel-Lundhagen 2010), with leading edge populations that colonised large parts of Europe, but several fringe populations became genetically divergent or morphologically different in highly isolated populations in the Balkan area. This pattern is also most likely true for the sibling pairs T. (M.) stigmatella / T. (M.) gjipeensis, with a larger distribution in the south-central part of Europe to Caucasus, but with morphologically deeply divergent T. (M.) gjipeensis from Albania, and less, but notable morphological differences between populations of T. (M.) stigmatella in the Balkan area, identified for example in Kavala (Greece) and Kulata (Bulgaria) (Figure 6B, G). The presence of morphologically divergent allopatric populations of T. (M.) stigmatella (possibly cryptic species) is likely a result of more recent isolation, followed by repeated dispersions and area fragmentations during the Pleistocene climate change. This needs to be subjected to a more comprehensive analyses of the species over its whole range.

Albania is located in the western part of the Balkan Peninsula and is one of the most important Mediterranean biodiversity hotspots (Caković et al. 2018, Szabolcs et al. 2017), but is still considered to be the last “terra incognita” for European biodiversity. A series of recent studies, which focused on different groups of plants and animals, brings major contributions to the diversity and distribution of a number of organisms from Albania (Barina et al. 2013, Graf et al. 2018, Kaltsas et al. 2008, Stevanović et al. 2007). The description of T. Mediotipula gjipeensis sp. n. is an important addition to the faunal list of the Albanian Tipulidae and highlights the importance of similarly isolated pristine ecosystems to local and regional diversity of the Mediterranean Area.

Ecological demands of the majority of Mediotipula species are largely overlooked because of a high number of undescribed larvae. Based on adult distributions, species inhabiting open woods and hedges exposed to the sun seem to have generally larger distributions (e.g., T. (M.) stigmatella, T. (M.) sarajevensis etc.) in comparison with species that are restricted to steep river valleys (e.g., T. (M.) brolemani, T. (M.) mikiana, T. (M.) gjipeensis sp. n.) (Oosterbroek 2018). Such humid and sheltered “ecological islands” set in larger xeric areas could act as refuges for a number of range-restricted or endemic species. For example, within the steep Gjipe Gorge (only a few kilometres in length), other than T. (M.) gjipeensis, the Mediterranean cranefly species Dolichopeza (D.) furiscipes Bergroth, 1889 was also detected (L Keresztes unpublished data), having a fragmented distribution in similar habitats in the southern part of continental Europe, but also on some Mediterranean islands (Mederos Lopez 2012, Oosterbroek 2018). The mayfly Electrogena hellenica Zurwerra & Tomka, 1986 has an even more restricted distribution in the Mediterranean area which is limited to western Greece, along rivulets in steep valleys at 300 m a.s.l. (Bauernfeind and Soldan 2012), but which was also collected by the first author of this paper from the Gjipe Gorge (L Keresztes unpublished data). Similar ecosystems in the Mediterranean area are rare and isolated but they are seriously affected by human activity (limestone and rock quarries, water extraction, habitat deterioration, discharge of sewage effluents, etc.) enforced by ongoing global climate change and therefore needing special attention and perhaps protection.