Discovery of a Lineage of Soil-Dwelling Medetera Species with Multi-Coloured Eyes in Southern Europe (Diptera: Dolichopodidae)

Simple Summary Long-legged flies or Dolichopodidae are one of the most speciose fly families of the order Diptera. At present, dolichopodid faunas in the tropics still encompass a large undescribed fraction, but in Europe new species can also be found. Recently, two new species of Medetera with a conspicuous eye colour pattern were discovered in Portuguese samples. Increased subsequent collecting efforts in southwestern Europe added another five species, most of which also featured a distinct eye colour pattern. All seven species are described in this paper with information on their distribution and ecology. An identification key to males is also provided. All these species share genital and some non-genital characters which suggests that they belong to the same lineage within this genus. Barcoding data seem to confirm this, as does the ecological information. Indeed, contrary to many Medetera species which are confined to tree trunks where their larvae feed on all stages of bark beetles, several of the new species are mainly found on hard, often rocky, substrates also in open habitats. Abstract Seven species in the genus Medetera (Diptera: Dolichopodidae) are described here: Medetera aglaops sp. nov., Medetera corsicana sp. nov., Medetera gibbosipyga sp. nov., Medetera hispanica sp. nov., Medetera lusitana sp. nov., Medetera parva sp. nov., and Medetera rectipyga sp. nov. They all originate from the wider Mediterranean region in southwestern Europe (Iberian Peninsula, southern France, Corsica, Sardinia). The most striking feature in most of the species is the bi- or multicolour pattern of the eyes, most conspicuous in Medetera aglaops sp. nov. and Medetera lusitana sp. nov. This character is shared by the male and female sex and is thus not regarded as Male Secondary Sexual Character. All species belong to the Medetera apicalis species group sensu Bickel and are closely related based on shared characters in the hypandrium and cercus. Interestingly, three species with and four species without the basal pair of anterodorsal and posterodorsal bristles on the mid tibia are represented. This suggests that this diagnostic character has less phylogenetic relevance than previously anticipated. Unlike most Palaearctic Medetera, at least five of the new species are mostly found on rocky substrates in dry biotopes with a sclerophyllous vegetation. This further supports their relationship with species of the Medetera muralis subclade sensu Pollet, Germann and Bernasconi.


Introduction
On a global scale, the ubiquitous Medetera Fischer von Waldheim, 1819 represents the third most speciose genus in Dolichopodidae (Diptera) with an apparent predominance in the Palaearctic [1]. In the latter realm this genus includes 190 species and three subspecies [2,3]. Overall, Medetera species range in size from very small (<2 mm) to rather large (>4.5 mm). All seven most recently described species from the western Palaearctic were detected in Switzerland [4,5]. However, this does not necessarily imply that only high altitude or latitude sites in the Palaearctic region, and Europe in particular, house yet undiscovered species. As such and based on current data and knowledge, overall this genus makes up a larger proportion of the dolichopodid fauna in northern and northwestern European countries as compared to southern ones [6]. However, these authors also reported 21 unidentified Medetera species from Portugal, accounting for 10% of the dolichopodid species registered for this country. Moreover, with 41 species, the entire genus represented even two times this proportion (i.e., 20.5%) in Portugal, which is three times higher than, e.g., Spain or Italy.
With respect to their biology, many Medetera can be found on tree trunks where their larvae live in galleries of scolytine beetles (Coleoptera: Curculionidae, Scolytinae) and feed on all stages of these bark beetles e.g., [7][8][9][10][11]. This holds especially true for the species groups of M. apicalis, M. crassivenis, and M. signaticornis-pinicola sensu Bickel, with the former two preferring deciduous and the latter one coniferous trees [12,13]. In the Holarctic realm, one lineage in particular deviates from this pattern by occurring, often in large numbers, on other hard, mostly vertical, substrates and also on bare or sparsely vegetated sandy soils, i.e., the M. diadema-veles species group sensu Bickel. This clade also includes the psammophilous species with one pair of scutellar bristles that were previously treated as a separate subgenus Oligochaetus Mik, 1878. Another lineage, the M. muralis species group sensu Pollet, Germann and Bernasconi (a subclade of the M. apicalis species group, see [13]) on the other hand, is also regularly encountered on hard substrates (rocks, walls).
During the examination of Portuguese dolichopodid samples [6] the first author (MP) noticed two Medetera species with a remarkable eye pattern: the lower 2/3 of the eye featured a usual red base colour with a brilliant green reflection while the upper 1/3 was conspicuously and contrastingly dark violet ( Figure 1). Increased attention during the collecting and continued processing of additional samples from the Iberian Peninsula and the Mediterranean region added another five undescribed Medetera species that appeared to be related. Moreover, some of these species also showed a distinct eye colour pattern.
In the present paper, seven southern European Medetera species are described, with information on their distribution and ecology, and a key to the males is provided. The significance of some morphological characters and the phylogenetic position of the species is discussed as well as issues with the verification of Medetera species identity and reasons for their surprisingly late discovery.

Materials and Methods
In addition to the 761 Portuguese samples [6], another 21.093 dolichopodid samples from 20 European countries were inspected for any multi-colour eyed Medetera species by

Materials and Methods
In addition to the 761 Portuguese samples [6], another 21.093 dolichopodid samples from 20 European countries were inspected for any multi-colour eyed Medetera species by the first author. None of the over 20,000 samples from 18 European countries that had been examined prior to 2018 contained any of these species, but recently acquired samples from southern Europe (Portugal, Spain, southern France, Corsica, Sardinia) did surprisingly often. Most of the samples were acquired thanks to special collecting efforts by Diptera workers and other people (see co-authors and Acknowledgements). No additional material from museum collections was examined. Actually, we have no knowledge of any dolichopodid collections in Portugal or Spain that might contain some of these Medetera species. Moreover, the probability of finding these species in the collections of the Muséum national d'Histoire naturelle (MNHN, Paris, France) was considered low. It must be taken into account, however, that in (dry) mounted specimens, the eye colour reflection fades away over time, while the colour itself might slightly change in specimens stored in alcohol solution.
Specimens from Corsica were collected in the frame of the most recent edition of the La Planète Revisitée (Our Planet Reviewed) series of surveys [14], organised in several undersampled biodiversity hotspots around the world since 2007 by, e.g., the MNHN (see [15]). The terrestrial part of this survey (along with the marine counterpart) focused on the diversity of-often poorly studied-invertebrates, including Arachnida, Mollusca as well as all major insect orders (i.e., Coleoptera, Diptera, Hymenoptera, Lepidoptera, Orthoptera, Hemiptera), fungi, and lichens [16]. The main objective was a comprehensive inventory of species in a series of localities in order to improve knowledge of the taxonomy and chorology, and to better understand community structures and their interactions within ecosystems. Wherever feasible, it aimed to contribute to a better management of the territory through assessments and monitoring. Species records will ultimately be disclosed and distributed in the frame of the Inventaire National du Patrimoine Naturel [17] and, in the case of this specific survey, via the portal of the MNHN collections [18]. Specimens from Sardinia were gathered during a CONECOFOR survey on the island conducted by G.L. Nardi and colleagues of the Centro Nazionale Carabinieri Biodiversità "Bosco Fontana" (CNCB) [19][20][21][22].
Species descriptions were based on a representative number of specimens of each species, all stored in alcohol solution. Features where an effect was expected due to the wet condition of the specimen (e.g., colour and pollinosity of face, frons, eyes) were described on the basis of temporarily dried specimens. A total of 173 character states were scored in each species, with 35, 61, and 77 related to the head, thorax/abdomen/wing and legs, respectively. This allowed us to determine the most reliable and consistent decisive diagnostic features that were subsequently applied in the identification key (see further). Photos of the general habitus and head of each species were produced by the last author (AS). The hypopygium and separate genital appendages of each species were drawn using a camera lucida. In each species, at least the hypopygium (in lateral view) and the hypandrium (in ventral view) are illustrated here. In describing the hypopygium, 'dorsal' and 'ventral' refers to the morphological position prior to genitalic rotation and flexion. Thus, in the drawings showing a lateral view of the hypopygium, the top is morphologically ventral, while the bottom is dorsal. Biometrics were based on 5 specimens of each gender in each species, if available or unless otherwise mentioned, and included: (i) face width, (ii) body length, (iii) wing length (= distance between basis of basicosta and wing apex), (iv) relative wing width, (v) proximal versus apical section of vein M 1 , (vi) proximal versus apical section of vein CuA 1 , (vii) CuA x ratio (= crossvein dm-cu versus apical section of vein M 1 ) and (viii) relative lengths ratio of femur, tibia, and tarsomeres of each leg. The latter relative lengths were recalculated so that the shortest leg part represented a value of "1". All values given in this paper are ranges or average values, unless otherwise mentioned. Palp and proboscis size were compared to the eye size, measured as the vertical diameter (from about ocellar tubercle to the lower eye margin). The surstylus length was defined as the distance between the insertion place of the apicoventral epandrial setae and the surstylus apex.
COI barcode sequences of ca. 500 b.p. lengths were obtained from specimens of four of the new species. In addition, barcodes of 20 specimens belonging to 8 other Medetera and 2 Thrypticus species were mined from the BOLD Systems repository [23] (see Discussion). All sequences were aligned using MAFFT [24]. Evolutionary distances were computed by use of the p-distance method [25], with pairwise deletion.
Capture locations of the species are indicated in Figure 2. Each location was positioned on the map as accurately as possible, based on the information available. In two cases (Alfaz del Pi and Elguera, both in Spain) that lacked latitude and longitude data, the symbol in Figure 2 is shown in the centre of the corresponding locality/location which might not necessarily correspond exactly with the actual collecting site. Capture locations of the species are indicated in Figure 2. Each location was positioned on the map as accurately as possible, based on the information available. In two cases (Alfaz del Pi and Elguera, both in Spain) that lacked latitude and longitude data, the symbol in Figure 2 is shown in the centre of the corresponding locality/location which might not necessarily correspond exactly with the actual collecting site.   The general morphological terminology followed [26], while [27] was used for male genitalia. The following abbreviations were used: ac: acrostichal bristles; ad: anterodorsal; ant pprn: anterior postpronotal (= humeral sensu Parent [28]); ap: apical; apv: apicoventral; av: anteroventral; bas pprn: basal postpronotal (= posthumeral sensu Parent); bv: basoventral; dc: dorsocentral bristle pairs; ds: dorsal; MSSC(s): male secondary sexual character(s); npl: notopleural; pal: postalar; pd: posterodorsal; psut ial: presutural intra-alar (= presutural sensu Parent); pv: posteroventral; S: abdominal sternite; spal: supra-alar; sut ial: sutural intra-alar (= sutural sensu Parent); ta: tarsomere, 1-5 in the descriptions of tarsi refers to basal (1) to apical (5) tarsomeres; T: abdominal tergite; vt: ventral; I, II, III refers to fore, mid and hind leg; 1-6 in the descriptions of abdominal segments (tergites/sternites) refers to basal (1) to caudal (6)  Species records are given in the following format (if available): "COUNTRY: m#, f#, province (or equivalent administrative division), locality, location (brief habitat description) (site code), latitude, longitude, altitude, sampling date (start)-sampling date (end), sampling method, collector (survey, if relevant)-sample cd: sample code [collection]". Locality is defined as the most accurate administrative geographical entity (e.g., village, city), and location as most relevant non-administrative entity (e.g., area, river, nature reserve). Identical information in successive records is only given in the first record and not repeated in the following ones. Data including an often more detailed sampling site description are also available as a dataset in GBIF (https://doi.org/10.15468/s8c7n9). All specimens examined were stored in 75% alcohol. Face with epistoma and clypeus strongly dusted greyish, and epistoma with multiple shallow diverging furrows. Eye with red base colour and brilliant green reflection in the lower 2/3, and dark violet in about the upper 1/3 (with smaller ommatidia). Mesonotum (incl. scutellum) bluish grey, strongly dusted, with rusty brown area between dc rows. Five dc with first dc small, about 0.4× as long as second dc bristle; more than six microscopic ac; one spal bristle. Wing slightly smoked brownish; halter yellowish white. All legs overall blackish brown, femora I-III with narrow reddish yellow knees. Tibia II with ad and pd bristle pair. Surstylus rather slender and S-shaped, with distinct split in ventral and dorsal lobe at half length; hypandrium straight dorsally (lateral view), rocket-shaped with lateral hooks at basal 1/3, and two dark stripes at apex (ventral view).   Description. Male. Body length: 1.9-2.4 mm; wing length: 2.0-2.3 mm, wing 0.4× as wide as long. Head. Face with both epistoma and clypeus strongly dusted greyish; epistoma sometimes with less dusted bronze spot in centre, narrowing below antennae, parallel-sided in middle (1/3 of eye width), and slightly diverging at clypeus, with multiple shallow diverging furrows; clypeus about as long as wide, bare. Frons metallic dark violet blue, with strong greyish dusting. Occiput bronze, strongly dusted greyish, distinctly concave. Palpus small, 1/7 of eye height, ovoid, dark brown, dusted grey, with slight bluish reflection, with yellow pubescence and yellow ap bristle. Proboscis dark brown. Eye with red base colour and brilliant green reflection in the lower 2/3, and dark violet in about the upper 1/3 (with smaller ommatidia), bare. All postocular bristles, most rather long, gently curved, white, with uppermost three distinctly shorter. One pair of minute brown postocellar bristles. Antenna entirely black, with scape bare and pedicel with apical crown of small bristles; postpedicel subcircular, rarely with small blunt apv process, about as long as deep, and about 0.8× as long as scape and pedicel combined, with microscopic pubescence; stylus apical, about 3.3× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum (incl. scutellum) bluish grey, strongly dusted, with rusty brown area between dc rows; pleura metallic bronze to bluish green, dusted greyish. Thoracic bristles black. Five dc (two presutural, one sutural, two postsutural), with first dc small, about 0.4× as long as second dc, and dc2-5 strong. More than six ac, biseriate, reaching beyond third dc, microscopic; three (one large black, two minute white) ant pprn, one external bas pprn, one rather strong sut ial, one npl, one spal, and one pal bristles. Scutellum with four bristles, lateral ones rather small, about 0.5× as long as median ones. With 2-3 white prothoracic bristles of subequal length, and about 3-5 minute pale setae between ant pprn bristle and first dc. Wing. Slightly smoked brownish, with pale brown veins. Vein R4+5 smoothly sinuous, M1 straight, both distinctly converging towards wing apex; distance at wing apex 0.5× distance at crossvein dm-cu. Proximal section of M1 0.9× as long as apical section. Proximal section of CuA1 3.2× as long as apical section. CuAx ratio: 0.8. Halter yellowish white, calypteral fringe yellow. Legs. Overall blackish brown, femora I-III with narrow reddish yellow knees, especially femur II. With most bristles pale, only ad and pd bristles on tibia II brown. Coxa I blackish brown, with Description. Male. Body length: 1.9-2.4 mm; wing length: 2.0-2.3 mm, wing 0.4× as wide as long. Head. Face with both epistoma and clypeus strongly dusted greyish; epistoma sometimes with less dusted bronze spot in centre, narrowing below antennae, parallel-sided in middle (1/3 of eye width), and slightly diverging at clypeus, with multiple shallow diverging furrows; clypeus about as long as wide, bare. Frons metallic dark violet blue, with strong greyish dusting. Occiput bronze, strongly dusted greyish, distinctly concave. Palpus small, 1/7 of eye height, ovoid, dark brown, dusted grey, with slight bluish reflection, with yellow pubescence and yellow ap bristle. Proboscis dark brown. Eye with red base colour and brilliant green reflection in the lower 2/3, and dark violet in about the upper 1/3 (with smaller ommatidia), bare. All postocular bristles, most rather long, gently curved, white, with uppermost three distinctly shorter. One pair of minute brown postocellar bristles. Antenna entirely black, with scape bare and pedicel with apical crown of small bristles; postpedicel subcircular, rarely with small blunt apv process, about as long as deep, and about 0.8× as long as scape and pedicel combined, with microscopic pubescence; stylus apical, about 3.3× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum (incl. scutellum) bluish grey, strongly dusted, with rusty brown area between dc rows; pleura metallic bronze to bluish green, dusted greyish. Thoracic bristles black. Five dc (two presutural, one sutural, two postsutural), with first dc small, about 0.4× as long as second dc, and dc2-5 strong. More than six ac, biseriate, reaching beyond third dc, microscopic; three (one large black, two minute white) ant pprn, one external bas pprn, one rather strong sut ial, one npl, one spal, and one pal bristles. Scutellum with four bristles, lateral ones rather small, about 0.5× as long as median ones. With 2-3 white prothoracic bristles of subequal length, and about 3-5 minute pale setae between ant pprn bristle and first dc. Wing. Slightly smoked brownish, with pale brown veins. Vein R 4+5 smoothly sinuous, M 1 straight, both distinctly converging towards wing apex; distance at wing apex 0.5× distance at crossvein dm-cu. Proximal section of M 1 0.9× as long as apical section. Proximal section of CuA 1 3.2× as long as apical section. CuA x ratio: 0.8. Halter yellowish white, calypteral fringe yellow. Legs. Overall blackish brown, femora I-III with narrow reddish yellow knees, especially femur II. With most bristles pale, only ad and pd bristles on tibia II brown. Coxa I blackish brown, with whitish yellow pubescence nearly exclusively on anterior face (lateral face nearly entirely bare), and four white ap bristles. Coxa II dark brown, with pubescence only on anterior face, and three white bristles on anterolateral margin, with the strongest bristle most apical. Coxa III blackish brown, with white external bristle, inserted at about basal 2/5 in anterior 1/3. Trochanters blackish brown, trochanter II with three minute white anterior bristles. Femur I blackish brown, with extreme apex paler. Femora II-III blackish brown, with apex reddish yellow, femur II with short white av and vt setae (longer than in Medetera lusitana sp. nov.). Femur III with one vt row of short white setae on apical 1/2, and with inconspicuous basodorsal row of small white bristles on basal 1/3, about 0.3× as long as femur is deep, with basal five bristles more erect. Tibiae I-III blackish brown. Tibia I without distinct bristles. Tibia II with one ad bristle at less than basal 1/3, and one pd bristle at basal 1/3, former not as long as tibia is deep and latter about as long as tibia is deep; with four small ap bristles. Tibia III with apicodorsal notch and weak ds serration, including one strongly inclined white bristle at apical 1/5, about 1.5× as long as tibia is deep, and two indistinct av bristles. Tarsi I-III blackish brown. Tarsus I: taI 1 with minute yellow ventral setae, and taI 1-4 with apv crown of dark setae. Tarsus II: taII 1-5 with many minute yellow and some darker setae, and taII 1-4 with apv crown of dark setae. Tarsus III: taIII 2-4 with apv crown of dark setae, and taIII 1 with indistinct blunt pv tooth at basis (MSSC). Ratio of femur/tibia/tarsomeres 1-5 in leg I: 10/9.3/4.4/2.1/1.6/1/1.3, in leg II: 8.9/9.2/5.1/2.5/1.7/0.9/1, and in leg III: 8.5/10.4/2.6/3.3/2/1/1. Abdomen. With seven pubescent segments. Tergites greenish to bluish bronze, brilliant on dorsum, more dusted on sides, with white pubescence and short bristles on posterior margins; bristles on sides of T 1 erect and large. Sternites dark brown, with weak metallic green reflection and weak dusting, with white, very short pubescence; S 2-5 with blunt incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium incl. epandrium brownish black; hypandrium reddish brown, rocket-shaped, with lateral hooks at basal 1/3 and two dark stripes at apex; with one small basal, and two larger more apical epandrial setae, latter on rather long stalks; surstylus dark brown, rather slender and S-shaped, with clear split in vt and ds lobe at less than apical 1 2 ; vt lobe with one modified seta; cercus pale brown, rather small, elongate triangular, with two ap flattened bristles.

Species Descriptions
Female. As male, except for: body length: 2.4-2.9 mm; wing length: 2.1-2.7 mm. Face 2/5 of eye width in middle. Wing with proximal section of CuA 1 3.5× as long as apical section; CuA x ratio: 0.9. Abdomen with five pubescent segments; segments 6-11 telescopic, and 12th segment with two black needle-like acanthophorites and two equal-sized brown cerci. Sternites coloured as in male but S 2-5 complete. Tarsomere III 1 without blunt basal pv tooth. Ratio of femur/tibia/tarsomeres 1-5 in leg I: 10.3/9.6/4.6/2.3/1.6/1/1.3, in leg II: 8.7/8.9/4.9/2.4/1.6/0.9/1, and in leg III: 8.2/10.8/2.6/3.5/2/1/1. Etymology. The specific epithet "aglaops" is retrieved from the ancient Greek Etymology. Ἀγλαωψ, which m the eyes in frontal Ecology. M. a cultural landscape rocks or other har collected in 83 dif widespread of all n together with M. l lowing species: M tipyga sp. nov. Du sp. nov. was colle sp.) forest above 1 than in white (n = 1 previously in tree-γλαωψ, which means "with beautiful eyes", referring to the unusual colour pattern of the eyes in frontal and lateral view. Ecology. M. aglaops sp. nov. has been encountered both in natural biotopes and agricultural landscapes from 2 m up to 2343 m a.s.l. It is mostly found in rather dry sites, on rocks or other hard substrates, often in forests but also in more open habitats. It has been collected in 83 different sites and four countries and as such is the most abundant and widespread of all new Medetera species described here. It was encountered in five samples together with M. lusitana sp. nov., and in four other samples together with one of the following species: M. corsicana sp. nov., M. gibbosipyga sp. nov., M. hispanica sp. nov., M. rectipyga sp. nov. During the Our Planet Reviewed expedition in Corsica (2019), M. aglaops sp. nov. was collected in highest numbers along a seep on rocky substrate in a fir (Abies sp.) forest above 1200 m a.s.l. In this site, yields were far higher in blue pan traps (n = 55) than in white (n = 11) or yellow traps (n = 1). This is a phenomenon that has been observed previously in tree-trunk dwelling species, and Medetera in particular e.g., [29,30]. Diagnosis. Very small species, wing length 1.7-1.9 mm (n = 3). Face with epistoma green, heavily dusted whitish; clypeus brilliantly green in middle. Eye uniformly red. Mesonotum uniformly metallic green-bronze. Five dc; four ac. Wing very slightly infuscate; halter with yellow knob and infuscate shaft. Coxae and femora overall blackish brown, with pale knees; tibiae brownish to reddish yellow, and tarsi with tarsomeres 1-2 pale with dark apex, and tarsomeres 3-5 dark. Tibia II with ad and pd bristle pair. Surstylus with indistinct apical split; hypandrium rather straight with weak bend at apex (lateral view), slightly tapering towards triangular apex (ventral view). cate; halter with yellow knob and infuscate shaft. Coxae and femora overall bla brown, with pale knees; tibiae brownish to reddish yellow, and tarsi with tarsomere pale with dark apex, and tarsomeres 3-5 dark. Tibia II with ad and pd bristle Surstylus with indistinct apical split; hypandrium rather straight with weak bend at (lateral view), slightly tapering towards triangular apex (ventral view).    Description. Male. Body length: 1.9-2.1 mm (n = 3); wing length: 1.7-1.9 mm (n = 3), 0.2× as wide as long. Head. Face with epistoma green, heavily dusted whitish, and clypeus brilliantly green in middle, narrowing below antennae, parallel-sided in middle (1/2 of eye width) and slightly diverging at clypeus; epistoma 2× as high as clypeus, latter slightly longer than wide, bare. Frons metallic green, with strong whitish dusting. Occiput bronze, with slight greyish dusting, distinctly concave. Palpus small, about 1/8 of eye height, ovoid, dark brown, shining, with yellow pubescence and one yellow apical bristle. Proboscis dark brown. Eye with red base colour and greenish reflection. Lowermost postocular bristles white, quite long and gently curved, and uppermost slightly darker, short, and erect. One pair of minute brown postocellar bristles. Antenna black, with scape bare and pedicel with apical crown of small bristles; postpedicel black, subcircular, sometimes with small apv process, about as long as deep, and 0.7× as long as scape and pedicel combined, with microscopic pubescence; stylus apical, about 4× as long as first three antennal segments combined, with first segment very short, bare. Thorax. Mesonotum incl. pleura and scutellum uniformly metallic green-bronze, with strong whitish dusting; scutellum with four bristles, lateral bristles 0.5× as long as median ones. Thoracic bristles black. Five dc (two presutural, one sutural, two postsutural), with first presutural and sutural bristle distinctly smaller than other dc, other dc increasing in length towards scutellum. About four ac, biserial, reaching nearly level of third dc (sutural), microscopic; three (one large black, two minute white) ant pprn, one external bas pprn, one small sut ial, one npl, one spal (two in HT), and one pal bristles. One-two white prothoracic bristles, with lower bristle considerably longer than upper one. Anterior surface of mesonotum with sparse white minute setae. Wing. Very slightly infuscate. Vein R 4+5 smoothly sinuous, M 1 nearly straight, both distinctly converging towards wing apex; distance at wing apex 0.5×distance at crossvein dm-cu. Proximal section of M 1 0.9× as long as apical section. Proximal section of CuA 1 3.1× as long as apical section. CuA x ratio: 0.8. Halter knob yellow, slightly infuscate, with infuscate shaft; calypteral fringe white. Legs. Coxae and femora overall blackish brown, latter with pale knees; tibiae brownish to reddish yellow, and tarsi with tarsomeres 1-2 pale with dark apex, and tarsomeres 3-5 dark. Legs largely devoid of bristles. With pale pubescence, only larger bristles brown. All coxae blackish brown; coxa I with one row of white setae on edge between anterior and lateral face, and with four white ap bristles. Coxa II with white pubescence on anterior face, and one large white bristle on anterolateral margin. Coxa III with one white external bristle, inserted in centre. Trochanters brown, trochanter II with one-three white anterior bristles. Femora blackish brown, femora I-II with apical 1/5, and femur III with extreme apex yellow. Femur III with two small av bristles and three strongly inclined bristles in basal 1/2, about 0.5× as long as femur is deep. Tibiae and tarsi variable in colour among specimens. Tibia I from brown to brownish yellow, without distinct bristles. Tibia II pale brown to brownish yellow, with one small ad bristle at less than basal 2/5 and one small pd bristle at basal 1/3, former as long as tibia is deep and latter nearly as long as tibia is deep; with four small ap bristles. Tibia III from brown to brownish yellow, with one yellow bristle at less than ap 1/6, with weak serration of short white setae along entire length, and 1-2 indistinct ap bristles. Tarsi with tarsomeres 3-5 entirely dark. Tarsus I usually with taI 1 yellow with dark apex, and taI 2 yellow with apical 1/2 dark (taI 1-2 in HT only slightly paler than taI 3-5 ); taI 1 with minute yellow ventral setae, and taI 1-4 with apv crown of dark setae. Tarsus II with taII 1-2 pale yellow with dark apex, taII 1-5 with several small dark vt setae, and taII 1-4 with apv crown of dark setae. Tarsus III with taIII 1 pale with dark apex, gradually darker from taIII 2 onwards; taIII 1 with two yellow apv bristles, as long as tarsomere is deep, and with quadrate pv tooth at basis (MSSC); tarsomeres III 1-4 with indistinct small vt bristles. Ratio of femur/tibia/tarsomeres 1-5 in leg I: 7.4/7.3/3.7/1.9/1.4/1/1.1, in leg II: 8.4/8.8/4.7/2.5/1.9/1/1, and in leg III: 7.6/9.7/2.3/3.8/2.2/1.1/1. Abdomen. With seven pubescent segments. Tergites greenish bronze, with strong whitish dusting, with white pubescence and short bristles on posterior margins; bristles on sides of T 1 more erect and large. Sternites dark brown, with white, very short bristles; S 2-5 with triangular incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium with epandrium brownish black; hypandrium reddish yellow, elongate, slightly narrower in middle, with rounded triangular apex; phallus with subapical cavity; with one very small basoventral, and two large apicoventral epandrial setae, latter on short stalks; surstylus brown, paler at apex, rather long, gently curved with incomplete split in ds and vt lobe, latter with modified bristles; cercus grey, rather small, elongate triangular, with two ap flattened bristles. Distribution. At present only known from Corsica (Corse-du-Sud). Etymology. The specific epithet "corsicana" refers to the island (Corsica) where the species has been discovered for the first time.
Ecology. The type location of this species is situated in a rather dry Quercus ilex forest in southern Corsica, the most common forest type on this island. M. corsicana sp. nov. has only been retrieved from Malaise trap samples, which suggests a primarily arboreal life history, similar to many other Medetera species but contrary to, e.g., M. aglaops sp. nov.
Description. Male. Body length: 2.1-2.5 mm; wing length: 2.0-2.8 mm, wing 0.3× as wide as long. Head. Face (epistoma and clypeus) entirely covered with strong yellowish grey pollinosity; narrowing below antennae, parallel-sided in middle and slightly diverging at clypeus; epistoma with one shallow central furrow, 2/5 of eye width in middle, bare. Frons (no ground colour visible) with strong yellowish grey dusting. Occiput dark brown, with slight yellowish dusting, distinctly concave. Palpus small, 1/8 of eye height, ovoid, dark brown, shining, with yellow pubescence and yellow ap bristle. Proboscis dark brown. Eye with red base colour and green reflection in lower 4/5 and reddish purple in dorsal 1/5, bare. Most postocular bristles white, with lowermost rather long, gently curved, and uppermost 2-3 shorter and mostly darker. One pair of minute brown postocellar bristles. Antenna entirely black, with scape bare and pedicel with apical crown of short bristles; postpedicel subcircular, without distinct apical process, as long as deep, and about 0.8× as long as scape and pedicel combined, with microscopic pubescence; stylus apical, 4× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum uniformly bronze (incl. pleura and scutellum), with strong yellowish grey dusting. Thoracic bristles black. Mostly five dc (two presutural, one sutural, two postsutural), dc1 0.5× as long as dc2-3, latter 0.5× as long as dc4-5; ac entirely absent in some specimens, but usually 1-3 ac present, biseriate, microscopic, as long as distance between rows, reaching level of third dc; three (one large black, two minute white) ant pprn, one external bas pprn, one strong sut ial, one npl, one spal, and one pal bristles. Scutellum with four bristles, lateral ones rather small, about 0.5× as long as median ones.
Three white prothoracic bristles of subequal length. Wing. Slightly infuscate with veins yellowish at basis. Vein R 4+5 smoothly sinuous, M 1 gently curved, both distinctly converging towards wing apex, parallel at wing apex; distance between R 4+5 and M 1 at wing apex 0.6× that at crossvein dm-cu. Proximal section of M 1 0.9× as long as apical section. Proximal section of CuA 1 3.1× as long as apical section. CuA x ratio: 0.8. Halter brownish, calypteral fringe white. Legs. Overall, mainly blackish brown, femora I-III with narrow reddish yellow knees, tarsi I-III paler, especially taI-III 1 , with tarsi II 1-2 largely yellowish brown. Legs with pale pubescence and bristles, only apical bristles of tibia II darker. Coxa I blackish brown, with white pubescence on anterior and lateral face, and four white ap bristles. Coxa II dark brown, with white pubescence on entire anterior face, and three white bristles on anterolateral margin, with the apicalmost bristle strongest. Coxa III blackish brown, with one white external bristle in centre. Trochanters blackish brown, trochanter II with three minute white anterior bristles. Femora I-III blackish brown, femora I-II with about apical 1/5 paler and femur III with less than apical 1/5 reddish yellow; femora largely devoid of bristles. Tibiae I-III dark brown, tibia II paler towards apex. Tibia I without distinct bristles. Tibia II with four ap bristles, with apv bristle largest. Tibia III with one yellow bristle at about apical 1/6, slightly longer than tibia is deep, and two indistinct av bristles; with pd serration of short white setae, especially on apical 1 2 . Tarsus I dark brown, with taI 1 slightly paler; taI 1-4 with apv crown of dark setae. Tarsus II dark brown, with taII 1-2 yellowish brown with dark apex; taII 1-5 with several small dark ventral setae, and taII 1-4 with apv crown of dark setae. Tarsus III dark brown, with taIII 1 pale brown; taIII 1-4 with apv crown of dark setae; taIII 1 with rather acute pv tooth at basis (MSSC). Ratio of femur/tibia/tarsomeres 1-5 in leg I: 7.5/7.3/3.7/2.1/1.4/1/1.1, in leg II: 8.8/9.5/5.4/2.8/1.9/1.1/1, and in leg III: 7.6/9.6/2.6/3.7/2.1/1.1/1. Abdomen. With 7 pubescent segments. Tergites greenish bronze, with rather strong yellowish grey pruinosity; with white pubescence and short bristles on posterior margins; bristles on sides of T 1 erect and large. Sternites concolorous with T, with white, very short pubescence; S 2-5 with blunt incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium incl. epandrium brownish black; hypandrium reddish brown, largely parallel-sided, with wide basis and distinctly enlarged tulip-shaped apex in ventral view; basis conspicuously raised (humpback-like) in lateral view; with one small basoventral, and two larger apicoventral epandrial setae, latter on short stalks; surstylus brown, of moderate length and width, with rather robust and slightly curved apex, latter with ds and vt process separated only at apex, both with flattened or feather-shaped setae; cercus greyish brown, rather small, elongate triangular, with two flattened ap bristles.
Ecology. M. gibbosipyga sp. nov. has been encountered at only two sites between 340 m and 1265 m which can be described as dry, open biotopes, with rocky substrates, shrubs, and coniferous trees.
Medetera hispanica Pollet sp. nov. (Figures 2, 6C and 7C) urn:lsid:zoobank.org:act:2A3914BB-60C3-4E01-B1A3-AAA187DC2C14 Diagnosis. Small species, wing length 2.2 mm. Face with epistoma metallic green in centre, clypeus mainly brilliantly bronze, both dusted greyish laterally. Eye with red base colour and green reflection in more than lower 2/3, upper part violet red. Mesonotum mainly metallic green on dorsum with humeral and notopleural areas metallic violet blue. Four dc; 6-7 strong ac. Wing hyaline, halter yellow. Legs with coxae and femora blackish brown, latter with pale knees; remainder of legs brown with apical part of tibiae I-III and tarsomeres I-III 1 largely yellowish brown. Tibia II without ad and pd bristle pair. Surstylus with small split in dorsal and ventral lobe at apical 1/4; hypandrium straight (lateral view), ribbon-shaped, with acute apex (ventral view).
Description. Male. Body length: 2.0 mm (n = 1); wing length: 2.2 mm (n = 1), wing 0.3× as wide as long. Head. Face with epistoma metallic green in centre, clypeus mainly brilliantly bronze, both dusted greyish laterally; mainly parallel-sided, only slightly widening towards antennae and clypeus, as wide in middle as 2× postpedicel (length); epistoma about 2× as high as clypeus, latter as long as wide, bare. Frons metallic greenish blue, with strong whitish dusting. Occiput bronze, with slight greyish dusting, distinctly concave. Palpus small (not possible to measure reliably), ovoid, dark brown, apparently shining, with yellow pubescence and yellow ap bristle. Proboscis dark brown. Eye with red base colour and green reflection in more than lower 2/3, upper part violet red (with smaller ommatidia-hard to assess due to shrinking of eyes), bare. Postocular bristles white, lowermost quite long and gently curved, upper ones becoming shorter and erect (uppermost bristles missing). One pair of (missing) postocellar bristles. Antenna entirely black, with scape bare and pedicel with an apical crown of small bristles; postpedicel subcircular, about 0.8× as long as deep, and about 0.8× as long as scape and pedicel combined, with microscopic pubescence; stylus strictly apical, about 3.6× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum mainly metallic green on dorsum, and humeral and notopleural areas metallic violet blue, with strong whitish dusting; pleura metallic green, bronze to violet, with weak whitish dusting; scutellum greenish blue, with strong whitish dusting, with four bristles (no reliable measurements possible due to the lack of the median bristles). Thoracic bristles black. With four dc (one presutural, one sutural, two postsutural; most bristles lacking). A total of 6-7 ac, biseriate, reaching beyond second (sutural) dc, as long as distance between rows; three (one large black, two minute white) ant pprn, one external bas pprn, one strong sut ial, one npl, one spal, and one pal bristles. With about six minute pale setae between humeral and first dc bristle. Two white prothoracic bristles, with lower bristle considerably longer than upper one. Wing. Hyaline, with dark brown veins. Vein R 4+5 smoothly sinuous, M 1 gently curved, both distinctly converging towards wing apex; distance at wing apex less than 0.3× distance at crossvein dm-cu. Proximal section of M 1 0.9× as long as apical section. Proximal section of CuA 1 2.8× as long as apical section. CuA x ratio: 0.7. Halter yellow, calypteral fringe white. Legs. Coxae I-III and femora I-III overall blackish brown, with pale knees, especially femora I-II; remainder of legs brown with apical part of tibiae I-III and tarsomeres I-III 1 largely yellowish brown. With pale pubescence and bristles. Coxa I with whitish yellow pubescence, nearly exclusively on anterior face (lateral face nearly entirely bare), and four white ap bristles. Coxa II with white pubescence on anterior face, and one large white bristle on anterolateral margin. Coxa III with one white external bristle in centre. Trochanters brown, trochanter II with three minute white anterior bristles. Femur I blackish brown, with ap 1/5 yellow. Femur II dark brown, with more than ap 1/4 pale yellow. Femur III blackish brown, with less than ap 1/5 reddish yellow; femora largely devoid of bristles. Tibia I brown, paler on ap 1/4, without distinct bristles. Tibia II yellowish brown at basis to brownish yellow at apex, with four small ap bristles. Tibia III brown, paler at apex, with one yellow bristle at less than ap 1/4, slightly longer than tibia is deep, amid serration of short white setae on ap 1/2, and two indistinct av bristles with pd and vt serration of short white setae on ap 1/2. Tarsus I mainly brown, with taI 5 dark brown; taI 1-4 with apv crown of dark setae. Tarsus II with taII 1 brownish yellow, darker from ap 1/3 onwards, with taII 2-5 dark brown; taII 1-5 with small dark vt setae and taII [1][2][3][4] with apv crown of dark setae. Tarsus III with taIII 1 yellowish brown, darker at apex, and taIII 2-5 dark brown; taIII 2-4 with apv crown of brown setae; taIII 1  With seven pubescent segments. Tergites greenish bronze, with rather weak whitish pruinosity, with white pubescence and short bristles on posterior margins; bristles on sides of T 1 erect and large. Sternites concolorous with T, with white, very short pubescence; S 2-5 with blunt incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium incl. epandrium brownish black; hypandrium brownish yellow, rather wide, only slightly narrowing towards rather acute apex; with two small basal, and two large apicoventral epandrial setae, latter on short stalks; surstylus brown, gently curved ventralwards, split in ds and vt lobe at about apical 1/4, both with modified setae; cercus grey, rather small, elongate triangular, with two flattened ap bristles. Etymology. The specific epithet "hispanica" refers to the country where the species has been discovered for the first time.
Ecology. Shared features of both capture sites suggest a preference of this species for open water (rivulet, reservoir) and possibly higher altitudes (605 m, 1692 m), but this remains to be confirmed by additional records. Diagnosis. Small but robust species, wing length 2.1-2.5 mm. Face with epistoma metallic green, strongly dusted yellowish, and clypeus brilliant green. Eye with red base colour and brilliant green reflection in lower 2/3, and dark violet in about upper 1/3 (with smaller ommatidia). Mesonotum (incl. scutellum) greenish blue with coppery area between dc rows extending upon prescutellar depression, with strong whitish dusting. Five dc, with first dc small, about 0.7× as long as second dc bristle; four strong ac; two spal bristles. Wing hyaline; halter dark. Legs overall blackish brown, and femora I-III with narrow reddish yellow knees. Tibia II with ad and pd bristle pair. Hypandrium slightly undulating ventrally (lateral view), stout, widest in middle with acute apex, without lateral hooks at basal 1/3 (ventral view). Diagnosis. Small but robust species, wing length 2.1-2.5 mm. Face with epistoma metallic green, strongly dusted yellowish, and clypeus brilliant green. Eye with red base colour and brilliant green reflection in lower 2/3, and dark violet in about upper 1/3 (with smaller ommatidia). Mesonotum (incl. scutellum) greenish blue with coppery area between dc rows extending upon prescutellar depression, with strong whitish dusting. Five dc, with first dc small, about 0.7× as long as second dc bristle; four strong ac; two spal bristles. Wing hyaline; halter dark. Legs overall blackish brown, and femora I-III with narrow reddish yellow knees. Tibia II with ad and pd bristle pair. Hypandrium slightly undulating ventrally (lateral view), stout, widest in middle with acute apex, without lateral hooks at basal 1/3 (ventral view).  Description. Male. Body length: 2.2-2.5 mm; wing length: 2.1-2.5 mm, wing 0.4× as wide as long. Head. Face with epistoma metallic green, strongly dusted yellowish and clypeus brilliant green; narrowing below antennae, parallel-sided in middle (1/3 of eye width) and slightly diverging at clypeus; epistoma with 2-3 shallow diverging furrows, clypeus about as long as wide, bare. Frons metallic violet blue, with strong whitish dusting. Occiput violet blue, strongly dusted, distinctly concave. Palpus small, 1/6 of eye height, ovoid, dark brown, shining, with yellow pubescence and brown ap bristle. Proboscis dark brown. Eye with red base colour and brilliant green reflection in lower 2/3, and dark violet in about upper 1/3 (with smaller ommatidia), bare. Most postocular bristles white, rather long, gently curved, with uppermost three distinctly shorter and darker. One pair of black postocellar bristles. Antenna entirely black, with scape bare and pedicel with apical crown of small bristles; postpedicel subcircular, with small blunt apv process, about as long as deep, and about 0.6× as long as scape and pedicel combined, with microscopic pubescence; stylus apical, above small blunt process, about 4× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum (incl. scutellum) greenish blue with coppery area between dc rows extending upon prescutellar depression, with strong whitish dusting; pleura metallic green, with weaker whitish dusting. Thoracic bristles black. Five strong dc (two presutural, one sutural, two postsutural), first dc 0.7× as long as second dc, posterior ones increasing in length towards scutellum. Four ac, biseriate, reaching until third dc, rather strong, about 1.5-2× as long as distance between rows; three (one large black, two minute white) ant pprn, one external bas pprn, one (minute, ac-sized) psut ial, one rather strong sut ial, one npl, two spal, and one pal bristles. Scutellum with four bristles, lateral ones strong, about 0.7× as long as median ones. With 2-3 white prothoracic bristles, lower bristle about 2× as long as upper bristles. In some specimens, about eight minute setae between ant pprn bristle and first dc. Wing. Hyaline, with dark brown veins. Vein R 4+5 smoothly sinuous, M 1 gently curved, both distinctly converging towards wing apex, and sometimes slightly diverging at wing apex; distance at wing apex 0.3× distance at crossvein dm-cu. Proximal section of M 1 0.9× as long as apical section. Proximal section of CuA 1 3.0× as long as apical section. CuA x ratio: 0.7. Halter black, both shaft and knob, calypteral fringe brown. Legs. Overall blackish brown, femora I-III with narrow reddish yellow knees, especially femur II. With pale vt and dark ds bristles. Coxae I-II blackish brown, coxa I with whitish yellow pubescence nearly exclusively on anterior face (lateral face nearly entirely bare), and four yellow ap bristles. Coxa II with whitish yellow pubescence only on anterior face, and three whitish yellow bristles on anterolateral margin, with the apicalmost bristle strongest. Coxa III blackish brown, with one whitish yellow external bristle, inserted at basal 2/5 in middle. Trochanters blackish brown, trochanter II with two minute brown anterior bristles. Femur I blackish brown, with paler extreme apex. Femora II-III blackish brown, with reddish yellow apex; femur II with very short pale av and vt setae. Femur III with some short yellow vt setae on apical 1/4, and with basodorsal row of strong brown bristles on mainly basal 2/5, with four erect basal bristles, longest ones as long as femur is deep. Tibiae I-III blackish brown. Tibia I without distinct bristles. Tibia II blackish brown, with one ad and one pd bristle at less than basal 1/3 (pd bristle slightly more apical than ad bristle), former 1.5× as long as tibia is deep and latter slightly longer than tibia is deep; with five ap bristles, two vt ones strongest. Tibia III with apicodorsal notch and weak ds serration, including one strongly inclined yellow bristle at ap 1/5, about as long as tibia is deep, and two indistinct av bristles; with pd serration of short white setae, especially on apical 1/2. Tarsi I-III blackish brown. Tarsus I: taI 1 with minute yellow vt setae, and taI 1-4 with apv crown of dark setae. Tarsus II: taII 1-5 with several small dark vt setae, and taII 1-4 with apv crown of dark setae. Tarsus III with short yellow setae mainly on taIII 1-2 , 2 longer vt brown setae at apex of taIII 1 , and taIII 1-4 with apv crown of dark setae. Ratio of femur/tibia/tarsomeres 1-5 in leg I: 10.1/9.3/4.7/1.9/1.5/1/1.3, in leg II: 10.3/10.3/5.7/2.5/1.8/1/1, and in leg III: 8.8/11.6/3.3/4/2.1/1/1. Abdomen. With seven pubescent segments. Tergites metallic green, with weak whitish pruinosity, with dark (brown) pubescence and short bristles on posterior margins; bristles on sides of T 1 pale brown to yellow, erect and large. Sternites dark brown, with weak metallic green reflection, with yellow, very short pubescence; S 2-5 with blunt incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium incl. epandrium brownish black; hypandrium reddish brown, wide, widest in middle, with triangular apex; with one small basal, and two larger apicoventral epandrial setae, latter on short stalks; surstylus brownish yellow, rather robust, with clear ds and vt lobe from Distribution. At present only known from northern and northeastern Portugal (Minho, Trás-os-Montes e Alto Douro, Douro Litoral, Beira Alta, Beira Baixa, Alto Alentejo) and northwestern Spain (Ourense).
Etymology. The specific epithet "lusitana" is derived from Lusitania, the name of a Roman province in the Iberian Peninsula, which encompasses most of modern Portugal. It refers to the country (Portugal) where the species seems to reach its main distribution.
Ecology. With Parque Biológico de Gaia (strongly impacted lowland area in Avintes at 60 m a.s.l.) as only exception, M. lusitana sp. nov. has only been collected at higher altitudes, between 575 m and 1645 m a.s.l., at rather humid spots (near waterfalls, small streams, riparian corridors) in an otherwise mainly open dry landscape with shrubs and scattered trees. Rocks were often present in these sites (see also M. aglaops sp.n.).
Medetera parva Pollet sp. nov. (Figure 2, Figure 10A,B and Figure 11A Etymology. The specific epithet "lusitana" is derived from Lusitania, the name of a Roman province in the Iberian Peninsula, which encompasses most of modern Portugal. It refers to the country (Portugal) where the species seems to reach its main distribution.
Ecology. With Parque Biológico de Gaia (strongly impacted lowland area in Avintes at 60 m a.s.l.) as only exception, M. lusitana sp. nov. has only been collected at higher altitudes, between 575 m and 1645 m a.s.l., at rather humid spots (near waterfalls, small streams, riparian corridors) in an otherwise mainly open dry landscape with shrubs and scattered trees. Rocks were often present in these sites (see also M. aglaops sp.n.).
Medetera parva Pollet sp. nov. (Figures 2, 10A   Diagnosis. Very small species, wing length 1.7-1.8 mm. Face with epistoma brilliant violet, and clypeus brilliant bluish green, both separated by narrow grey pollinose zone. Eye with red base colour, with three zones, middle zone purely red, and upper (with smaller ommatidia) and lower zones with greenish reflection. Mesonotum mainly bluish green on dorsum, with distinct blue violet humeral and notopleural zones, with strong whitish dusting. Three-four dc; ac absent. Wing very slightly infuscate; halter yellow. Legs overall mainly yellowish to pale brown, coxae II-III entirely and coxa I in part brown at basis, and tarsi I-III only slightly darker towards apex. Tibia II without ad and pd bristle pair. Surstylus straight and short, with split at apical 1/3; hypandrium straight dorsally (lateral view), with two lateral apical processes (ventral view).
Description. Male. Body length: 1.8-2.0 mm (n = 3); wing length: 1.7-1.8 mm (n = 3), wing 0.4× as wide as long. Head. Face with epistoma brilliant violet, and clypeus brilliant Diagnosis. Very small species, wing length 1.7-1.8 mm. Face with epistoma brilliant violet, and clypeus brilliant bluish green, both separated by narrow grey pollinose zone. Eye with red base colour, with three zones, middle zone purely red, and upper (with smaller ommatidia) and lower zones with greenish reflection. Mesonotum mainly bluish green on dorsum, with distinct blue violet humeral and notopleural zones, with strong whitish dusting. Three-four dc; ac absent. Wing very slightly infuscate; halter yellow. Legs overall mainly yellowish to pale brown, coxae II-III entirely and coxa I in part brown at basis, and tarsi I-III only slightly darker towards apex. Tibia II without ad and pd bristle pair. Surstylus straight and short, with split at apical 1/3; hypandrium straight dorsally (lateral view), with two lateral apical processes (ventral view).
Description. Male. Body length: 1.8-2.0 mm (n = 3); wing length: 1.7-1.8 mm (n = 3), wing 0.4× as wide as long. Head. Face with epistoma brilliant violet, and clypeus brilliant bluish green, both separated by narrow grey pollinose zone; mainly parallel-sided, only slightly widening towards antennae and clypeus, 1/2 of eye width in middle, epistoma 1.5× as high as clypeus, latter about as long as wide, bare. Frons metallic blue, with strong whitish dusting. Occiput bronze, with slight greyish dusting, distinctly concave. Palpus small, 1/5 of eye height, ovoid, dark brown, with grey dusting, with yellow pubescence and yellow ap bristle. Proboscis dark brown. Eye with red base colour, with three zones, middle zone purely red, and upper (with smaller ommatidia) and lower zones with greenish reflection, bare. Postocular bristles all white, with lowermost quite long and gently curved, and uppermost short and erect. One pair of minute brown postocellar bristles. Antenna entirely dark brown, with scape bare and pedicel with an apical crown of small bristles; postpedicel subquadrate (with ventral apex more protruding), about as long as deep, distinctly smaller than pedicel, and 0.7× as long as scape and pedicel combined, with microscopic pubescence; stylus apical, about 3.4× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum mainly bluish green on dorsum, with distinct blue violet humeral and notopleural zones, with strong whitish dusting; pleura metallic green, bronze to violet, with weak whitish dusting; scutellum greenish blue, with strong whitish dusting, with four bristles (but lacking). Thoracic bristles dark brown. With 3-4 dc (one small sutural, two larger postsutural, and sometimes one small presutural). Ac absent; seemingly two (one large dark brown, one minute white) ant pprn, one external bas pprn, one npl, one spal, and one pal bristles. With 2-3 white prothoracic bristles, with lower bristle longest. Wing. Very slightly infuscate. Vein R 4+5 and M 1 gently curved (latter sometimes nearly straight), distinctly converging towards wing apex; distance at wing apex 0.3× that at crossvein dm-cu. Proximal section of M 1 0.8× as long as apical section. Proximal section of CuA 1 2.5× as long as apical section. CuA x ratio: 0.7. Halter yellow, calypteral fringe white. Legs. Overall, mainly yellowish to pale brown, coxae II-III entirely and coxa I in part brown at basis, and tarsi I-III only slightly darker towards apex. With pale pubescence and bristles. Coxa I mainly yellowish brown, brown on outer 1/2, with white, rather strong and erect pubescence on entire face, and four white ap bristles. Coxae II-III blackish brown; coxa II with white pubescence on anterior face, and three white bristles on anterolateral margin, with the apicalmost bristle strongest; coxa III with one white external bristle at ap 1/2 in anterior 1/3. Trochanters brown, trochanter II with three minute white anterior bristles. Femur I yellowish to pale brown, slightly infuscate dorsally, paler at apex, with one pv row of minute erect white setae along entire length. Femora II-III yellowish to pale brown, with narrow paler knee; femur III with one av row of minute inclined white setae along entire length. Tibiae I-III yellowish to pale brown. Tibia I without distinct bristles. Tibia II with four small ap bristles. Tibia III with one yellow bristle at about apical 1/7, with weak serration of short white setae along entire length, and two indistinct av bristles. Tarsi I-III yellowish brown to brown, often darker towards apex. Tarsus II: taII 1-4 with apv crown of brown setae. Tarsus III: taIII 1 with indistinct blunt pv tooth at basis (MSSC). Ratio of femur/tibia/tarsomeres 1-5 in leg I: 9.2/8.6/4.4/2.2/1.5/1/1.2, in leg II: 9.3/9.5/5.6/2.7/2.1/1/1, and in leg III: 7.5/9.5/2.6/3.8/2/1/1. Abdomen. With 7 pubescent segments. Tergites greenish bronze, with rather weak whitish pruinosity, with white pubescence and short bristles on posterior margins; bristles on sides of T1 more erect and large. Sternites concolorous with T, with white, very short pubescence; S 2-5 with blunt incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium with epandrium brownish black, rather robust; hypandrium reddish yellow, slightly narrowing towards apex, with two lateral square ap processes; with one small basal, and two larger apicoventral epandrial setae, latter on very short stalks; surstylus reddish yellow to yellowish brown with darker basis, robust and rather short, separated from epandrium by suture, split in ds and vt lobe at ap 1/3; ventral lobe with one modified seta; cercus rather small, elongate triangular, with two ap flattened bristles.
Female. Unknown. Distribution. At present only known from Sardinia (Carbonia-Iglesias) (Italy). Etymology. The specific epithet "parva" is derived from latin "parvus" and refers to the small size of this Medetera species.
Ecology. The type locality is the permanent level II monitoring plot of the CONECOFOR-ICP forest network [22], adjacent to an ancient holm oak coppice on a south-facing slope, belonging to the Viburnum-Quercetum ilicis association. The shrub layer is characterised by Ilex aquifolium [21].
Description. Male. Body length: 2.0-2.5 mm; wing length: 2.0-2.4 mm, wing 0.4× as wide as long. Head. Face with epistoma metallic bronze in centre, clypeus mainly brilliant bronze or green, both dusted greyish laterally; narrowing below antennae, parallel-sided in middle (1/2 of eye width) and slightly diverging at clypeus; epistoma with one small central bulge, 1.5× as high as clypeus, latter as long as wide, both bare. Frons metallic greenish blue, with weak greyish dusting. Occiput bronze, with slight greyish dusting, distinctly concave. Palpus small, 1/7 of eye height, ovoid, dark brown, shining, with yellow pubescence and yellow ap bristle. Proboscis dark brown. Eye with red base colour and green reflection in lower 2/3-1/2, purple red in upper 1/3-1/2 (with smaller ommatidia), bare. Postocular bristles all white, with lowermost quite long and gently curved, and uppermost short and erect. One pair of minute brown postocellar bristles. Antenna entirely black, with scape bare and pedicel with apical crown of small bristles; postpedicel subquadrate (with ventral apex slightly protruding), slightly longer than deep, and about 0.8× as long as scape and pedicel combined, with microscopic pubescence; stylus apical (dorsad of ventral process), about 4× as long as first three antennal segments combined, with very short first segment, bare. Thorax. Mesonotum (incl. scutellum) reddish bronze in middle of dorsum, with distinctly metallic violet blue humeral and notopleural areas, with strong greyish dusting; pleura metallic greenish bronze, with weak greyish dusting. Thoracic bristles black. With three strong dc (one presutural, two postsutural), increasing in length towards scutellum. Ac absent. Two (one large black, one minute white) ant pprn, one external bas pprn, one rather strong sut ial, one npl, one spal, and one pal bristles. Scutellum with four bristles, lateral ones rather small, about 0.4× as long as median ones. With 2-3 white prothoracic bristles, with lower bristle longest. Wing. Slightly infuscate, with brown veins. Vein R 4+5 smoothly sinuous, M 1 gently curved, both distinctly converging towards wing apex, parallel at wing apex; distance at wing apex 0.4× that at crossvein dm-cu. Proximal section of M 1 0.9× as long as apical section. Proximal section of CuA 1 2.9× as long as apical section. CuA x ratio: 0.7. Halter yellowish, at most slightly infuscate, calypteral fringe yellow. Legs. Overall mainly pale brown to brown, with coxae I-III, femora I and III blackish brown, and femora I-III with paler knees, most distinct in femur II. Pubescence and bristles pale. Coxae I-III blackish brown, with coxa I paler on apical 1/2, latter with white pubescence, nearly exclusively on anterior face, and four white ap bristles. Coxa II with white pubescence on anterior face, and one large white bristle on anterolateral margin. Coxa III with one white external bristle in centre. Trochanters brown, trochanter II with three minute white anterior bristles. Femur I blackish brown, with extreme apex paler. Femur II dark brown, with about ap 1/4 paler. Femur III blackish brown, with extreme apex reddish yellow; femora largely devoid of bristles. Tibiae I-III dark brown. Tibia I without distinct bristles. Tibia II with four small ap bristles. Tibia III with one yellow bristle at ap 1/5, slightly longer than tibia is deep, and two indistinct av bristles. Tarsi I-III dark brown. Tarsus I with taI 1-4 with apv crown of dark setae. Tarsus II with taII 1-5 with several small dark vt setae, and taII 1-4 with apv crown of dark setae. Tarsus III with taIII 2-5 with several small dark vt setae, and taIII 2-4 with apv crown of dark setae; taIII 1 with rather acute pv tooth at basis (MSSC). Ratio of femur/tibia/tarsomeres 1-5 in leg I: 7.9/7.7/4.1/2.1/4.1/1/1.1, in leg II: 8.9/9.4/5.7/2.6/1.8/1/1, and in leg III: 6.9/8.9/2.5/3.8/2/1/1. Abdomen. With seven pubescent segments. Tergites greenish bronze, with rather strong yellowish grey pruinosity, with white pubescence and short bristles on posterior margins; bristles on sides of T 1 erect and large. Sternites concolorous with T, with white, very short pubescence; S 2-5 with blunt incision in middle of posterior margin, S 6 entirely unsclerotised. Hypopygium incl. epandrium brownish black; hypandrium reddish brown, rather wide, parallel-sided with rounded apex; with one small basal, and two larger apicoventral epandrial setae, latter on short stalks; surstylus dark brown, conspicuously straight, rather slender, with split in ds and vt lobe at about ap 1/3, with most setae unmodified; cercus grey, rather small, elongate triangular, with two flattened ap bristles.
Etymology. The specific epithet "rectipyga" refers to the straight slender shape of the surstylus, which is an important diagnostic feature in this species.
Ecology. In northeastern Spain, M. rectipyga sp. nov. has been collected at higher altitudes (1410-1560 m) in open mosaic habitats, mostly with grasses and shrubs. In southeastern France, it has indifferently been collected on rocks in different biotopes, from garrigue (dry open areas with shrubs) to stream banks.

Discussion
Establishing the identity of many Medetera species is very often hampered by a lack of decisive diagnostic features. Indeed, most Medetera males do not feature specific Male Secondary Sexual Characters, which are common in other dolichopodid lineages and a valuable tool for identification. With the exception of only a few species, in the Palaearctic, females of most Medetera species cannot be identified with absolute certainty. Negrobov and Stackelberg [31,32] and Negrobov [33] provided a key to both sexes but many couplets end with male genital characters which excludes the identification of females. Even the most recent comprehensive key by Negrobov and Naglis [2] only included the male sex. As demonstrated here, part of the European Medetera diversity still remains to be explored, especially in the south. Moreover, this certainly holds true for most of the eastern parts of the Palaearctic as well. As females are often collected in larger numbers than males, there is a fair chance that some of these new species are only represented by female specimens in samples. For that reason, we considered a key to females (not only for the seven species treated here but for any Medetera fauna) unreliable, until more useful and reliable diagnostic characters are available. Barcoding might represent a promising tool for this purpose. In fact, once female specimens have been identified in this way, the search for reliable characters (also biometrics) can be seriously pursued.
Despite this poor set of diagnostic characters, we are confident that the seven species described here are new to science. In fact, none of them matches a species in the key by Negrobov and Naglis [2]. All four of our species without the ad-pd bristle pair on the mid tibia show pale postoculars, such as M. glaucella Kowarz, 1878 and M. glaucelloides Naglis, 2013, but clearly differ from either of these species. In addition, they also differ from M. storai Frey, 1935 (endemic to the Canary Islands) by a strongly pollinose mesonotum, size (wing length >1 mm) and CuA x ratio (<1.0). In addition, M. storai does not seem to have a particular eye colour pattern. Both sexes of M. aglaops sp. nov., M. gibbosipyga sp. nov., M. lusitana sp. nov. and M. rectipyga sp. nov. show a distinct eye colour pattern. This character can thus not be regarded as a Male Secondary Sexual Character and most presumably does not play a role in courtship behaviour. Thus far, no females of M. corsicana sp. nov., M. hispanica sp. nov., or M. parva sp. nov. have been detected.
Based on COI sequences in BOLD Systems (see Figure 12), M. aglaops sp. nov., M. gibbosipyga sp. nov., M. lusitana sp. nov., and M. parva sp. nov. seem to belong to the Medetera apicalis species group sensu Bickel [12]. More specifically, they best fit the strongly supported M. muralis subclade sensu Pollet, Germann and Bernasconi [13], thus far only comprising M. muralis Meigen, 1824 and M. belgica Parent, 1936. Both latter species lack the ad-pd bristle pair of the mid tibia, which was thus far considered of great phylogenetic significance. However, shared characters in genital appendages, in particular the shape of the hypandrium and cercus, suggest that all seven species described here are closely related and even form a distinct lineage within the M. apicalis species group. Indeed, other species of the latter species group show a cercus with a distinctly different bristle arrangement and shapes, and quite often a hypandrium with a terminal enlargement (see [31][32][33]). This seems to imply that the absence or presence of the ad-pd bristle pair might not be as phylogenetically relevant as initially anticipated. The same holds true for acrostichal bristles on the mesonotum which were always present in four species, always lacking in two species, and of a variable status in one species. Moreover, from an ecological perspective, most of the new species differ from m species of the M. apicalis species group, members of which are most often found on trun of deciduous trees. As all specimens of M. corsicana sp. nov. and M. parva sp. nov. origin from Malaise traps samples, no information on their (micro)habitat preference is availab However, all five remaining species were mainly encountered in rather dry biotopes, w sclerophyllous vegetation types and/or open (often coniferous) forest where they mos occurred on hard, rocky substrates. As pointed out previously [13], this behaviour is a observed in M. muralis and M. belgica which further supports their phylogenetic relatio Moreover, from an ecological perspective, most of the new species differ from most species of the M. apicalis species group, members of which are most often found on trunks of deciduous trees. As all specimens of M. corsicana sp. nov. and M. parva sp. nov. originate from Malaise traps samples, no information on their (micro)habitat preference is available. However, all five remaining species were mainly encountered in rather dry biotopes, with sclerophyllous vegetation types and/or open (often coniferous) forest where they mostly occurred on hard, rocky substrates. As pointed out previously [13], this behaviour is also observed in M. muralis and M. belgica which further supports their phylogenetic relationship.
The question remains why these species have been discovered only recently despite their conspicuous eye colour pattern. Species featuring eyes with different colour zones are known in Diaphorinae, e.g., Cryptophleps Lichtwardt, 1898 and Diaphorus Meigen, 1824, but the species described here are the first recorded in the genus Medetera. The first collected specimen (M. aglaops sp. nov.) in our data set dates back from 2004 (CONECOFOR survey, Sardinia), but a steady influx of collected specimens has been reported in the past ten years or so. Pictures of Portuguese and Spanish species (even with the head in frontal view) have been available on the Spanish citizen science biodiversity portal Biodiversidad Virtual ( [34]; check for pictures of Medetera) for some time, but without any attempt to explore them further. The aim of this portal is to gather data on the distribution of mainly Spanish species via the registration of photographs of specimens by citizen scientists, and subsequent identification by experts. The reason for this situation seems to be a combination of several factors. First of all, dry habitat types where most of these species thrive are not among the standard sites visited and investigated by dolichopodid workers. Moreover, those interested in Medetera most often use Malaise traps or actively inspect tree trunks for specimens. As a result, these biotopes remain largely overlooked. Secondly, not many naturalists or Diptera workers in Europe are actively involved in observing and/or collecting dolichopodids. Moreover, even if conspicuous species are detected, at most a handful of taxonomic specialists in Europe are capable of properly treating them. This might also be considered part of the taxonomic impediment or Linnean shortfall [35]. Thirdly, most of the latter experts are not employed as entomologists and carry out their research in their spare time, which inevitably leads to delays. Finally, Medetera is undoubtedly one of the most challenging genera to study, in part due to the lack of distinct diagnostic features. It thus takes quite a lot of effort and time to verify whether a species is new to science or not, which often includes the examination of type specimens and/or comparison with specimens from reference collections.

Conclusions
This paper represents an important addition to the knowledge on a previously underexplored part of Medetera diversity in Europe. With this publication, we hope to encourage both Diptera workers and general naturalists to keep an eye open for these insects or search for them actively during their upcoming (collecting) trips. In this way, our knowledge on their distribution and ecology could increase substantially and possibly even additional species new to science might be detected. In this respect, blue or other dark coloured pan traps might be a promising collecting tool. Indeed, Medetera are most attracted to this colour range, regardless of whether tree-trunk dwelling or xerophilous species are concerned. Moreover, pan traps can produce fair yields in less than one hour [36]. Funding: Some specimens of M. aglaops sp. nov. were collected during the Our Planet Reviewed expedition (Corsica 2019-2021) which was funded by the Collectivité de Corse (CdC) and the Office Français de la Biodiversité (OFB) (both France). M.P. participated to this expedition.

Data Availability Statement:
The data presented in this study i.e., detailed distribution records of the 7 described species including habitat descriptions, are openly available as dataset in GBIF at https://doi.org/10.15468/s8c7n9.