Description based on Kjærandsen et al. (2009): On the genus Urytalpa Edwards (Diptera: Keroplatidae) in the Nordic and Nearctic regions, with fixation of a new type species and a key to world males

Most similar to U. dorsalis but differs by having more slender and less petiolated and less laterally compressed abdomen and by having the thoracic stripes distinctly separated. The larger apicomedial outgrowth of the gonocoxite with 5–6 strong setae in a row is a distinctive character for this species. Urytalpa dorsalis and U. trivittata differ from the other Nordic species in having gonocoxites without larger outgrowths and the gonostylus is retracted dorsally into the gonocoxites. In U. trivittata, however, the gonostylus is subtriangular in lateral view and somewhat larger. The female can be separated from U. dorsalis and U. macrocera by the combination of an oblong and petiolated cercus, sternite VIII having truncated apicomedial corners with a narrow setose excavation, and by having distinctly ovate spermathecae with a relatively thin inner wall.

Male

Coloration (specimen in alcohol). Head brown with mouth parts paler. Antenna brown, scape, pedicel and basal part of first flagellomere paler. Thorax yellow with pale antepronotum; dark brown mesonotal stripes distinctly separated,narrowly surrounded by pale yellow ground; humeral area pale, extending laterally to behind wing base. Wings clear, yellow tinged, veins brown. Halter pale. Legs slightly paler than thorax. Abdomen brown;tergites I–V with narrow pale bands apically; tergites VI–IX dark brown; sternites I–V pale; terminalia yellowish brown.

Terminalia (Fig.). Gonocoxite connected ventrally by a narrow strip only; apically with a distinct apicomedial outgrowth with 5–6 strong setae in a row (A). Large hypandrial lobe forming thin hyaline plate ventromedially (A). Gonostylus retracted into gonocoxite, small and subtriangular in lateral view with the tip pointing dorsally (D). Aedeagal apparatus long but not high, with less compressed plate extending anteriorly into segment V, and long associated apodemes laterally. Tergite IX without outgrowths, apical corner pointed ventrally, without patch of short internal setae; with shallow posterior and deep anterior U-shaped incision (B). Proctiger small and short, cercus broadly ovate in lateral view (A).

Female.

Coloration. As in male with dark brown mesonotal stripes distinctly separated.

Terminalia (Fig.). Cercus oblong and petiolated (A.). Sternite VIII with truncated corners, with a narrow excavation apicomedially covered with short stiff setae. Spermathecae distinctly ovate, spermathecae and ducts with medium thick inner walls (B.).

Male (n=5). Body length 6.5–8.5, 7.1 (n=10) mm. Wing length 5.14–5.88, 5.5 mm, or3.24–3.64, 3.39 as long as profemur. Antenna length 2.2–2.64 (n=4) mm.

Female (n=1). Body length 7.5 mm. Wing length 6 mm. Antenna length 1.82–1.86 mm.

European; with scattered records only from Finland, Germany, Italy, Norway and Sweden.Possibly boreal-mountainous with main distribution in northern parts of the boreal zone.

Description based on Kjærandsen et al (2009): On the genus Urytalpa Edwards (Diptera: Keroplatidae) in the Nordic and Nearctic regions, with fixation of a new type species and a key to world males

This species shares terminalia with fused gonocoxites and very long aedeagal apparatus with U. dorsalis and U. trivittata. It can be distinguished from these and other species by having long, digitateprojections from tergite IX and relatively large and exposed gonostyli. The shape of the bifidgonostylus is unique with a brush of strong setae on the inner smaller branch

Male

Coloration (dry, pinned specimen). Head dark blackish brown with pale yellowishbrown mouth parts and palps. Antenna dark brown; scape, pedicel and basal part of first flagellomere paleryellow. Thorax yellow with mediotergite dark brown; preepisternum with brown posterior part and anterioredge; thoracic stripes brown, narrowly surrounded by pale yellow ground, humeral area pale, extending laterally to behind wing base. Wings clear, yellow tinged. Halter yellow. Legs yellow. Abdomen yellow withtergites VI–IX dark brown, sternites VII–VIII brownish yellow.

Terminalia (Fig.). Gonocoxites connectedby a narrow strip and prolonged apicolaterally (A). Gonostylus bifurcate, with a broad base; ventral branch strong,ending in a sclerotized fold; dorsal branch shorter with about 5 long strong setae forming a brush apically (D) . Aedeagal apparatus long but not high, with compressed plate extending anteriorly into segment V, and long associated apodemes laterally. Tergite IX with a long, narrow, digitate projection apicolaterally without patchof short internal setae; with deep posterior and anterior U-shaped incision (B&C). Proctiger small and short, cercus thin, rhombic in lateral view (B&C).

Female unknown.

Male (n=1). Body length 6 mm. Wing length 4.84 mm or 3.36 as long as profemur. Antenna length 2.26 mm.

Female. Unknown

North-western Europe; known only from southern England, the Netherlands, Norway and Sweden.

The text is based mainly on Kjærandsen (2009): The genus Pseudexechia Tuomikoski re-characterized, with a review of European species (Diptera: Mycetophilidae).

The genus Pseudexechia (•) was established by  Tuomikoski (1966) for a small group of closely related species in the tribe Exechiini, segregated from Exechia Winnertz by the absence of discal bristles on the mesoscutum (F), ovate clypeus (E) and distinctive features of the male terminalia such as the bud-like hypandrial lobe (B) (Chandler 1978, Kjærandsen & Chandler 2006). Staeger (1840) described the first species of Pseudexechia as Mycetophila trivittata Staeger, 1840. Zetterstedt (1852) then described a pale form of M. trivittata, later illustrated by Lundström (1909) and now known as Pseudexechia aurivernica Chandler, 1978 (Chandler 1978, Kjærandsen 2005).

Tuomikoski (1966) included seven species in Pseudexechia, six European, one North American and one Afrotropical. He designated Exechia trisignata Edwards, 1913, described from Scotland, as the type species and noted that he had seen several undescribed species from Europe and Asia in the collections at the Zoological Museum, University of Helsinki, Finland. At present 26 species are associated to Pseudexechia (•): 16 are known from the Holarctic region (Tuomikoski 1966, Chandler 1978, Ostroverkhova 1979, Zaitzev 1982, Zaitzev 1988, Ostroverkhova & Stackelberg 1988, Chandler & Blasco-Zumeta 2001, Zaitzev 2003, Kjærandsen & Chandler 2006, Kjærandsen et al. 2007, Kjærandsen 2009), 3 are known from the Oriental region (Kjærandsen 1994, Kallweit & Martens 1995, Wu & Yang 2003) and 7 are known from the Afrotropical region (Matile 1971, Kjærandsen 1994). However, several further species from the Afrotropical, the Oriental and the eastern Palaearctic regions await description and a few that are described in other genera probably belong to Pseudexechia.

Little is known about larval habitats of Pseudexechia. P. trisignata s. l. has been reared from soft gill fungi like Naucoria sp. and Galerina sp. (Chandler 1993) and Psathyrella piluliformis (Sasakawa & Ishizaki 1999). P. tristriata has been reared from Thelephora terrestris (Yakovlev 1994). P. trivittata has been reared from fruiting bodies of coprophilous agarics like Coprinus, Psathyrella and Panaeolus (Jakovlev et al. 2008). Kjærandsen (2009) mainly reported Pseudexechia collected with aspirator in caves in wintertime (55%) (see Kjærandsen 1993), with window traps (29%) or with sweep net (10%). It is noteworthy that although large Malaise trap collections have been examined in search of Pseudexechia, only about 1% of the examined material originates from Malaise trap collections. This under-representation in Malaise trap collections seems to hold for several of the Exechiini genera, and might be explained by a general negative phototaxis for many members of the tribe.

Key to European males of Pseudexechia

1 Terminalia large, stout (Fig. 6A); dorsal branch of the gonostylus with a characteristically smooth whitish apex; ventral branch forming a thin plate shaped more or less like a spatula (Fig. 6B); hypandrial lobe heavily sclerotized, bud-like by elaborate folding, triangular to subrectangular (Fig 6A) …… 2

- Terminalia more slender (Fig. 14A), with elongated dorsal and ventral branches of the gonostylus (Fig. 14B); hypandrial lobe narrow rectangular, forming parallel branches medially (Fig. 14A) …… trivittata-group 8

2 Median ocellus small, but distinctly present (Fig. 4A); vein R₄₊₅ distinctly downcurved (C > D see A); hypandrial lobe stout, subrectangular (Fig. 6A) …… trisignata-group 3

- Median ocellus absent or at most tiny and vestigial; vein R₄₊₅ almost straight (C ≤ D see D); hypandrial lobe conic, triangular (Fig. 9A) or enlarged and diverging apically (Fig. 11D) …… canalicula-group 5

3 A dull brown species with a distinct greyish dusting (A); hypandrial lobe with rounded corners (Fig. 6A); ventral branch of gonostylus with angular basodorsal corner making the spatula broadest basally (Fig. 6B); smooth whitish tip of dorsal branch of gonostylus evenly thick (Fig. 6B) …… Pseudexechia trisignata

- Moderately to distinctly bi-coloured species without greyish dusting; hypandrial lobe sharply pointed apically (Fig. 7A); ventral branch of gonostylus without angular basodorsal corner; smooth whitish tip of dorsal branch of gonostylus slightly dilated or constricted … 4

4 Broad pale band along whole margin mesonotum; ventral branch of gonostylus forming small, symmetric and round spatula (Fig. 7B); smooth whitish tip of dorsal branch of gonostylus slightly constricted (Fig. 7B) …… Pseudexechia pectinacea

- Without or at most narrow pale band along margin of mesonotum; ventral branch of gonostylus forming large, asymmetric spatula that is broadest apically (Fig. 8B); smooth whitish tip of dorsal branch of gonostylus slightly dilated (Fig. 8B) …… Pseudexechia tuomikoskii

5 Larger species, distinctly bi-coloured in dark greyish brown and yellow, with sharply defined mesonotal stripes (B) …… 6

- Smaller species, weakly bi-coloured to dull brown, with indistinct or fused mesonotal stripes …… 7

6 Gonostylus large, exposed (Fig. 9A); dorsal lobe distinctly dilated apically (Fig. 9B); ventral lobe forming large, slightly asymmetrical spatula (Fig. 9B) …… Pseudexechia canalicula

- Gonostylus small, retracted (Fig. 10A); dorsal lobe not dilated apically (Fig. 10B); ventral lobe forming narrow, angular boot-shaped spatula (Fig. 10B) …… Pseudexechia aurivernica

7 Hypandrial lobe enlarged, diverging apically (fig. 11A&D); dorsal lobe of gonostylus apically strongly dilated, campanulate (Fig. 11B); dorsointernal branch small (Fig. 11B); ventral branch narrow, angular boot-shaped (Fig. 11B) …… Pseudexechia monica

- Hypandrial lobe not enlarged, conic triangular (Fig. 12A); dorsal lobe of gonostylus apically dilated, but not campanulate (Fig. 12B); dorsointernal branch large (Fig. 12B); ventral branch forming medium sized spatula with acute angled apicodorsal corner (Fig. 12B) …… Pseudexechia parallela

8 Dorsal branch of gonostylus subrectangular, with sharply truncated, whitish tip (Fig 13A&B); dorsointernal branch forming narrow, elongated lamellate fan (Fig. 13B); hypoproct reduced, hyaline (Fig. 13C) …… Pseudexechia latevittata

- Dorsal branch of gonostylus oblong to lanceolate, without sharply truncated, whitish tip (Fig. 14A&B); dorsointernal branch reduced to hyaline knob basally on dorsal branch (Fig. 14B); hypoproct sclerotized, pointed (Fig. 14C) …… 9

9 A distinctly bi-coloured species in dark greyish brown and yellow, with sharply defined thoracic stripes and triangular pale bands on abdominal tergites; dorsal branch of gonostylus shorter and smaller than ventral branch which has medial surface covered with setae and no brush apically (Fig. 14B) …… Pseudexechia tristriata

- A dull brown species with fused, hardly discernible thoracic stripes and indistinct, narrow (if any) pale bands on abdominal tergites; dorsal branch of gonostylus longer than ventral branch which has medial surface devoid of setae but a narrow brush of strong setae apically (Fig. 15B) …… Pseudexechia trivittata

Key to European females of Pseudexechia (female of Pseudexechia monica is unknown)

1 Cercus two segmented (e.g. •) …… 2

- Cercus one-segmented (e.g. Fig 6D) …… 3

2 Tergite VII prolonged dorsally, with smooth, straight posterior edge; postgenital plate stout (Fig. 9D) …… Pseudexechia canalicula

- Tergite VII emarginated dorsally and smoothly convex laterally; postgenital plate with a more tapered apex (Fig. 12D) …… Pseudexechia parallela

3 Tergite VII with strongly dentate to laciniate posterior edge, widely excavated dorsally (Fig. 10D) …… Pseudexechia aurivernica

- Tergite VII with smooth or at most weakly dentate posterior edge …… 3

3 Apicolateral corner of tergite VII with nude area, cercus and postgenital plate in lateral view slender and pointed (Fig. 8D) …… trisignata-group 4

- Tergite VII evenly covered with setae; cercus and especially postgenital plate in lateral view broader and less stretched …… trivittata-group 6

4 A dull brown species with a distinct greyish dusting, usually without distinct pale bands on abdominal tergites; tergite VII widely but shallowly excavated dorsally, with rounded, weakly crenulated posterior edge; seta along apical margin long, slender (Fig. 6D) …… Pseudexechia trisignata

- Moderately to distinctly bi-coloured species in dark greyish brown and yellow, with a pale band along lateral side of mesonotum and distinct triangular pale bands on abdominal tergites; tergite VII not excavated dorsally, with almost straight and smooth posterior edge; seta along apical edge long, slender or short, stout …… 5

5 Seta along apical margin of tergite VII long, slender; sternite VIII with rounded apex (Fig. 7D) …… Pseudexechia pectinacea

- Seta along apical margin of tergite VII short, stout; sternite VIII subsquare, with truncated apex (Fig. 8D) …… Pseudexechia tuomikoskii

6 Tergite VII with distinctly pointed margin laterally; sternite VIII with pointed apex …… 7

- Tergite VII with smoothly rounded margin laterally; sternite VIII with truncated apex, appearing almost rectangular in lateral view (Fig. 13D) …… Pseudexechia latevittata

7 A dull brown species with fused, hardly discernible thoracic stripes and indistinct, usually narrow pale bands on abdominal tergites (Fig. 15D) …… Pseudexechia trivittata

- A distinctly bi-coloured species in dark greyish brown and yellow, with distinct, sharply defined thoracic stripes and broad, triangular pale bands on abdominal tergites (Fig. 14D) …… Pseudexechia tristriata

Adults:

Head: Antenna (B&C) with 14 flagellomeres; scape and pedicel with a few close set stout bristles ventromedially and dorsally, otherwise with scattered small setae apically; flagellars long rectangular, densely covered with medium sized pale, decumbent setae, some short stiff setae along ventral side; scape, pedicel and half of first flagellar pale, rest of flagellum darker. Vertex with five strong orbital bristles, otherwise covered with medium sized, decumbent dark setae. Ocelli (A) three or two, lateral ocellus touching eye margin, median ocellus either small but distinct or vestigial but usually traceable. Frontal furrow reduced, not reaching frontal tubercle. Face (E) wide rectangular, with scattered small setae. Clypeus (E) long ovate to subcircular, covered with small setae. Palp (A&D) with four distinct palpomeres; sensory pit in third palpomere forming an ovate open furrow medially, with trichoid sensillae in internal sac; fifth palpomere as long as or longer than third and fourth palpomere combined.

Thorax (F). Proepisternum with 1–2 and antepronotum with 3 strong bristles. Scutum without distinct acrostichals and dorsocentrals, with strong prealar and postalar and sometimes with one pair of posteriorly situated bristles, otherwise covered with small to medium sized setae; with or without dark thoracic stripes on pale ground and pale band along lateral margin. Scutellum with one strong and one weaker pair of bristles otherwise covered with small setae. Anepisternum, anepimeron and preepisternum completely devoid of setae. Laterotergite scattered with tiny, thin setae and some large bristles. Mediotergite bare or at most with a couple of setae. Metepisternum posteriorly with a few bristles and some tiny setae. Metepimeron with some scattered tiny setae.

Wings (•). Wing membrane unspotted yellowish tinted or with faintly smoked apical half and faint cloud around branching of media; with microtrichia only, trichia dark and arranged into regular rows apically. Basicosta with 1–2 strong bristles. Crossvein h without setae. Distal medial plate without setae both on dorsal and ventral side. Costa, R, R₁and R₅ with both dorsal and ventral setae. Sc, tb, ta, M, CuA, CuP, A₁ and A₂ without setae. Costa terminates at tip of R₅. R₄ absent. R₅ straight to moderately curved posteriorly. Crossvein ta with small white spot. M-fork long, M-petiole subequal in length to crossvein ta (0.87–1.56, 1.16, n=65). CuA-fork shorter, starts (with one exception, see Kjærandsen 1994) distinctly beyond M-fork. CuP long and basally strong, fading out about at level of CuA branching. A₁shorter, distinct and strong, breaking abruptly well before CuA-fork. A₂ distinct, fading out about at level of A₁.

Legs (F&G-J). Setosity dark. Fore coxa covered with small setae on anterior and lateral surface, anteriorly and apically with strong bristles. Mid coxa with narrow row of small setae anteriorly; bare basolaterally, apical third with narrow row of small setae laterally; apically with larger setae and some bristles. Hind coxa with one strong bristle basolaterally; with narrow row of small setae along posterolateral surface; apically with larger setae and some bristles. Femora uniformly covered with small setae. Tibiae with trichia in regular rows. Fore tibia with short anteroventral and posterior bristles, anteroapically with round depressed area, covered with trichia. Mid tibia with row of small, close set anterior bristles and a few posterior and posterodorsal bristles. Hind tibia with a few large anterior bristles; some large posterodorsal bristles; several small, close-set bristles in one row posterodorsally; tibial comb consisting of triangular area densely covered with long microtrichia posteroapical and complete transverse of setae along apical margin (J). Fore tarsus without distinct spine-like setae ventrally. Empodia (H) rudimentary, thread like.

Abdomen (•). Pale abdominal markings present along posterior margin of tergites; more or less extended anteriorly to form larger triangular or complete pale areas laterally. Preterminal segments often darker than rest of abdomen.

Male terminalia (•). Tergite IX medium sized, wide to long rectangular, more or less divided mesally, usually with sclerotized mesal suture; scattered with setae that get larger towards apicolateral corners, without any outstanding strong setae. Cercus small ovate knob; scattered with small, thin setae. Gonocoxite (B) large, moderately to deeply incised ventrally in which a usually bud-shaped, strongly sclerotized hypandrial lobe is situated; apically divided into an outer wall (section II) and a medioventral, inner wall (section III). Epiproct (B) pointed triangular, very hyaline, without setae. Hypoproct (B, 6C) usually forming long tapered posterior process, straight or downcurved. Lateral margin of tergite X forming slender, setose lobe (“pseudocercus”); clearly articulated against rest of segment; of variable length. Aedeagus (B) elongated, hyaline, tapered apically, well retracted within gonocoxite, basally jointed with strong gonocoxal apodemes. Aedeagal guides (B, 6A) large, hyaline lobes; rectangular or elongated; situated dorsolaterad of hypandrial lobe. Hypandrial lobe (Fig. 5B) well developed, usually bud-shaped, of medium size and strongly sclerotized; its angle in relation to gonocoxite variable, usually exposed and aligned with gonocoxite, sometimes retracted into gonocoxite and produced interodorsad; basolaterally with patch of placoid sensillae; with a small split apicomedially. Gonostylus divided into six branches (A). Dorsal branch short with smooth whitish rounded tip or moderately to extremely elongated; without blunt lamellae; lateral surface always covered with strong setae. Dorsointernal branch usually present as a fan-shaped outgrowth of the ventrointernal margin of the dorsal branch; with row of small, blunt lamellae along entire internal margin; without setae, sometimes reduced to bifurcated or small bare knob (Fig. 14B). Medial branch reduced, present as small to large knob, with a few setae. Ventral branch large, usually shaped as a thin spatulate plate, sometimes elongated, lanceolate; typically with a few characteristically fan-tipped setae ventrolaterally and some strong setae apicomedially. Anterior branch forming ventrally directed, subrectangular to triangular cushion; without setae, sometimes with numerous small, blunt projections caudally (Fig. 14B). Internal branch forming medium sized, bulbous, largely striated pouch; posteriorly with a few setae, sometimes with a small, digitate lobe (Fig. 14B).

Female terminalia (•). Usually partly retracted within tergite VII. Tergite VIII well developed, subrectangular, devoid of setae. Sternite VIII large; ventrally scattered with small setae; fused with a well-developed, apically truncated or pointed gonocoxite VIII, bearing several strong setae along apical margin. Gonapophysis VIII present as hyaline tapered protrusion, usually extending beyond apex of gonocoxite VIII, without setae. Labia not discernible, or fused basally with gonapophysis VIII. Tergite IX well developed and partly fused with gonocoxite IX, without setae. Spermathecal duct ending in constricted, sclerotized eminence. Tergite X reduced or fused with epiproct. Sternite X apparently fused basally with gonapophysis IX; forming a stout, sclerotized, elongated postgenital plate; apically covered with small setae. Cercus one- or two-segmented, scattered with small setae; elongated to moderately truncate; apical segment when present short, ovate.

Larva unknown.

Adults: Medium sized to small, slender with long legs and long abdomen (Fig. 2), body length 3.5–6.5 mm.

Tuomikoski (1966) considered Pseudexechia to be more related to Allodiopsis and Allodia than to Exechia and Exechiopsis. In phylogenetic analyses based on morphological characters Rindal & Søli (2006) placed Pseudexechia as sister taxon to Tarnania, whereas Kjærandsen (2006) in a review of Tarnania and the Rymosia genus group, did not include Pseudexechia but found Rymosia and Pseudorymosia to be close relatives of Tarnania. The genus Pseudexechia was not included in the molecular studies presented so far, and it has shown difficult to get support for a rigid classification of the tribe Exechiini based on molecular data (Rindal et al. 2007, Rindal et al. 2009). Species of Pseudexechia show intrageneric variation in several characters that usually are constant (though not universally) on generic level in the Exechiini, such as presence/absence of the median ocellus, Cu-fork usually branching beyond, but sometimes before the M-fork (see Kjærandsen 1994), and female cercus being one- or two-segmented. The placement of Pseudexechia in relation to other genera of the tribe Exechiini is thus an intriguing and unsettled issue, and homology assessments of structures in their terminalia will hopefully add character systems aiding to solve intergeneric relationships within the tribe. A preliminary first step to organize characters from the terminalia within the entire Exechiini into a transformational framework is in progress but still pending better character definitions to form basis for a phylogenetic analysis. Kjærandsen (2009) restricted the classification to present four tentatively defined species groups for the World species of Pseudexechia (•). The step forward will be to try to condense informative transformational signals from the preliminary analysis into fewer, more complex and independently evolving character systems (sensu Wheeler 2008), that hopefully, and with the aid of new molecular data (see Scotland et al. 2003), will bring new insights into the evolutionary history of the Exechiini.