Cheilosia morio ( Zetterstedt, 1838 )

Bot, Sander, Ståhls, Gunilla, Bygebjerg, Rune, Doczkal, Dieter & Vujić, Ante, 2025, Revision of the European species of the subgenus Neocheilosia Barkalov (Diptera, Syrphidae: Cheilosia), European Journal of Taxonomy 997, pp. 1-27 : 15-21

Cheilosia morio ( Zetterstedt, 1838)

Figs 3–4 , 5B, E, G

Eristalis morio Zetterstedt, 1838: 612 . Type locality: “in Lapponia septentrionali … ad Juckasjervi Lapponia Tornenesis … Lapponia” [ Sweden] (holotype, ♂, MZLU, Fig. 4 , examined by Claussen).

Chilosia scanica Ringdahl, 1937: 27 . Type locality: “Söderåsen” [ Sweden] (holotype, ♂, MZLU, Fig. 4 , examined by Claussen). The holotype is in good condition. Identity: a junior synonym of C. morio ( Zetterstedt, 1838) . Syn. nov.

Cheilosia scanica – Bańkowska 1963: 114. — Stackelberg 1970. — van der Goot 1981: 162. — Violovitsh 1983: 78. — Mazánek 2006: 83. — Heimburg et al. 2022: 169 .

Cheilosia morio – Kassebeer 1993: 89. — Dziock 1997: 134. — Mutin & Barkalov 1999: 422 (in part). — Veen 2004: 61 (in part). — Haarto & Kerppola 2007: 254 (in part). — Nilsson et al. 2012: 148. — Bot & Van de Meutter 2023: 48, 227.

Cheilosia “ morio B” – Bartsch et al. 2009: 55, 106. — van Steenis 2011: 188.

Material examined

FINLAND – Åland • 1 ♂; Jomala; 60.158572° N, 19.829543° E; 10 May 2005; Milankov and Ståhls leg.; http://id.luomus.fi/ GJ.6062 ; MZH. – Etelä Häme • 1 ♂; Somero ; 60.63° N, 23.46° E; 19 May 1962; Nurminen leg.; http://id.luomus.fi/ GV.93934 ; MZH • 1 ♀; same data as for preceding; http://id.luomus.fi/ GV.93933 ; MZH • 1 ♂; Urjala; 61.08° N, 23.49° E; 28 Apr. 1964; Brander leg.; http://id.luomus.fi/ GV.93931 ; MZH • 1 ♀; Forssa; 60.85° N, 23.62° E; 14 May 1964; Käpylä leg.; http://id.luomus.fi/ GV.93945 ; MZH • 1 ♂; Urjala ; 61.08° N, 23.49° E; 30 April 1965; Brander leg.; http://id.luomus.fi/ GV.93943 ; MZH . – Etelä-Savo • 1 ♂; Savonlinna; 61.781651° N, 29.36578° E; 29 May 1936; http://id.luomus.fi/ GV.21422 ; MZH . – Ladoga Karelia • 3 ♂♂; Rautjärvi; 61.41° N, 29.39° E; 15 May 1944; Tiensuu leg.; http://id.luomus.fi/ GV.93930 , http://id.luomus.fi/ GV.93938 , http://id.luomus.fi/ GV.93941 ; MZH . – South Karelia • 1 ♀; Summajoki, Pitkäkoski ; 60.67577° N, 27.079224° E; 10 May 1964; Tiensuu leg.; http://id.luomus.fi/ GV.93936 ; MZH • 1 ♂; Hamina, Leluntie ; 60.558704°N, 27.33415°E; 10 May1970; Tiensuu leg.;http://id.luomus.fi/ GV.93929 ; MZH • 1♂; Hamina Kitula, Tupenmäki ; 60.734° N, 27.211° E; 11 May 1976; Tiensuu leg.; http://id.luomus.fi/ GV.93940 ; MZH . – Uusimaa • 1 ♂; Helsinki; 60.191° N, 24.875° E; Johansson leg.; http://id.luomus.fi/ GV.93935 ; MZH • 1 ♂; Hanko, Tvärminne ; 59.843° N, 23.206° E; Häyren leg.; http://id.luomus.fi/ GV.93932 ; MZH • 1 ♂; Vantaa; 60.27° N, 24.96° E; 1–31 May 1905; Frey leg.; http://id.luomus.fi/ GV.93946 ; MZH • 1 ♀; Vantaa ; 60.27° N, 24.96° E; 1920; Wegelius leg.; http://id.luomus.fi/ GV.93937 ; MZH • 1 ♀; Helsinki; 12 May 1945; Nuorteva, Matti leg.; http://id.luomus.fi/ GV.93942 ; MZH • 1 ♀; Mäntsälä, Sahajärvi ; 60.7159° N, 25.4429° E; 10 May 2005; Ståhls leg.; http://id.luomus.fi/ GJ.6063 ; MZH • 1 ♂ *; Sipoo, Hindsby ; 60.3508° N, 25.2001° E; 18 May 2022; Neuvonen leg.; http://id.luomus.fi/ GJ.6271 ; MZH • 1 ♀ *; same data as for preceding; http://id.luomus.fi/ GJ.6270 ; MZH . – Varsinais-Suomi • 1 ♀; Salo, Eriksberg ; 60.374° E, 23.296° N; von Bonsdorff leg.; http://id.luomus.fi/ GV.93939 ; MZH • 1 ♂; Lieto; 60.54° N, 22.5° E; Niemelä leg.; http://id.luomus.fi/ GV.93944 ; MZH • 1 ♀; Salo ; 60.189835° N, 22.876551° E; 16 May 1944; Hellman leg.; http://id.luomus.fi/ GV.21348 ; MZH • 1 ♀; Salo ; 60.189835° N, 22.876551° E; 17 May 1944; Hellman leg.; http://id.luomus.fi/ GV.21349 ; MZH .

GERMANY – Baden-Württemberg • 1 ♂; Schwarzwald, Zastler Hütte ; 1256 m a.s.l.; 15 May 1992; Stuke leg.; CNC Diptera 101714 . – Lower Saxony • 1 ♂; Lopautal; 12 Apr. 1991; Kassebeer leg.; CNC Diptera 101817 .

ITALY – Val Pusteria • 1 ♀; Monguelfo, Rienzi ; 1000 m a.s.l.; 14 May 1985; Verlinden leg. ; • 1 ♀; same data as for preceding; 16 May 1985. Most of Verlindens collection is destroyed now by Anthrenus museorum (Linnaeus, 1761) and not accessible anymore .

SWEDEN – Småland • 1 ♂ *; Stenbrohult; 26 Apr. 2010; Nilsson leg.; MZH . – Uppland • 1 ♀; Uppsala, Dalkarlskärret ; 1 May 1997; J. van Steenis leg.; JSB • 1 ♀; Halstavik, Pansarudden ; 8 May 1997; J. van Steenis leg.; JSB • 1 ♀; Uppsala, Kodöden ; 11 May 1997; J. van Steenis leg.; JSB • 1 ♀; Uppsala, Nåsten ; 9 May 2002; J. van Steenis leg.; JSB .

Specimens used for molecular analysis are indicated with an asterisk (*) and listed in Table 2 .

Description

Male

LENGTH. Body 7.5–9.5 mm, wing 6–8.1 mm.

HEAD. Eye with brownish hairs. Anterior eye angle 120°–130°. Frons swollen, with median furrow running over entire length, obscured by faint pruinosity, with long, erect black hairs. Ocellar triangle equilateral, with long black hairs. Gena wide, viewed obliquely from below about as wide as 3/5 length of protibia. Face wide, ratio of width of face at level of facial tubercle to maximum width of head = 0.60–0.66: 1; face slightly shining, obscured by faint pruinosity and a narrow streak of pruinosity just below antennal insertion. Sides of face with long black hairs, spreading from level of antennal insertion towards level of facial tubercle. Parafacia narrow, fully developed only lateral to facial tubercle, about as wide as one third width of 3 rd antennal segment, above posterior tentorial pit strongly compressed toward eye margin by a haired bulge. Antennal pits separated. Lunule dark-brown to black.Antenna with scape and pedicel usually black, pedicel reddish to varying extents in individual specimens. 3 rd antennal segment sub-circular, usually velvet-black, but partly or entirely reddish in some specimens. Arista usually black, but occasionally more or less reddish in correspondence with colour of basoflagellomere; hairs on arista much shorter than maximum thickness of arista.

THORAX. Scutum faintly brownish pruinose, anteriorly with a pair of contrasting sub-median pale pruinose vittae, best visible if viewed from behind; in well preserved specimens two less distinct lateral vittae perceptible; occasionally scutal vittae more or less confluent, displaying a joined pruinose area; hairs long black, erect, of about even length. Colour and hairs of scutellum similar to those of scutum, without distinct marginal setae, but occasionally with some marginal hairs slightly stronger than on disc. Sub-scutellar fringe black and long. Pleurae with long black hairs on posterior anepisternum, anepimeron and on katepisternum, dorsal and ventral katepisternal hair patches confluent. Metasternum haired.

WING. Membrane entirely microtrichose, more or less brownish tinged, especially so in anterior half; veins dark, basal half of RS usually with a few dark setulae. Calypter brownish-grey to blackish, with dark rim; marginal fringe on dorsal lobe partly with black setae. Haltere with stem brownish and black knob.

LEGS. Pro- and metalegs usually black, mesotibia often reddish basally, but sometimes up to basal one third and extreme apices of all tibiae, and apices of femora may be more or less reddish-yellow to brownish in individual specimens. Femora with black to brownish hairs, occasionally intermixed with a few paler hairs, especially so posteriorly on metafemur; ventral surface of metafemur with black setae on basal two thirds, but without setae apically. Tibiae covered in short, dark reddish-brown and black hairs, but hairs on anterior surface of protibia entirely and densely reddish brown. Tarsi with hairs on dorsal surface short black or mixed black and reddish-brown, hairs on ventral surface of pro- and metatarsi usually reddish-brown, but often intermixed with black hairs. Tarsi of mesolegs ventrally with black setulae.

ABDOMEN. Tergite 4 and sides of tergites 1–3 slightly shiny, tergites 2–3 velvet-black on disc; pruinosity of tergites – viewed obliquely from front – dark brown; hairs of tergites long black, erect. Sternites moderately shining, faintly greyish-brown pruinose, with black hairs, hairs long and erect on sternites 1–2 and laterally on sternites 3–4, remaining hairs short, appressed or semi-appressed.

GENITALIA. Right and left surstylus and gonostyli slightly asymmetrical. Ventral margin of surstylus with a strong basal convexity; hypandrium in lateral view about as long as wide; sclerite of distiphallus broadly fused dorsally, with short dorsal lobes.

Female

LENGTH. Body 7–8 mm, wing 7–8 mm.

The ♀ differs from the ♂ in the following characters: hairs much shorter and predominantly pale yellowish-brown.

HEAD. Hairs of eyes obviously shorter than width of postpedicel. Frons exceptionally wide, at level of lunule about half as wide as maximum width of head, with a distinct transverse sulcus at level of about lower one third of frons and with remnant of a median furrow between lunule and transverse sulcus; transverse sulcus and median furrow faintly grey pruinose, frontal areas above and below transverse sulcus otherwise shining; lateral channels narrow, widening from inner dorsal corner of eye toward transverse sulcus, where inner margin of channel encloses a small semicircular area of dense grey pruinosity; hairs of frons erect, not longer than half width of 3 rd antennal segment, varying in colour from entirely yellow to entirely black. Occiput dorsally much wider than in male, faintly grey pruinose, with short yellow hairs, or with a mixture of yellow and black hairs. Gena with yellow hairs. Face at level of facial tubercle about 0.5 times as wide as maximum width of head; faintly grey pruinose, except for a narrow non-pruinose stripe, between dorsal margin of facial tubercle and upper margin of oral cavity, spreading toward lower corner of oral cavity. Facial hairs yellow, short, occasionally inconspicuous. Parafacia usually less strongly compressed above level of facial tubercle. 3 rd antennal segment larger, most often bright orange-coloured, or with a black apico-dorsal rim.

THORAX. Scutum and scutellum less densely pruinose, but with pair of pale pruinose sub-median vittae anterior on scutum distinct; hairs short, about as long as distance between rear ocelli, yellow, intermixed with scattered, somewhat longer black hairs. Scutellum usually with a few (2–4) black or yellow marginal setae, sub-scutellar fringe short and yellow. Pleurae with yellow hairs, pattern of hairs as in male. Calypter whitish-orange, with darker rim and yellow fringe. Haltere stem brownish, knob yellow.

LEGS. Legs black, but basal 1/3–2/5 of tibiae and often extreme apices of tibiae and femora reddish-yellow. Femora predominantly with yellow hairs, but apices anteriorly and dorsally with short appressed black hairs, posteriorly occasionally with a few longer, thin black setae. Ventral surface of metafemur basally without black setulae.

ABDOMEN. Tergites slightly shiny, especially tergites 2–3 much less pruinose on disc, hairs on tergites entirely yellow, short, erect. Sternites greyish pruinose to varying extents, from entirely pruinose to slightly shiny, with short yellow hairs; hairs erect on sternites 1–2 and on anterior corners of sternite 3, remaining hairs more or less appressed.

Distribution

Austria, Czech Republic, Finland, France, Germany, Greece, Italy, Montenegro, Norway, Poland, Russia, Slovakia, Sweden, Switzerland.

Distribution reported here for Austria, Finland, Norway and Switzerland were not reported before in the IUCN Red List assessment ( Vujić et al. 2021).

Differential diagnosis

In its overall appearance similar to Cheilosia luteicornis , with the following differences: Sides of face haired, ♂ with long black hairs, ♀ with yellowish hairs which are less conspicuous. Parafacia narrow, about 1/3 of the width of postpedicel. Face and frons slightly wider than in C. luteicornis . ♀ with hairs on scutum of about equal length, with only individual black hairs intermixed. ♂: face with a slight, but distinct haired bulge on each side, just dorsal to the facial prominence. Bases of pro- and metatibiae usually blackish or obscured reddish. Abdomen entirely black-haired. Calypter brownish-grey to blackish. Genitalia: surstylus with strong basal convexity; hypandrium about as long as wide.

Remarks

The holotype specimen bears labels with what could seem to be contradicting information on the locality, but there is no doubt that this specimen is the holotype collected in Lapland. The label mentioning E. lineata and Holmia is similar to other bottom-drawer labels used by Zetterstedt for species of which he had no material, and most likely this label was added to the specimen by Zetterstedt himself when he synonymized E. lineata with E. morio .

The type accords well with the original diagnosis and morphological description and with its subsequent additions ( Zetterstedt 1843: 795), but the description of the facial hairs does not: The face of the male is described as “hypostoma nudum [!], nitidum, atrum [face bare, shiny, black] and later ( Zetterstedt 1843: 795) as “epistomate bituberculate, nudo [!], nitido” [face bituberculate, bare, shiny black], by this giving the impression of a species with a face lacking hairs. Actually, the face of the holotype clearly has long, black hairs laterally below the antennal insertion, with individual hairs reaching the level of facial tubercle. As a consequence of this discrepancy between the description and the characters actually observed, C. morio was erroneously and almost consistently regarded as a species with a bare face throughout the central European literature. The nomenclatural consequences will be discussed below.

DNA barcoding

A total of 18 COI barcodes of 633 bp length representing four species of the subgenus Neocheilosia and additionally the barcodes of two species of the subgenus Convocheila ( Barkalov 2002) and one species of the subgenus Montanocheila Barkalov, 2002 were used for the NJ distance tree (for specimen data and GenBank accession numbers see Table 2 ). The NJ tree ( Fig. 6 ) consistently resolved the included male and female individuals of Cheilosia barovskii , C. luteicornis , C. morio and C. shiranesana in separate clusters, respectively. All the bootstrap values supporting the nodes of the species clusters were high (99–100%). The uncorrected interspecific pairwise distances among the included species of the subgenus Neocheilosia ranged from 2.96% (between C. luteicornis and C. morio ) to 7.57% (between C. barovskii and C. shiranesana ).

Figures

Fig. 3. Cheilosia morio (Zetterstedt, 1838). A. ♂ (JSB); habitus dorsal view; collected in Sweden; body length 9 mm. B. ♂ (CNC); head lateral view; collected in Germany; head height 2.7 mm. C. ♂ (CNC); head anterior view; collected in Germany; head height 2.7 mm. D. ♀ (JSB); head lateral view; collected in Sweden; head height 2.4 mm. E. ♀ (ZFMK); head anterior view; collected in Germany; head height 2.4 mm. Not to scale.

Fig. 4. Holotypes (MZLU).A–C. Cheilosia morio(Zetterstedt, 1838). A. Habitus dorsal view.B. Habitus lateral view. C. Labels. D–F. Cheilosia scanica Ringdahl, 1937 syn. nov. of C. morio. D. Habitus dorsal view. E. Habitus lateral view. F. Labels. Scale bars = 1 mm. (Photos by C. Fägerström, MZLU.)

Fig. 5. Cheilosia sp., male terminalia. A–E. Left superior lobe. A. C. luteicornis (Zetterstedt, 1838). B. C. morio (Zetterstedt, 1838). C. C. barovskii Stackelberg, 1930. D. C. luteicornis. E. C. morio. F–H. Aedeagus with apodeme. F. C. luteicornis. G. C. morio. H. C. barovskii. Scale bar = 0.2 mm.

Fig. 6. Neighbor-Joining tree based on COI barcodes and the K2P evolutionary model with nonparametric bootstrap values indicated on nodes (1000 replicates).