Merodon bequaerti Hurkmans, 1993

Vujic, Ante, Likov, Laura, Radenkovic, Snezana, Tubic, Natasa Kocis, Djan, Mihajla, Sebic, Anja, Perez-Banon, Celeste, Barkalov, Anatolij, Hayat, Ruestem, Rojo, Santos, Andric, Andrijana & Stahls, Gunilla, 2020, Revision of the Merodon serrulatus group (Diptera, Syrphidae), ZooKeys 909, pp. 79-158 : 79

Merodon bequaerti Hurkmans, 1993 Figs 8A, B , 9A-C, J , 10A, B , 11A-C

Diagnosis.

Large (8-11.9 mm), dark brown species with pairs of narrow microtrichose fasciae on terga 2-4 in males, in some specimens absent; metafemur with long pile on ventral margin; the longest pile as long as one third to half of width of metafemur (Fig. 8 ); apical part of anterior surstyle lobe rhomboid shape, covered with dense, short pile, and strong dark brown marginal pile on posterior surstyle lobe (Fig. 9A : al, J); females with very narrow microtrichose fasciae on terga 2-4 and sparse pilosity on ventral margin of metafemur, only with few longer pile. Similar to Merodon sacki but differs in a less curved metafemur and generally shorter body pile in males, clearly visible on tergum 4 (Fig. 10 ), and by well separated anterior and posterior surstyle lobe (Fig. 9A ), almost fused in M. sacki (Fig. 9D ). Related to M. sophron , but differs in more incrassate metafemur (Fig. 8A, D ), longer pile on ventral margin of metafemur in both sexes (Fig. 8 ), and presence of dense, dark brown marginal pile on apical part of anterior surstyle lobe (Fig. 9A, J ), less dense and light yellow in M. sophron (Fig. 9G, K ).

Redescription

(based on the type material and additional specimens). Male. Head. Antennae black to dark brown; basoflagellomere 1.7-2.1 times as long as wide, and 2.3 times as long as pedicel, concave dorsally with acute apex; fossette dorsolateral (Fig. 11 ); arista dark and thickened at basal one third, covered with dense microtrichia; arista 1.4-1.7 times as long as basoflagellomere (Fig. 11A, B ); face and frons black with gray microtrichia, face covered with dense whitish gray, and frons with yellowish gray pile; oral margin shiny with microtrichose lateral areas; lunule shiny black, bare; eye contiguity 10-12 facets long; vertex isosceles, shiny covered with golden microtrichia in front of ocellar triangle; vertex with long, pale whitish yellow pile mixed with black pile on the ocellar triangle; ocellar triangle equilateral; occiput shiny, with gray-yellow pile, covered with a dense, gray microtrichia in ventral half; eyes covered with dense pile.

Thorax. Scutum and scutellum black with bronze luster, covered with dense, erect, yellow pile; scutum at wing basis with short black pile, in some specimens with fascia of black pile between wing basis; scutum with two or more microtrichose vittae, anteriorly connected and posteriorly reaching the scutellum; posterodorsal part of anterior anepisternum, posterior anepisternum (except anteroventral angle), anterior anepimeron, dorsomedial anepimeron, and posterodorsal and anteroventral parts of katepisternum with long, pale yellow pile and grayish microtrichia; wings entirely covered with microtrichia; wing veins brown; calypteres and halteres pale yellow; legs without spinae or other protuberances; legs mostly black, except brown tarsi ventrally in some specimens; pile on legs pale yellow, except black pile at apical one fourth of metafemur; metafemur curved and incrassate, ca. three times longer than wide; pile on postero- and anteroventral surface long, and ca. one third to half of width of metafemur, slightly longer than pile on dorsal margin (Fig. 8A ).

Abdomen. Wide, tapering, 1.2 times longer than mesonotum; terga dark brown to black, with or without pairs of narrow microtrichose fasciae; tergum 2 with orange lateral maculae; pile on terga all yellow, except few black pile on medial part of terga 3 and 4 in some specimens (Fig. 10A, B ); sterna dark brown, covered with long whitish/yellow pile.

Male genitalia. Apical part of anterior surstyle lobe rhomboid shape, 1.5 times longer than wide, covered with dense, short pile, and strong dark brown marginal pile (Fig. 9A : al, J); posterior surstyle lobe oval (Fig. 9A : pl) with basolateral protrusion (lateral hump) (Fig. 9A, B : bp); hypandrium sickle-shaped, without lateral projections; lingula small (Fig. 9C : l).

Female. Similar to the male except for normal sexual dimorphism and for the following characteristics: antennae with rounded tip, basoflagellomere 1.7-1.9 times longer than wide (Fig. 11C ); frons with microtrichose vittae along eye margins; frons covered with pilosity of variable color, from mostly gray-yellow until predominantly black; ocellar triangle covered with black pile; ventral margin of metafemur with sparse pilosity, only few pile longer (Fig. 8B ); lateral side of terga, anterior two third of tergum 2 and all tergum 5 with yellow pile; terga 2-4 with short adpressed black pile and with very narrow microtrichose fascia.

Distribution.

Merodon bequaerti is distributed in north-western Africa (Algeria, Libya, Morocco, and Tunisia) (Fig. 7 ).

Ecology.

Preferred environment: unimproved montane grassland, including open, grassy areas in pine forest or Mediterranean scrub. Flowers visited: no data. Flight period: February-June.

Type material.

Holotype [original designation by Hurkmans (1993: 194)]: male. Original label: " Merodon bequaerti / spec. nov. HOLOTYPE / ♂. W. Hurkmans 1988." [red label handwritten], " Merodon / parietum / Mg ♂" [label handwritten], "Noiseux Oran / Algeria / Dr. J. Bequaert" “23-IV-l0” [handwritten on the back side] (MNHN) (See Supplementary file 1: Figure 1A ). Paratype: female. Same label data as holotype (MNHN) (studied).

Other material.

Algeria • 1 ♂; Kabylie, Tikjda; 36°27'00"N, 4°07'60"E; 28 Jun. 1954; NBCN • 1 ♂; Jijel, Oued el Kebir; 36°35'22"N, 6°16'16"E; 20 May 1981; NBCN • 1 ♂; Jijel, Foce Oued El Kebir; 36°35'45"N, 6°15'29"E; 20 May 1981; I. Aslan leg.; NBCN 05636 • 1 ♀; El Kseur, Akfadou; 36°37'60"N, 4°36'00"E; 22-23 May 1981; NBCN 04079.

Libya • 1 ♀; Tripolitania, Garian; 32°10'46"N, 13°01'53"E; "2.500 feet" [760 m a.s.l.]; 22 Feb. 1954; K. M. Guichard leg.; NHMUK 04353.

Morocco • 1 ♂; Moyen Atlas, Azrou; 33°25'48"N, 5°12'36"W; 15 Jun. 1928; R. Benoist leg.; MNHN 22623 • 8 ♂♂; Mountain de Beni-Snassen 2; 34°48'43"N, 2°24'08"W; 29 Apr. 2013; A. Vujić, S. Radenković leg.; FSUNS Đ 13, Đ 14, Đ 16 to Đ 21.

Tunisia • 1 ♂; Jundubah, 40 km W from Jendouba; 36°31'54"N, 8°28'25"E; 17 May 1988; ZMUC 02497 • 1 ♂; same data as for preceding; 36°34'33"N, 9°02'12"E; ZMUC 02498.

Figures

Figure 1. Merodon serrulatus male genitalia. A Epandrium, lateral view B Epandrium, ventral view C, D Posterior surstyle lobe, lateral view E Hypandrium, lateral view F Part of hypandrium, ventral view G Aedeagus, lateral view. Abbreviations: al-anterior surstyle lobe, bp-basolateral protrusion, c-cercus, l-lingula, pl-posterior surstyle lobe, s-lateral sclerite of aedeagus. Scale bar: 0.2 mm.

Figure 7. Distribution map of Merodon serrulatus species group.

Figure 8. Metaleg, lateral view. A Merodon bequaerti, male B Merodon bequaerti, female C Merodon sacki, male D Merodon sophron, male. Scale bar: 2 mm.

Figure 9. Male genitalia. A Merodon bequaerti, epandrium, lateral view B Merodon bequaerti, epandrium, ventral view C Merodon bequaerti, hypandrium, lateral view D Merodon sacki, epandrium, lateral view E Merodon sacki, epandrium, ventral view F Merodon sacki, hypandrium, lateral view G Merodon sophron, epandrium, lateral view H Merodon sophron, epandrium, ventral view I Merodon sophron, hypandrium, lateral view J Merodon bequaerti, anterior surstyle lobe, lateral view K Merodon sophron, anterior surstyle lobe, lateral view. Abbreviations: al-anterior surstyle lobe, bp-basolateral protrusion, l-lingula, pl-posterior surstyle lobe. Scale bar: 0.2 mm.

Figure 10. Abdomen of males. A Merodon bequaerti, dorsal view B Merodon bequaerti, lateral view C Merodon sacki, dorsal view D Merodon sacki, lateral view. Scale bar: 2 mm.

Figure 11. Antenna. A Merodon bequaerti, outer side, lateral view, male B Merodon bequaerti, inner side, lateral view, male C Merodon bequaerti, outer side, lateral view, female D Merodon sacki, outer side, lateral view, male E Merodon sacki, inner side, lateral view, male F Merodon sacki, dorsal view, male G Merodon sophron, outer side, lateral view, male H Merodon sophron, inner side, lateral view, male I Merodon sophron, outer side, lateral view, female. Scale bar: 1 mm.