Revision of the Merodon serrulatus group (Diptera, Syrphidae) Author Vujic, Ante Author Likov, Laura Author Radenkovic, Snezana Author Tubic, Natasa Kocis Author Djan, Mihajla Author Sebic, Anja Author Perez-Banon, Celeste Author Barkalov, Anatolij Author Hayat, Ruestem Author Rojo, Santos Author Andric, Andrijana Author Stahls, Gunilla text ZooKeys 2020 909 79 158 http://dx.doi.org/10.3897/zookeys.909.46838 journal article http://dx.doi.org/10.3897/zookeys.909.46838 1313-2970-909-79 22B7FF16D0A240F9B20EF7C6E0AF1842 0AEF1785B8655964A36D859FBA7D8755 Merodon medium Vujic , Likov & Radenkovic sp. nov. Figs 6H , 19I, J , 22C, D , 24A, B , 25A-C Diagnosis. Large species (10.3-13 mm) with wide dark brown abdomen and yellow-orange maculae on lateral sides of tergum 2 (Fig. 24A, B ); basoflagellomere elongated, ca. 2.5 times longer than broad (Fig. 19 I, J ,); metafemur incrassate (Fig. 22C, D ); terga 2-4 with conspicuous microtrichose fasciae (Fig. 24A, B ). Similar to some populations of Merodon serrulatus , but clearly differs in shape of abdomen: relation between maximum width of tergum 2 and its medial length is 3.3 in male and 3.5 in female of M. medium sp. nov. compared with 2.3 in M. serrulatus male and 2.7 in female; male genitalia: anterior surstyle lobe with concave margin in M. medium sp. nov. (Fig. 6H : marked with arrow), convex in M. serrulatus (Fig. 6G : marked with arrow); apical microtrichose area of anterior surstyle lobe 2.5 times broader than long in M. medium sp. nov. (Fig. 6G : al), less than one time in M. serrulatus (Fig. 6G : al); molecular data and distribution ( M. medium sp. nov. is an endemic to the island of Crete in Greece). Figure 24. Merodon medium sp. nov., abdomen, dorsal view. A male B female. Scale bar: 2 mm. Description. Male. Head. Antennae black to dark brown; basoflagellomere elongated ca. 2.2 times as long as wide, and ca. 2.5 times as long as pedicel, concave dorsally with acute apex; dorsolateral fossette narrow; arista dark and thickened at basal one third, covered with dense microtrichia, ca. 1.5 times as long as basoflagellomere (Fig. 19I ); face and frons black with gray microtrichia, face covered with dense whitish gray, and frons with yellowish gray pile; oral margin microtrichose with shiny lateral areas; lunule shiny black, bare; vertex shiny black, except microtrichose area in front of anterior ocellus; vertex isosceles, with long, pale whitish yellow pile, mixed with few black pile on the ocellar triangle; ocellar triangle equilateral; eyes covered with dense pile; occiput with gray-yellow pile, ventrally covered with a dense, gray microtrichia; eye contiguity 10-12 facets long; vertical triangle: eye contiguity: frons = 1.2: 1: 2. Thorax. Scutum and scutellum black with bronze luster, covered with dense, erect, yellow pile, except sides of scutum at wing basis with patch of short black pile and fascia of black pile between wing basis; scutum with two or more microtrichose vittae, anteriorly connected and posteriorly reaching the scutellum; scutum dull; 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 yellowish; legs mostly black, except brown tarsi ventrally in some specimens; pile on legs pale yellow, except few black pile in apical fifth of metafemur in some specimens; metafemur incrassate, ca. three times longer than wide; pile on postero- and anteroventral surface short, except few sparse pile approximately the same length as pile on dorsal surface (Fig. 22C ). Abdomen. Broad, tapering, 1.2 times longer than mesonotum; terga dark, except for a pair of yellow-orange, triangular, lateral maculae on tergum 2; terga 2-4 each with a pair of white microtrichose, oblique fasciae (on tergum 2 more triangular); pile on terga all yellow (Fig. 24A ); 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 (Fig. 25A : al) and with concave margin (Fig. 6H : marked with arrow); posterior surstyle lobe oval with basolateral protrusion (lateral hump) (Fig. 25B : bp) and basal hook-like extension (Fig. 25A : marked with arrow); hypandrium sickle-shaped, without lateral projections; lingula medium sized (Fig. 25C : l). Figure 25. Male genitalia. A Merodon medium sp. nov., epandrium, lateral view B Merodon medium sp. nov., epandrium, ventral view C Merodon medium sp. nov., hypandrium, lateral view D Merodon nigrocapillatus sp. nov., epandrium, lateral view E Merodon nigrocapillatus sp. nov., epandrium, ventral view F Merodon nigrocapillatus sp. nov., hypandrium, lateral view. Abbreviations: al-anterior surstyle lobe, bp-basolateral protrusion, l-lingula; arrow marks the hook-like extension in A . Scale bar: 0.2 mm. Female. Similar to the male except for normal sexual dimorphism and for the following characteristics: antennae with rounded tip, basoflagellomere ca. two times longer than wide, (Fig. 19J ); frons with broad microtrichose vittae along eye margins; frons covered with pilosity of variable color, from mostly gray-yellow until predominately black pile; ocellar triangle covered with black pile; metafemur incrassate, pile on postero- and anteroventral surface short (Fig. 22D ); terga pale yellow pilose at lateral sides, anterior two thirds of tergum 2 and all terga 4 and 5; terga 2 and 3 medially with short adpressed black pile; microtrichose fasciae on terga 3 and 4 broad (Fig. 24B ). Etymology. Medium (middle, center) refers to the species' distribution, being the only taxon of the group found on Crete, in the middle of Mediterranean Sea. Distribution. Merodon medium sp. nov. is endemic to the Greek island of Crete (Fig. 7 ). Ecology. Preferred environment: forest/open ground; evergreen oak forest, dry Pinus forest; scrub with Pistacia lentiscus L.; well-vegetated, unimproved grassland. Flowers visited: Ornithogalum spp., Potentilla spp. and Thymus spp. Flight period: May. Type material. Holotype . Greece • ♂; Crete, Chania, Omalos plain; 35°19'21"N , 23°55'50"E ; 28 May 2014; A. Vujic leg.; FSUNS 06729. Original label: "HOLOTYPE of Merodon / medium Vujic , Likov et / Radenkovic sp.n. 2019" [red label], "Greece, Crete, Chania, / Omalos plain / 28.05.2014. 35.322593 / 23.930496 Leg. Vujic" , "AU298" , "06729" (See Supplementary file 3: Figure 3 ). Paratypes . Greece • 1 ♀; Crete, Chania, Imbors; 35°15'08"N , 24°10'28"E ; 27 May 2014; A. Vujic leg.; FSUNS 06706 • 1 ♂; Crete, Chania, Omalos plain; 35°19'06"N , 23°54'51"E ; 28 May 2014; A. Vujic leg.; FSUNS 06723 • 1 ♂; Crete, Chania, Omalos plain; 35°19'21"N , 23°55'50"E ; 28 May 2014; A. Vujic leg.; FSUNS 06731 • 1 ♀, Crete, Chania, Mescla, 35°24'05"N 23°56'26"E ; 28 May 2014; A. Vujic leg.; FSUNS 06718.