Mesembrius madagascariensis Keiser, 1971

Jordaens, Kurt, Goergen, Georg, Skevington, Jeffrey H., Kelso, Scott & Meyer, Marc De, 2021, Revision of the Afrotropical species of the hover fly genus Mesembrius Rondani (Diptera, Syrphidae) using morphological and molecular data, ZooKeys 1046, pp. 1-141 : 1

publication ID	https://dx.doi.org/10.3897/zookeys.1046.57052
publication LSID	lsid:zoobank.org:pub:66E61C4E-FAFE-45DE-9145-DB38199BDEC3
persistent identifier	https://treatment.plazi.org/id/D68C114E-ABBE-5067-8F15-29F49480749B
treatment provided by	ZooKeys by Pensoft
scientific name	Mesembrius madagascariensis Keiser, 1971
status

Treatment

Mesembrius madagascariensis Keiser, 1971 Figs 13 View Figures 13, 14 , 34 View Figures 33, 34 , 56 View Figures 52–57 , 93 View Figures 89–94 , 115 View Figures 113–118 , 136 View Figures 135–138 , 180 View Figures 177–180 , 215 View Figures 205–216

Mesembrius madagascariensis Keiser, 1971: 261.

Mesembrius madagascariensis - Smith and Vockeroth (1980): 504.

Differential diagnosis.

Mesembrius madagascariensis males lack an apical pile brush on the profemur and have an unmodified metatibia. The profemur is dorsally flattened and the metabasitarsus does not have a lobe as in some males of M. simplicipes . The male of M. madagascariensis cannot be confused with any other species by the strong difference in the pile colour and length between the proximal and distal part of the mesotibia which is long and yellow pile in the proximal 2/3 and short and black in the distal 1/3. The female of M. madagascariensis can be distinguished from any other species (except from M. simplicipes ) by the nearly black abdomen (clearly yellow to orange and black in other species). It can be distinguished from M. simplicipes by the pro- and mesolegs which are extensively brown and black (reddish-brown in M. simplicipes ).

Examined material.

Mesembrius madagascariensis Keiser: Holotype, male, Madagascar, Antananarivo, M, 13 Dec 1957, F. Keiser (MNHN: type not studied; see comments).

Mesembrius madagascariensis Keiser: Allotype, female, "ALLO // TYPUS" " Madagascar. TAN. // Tananarive // 13.XII.1957 // F. KEISER" " Mesembrius // madagascar- // iensis" [NMB].

Paratypes: Madagascar • 7♂♂ 21♀; Tananarive ; 13 Dec 1975; F. Keiser leg.; NMB • 1♀; Lac Kavitaha, Ampefy ; 20 Mar 1958; F. Keiser; NMB • 4♂♂ 2♀♀; Ambalavao , Fianarantsoa; 28-29 Jan 1958; F. Keiser; NMB • 9♂♂ 2♀♀; Tzimbazaza Park , Antananarivo; 7-8 Feb 1968; F. Keiser leg.; NMB • 1♀; Station Agric., Alaotra, District Anbatondrakzaka ; 24 Dec 1957; B.R. Stuckenberg leg.; NMSA • 4♂♂ 2♀♀; Antananarivo; 1 Jan 1958; B.R. Stuckenberg leg.; NMSA .

Other material

Madagascar • 1♀; Antananarivo, Tsimbazaza ; 16 Oct 1993; M. Hauser leg.; CAS • 1♂; Antananarivo, Tsimbazaza ; 16-22 Oct 1993; C. Kassebeer leg.; CAS • 1♂ 1♀; Antananarivo, Tsimbazaza ; 16-22 Oct 1993; C. Kassebeer leg.; CNC • 1♂; Antananarivo, Tsimbazaza ; 14 Oct 1993; C. Kassebeer leg.; NHMUK • 1♀; Antananarivo, Tsimbazaza ; 26 Oct 1993; C. Kassebeer leg.; NHMUK • 1♀; Atsimo, Andrefana ; 6-16 Jul 2012; M. Irwin and R. Harin’Hala leg.; CAS • 1♀; Atsimo, Andrefana ; 31 May 2012; M. Irwin and R. Harin’Hala leg.; CAS • 1♀; Tananarive ; 13 Dec 1957; F. Keiser leg.; NMB • 1♀; Tananarive ; 15 Dec 1957; F. Keiser leg.; NMB • 1♂ 1♀; Tananarive ; 29 Dec 1957; F. Keiser leg.; NMB • 1♀; Tananarive ; 17 Apr 1958; F. Keiser leg.; NMB • 2♀♀; Tananarive ; 26-30 Apr 1968; K.M. Guichard leg.; NHMUK .

Re-description male

(Fig. 13 View Figures 13, 14 ). Body length: 13.7-14.6 mm. Wing length: 9.6-10.5 mm.

Head (Fig. 56 View Figures 52–57 ). Eyes bare; holoptic, length of eye contiguity approx. length of ocellar triangle. Face white with dark medial vitta; white pilose; white pollinose. Vertical triangle black pilose on ventral half and at ocellar triangle, yellow pilose on dorsal half; yellow pollinose until just before anterior ocellus. Lateral ocellus touching eye margin. Occiput yellow; yellow pilose; yellow and white pollinose. Frontal prominence shiny black; black pilose. Antenna, scape and pedicel reddish-brown; postpedicel black; antennal arista reddish-brown.

Thorax. Scutum black; dorsally with a pair of well-demarcated yellow vittae and a faint yellow medial line; vittae and medial line become faint posteriorly; yellow vague lateral vitta; yellow pilose. Scutellum uniformly yellow-brown; yellow pilose.

Legs. All legs dark chocolate-brown to black, except for pro- and mesotibiae and basitarsi which are reddish-brown. Proleg: Femur dark chocolate-brown to black; without apical pile brush; pile inconspicuous, except for long yellow pile on the anterodorsal side which, dorsally, is bordered with a row of largely spaced black pile. Tibia reddish-brown; yellow pilose with some short black pile on distal end dorsally. Basitarsus orange-brown; black pilose with some longer yellow pile posteriorly. Other tarsi black; black pilose, with some longer yellow pile posteriorly, except on the two most distal tarsi. Mesoleg (Fig. 180 View Figures 177–180 ): Femur with predominantly long yellow pile on ventral and posteroventral side, with shorter black pile on anterodorsal side. Tibia reddish-brown; proximal half with a comb of long, curved yellow pile on proximal half; with much shorter, yellow and black pile on distal half. Basitarsus orange-brown; black pilose with some longer yellow pile posteriorly. Other tarsi black; black pilose, with some longer yellow pile posteriorly, except on the two most distal tarsi. Metaleg: Femur dark chocolate-brown to black; with long, thin yellow pile, especially anteriorly; ventrally with less black pile. Tibia dark chocolate-brown to black; unmodified; with short, black pile throughout and short, yellow pile on anteroproximal half. Basitarsus and second tarsomere orange-brown, other tarsi black; black pilose.

Wing (Fig. 136 View Figures 135–138 ). Entire wing uniformly microtrichose.

Abdomen (Fig. 93 View Figures 89–94 ). Tergite II with a pair of yellow-orange, rounded maculae; black marking broadly hourglass-shaped; yellow pilose, except for posterior half of posterior black marking where pile is black; with a stretch of yellow pollinosity on anterior part of black marking. Tergite III with a pair of small, anterolateral maculae; yellow-white pilose; white pollinose on posterior half. Tergite IV dark chocolate-brown; yellow-white pilose; white pollinose.

Genitalia (Fig. 215 View Figures 205–216 ). Epandrium: Dorsal lobe of surstylus club-shaped; distal end densely covered with black spines; proximal half ( ‘stalk’) long yellow pilose dorsally and with some shorter, thicker black pile laterally. Ventral lobe of surstylus with one very long and thick black setula distally.

Re-description female

(Fig. 34 View Figures 33, 34 ). Body length: 12.5-13.5 mm. Wing length: 8.7-9.3 mm.

Head. Eyes bare; dichoptic. Face white with dark medial vitta; white pilose, white pollinose. Frons black, but strongly white pollinose on ventral 4/5; black pilose on ocellar triangle and just ventral of ocellar triangle; white pilose. Distance between lateral ocellus and eye margin approx. 1½ x width of ocellus. Occiput yellow-white; yellow-white pilose; yellow-white pollinose. Frontal prominence shiny black, orange-brown at distal end. Antenna, scape and pedicel orange-brown; postpedicel black, white pollinose; antennal arista yellow-orange.

Thorax. Scutum dark brown to black with a pair of dorsolateral white-grey pollinose vittae; with lateral grey pollinose vague vitta; yellow and black pilose. Scutellum yellow-brown; yellow and black pilose.

Legs. Pro- and mesoleg: Femur black, distal end reddish-brown; short black and longer yellow pilose. Tibia reddish-brown; yellow and black pilose dorsally; yellow pilose ventrally. Basitarsus reddish-brown; black pilose dorsally; orange-yellow pilose ventrally. Other tarsi black; black pilose dorsally, orange-yellow pilose ventrally. Metaleg: Femur black, distal 1/5 reddish-brown; yellow-white pilose, with scarce very short black pile ventrally. Tibia reddish-brown; white pilose, short black pilose posteriorly. Basitarsus dark reddish-brown; black pilose dorsally, yellow and black pilose ventrally. Other tarsi black; predominantly black pilose dorsally, densely yellow-orange pilose ventrally.

Wing. Entire wing uniformly microtrichose.

Abdomen (Fig. 115 View Figures 113–118 ). Dark brown to black; largely white pollinose, except for anterior border and medial area of tergite II and posterior half of tergite V; short black and white pilose, except for non-pollinose areas with white pilose only.

Distribution.

Madagascar.

Comments.

The type series comprises more than 50 specimens of both sexes collected from a dozen of sites from the central and eastern domains of Madagascar ( Keiser 1971). The holotype of the species should be in the collection at MNHN ( Keiser 1971), but neither could we trace the holotype in the MNHN collection, nor is it listed on the MNHN entomology collection webpages.