Melanostomini (Mengual, 2020)

Montoya, Augusto L. & Wolff, Marta, 2023, Taxonomic revision of the Neotropical genus Argentinomyia Lynch-Arribálzaga, 1891 (Diptera: Syrphidae), with description of 16 new species, Zootaxa 5234 (1), pp. 1-157 : 12-13

publication ID

https://doi.org/ 10.11646/zootaxa.5234.1.1

publication LSID

lsid:zoobank.org:pub:A540F250-BDE2-43F7-83A1-DA261F914B41

DOI

https://doi.org/10.5281/zenodo.7621110

persistent identifier

https://treatment.plazi.org/id/03C03256-AC4C-FFE3-0FF9-FBB5F7BEF983

treatment provided by

Plazi

scientific name

Melanostomini
status

 

Identification key to the Neotropical genera of Melanostomini and Bacchini

A key to the genera of Neotropical Melanostomini and Bacchini was prepared based on characters proposed by Fluke (1945, 1957), Thompson (1999a), Thompson (2006), Thompson et al. (2010), Huo (2014), Thompson & Skevington (2014), Young et al. (2016), Miranda & Moran (2017), Ramage et al. (2018) and Mengual (2020).

1. Postpronotum pilose (MCAD Fig. 30 View FIGURE 30 ); male abdomen with four unmodified pregenital segments; 5 th tergum usually not visible in dorsal view (MCAD Figs 1 View FIGURE 1 , 4 View FIGURE 4 ); female abdomen tergum 6 th hardened or membranous, visible, if tergum 6 th and onward visible, then these are membranous; epiproct as two plates that may be connected to the base, or as a single plate, or as a band with two projections (subfamilies Eristalinae View in CoL , Microdontinae View in CoL and Pipizinae).... other flower flies (“MCAD key couplet 2”)

- Postpronotum bare; male abdomen with five unmodified pregenital segments; 5 th tergum visible in dorsal view (MCAD Figs 53–61 View FIGURE 53 View FIGURE 54 View FIGURE 55 View FIGURE 56 View FIGURE 57 View FIGURE 58 View FIGURE 59 View FIGURE 60 View FIGURE 61 ); female abdomen tergum 6 th hardened, visible; epiproct divided into two plates that may be connected to the base (subfamily Syrphinae )................................................................................. 2

2. Face and/or scutellum partially yellow or yellowish-brown in background color; phallus (aedeagus) two-segmented........................................................................................ other Syrphinae genera

- Face and scutellum entirely black in background color (some species with partly pale face or scutellum); phallus (aedeagus) simple, unsegmented (Bacchini and Melanostomini )......................................................... 3

3. Face usually straight, oral margin and antennal bases in line, without tubercle, flat, straight or convex; abdomen petiolate, distinctly narrower than thorax ( Fig. 4A View FIGURE 4 , MCAD Figs 59 View FIGURE 59 , 60 View FIGURE 60 ); male: 2 nd tergum narrow, narrower than 3 rd and 4th terga ( Mengual et al. 2018, Fig. 18 View FIGURE 18 ); female abdominal tergum 6 th, not noticeable nor visible without dissection, tergum 6 th internal to the 5 th, tergum 5 th 1/10 of the length of tergum 4 th, almost inconspicuous ( Miranda & Moran 2017, Figs 59 View FIGURE 59 , 80 View FIGURE 80 and 90 View FIGURE 90 )................................................................................................ Leucopodella Hull View in CoL

- Face with tubercle; abdomen parallel-sided or narrowly oval (MCAD Figs 55 View FIGURE 55 , 58 View FIGURE 58 ); other characters variable; female tergum seventh visible without dissection........................................................................ 4

4. Antennal cavities broadly confluent (MCAD Fig. 24 View FIGURE 24 ); face narrow, with distinctive, rounded facial tubercle; metathoracic pleuron with several fine subappressed pile ventral to spiracle; katepisternum with pile patches broadly separated posteriorly, but joined anteriorly; abdomen oval, wide and flat, clearly broader than scutum, usually with yellow-orange maculae on 2 nd to 4 th terga; surstyli elongated, one-lobed, digitiform or pointed, generally widened apically, postgonites small, squarish or triangular in shape ( Fluke 1957: 278, Figs 119–122; Borges & Pamplona 2003); female tergum 5 th 1/3 of the length of tergum 4 th, tergum 6 th 1/3 of the length of 5 th ( Miranda & Moran 2017, Figs 66 View FIGURE 66 , 84 View FIGURE 84 and 97)................. Xanthandrus Verrall View in CoL

- Antennal cavities broadly separated (MCAD Fig. 23 View FIGURE 23 ); metathoracic pleuron bare; katepisternum with pile patches usually broadly separated throughout; abdomen variable, slender and parallel-sided, as broad as scutum; other characters variable... ................................................................................................... 5

5. Metasternum greatly reduced to a small diamond-shaped area ( Figs 3A View FIGURE 3 , 5J View FIGURE 5 ; Andersson 1970: 273, Fig. 1C View FIGURE 1 , 3C View FIGURE 3 ; Shatalkin 1975: 118, Fig. 11 View FIGURE 11 ; Thompson et al 2010: 771, Fig. 34 View FIGURE 34 ; Haarto and Ståhls 2014: 95, Figs 1A View FIGURE 1 ; Thompson & Skevington 2014); antenna short, with scape and basoflagellomere as long as wide; face not produced below, with small tubercle, facial pollinosity neither punctate nor rippled (MCAD Fig. 28 View FIGURE 28 ); male abdomen nearly parallel-sided, from two to five times as long as greatest width, female with abdomen varying from nearly parallel-sided to oval, from 1.7 to 2.5 times as long as greatest width; usually with triangular or subquadrate shaped yellow maculae; male genitalia with surstyli simple, one-lobed, elongate, straight and thin, with a small basomedial tubercle; postgonites (apex of hypandrium) massive, irregular or squarish in shape; female tergum 5 th 1/4 of the length of tergum 4 th, tergum 6 th 1/5 of the length of tergum 5 th ......................... Melanostoma Schiner View in CoL [Note: A new species described from Cameroon by Mengual (2020) does not have the reduced metasternum]

- Metasternum entire, not reduced ( Fig. 3B View FIGURE 3 ; MCAD Fig. 35 View FIGURE 35 ; Haarto and Ståhls 2014: 95, Fig. 1B View FIGURE 1 ; SNLSA Fig. 12C View FIGURE 12 ); face variable, almost straight in profile with weak tubercle or moderately to strongly produced forward ventrally, sometimes with pollinosity forming punctuate or rippled pattern, other characters variable........................................ 6

6. Face produced forward into a snout, with a very prominent and abrupt tubercle closer to the antennal base than to the oral opening apex ( Fig. 4N View FIGURE 4 , Fluke 1943: 427, Figs 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 ); face sparsely pollinose and without punctate shiny (bare) maculae ( Fig. 4N View FIGURE 4 ); head as long as or longer than high, wider than thorax; male eyes dichoptic or holoptic; antenna elongate, as long as or longer than face; basoflagellomere elongate, four or more times as long as broad, near equal to scape and pedicel together ( Fig. 4N View FIGURE 4 ); notopleura without a distinct tubercle; subscutellar fringe short, thin and white; prolegs simple in male, sometimes with a curled tibial seta ( Fig. 4N View FIGURE 4 , Fluke 1943: 427, Figs 8–9 View FIGURE 8 View FIGURE 9 ); male genitalia with surstyli curved; superior lobes transverse and elongated; ejaculatory apodeme elongate and knobbed toward the apex ( Fluke, 1957: 278, Figs 124–125; Shatalkin 1975: 118, Fig. 12 View FIGURE 12 ); small species, shining black or blue metallic, 7mm or less.............. Platycheirus (Tuberculanostoma) Fluke

- Face straight or slightly produced anteriorly, with a low and indistinct tubercle, frequently densely pollinose and with small shiny punctate-like bare maculae; head higher than long; male eyes face not greatly produced anteriorly; basoflagellomere oval or slightly elongate, never more than twice as long as broad; notopleura with a distinct tubercle; subscutellar fringe complete; male sometimes with legs modified, either broadened or with special bristles, pile tufts, modified hairs or none; frequently medium to large flies, sometimes with pale to metallic colored markings......................................... 7

7. Face slightly receding to rather strongly produced below, with obscure to prominent tubercle, densely pollinose and sometimes with pollinosity forming a distinctive bare punctum or rippled pattern ( Fig. 4M View FIGURE 4 ); male protibia usually with long black bristles posteriorly, sometimes protibia and/or tarsus expanded, usually with specialized setae ( Fig. 4M View FIGURE 4 ); abdomen nearly parallel-sided in males, narrowly oval in the female; with yellow to orange or silver-gray pollinose on bluish submetallic macula, generally with quadrate markings; surstyli bifid or bilobed with a long, slightly curved lateral lobe and a short, stout basomedial lobe, superior lobes usually slender, recurved and crescent-shaped ( Vockeroth 1990: Fig. 83 View FIGURE 83 ; Thompson & Skevington 2014; Young et al. 2016); female tergum 5 th 1/3 of the length of tergum 4 th, tergum 6 th 1/5 of the length of tergum 5 th ( Miranda & Moran 2017, Figs 70 View FIGURE 70 , 71 View FIGURE 71 , 86 View FIGURE 86 and 100).......................................................... Platycheirus (Carposcalis) View in CoL

- Face straight in profile, not produced anteriorly, usually uniformly pollinose, sometimes with shiny (bare) punctate maculae; male legs slender, without bristles, pile tufts, or modified hairs; abdomen frequently with pale-colored maculae; surstyli elongate, one-lobed, postgonites massive, irregular, elongate, triangular, or squarish in shape......................... 8

8. Antennae short, scape broader than long, scape nearly equal to pedicel, basoflagellomere large, slightly oval and apically rounded; face slightly receding to perpendicular with a well-rounded tubercle, never with transverse grooves dorsally along tubercle neither broadly (bare) punctuate ( Fig. 6D View FIGURE 6 ); mesocoxa pilose posteriorly ( Fig. 6E View FIGURE 6 , SNLSA Figs 12–13 View FIGURE 12 View FIGURE 13 ); abdomen elongated or with parallel sides, with four to five pairs of large rounded to triangular markings on terga, always with small macula on 5 th tergum; male genitalia greatly enlarged and strongly sclerotized, apex of hypandrium (superior lobes) and cerci elongated, surstyli three to four times longer than wide ( Fig. 6G View FIGURE 6 , Fluke 1957: 278, Fig. 123; SNLSA Figs 14A–D View FIGURE 14 ); female tergum 5 th 1/4 of the length of tergum 4 th, tergum 6 th 1/5 of the length of tergum 5 th (SNLSA Figs 13E View FIGURE 13 )...... Talahua Fluke View in CoL [Note: Montoya & Wolff (2020) provided a complete redescription for Talahua View in CoL , differential diagnosis, images of the habitus and illustrations of male genitalia]

- Antenna elongate, scape longer than broad; basoflagellomere oval or elongate; face straight in profile ( Figs 4 View FIGURE 4 , 6 – 9 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 , MCAD Fig. 22 View FIGURE 22 ), facial tubercle low dorsally, not distinct ( Figs 4 View FIGURE 4 , 6 – 9 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 ); mesocoxa bare posteriorly; male genitalia normal size, apex of hypandrium (superior lobes) triangular to rectangular, irregular in shape and cercus short; female tergum 5 th 1/3 of the length of tergum 4 th, tergum 6 th 1/4 of the length of tergum 5 th ( Figs 5 View FIGURE 5 , 6 View FIGURE 6 and 9 View FIGURE 9 )................. Argentinomyia Lynch-Arribálzaga View in CoL

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Syrphidae

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