Scutops Coquillett, 1904

Freitas, Geovânia & Ale-Rocha, Rosaly, 2023, Taxonomic revision of the Neotropical genus Scutops Coquillett, 1904 (Diptera: Periscelididae), Zootaxa 5244 (5), pp. 401-427 : 402-404

Scutops Coquillett, 1904

Scutops Coquillett, 1904: 97 .

Type species Scutops fascipennis Coquillett, 1994 (monotypy).

Melander, 1913: 167 (key to genera); Malloch, 1926: 24–25 (classification); Curran, 1934: 322–323 (key to genera); Sturtevant, 1954: 555 (key to genera); Prado, 1975: 2 (Neotropical catalog); Amorim & Vasconcelos, 1989: 39–44 (phylogeny, key to species); Mathis & Papp, 1992: 366–372 (classification); Mathis & Rung 2011: 358–359 (world catalog).

Panamenia Curran, 1934: 323 . Type species: Panamenia chapmani Curran (original designation). Sturtevant, 1954: 556 (synonymy).

Diagnosis. Medium-sized flies with robust body; 1 fronto-orbital seta; 1 par of ocellar seta well developed; face protruded, flattened or slightly convex dorsally, shield-shaped; palpus developed, slightly to broadly spatulate; 1–2 dorsocentral setae; 2 katepisternal setae; postpronotal lobe with 1 conspicuous seta; wing with basal 1/3 to ½ yellow, remaining part dark brown with hyaline preapical transversal band; Costa extended to vein R4+5; vein R 1 lacking dorsal setae, cell cup partially closed or absent; acrostichal prescutellar seta lacking; anepisternum bare.

Redescription. Body length: 3.0–5.0 mm; wing length: 2.7–4.2 mm. Head. Occiput concave; lateral margin of frons with series of minute setae; face protruded ventrally, dorsal portion flattened, somewhat shield-shaped and usually surrounded by a ridge around the margin, with apical margin rounded or subtriangular; gena and postgena with conspicuous setae. Antenna. Scape short; pedicel with dorsal and ventral setae; postpedicel rather cylindrical with rounded apex; arista sub-basal dorsal, with seven to eleven dorsal branches and four to five ventral branches. Palpus spatulate. Setae: outer vertical divergent, shorter, and more slender than inner vertical, 1 inner vertical convergent (not crossing); 1 ocellar pair parallel; 1 postocellar divergent. Thorax. Scutum usually with one or two longitudinal stripes contrasting with the background color; postpronotal lobe whitish with dense silver pruinescence; mesonotum densely to sparsely covered with short setulae, sub-shining to shining, with sparse pruinescence in some regions. Setae: 1 supra-alar post-sutural and 1 post-alar; 2 notopleural, 1–2 dorsocentral; katepisternum setulose with 2 katepisternal; 2 scutellar. Legs. Fore femur with row of posteroventral robust setae; mid tibia with one black and robust ventroapical spine; mid tarsomeres with brown to short black spines ventrally on distal margin. Wing. Basal third to half yellow, remaining part pale brown to dark brown with a preapical transversal hyaline stripe; R 1 lacking dorsal setae; vein M4 ending near or in the wing margin. Abdomen. Broad, sub shining, covered with short brown setae, lateral setae longer. Tergite 1+2 with two membranous lines, one medial longitudinal extending from the base to middle of segment and one horizontal line occupying 1/3 medial of the width of the segment, forming an inverted “T”. Male terminalia symmetrical; tergite 6 wide, sternite 6 rectangular, syntergosternite 7+8 wide, symmetrical, free from tergite 6; phallus ribbon-like; surstylus weakly developed, not articulated, arising from inner wall of epandrium; hypandrium+phallapodeme forming a deeply concave pouch; cercus developed, setose. Female terminalia: tergite and sternite 7 fused, forming a complete ring; tergite and sternite 8 free; cercus small and usually ellipsoid.

Geographical distribution. Neotropical: Belize, Guatemala, El Salvador, Nicaragua, Costa Rica, Panama, Guyana, Ecuador, Peru, Brazil and Bolivia ( Figs 21 , 22 ).

Comment. Scutops can be differentiated from other genera of Periscelidinae by the following combination of characters: face flattened dorsally to slightly convex, shield-shaped; wing brown on apical 1/3 to ½ and with one transversal preapical hyaline band; vein R 1 without setae; prescutellar acrostichal seta absent; and arista with six or more dorsal branches. The following putative synapomorphies unite Scutops , Marbenia and Neoscutops within Periscelidinae : surstylus undifferentiated from the epandrium (except for some species of the Neoscutops rotundipennis Malloch group which have a differentiated surstylus ( Ale-Rocha & Freitas 2011). Scutops can be easily distinguished from both genera by the absence of setae on vein R 1; from Marbenia by the dorsally convex vein R 2+3 and face lacking transverse furrows (vein R 2+3 not distinctly convex and face with transverse furrows in Marbenia ); and from Neoscutops by the complete CuA and cell cup being closed apically, R 4+5 and M 1 are almost straight and parallel, R 4+5 ending at apex or very close to apex of the wing (CuA incomplete or indistinct, cup incomplete, and R 4+5 and M 1 distinctly divergent in Neoscutops ).

Identification key for species of Scutops Coquillett, 1904

1. Wing with transversal hyaline preapical band complete, extended from anterior to posterior margins of the wing (e.g., Figs 19A, B, J )...............................................................................................2

- Wing with transversal hyaline preapical band incomplete, not reaching the margins of the wing ( Figs 19C–I )............ 4

2. Scutum brown with slender yellow longitudinal dorsocentral stripe ( Figs 17A, C ); frons lacking median brown spot below ocellar triangle ( Fig. 17B ); femora and tibiae black; apex of wing with hyaline spot large and rounded ( Fig. 19J ) ( Panama).................................................................................. S. spinophallus sp. nov.

- Scutum brown with wide yellow to pale-yellow longitudinal median stripe; frons with median brown spot below ocellar triangle; femora and tibiae yellow with brown spots or rings; hyaline spot at apex of wing small and slender............. 3

3. Median stripe of scutum yellow, long, with anterior margin triangular ( Fig. 3C ); median spot of frons pale brown and slender ( Fig. 3B ) ( Belize, Costa Rica, El Salvador, Guatemala, Guyana, Nicaragua, Panama)............. S. fascipennis Coquillett

- Median stripe of scutum whitish yellow, short, almost quadrate, with anterior margin truncate ( Fig. 1C ); median spot of frons dark brown, wide on vertex and narrowed towards the base of the antennae ( Fig. 1B ) ( Costa Rica and Panama).............................................................................................. S. chapmani (Curran)

4. Scutum totally yellow or predominantly yellow............................................................. 5

- Scutum brown with a wide acrostichal yellow spot.......................................................... 7

5. Scutum yellow with a pair of dorsocentral short slender brown stripe on posterior half ( Fig. 12C ); scutellum with transversal grooves ( Fig. 12C ); abdominal tergites yellow 3–7 with mediodorsal brown spot ( Fig 12A ) ( Brazil).... S. melinus sp. nov.

- Scutum totally yellow; scutellum without transversal grooves; abdominal tergites brown............................ 6

6. Legs yellow except coxae dark brown, femora dark brown with yellow apex, fore tibia brown with apex and base yellow ( Fig. 13A ) ( Brazil, Ecuador, Peru)............................................................. S. peruanus Hennig

- Legs totally yellow ( Fig. 5A ) ( Brazil, Ecuador, Peru)....................................... S. flavithorax sp. nov.

7. Median longitudinal yellow stripe of the scutum wide, truncate anteriorly, quadrangular ( Fig. 7C ) ( Brazil)................................................................................................. S. ipixunensis sp. nov.

- Median longitudinal yellow stripe of the scutum narrowed anteriorly, rather triangular on anterior margin............... 8

8. Median longitudinal yellow stripe of the scutum short, not reaching the presutural area ( Brazil)............................................................................................. S. goianiensis Amorim & Vasconcelos

- Median longitudinal yellow stripe of the scutum elongate, reaching the presutural area.............................. 9

9. White band of occiput incomplete, not reaching the gena ( Figs 15A, D ); gena and postgena brown ( Figs 15A, D ); femora brown ( Figs. 15A, D ) ( Brazil, Bolivia, Ecuador)................................................... S. robustus sp. nov.

- White band of occiput complete, reaching the gena; gena and postgena yellow; femora brown with apex yellow......... 10

10. Frons with median vertical pale brown spot below ocellar triangle ( Fig. 9B ); median longitudinal yellow stripe of the scutum not reaching the anterior margin ( Fig. 9C ) ( Brazil, Ecuador, Venezuela)................. S. lopesi Amorim & Vasconcelos

- Frons without median vertical brown spot below ocellar triangle ( Fig. 11B ); median longitudinal yellow stripe of the scutum reaching the anterior margin ( Fig. 11C ) ( Brazil)................................ S. marcgrafi Amorim & Vasconcelos

Figures

FIGURE 1. Scutops chapmani Curran, 1934. A–C male (Costa Rica, Pedregoso). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 3. Scutops fascipennis Coquillett, 1904. A–B (holotype), C (Costa Rica, Guan Sta. Rosa).A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 5. Scutops flavithorax sp. nov.. A–C (holotype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 7. Scutops ipixunensis sp. nov.. A (paratype), B–C (holotype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 9. Scutops lopesi Amorim & Vasconcelos, 1989. A–C (holotype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 11. Scutops marcgrafi Amorim & Vasconcelos, 1989. A–C (holotype).A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 12. Scutops melinus sp. nov.. A–C (holotype), D (paratype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view; D. Female terminalia, posteroventral view.

FIGURE 13. Scutops peruanus Hennig, 1952. A–C (holotype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 15. Scutops robustus sp. nov. A (holotype), B–D (paratype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view; D. Female terminalia, posteroventral view.

FIGURE 17. Scutops spinophallus sp. nov. A–C (holotype). A. Habitus, lateral view; B. Head, frontal view; C. Thorax, dorsal view.

FIGURE 19. Wings. A. Scutops chapmani Curran, 1934; B. Scutops fascipennis Coquillett, 1904; C. Scutops flavithorax sp. nov. (paratype male); D. Scutops ipixunensis sp. nov. (paratype female); E. Scutops lopesi Amorim & Vasconcelos, 1989; F. Scutops marcgrafi Amorim & Vasconcelos, 1989; G. Scutops melinus sp. nov. (holotype female); H. Scutops peruanus Hennig, 1952; I. Scutops robustus sp. nov. (paratype female). J. Scutops spinophallus sp. nov. (holotype male).

FIGURE 21. Distributional map with records of S. chapmani, S. fascipennis, S. lopesi, S. melinus sp. nov., S. peruanus and S. spinophallus sp. nov..

FIGURE 22. Distributional map with records of S. flavithorax sp. nov., S. goianiensis, S. ipixunensis sp. nov., S. marcgrafi and S. robustus sp. nov..