Leptostylum oligothrix Gudin and Messas, 2018

Gudin, Filipe Macedo & Messas, Yuri Fanchini, 2018, On taxonomy and hosts of Leptostylum Macquart, 1851 (Diptera: Tachinidae: Blondeliini), with description of a new species and a new host record, Journal of Natural History (J. Nat. Hist.) 52 (21 - 22), pp. 1395-1415 : 1404-1409

Leptostylum oligothrix Gudin and Messas sp. nov.

( Figures 5 , 6 )

Type material examined

Holotype male ( Figure 5a–c,g,i–k ): ‘ Brasil, SP, Jundiaí/Arredores Base Ecológica da/Serra do Japi/23°13 ʹ 53.82 ʹ S 46°56 ʹ 08.84 ″ W / 05.v.2016, pupa: 22.iv.2016 /Messas Y. col.’/‘Hosp [host]: Automeris naranja aff./( Lepidoptera : Saturniidae )/Coletada em [collected on] 20.iv.2016 ’/ ‘Holótipo [red label]’ ( MZSP). Paratypes: 9 males (two dissected), 12 females (two dissected): ‘ Brasil, SP, Jundiaí/Arredores Base Ecológica da/Serra do Japi/23°13 ʹ 53.82 ʹ S 46°56 ʹ 08.84 ″ W / 05.v.2016, pupa: 22.iv.2016 /Messas Y. col.’/‘Hosp [host]: Automeris naranja aff./( Lepidoptera : Saturniidae )/Coletada em [collected on] 20.iv.2016 ’/‘Parátipo [green label]’ ( MZSP).

Type locality

Brazil, São Paulo, Jundiaí.

Etymology

The name refers to the low density of the ommatrichia. ‘Oligos’ (Greek) = few, scanty; ‘thrix’ (Greek) = hair.

Diagnosis

Leptostylum oligothrix sp. nov. can be distinguished from other species of Leptostylum by having ocellar triangle and fronto-orbital plate with golden pruinosity, contrasting to silver pruinosity of the head ( Figure 5a–f ); ocellar setae well developed ( Figure 5a,d ); eyes sparsely haired, with short ommatrichia; palpi yellowish; tegula and basicosta black; calypteres white, with yellowish border; basal dorsal surface of tergites 3, 4 and 5 with faint yellowish pruinosity; sex patches on tergites 3, 4 and 5 ( Figure 5k ); postgonite subtrapezoidal, narrowing towards apex, with slight bend at apex ( Figure 6a ). According to type localities, L. auratum , L. itaquaquecetubae and, probably, L. pulchellum are also distributed through Atlantic Forest. However, all of them present densely haired eyes ( Figure 1c ). Additionally, L. auratum differs from L. oligothrix sp. nov. by having head, thorax and abdomen entirely covered by golden pruinosity ( Figure 1a–d ); thorax with four distinct, black presutural vitta; and yellow calypteres ( Figure 1e ). Leptostylum itaquaquecetubae differs from L. oligothrix sp. nov. by having head entirely covered with silver pruinosity; ocellar setae hair like; and sex patch only on tergite 4 (also characteristic of L. pulchellum ). Leptostylum leuconotum is easily distinguished by the constricted frontal vitta ( Figure 4a,b ) and whitish pruinosity ( Figure 4d ). Leptostylum griseum and L. curepeiense present bare eyes and different shapes of postgonite ( Thompson 1968). There is no information about eye pilosity in L. fasciatum and L. flavocalyptratum , however. Nevertheless, according to the original descriptions, these species present distinct colour and pruinosity patterns from those of L. oligothrix sp. nov.

Description of holotype

Body length. 6.32 mm. Wing length: 5.05 mm.

Colouration. Head pruinosity silver, except ocellar triangle and fronto-orbital plate, with golden pruinosity to the level of the second anterior frontal seta ( Figure 5a,b ). Frontal vitta and lunule dark brown. Antenna black, first flagellomere covered with fine microtrichia, giving a greyish tone. Parafacial, gena, facial ridge and face grey. Clypeus black. Palpi yellowish. Labella reddish-brown. Occiput grey. Thorax pruinosity silver, except scutum and scutellum, with faint yellowish pruinosity ( Figure 5g ). Scutum black, with four weak, thin, grey presutural vitta, not reaching the suture; postsutural area with one dark, median spot, extending about halfway to scutellum. Lateral surface of thorax and spiracles shining black ( Figure 5i ). Scutellum and subscutellum black. Wing hyaline ( Figure 5j ). Tegula and basicosta black. Veins light brown. Halter brown at the base, becoming light yellow at the apex. Calypteres white, with yellowish border. Legs black. Tarsal claws black. Pulvilli yellowish. Abdomen pruinosity silver, except basal dorsal surface of tergites 3, 4 and 5, with faint yellowish pruinosity ( Figure 5g ). Tergite 1 + 2 shining black. Tergites 3, 4 and 5 apical half shining black. Sex patches black ( Figure 5k ).

Head. ( Figure 5a–c ). Ratio of head height/head width 1.34. Ratio of frontal vitta width/fronto-orbital plate width 0.86. Dichoptic. Eye sparsely haired, with short ommatrichia. Antenna inserted in the middle level of the eye, reaching lower facial margin. Scape short. Pedicel dorsally setulose. First flagellomere subrectangular, about 4.7 times longer than pedicel. Arista bare, long, with base pubescent, arising in basal dorsal surface of first flagellomere. Frontal setae five, from level of anterior margin of pedicel to proclinate ocellar seta level, second and fifth setae stronger, subequal to posterior reclinate orbital seta length, first and third setae weaker, about two-thirds the length of fifth, and fourth seta weak, about one-third the length of fifth. Proclinate orbital seta strong, subequal to anterior reclinate orbital seta length. Posterior reclinate orbital seta about two-thirds the length of anterior reclinate orbital seta. Ocellar triangle densely setulose, with one pair of proclinate ocellar setae, subequal to postocellar setae length, arising posterolaterally to anterior ocellus. Anterior ocellus twice the size of posterior ocelli. Postocellar setae two. Inner vertical setae reclinate, subparallel. Outer vertical setae weaker, about one-fifth the length of inner vertical. Fronto-orbital plate setulose to the level of second anterior frontal seta. Parafacial bare, about half the width of fronto-orbital plate, tapering slightly towards the lower margin of eye. Facial ridge bare, except on lowest one-fourth, with three, weak supravibrissal setae. Vibrissa strong and crossed, arising at the level of lower facial margin, with one subvibrissal seta. Face flat, not protruding in lateral view. Genal setae three, with gena about 0.1 times the height of head in lateral view. Genal dilation and postgena setulose, with patches of long, silver setulae. Clypeus U-shaped. Palpi clavate. Prementum short, setulose. Labella padlike.

Thorax. ( Figure 5g,i,j ). Prosternum setulose. Proepimeral setae two, strong, upcurved, with setulae at the base. Anterior spiracle with anterior lappet developed, covering almost entire opening. Posterior spiracle with posterior lappet shaped as an operculum. Postpronotal setae three, in a slight arc, with inner seta weaker. Acrostichal setae 3 + 3. Dorsocentral setae 2 + 3. Intra-alar setae 2 + 3. Supra-alar setae 2 + 3, with first postsutural seta weaker than the second, strong and subequal to posterior postalar seta length. Notopleural setae two, subequal to outer postpronotal seta length. Postalar setae two, with anterior weaker. Katepisternal setae two, divergent, with posterior seta stronger. Anepisternum anterodorsal corner with three weak setae, about one-fourth the length of notopleural setae, and posterior row with six setae. Anepimeral seta one, with patch of setulae at the base. Meral setae five. Basal scutellar setae slightly convergent. Lateral scutellar setae subparallel, shorter than subapical setae. Subapical scutellar setae divergent. Apical scutellar setae crossed, weak, subequal to discal setae length. Discal scutellar setae arising at the level of subapical setae. Wing: Vein C ending at R4 + 5, just before wing apex. Vein R4 + 5 dorsally setose more than halfway to crossvein r-m. Bend of M obtuse, sharply curved to wing margin. Cell r4 + 5 open, with opening length subequal to crossvein r-m. Legs: Fore femur with dorsal and posteroventral rows of setae from base to apex; anterodorsal row of setae from mid to apex. Fore tibia with anterodorsal row of setae from base to mid, one strong preapical seta; two posterior setae. Mid femur with anterior setae, arranged in a row of three setae and one strong seta. Mid tibia with two anterior setae; three posterodorsal setae; one strong, posteroventral apical seta; one strong, mid ventral seta; one strong, anteroventral seta. Hind femur with two strong, anteroventral setae interspersed by weaker setae. Hind tibia with anterodorsal row of setae from base to apex, with mid seta strong; one dorsal apical seta; three strong, posterodorsal setae, interspersed by weaker setae. Tarsal claws short, smaller than last tarsomere.

Abdomen. ( Figure 5g,k ). Subtriangular, tapering towards posterior end. Syntergite 1 + 2 with mid-dorsal depression extending more than halfway to hind margin. Syntergite 1 + 2 and tergite 3 with one pair of lateral marginal and one pair of median marginal setae. Tergite 4 with row of eight marginal setae. Tergite 5 with irregular row of discal and marginal setae. Sex patches on ventral surface of tergites 3, 4 and 5. Sternites completely overlapped by tergites.

Terminalia. ( Figure 6a ). Sternite 5 subtrapezoidal; posterior margin with a pair of projected lobes; inner margin of lobes covered with short microtrichia. Bacilliform sclerite slender, curved towards hypandrial arms. Hypandrial arms free, not fused. Surstylus, in posterior view, thin, about two-thirds cercus width; not fused with epandrium; shorter than cercus, extending to the beginning of apical quarter of cercus; straight, with short setae on outer surface. Phallapodeme flat, subequal to hypandrium length. Ejaculatory apodeme small, bent, with upper area globose. Aedeagus with epiphallus perpendicular to basiphallus, about one-third postgonite length. Basiphallus and distiphallus not articulated, without bend; anterior sclerite of distiphallus with anterior margin slightly serrated. Pregonite subtriangular, with anterior margin deeply fused with hypandrium; posterior margin with four setae in apical half. Postgonite subtrapezoidal, narrowing towards apex, with slight bend at apex; about two-thirds pregonite length. Cerci, in posterior view, not fused, with narrow median cleft; covered with setae; basal three-quarters width evenly narrowed to apex, with apical quarter smoothly narrow; in lateral view, wider than surstylus width.

Variation found in male paratypes

Body length. 6.04–7.68 mm (mean = 6.82 mm; n = 9). Wing length: 4.02–5.64 mm (mean = 5.17; n = 9).

Head. Ratio of head height/head width 1.28–1.38 (mean = 1.33). Ratio of frontal vitta width/fronto-orbital plate width 0.64–0.89 (mean = 0.81). Ratio of first flagellomere length/pedicel length 2.07–4.31 (mean = 3.06). Frontal setae 4–5, with fourth seta sometimes missing.

Description of female paratypes

Differs from male as follows: Body length: 5.41–6.38 mm (mean = 6.05 mm; n = 10). Wing length: 4.50–5.12 mm (mean = 4.88 mm; n = 10).

Colouration. Fronto-orbital plate with golden pruinosity varying from second to fourth anterior frontal seta ( Figure 5d,e ).

Head ( Figure 5d–f ). Ratio of head height/head width 1.33–1.44 (mean = 1.39). Ratio of frontal vitta width/fronto-orbital plate width 0.68–0.90 (mean = 0.81). Ratio of first flagellomere length/pedicel length 2.15–3.60 (mean = 2.72). Proclinate orbital setae two, with anterior seta arising between last frontal and anterior reclinate orbital setae and posterior seta between the latter and posterior reclinate orbital setae.

Abdomen ( Figure 5h ). Ellipsoidal, tapering towards posterior end. Without sex patches.

Terminalia ( Figure 6b ). Telescoped. Tergites 6, 7 and 8 as paired lateral plates, setose, except tergite 8, bare. Epiproct small, bare. Both spiracles 6 and 7 situated in membrane. Sternites bare; sternite 7 anterior margin with median projection. Hypoproct bare, subtriangular, forked, apex of arms bent ventrally, with inward projection. Cerci free, setulose.

Remarks

This species was determined in Leptostylum through the valuable keys for New World Blondeliini ( Wood 1985) and Central America Tachinidae ( Wood and Zumbado 2010) . The couplets to Leptostylum in both keys, however, imply that all species of the genus have densely haired eyes, which is not the case of L. oligothrix sp. nov. and other species of the genus. In spite of that, L. oligothrix sp. nov. exhibits all genus characters, such as males with only one pair of proclinate orbital setae, facial ridge bare, short tarsal claws and male with sex patches present on ventral surface of tergites. The proposition of this new species is based mainly on comparison with type material deposited at MZSP and original descriptions. Female terminalia of L. oligothrix sp. nov. follow a similar structure described by Herting (1957) for oviparous Exoristini and Winthemiini (both in Exoristinae ), with a small and simplified sternite 8 and a forked hypoproct with apical projections. However, the forked hypoproct of the species included in that study do not present arms as developed as viewed in L. oligothrix sp. nov., especially with the development of inner projections and bends at the apex ( Figure 6b ). Unfortunately, female terminalia descriptions of oviparous Blondeliini with telescoped ovipositor are extremely scarce in literature, precluding additional comparisons for Leptostylum . Although Cantrell (1988) had included some oviparous Blondellini species with telescoped ovipositor in his study, the hypoproct is briefly described and poorly illustrated.

Figures

Figure 1. Male paralectotype of Anaphorinia aurata Towsend, 1927,deposited at MZSP.(a) Head, frontal view. (b) Head, lateral view. (c) Dorsal habitus. (d) Lateral habitus. (e) Wing, ventral view. (f) Abdomen, latero-ventral view, showing sex patches on tergites 3, 4 and 5. (g) Label. Scale bars: 1 mm.

Figure 4. Male of Leptostylum leuconotum (Wulp, 1892), deposited at MZSP. From Serra da Cantareira, São Paulo, Brazil. (a) Head, dorsal view. (b) Head, frontal view. (c) Head, lateral view. (d) Dorsal habitus. (e) Lateral habitus. (f) Wing, dorsal view. (g) Abdomen, latero-ventral view, showing sex patch on tergite 4. Scale bars: 1 mm.

Figure 5. Male holotype (a–c, g, i, j, k) and female paratype (d–f, h, l, m) of Leptostylum oligothrix Gudin and Messas sp. nov., deposited at MZSP. From Jundiaí, São Paulo, Brazil. (a) Head, male, dorsal view. (b) Head, male, frontal view. (c) Head, male, lateral view. (d) Head, female, dorsal view. (e) Head, female, frontal view. (f) Head, female, lateral view. (g) Dorsal habitus, male. (h) Dorsal habitus, female. (i) Lateral habitus, male. (j) Wing, male, dorsal view. (k) Abdomen, latero-ventral view, showing sex patches on tergites 3, 4 and 5. (l) Lateral habitus, female. (m) Wing, female, dorsal view. Scale bars: 1 mm.

Figure 6. Male and female terminalia of Leptostylum oligothrix Gudin and Messas sp. nov. (a) Male terminalia, exhibiting posterior and lateral views, respectively. (b) Female terminalia, exhibiting dorsal, lateral and ventral views, respectively. Scale bar: 1 mm. Abbreviations: bac scl, bacilliform sclerite; cerc, cercus; distph, distiphallus; ej apod, ejaculatory apodeme; epand, epandrium; epiph, epiphallus; epiprct, epiproct; hypd, hypandrium; hyprct, hypoproct; pgt, postgonite; phapod, phallapodeme; pregt, pregonite; st, sternite; sur, surstylus; tg, tergite.