Culicoides guarani Ronderos & Spinelli

Ayala, Mahia M., Spinelli, Gustavo R., Funes, Amparo & Ronderos, María M., 2015, Additional notes on biting midges from the subtropical forest of northeastern Argentina (Diptera: Ceratopogonidae), Zootaxa 3941 (1), pp. 79-90 : 80-81

Culicoides guarani Ronderos & Spinelli

( Figs. 1–21 )

Culicoides guarani Ronderos & Spinelli, 1994: 48 (female; Argentina); Borkent & Wirth, 1997: 69 (in World catalogue); Spinelli, 1998: 325 (in list, Argentina); Borkent & Spinelli, 2000: 39 (in catalogue south of USA); Spinelli et al., 2005: 140, 145 (in key; wing photo); Borkent & Spinelli, 2007: 72 (in Neotropical catalogue); Borkent, 2015: 86 (in online World catalogue).

Male adult ( Figs. 1–4 , 15–16 ). Head ( Figs. 1–2 ) dark brown. Eyes bare, forming a V-shaped where they contact. Antennae with flagellomeres pale brown, 2–10 fused ( Fig. 2 ); sensilla coeloconica in flagellomeres 1, 11–13. Third palpal segment stout, with deep, rounded subapical sensory pit ( Figs. 1–2 ). Thorax dark brown, scutum without definite pattern, only slightly paler areas laterally. Legs dark brown, knees blackish, fore and midfemora with subapical, tibiae with subbasal narrow pale rings; hind tibial comb with 4 spines, second from spur longest. Wing length 1.00 (0.98–1.02, n = 2) mm, width 0.41 (0.40–0.42, n = 2) mm; pattern as in Fig. 3 ; CR 0.54 (n = 2); macrotrichia sparse on distal half of wing, none in mcu1 and anal cell; halter brown. Genitalia ( Fig. 4 ): tergite 9 long, tapering, with short, pointed apicolateral processes, distal margin truncate, pair of evident, pilose, median cerci; sternite 9 with narrow, V-shaped, posteromedial excavation. Gonocoxite stout, twice longer than greatest breadth, ventral root foot-shaped, posterior heel evident, dorsal root slender; gonostylus as long as gonocoxite, slender, slightly curved to pointed tip. Parameres ( Fig. 15 ) separate, subparallel, each stout, with strongly sclerotized basal knob; stem curved near base, midportion of stem slightly swollen, nearly straight, distal portion slender, bent ventromesad, taperering to fine point with lateral fringe of stout spines, the portion at the base of the fringe slightly expanded. Aedeagus ( Fig. 16 ) Y-shaped; basal arch pointed caudad, extending to 0.75 of total length; basal arms slender, strongly sclerotized, nearly straight; posteromedial projection lightly sclerotized tapered to slender, broad tip, with pair of conspicuous lateral processes.

Male pupa ( Figs. 5–6, 8–13 ). Exuviae general coloration pale brown. Flagellum against lateral margin of face ( Fig. 5 ). Total length 2.20–2.40 (2.31, n=3) mm. Length of cephalothorax 1.00–1.15 (1.07, n= 3) mm, width 0.62 –0.70 (0.65, n= 3) mm. Dorsal apotome ( Fig. 6 ) without ventral line of weakness, dorsomedial tubercle and central dome; slightly wider than long, distal margin truncate, smooth, except for few small wrinkles; disc surface covered by stout rounded spinules; raised areas present; tubercles of dorsal apotome sensilla well-developed, bearing 2 dorsal apotome sensilla as follows: DA-1-H, long, stout seta, DA-2-H campaniform sensillum at tubercle base; DAL 0.13–17 (0.12, n=3) mm; DAW 0.12–0.17 (0.14, n=3) mm; DAW/DAL 0.86–1.26 (0.95, n=3). Cephalothorax rectangular ( Fig. 5 ), surface covered with stout rounded spinules, antenna extending posteriorly to various points along anterior margin of wing; mouthparts ( Figs. 11 , 17 ) with mandible, lacinia well developed; palpus extending equal to posterolateral margin of labium; labium separated medially by labrum; apex of labrum rounded. Cephalothoracic sensilla ( Figs. 8–11 , 17, 19 ) as follows: one anteriomedial AM-1-T ( Fig. 9 ) minute seta on small tubercle, 2 dorsolateral cephalic sclerite sensilla ( Fig.10 ): DL-1-H long, thin seta, DL-2-H short, stout seta on rounded strong tubercle; 3 anterolaterals ( Fig. 8 ): AL-1-T short, thin seta, Al-2-T long, thin seta, AL-3-T short, stout seta, all sensilla on prominent tubercle; clypeal labrals (Figs: 11, 17): CL-1-H campaniform sensillum, CL-2- H medium-sized, thin seta; oculars (Figs. 11,17): O-1-H, O-3-H long, thin setae, O-2-H campaniform sensillum Respiratory organ ( Figs. 5, 8–9 ) elongated, slender, uniformly brown, medium-sized, circular in cross-section, wider at base, covered with scale-like spinules; 6–7 apical pores, 2–3 lateral; pedicel ( Fig. 9 ) short, stout, P length 0.02–0.03 (0.025, n=3) mm, RO length 0.195–0.20 (0.197, n=3) mm, RO wide 0.025–0.03 (0.027, n=3) mm; P/RO 0.10–0.15 (0.126, n=3); 5 dorsal setae ( Fig. 18 ): D-1-T, D-2-T, D-4-T long, stout setae, D-2-T longer than D-1-T and D-4-T; D-3-T campaniform sensillun, D-5-T minute seta, all setae on rounded tubercles, SA-2-T present. Metathoracics ( Fig. 19 ): M-2-T long, thin seta, M-3-T campaniform sensillum, M-3-T near anterior margin. Abdominal segments with smooth integument, with scarse, scattered spicules on anterior and posterior portions; each segment without pigmentation pattern. First abdominal segment ( Figs. 5 , 20 ) with setae as follows: 3 anteromesal setae, D- 2-I short, stout seta, D- 3-I long, thin seta, D- 7-I campaniform sensillum; 3 posterior setae, D- 4-I medium-sized, thin seta, D- 8-I short, thin seta, D- 9-I minute seta; 3 lateral setae: L- 1-I long, thin seta, L- 2-I, L- 3-I campaniform sensilla. Fourth segment ( Figs. 5 , 21 ) with dorsal and ventral tubercles with small base: D- 1-IV minute seta, D- 2-IV, D- 3-IV medium-sized, thin setae, D- 3-IV longer and thinner than D- 2-IV; D- 4-IV, D- 7-IV without setae, D- 5-IV, D- 8-IV minute setae, D- 9-IV short, curved seta; V- 1-IV, V- 2-IV campaniform sensilla, V- 5- IV short seta, V- 6-IV long, thin seta, V- 7-IV minute seta, all on notorious pointed lateral tubercles with wide base: L- 1-IV short seta, tubercle smaller than others, L- 4-IV short, stout seta, L- 2-IV, L- 3-IV medium-sized, stout setae. Segment 9 ( Figs. 5, 13 ) approximately 1.14 X longer than greatest width, length 0.20–0.205 (0.202, n= 3) mm, width 0.155–0.185 (0.177, n= 3) mm; posteriorly directed spicules restricted dorsally to mesal area, terminal processes triangular, these moderately elongated, subparallel, pointed; ventral surface of processes spiculate, D- 5- IX, D- 6-IX campaniform sensilla ( Fig. 13 ), genital lobe moderately long, globose, extending under posterior margin.

Female pupa ( Figs. 7, 14 ). Similar to male with usual sexual differences. Total length 2.33–2.40 (2.37, n=3) mm. Dorsal apotome ( Fig. 7 ) with DAL 0.14–0.16 (0.15, n=2) mm; DAW 0.125–0.135 (0.13, n=2) mm, DAW/ DAL 0.82–0.90 (0.85, n=2). Respiratory organ: RO length 0.19–0.21 (0.20, n=3) mm, RO width 0.03–0.04 (0.035, n=3) mm; pedicel length 0.025 (n=2) mm, P/RO 0.119–0.125 (0.122, n=2). Cephalothorax length 1.00–1.04 (1.02, n=3) mm, width 0.62– 0.65 (0.64, n=3) mm. Segment 9 ( Fig. 14 ) length 0.20–0.215 (0.207, n=3) mm, width 0.145–0.150 (0.148, n=3) mm; terminal processes ( Fig. 14 ) length 0.065–0.075 (0.072, n=3) mm, width 0.015–0.040 (0.025, n=3) mm.

Distribution. Argentina (Misiones).

Taxonomic discussion. Culicoides guarani is one of the 14 species included in the Culicoides eublepharus group. All these are known only through adults and seven of them, including C. guarani , just from females.

The pupa of this new species is similar to C. debilipalpis Lutz , a species placed in the subgenus Haematomyidium that also breeds in tree holes. However, in the latter species the exuviae is pale yellowish brown, the respiratory organ is yellowish except the distal half brown with its pedicel longer, the posteriorly directed spicules of the caudal segment are restricted to a narrow anterior band and not connected to the mesal inverted Vshaped patch of spicules, and the terminal processes are subparallel with pointed and dark tips. Although the general chaetotaxy is similar, the setae are of cephalothorax and abdomen are thinner and shorter than in C. debilipalpis .

The male genitalia of this species is similar to the one illustrated by Wirth & Lee (1967) for C. tamboensis Wirth & Lee , a species inhabiting high altitudes of Colombia except for the sternite 9 with V-shaped and deep caudomedian excavation (very shallow in C. tamboensis ) and by the posteromedial projection of the aedeagus without lateral processes. Moreover, the latter species is larger (wing length 1.20 mm), the third palpal segment is shorter, the flagellomere 13 lacks sensilla coeloconica and the halter knob is pale at tip.

Culicoides propiipennis Macfie from Mexico to Ecuador, Venezuela and northern Brazil also have very similar genitalia, but the sternite 9 exhibits a very shallow caudomedian excavation, the parameres are convergent and the posteromedial projection of the aedeagus is slender and lacks lateral processes.

Specimens examined. Argentina, Misiones Prov., Garupá, Barrio Santa Inés, Estancia Santa Inés, 27° 31' 40.9'' S, 55° 51' 59.4'' W, 9-XI-2013, M. Ayala, 2 males, 3 females (with pupal exuviae).

Figures

FIGURES 1 – 4. Culicoides guarani Ronderos & Spinelli, male. 1, head, in anterior view; 2, flagellum; 3, wing; 4, genitalia (ventral view). Scale bars: 0.05 mm.

FIGURES 5 – 14. Culicoides guarani, 5 – 6, 8 – 13, male pupa; 7, 14, female pupa. 5, entire pupa; 6 – 7, dorsal apotome and dorsal apotome sensilla (DA-H); 8, respiratory organ (RO) and anterolateral sensilla (AL-T); 9, respiratory organ (RO), detail of pedicel (P) and anteromedial sensillum (AM-T); 10, dorsolateral cephalic sclerite sensilla (DL-H); 11, clypeal / labrals sensilla (CL) and oculars sensilla (O), details of mouthparts; 12, fourth abdominal segment chaetotaxy (dorsal and ventral views); 13, Segment 9, detail of ventral surface, genital lobe (GL), terminal processes (TP); 14, Segment 9. Scale bars: 0.05 mm

FIGURES 15 – 21. Culicoides guarani, 15 – 16, male adult; 18 – 21, male pupa. 15, parameres; 16, aedeagus, 17, clypeal / labrals sensilla (CL) and oculars sensilla (O), details of mouthparts; 18, dorsal setae (D-T), supraalar (SA); 19, metathorax chaetotaxy (M-T); 20, first abdominal segment chaetotaxy (dorsal view); 21, fourth abdominal segment chaetotaxy (dorsal and ventral views), with detail of setae and tubercles. Scale bars: 0.05 mm.