Stilobezzia (Eukraiohelea) elegantula (Johannsen)

Bauer, Maria Luiza Felippe, 2017, Contributions to the knowledge of predaceous midges of the subgenus Eukraiohelea Ingram & Macfie of Stilobezzia Kieffer (Diptera: Ceratopogonidae), from Brazil, Zootaxa 4324 (3), pp. 557-570 : 559-562

Stilobezzia (Eukraiohelea) elegantula (Johannsen)

( Figs. 1 ¯14)

Bezzia elegantula Johannsen, 1907: 109 (female; U.S.A., Kansas).

Probezzia elegantula: Malloch 1914: 137 (combination).

Parabezzia elegantula: Malloch 1915: 359 (combination).

Parabezzia (Eukraiohelea) elegantula: Johannsen 1934: 345 (notes; change of status).

Eukraiohelea elegantula: Johannsen 1943: 781 (combination).

Stilobezzia (Eukraiohelea) elegantula: Wirth 1953: 62 (in part, female; combination; redescription; distr.); Wirth 1974:43 (in Neotropical catalogue; distribution); Wirth & Grogan 1981: 78 (in part, female; redescription; figs.); Wilkening et al. 1985: 525 (Florida records); Wirth & Spinelli 1992: 343 (redescription; distribution); Spinelli & Cazorla 2005: 72 ( Argentina, Paraguay records; distribution); Borkent and Spinelli 2007: 86 (in Neotropical catalogue); Borkent and Grogan 2009: 22 (in Nearctic catalogue north of Mexico; distribution); Grogan et al. 2010: 39 (Florida record); Torreias et al. 2014: 117 (Amazon records; distribution); Borkent 2016: 140 (in online catalogue); Santarém & Felippe-Bauer 2017: 19 (in Brazilian catalogue).

Stilobezzia (Eukraiohelea) maculitibia Lane & Forattini, 1956: 207 (female, male; Panama); Lane & Forattini 1961: 84 (in key); Wirth 1974:43 (in Neotropical catalogue; distr.); Wirth & Spinelli 1992: 344 (as synonym of S. elegantula ).

Stilobezzia subsessilis Kieffer, 1917: 311 (female; Paraguay); Lane & Forattini 1961: 88 (subgeneric position); Wirth & Spinelli 1992: 348 (as species inquirenda); Spinelli & Cazorla 2005: 73 (as synonym of S. elegantula ).

Diagnosis. The only American species of Stilobezzia (Eukraiohelea) of medium to large size (wing length 1.27 – 1.48 mm) with pale yellowish coloration and distinctive L-shaped dark brown spots on abdominal tergites and basal 1/3 of hind femur brown. Male with proximal 1/3 of gonocoxite pale yellowish and the distal 2/3 contrasting dark brown, and a rectangular sclerite located ventrally at midlength of stem of parameres. Female with two pairs of batonnets on tarsomere 5 of all legs.

Redescription of male. Head ( Fig. 1 ) dark brown. Antenna with flagellomeres 1–10 pale yellowish basally, brown distally, flagellomeres 11–13 dark brown with pale yellowish basal ring; flagellomere 13 nearly twice as long as 12; plume dark brown, dense; antennal ratio 1.09–1.23 (1.17, n = 7). Palpus ( Fig. 2 ) dark brown; third segment moderately stout with subapical, round shallow sensory pit; palpal ratio 2.37–3.14 (2.87, n = 7).

Thorax. Scutum brown (as Fig. 8 , female), anterolateral margins darker, prescutellar depression pale yellowish; scutellum pale yellowish except narrow lateral margins brown, with 4 stout setae, 0 – 2 thinner setae; postscutellum dark brown. Legs pale yellowish; trochanters dark brown; apex of fore tibia dark brown; basal 1/3, narrow apex of hind femur brown; basal 1/3, narrow apex of hind tibia dark brown; fore femur with 2 – 3 short, stout ventral spines; tarsomere 1 of mid leg with basal, slender, straight spine; tarsomere 1 of hind leg with basal, stout, curved spine; hind tibial comb with 5 spines; fore leg tarsal ratio 2.21–2.63 (2.34, n = 8); mid leg tarsal ratio 2.78 – 3.03 (2.87, n=8); hind leg tarsal ratio 2.40–2.62 (2.49, n= 8); tarsomere 5 of all legs ( Fig. 3 ) with 1 pair of batonnets, claws large, shorter than their respective tarsomere 5 with long basal tooth, hind claws longest. Wing ( Fig. 4 ) membrane hyaline; r-m crossvein oblique; cubital fork distal to level of base of r-m crossvein; wing length 1.27–1.45 (1.35, n = 8) mm, width 0.44–0.48 (0.45, n = 8) mm; costal ratio 0.72–0.75 (0.74, n = 8). Halter stem pale; basal half of knob dark brown, distal half pale.

Abdomen. Pale yellowish, with distinctive dark marks on the lateral margins of the tergites. Genitalia ( Figs. 5 – 7 ): tergite 9 extending to apex of gonocoxites, distal margin rounded with small mesal notch; cerci slender, rectangular; sternite 9 2.80 X broader than long with convex posteromedian projection. Gonocoxite nearly triangular, stout, 1.7 X longer than greatest breadth, proximal 1/3 pale yellowish, distal 2/3 dark brown with a hyaline membrane extending from dorsal inner margin to near apex of parameres, the basolateral margins slightly sclerotized, lobe-shaped, distal margin rounded; gonostylus pale yellowish, slender, 0.75 X the length of gonocoxite, tip curved. Parameres separate, subparallel, heavily sclerotized; basal apodemes stout with stem not reaching margin of tergite 9; proximal 1/2 of parameres slender basally, distal 1/2 gradually broadening, apices recurved ventrally, tips pointed ( Fig. 7 ); a rectangular sclerite located ventrally at midlength of stem of parameres. Aedeagus represented by 2 slender, arched sclerites; basal portion heavily sclerotized, curved, basal arms recurved; distal portion sclerotized, apices pointed, overlapping.

Redescription of female ( Fig. 8 ). Similar to male, with the following notable sexual differences. Head ( Fig. 9 ). Antenna with flagellomeres 1–8 pale yellowish basally, brown distally, flagellomeres 9–13 brown with pale basal ring; antennal ratio 1.35–1.53 (144, n = 7). Palpal ratio 2.75–3.00 (2.90, n = 8). Mandible with 6 – 8 teeth.

Thorax. ( Fig. 8 ). Legs ( Fig. 10 ): fore femur with 2 ventral spines; tarsomere 5 of all legs with 2 pairs of batonnets ( Fig. 11 ); fore tarsal ratio 2.21– 2.36 (2.30, n = 8), mid tarsal ratio 2.64– 2.83 (2.73, n = 8), hind leg tarsal ratio 2.30–2.70 (2.53, n = 8); tarsomere 5 of all legs with claws almost as long as tarsomere with long basal tooth. Wing ( Fig. 12 ) length 1.33–1.48 (1.40, n = 8) mm, width 0.55–0.60 (0.58, n = 8) mm; costal ratio 0.75–0.80 (0.79, n = 8).

Abdomen ( Figs. 8, 13 ). Lateral broad margins of segment 8 dark brown. Genitalia ( Fig. 14 ): sternite 8 pale, with U-shaped posteromedian excavation; sternite 9 divided, each half slender with inner 1/3 straight, sclerotized, margin recurved; sternite 10 pale with 3 – 4 pairs of setae; cercus rounded, short; two large, subequal, ovoid spermathecae with moderately wide, short necks, measuring 53–58 (55, n = 5) µ by 40–48 (43, n = 5) µ and 50–55 (50, n = 5) by 38–45 (40, n = 5) µ; a small, round, rudimentary third spermatheca measuring 10 (n = 7) µ.

Distribution. Argentina (Chaco, Misiones), Brazil (Amazonas, Rio de Janeiro), Mexico, Panama, Paraguay, (?) Puerto Rico, USA (Kansas to Maryland, south to Louisiana and Florida).

Types. Types of Bezzia elegantula not designated by Johannsen (1907). Wirth & Spinelli (1992) noted that females were labeled "Collected in July at electric light on bridge across Kansas river at Lawrence, Douglas County, Kansas, by E. S. Tucker.”, in the Snow Entomological Collection, University of Kansas, Lawrence.

Material examined. 9 males, 10 females, as follows: 8 males, 9 females, BRAZIL, Rio de Janeiro, Casimiro de Abreu, Union Biological Reserve (22°25’35” S 42°2’4”W), 07.XI – 13.XII.2013, "Biota Diptera Fluminense " team col., Malaise trap ( CCER) ; 1 male, 1 female, same data except 25.VIII – 26.XI.2013 ( CCER) .

Discussion. The American species Stilobezzia (E.) elegantula is similar to S. (E.) punctifemorata Das Gupta & Wirth , from Southeast Asia. The latter species can be clearly distinguished by the yellowish thorax with a peculiar dark brown pattern of coloration on the scutum, the presence of only one pair of batonnets on the female hind tarsomeres 5 and the aedeagal sclerites have a large expansion at their distomesal end. Furthermore, the presence of a rectangular sclerite located anterior to the parameres of S. elegantula resembles the male genitalia of S. (E.) brevicostalis Das Gupta & Wirth , another species from Southeast Asia in which the parameres are enclosed within a dark band-like sclerotized bridge. This Asian species differs from S. elegantula by the stout black spine near the base of the male hind femur and the parameres have a large lateral lobe and a slender anterior arm.

Wirth (1953) noted that males of the subgenus Eukraiohelea have an aedeagus with a hyaline posterior membrane. We confirm that males of S. elegantula have such a hyaline membrane, but it extends from the dorsal inner margin of the gonocoxites to near the apex of the parameres and that the lateral margins are lightly sclerotized. Finally, in males of S. (E.) elegantula , the apices of the parameres are usually pointed, however in some specimens the apices are difficult to see and they are apparently blunt ( Fig. 6 ).

Figures

FIGURES 1 – 7. Stilobezzia (Eukraiohelea) elegantula (Johannsen). Male. 1. head, dorso-frontal view. 2. apex of proboscis and palpi. 3. tarsomeres 5 and claws. 4. wing. 5. genitalia, dorsal view. 6. genitalia, ventral view. 7. apices of parameres. Scale bars 0, 0 5 mm.

FIGURES 8 – 14. Stilobezzia (Eukraiohelea) elegantula (Johannsen). Female. 8. thorax and abdomen, dorsal view. 9. head, frontal view. 10. legs. 11. tarsomeres 5 and claws. 12. wing. 13. abdomen, ventral view. 14. sternites 7 – 10 of abdomen and spermathecae, ventral view. Scale bars: 0, 0 5 mm.