Asindulum flavidum Fitzgerald, 2023

Fitzgerald, Scott J., 2023, The Nearctic species of Asindulum Latreille and Macrorrhyncha Winnertz (Diptera: Keroplatidae), Zootaxa 5351 (1), pp. 72-106 : 80-82

Asindulum flavidum Fitzgerald n. sp.

Figs. 16–27 , 85

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Type Material. Holotype male ( CNCI), pinned ( Fig. 16 ): USA: FLORIDA: Wakulla Co., Ochlockonee State Pk., IV.30.1980, J.F. Burger . Paratypes: USA: FLORIDA: Gainesville , 25.IV.1952, G.S. Walley, 1m ( CNCI) ; Gulf Hammock , 23.IV.1952, J. R. Vockeroth , 1m 1f on same pin ( CNCI) ; GEORGIA: McIntosh Co., Sapelo Island , 17 May 1978, J. R. Powers , 1m ( CASC) .

Additional material examined (see Comments). USA: NORTH CAROLINA : Cumberland Co., Fort Bragg, 6–13. VI.1967, J.D. Birchim , 1m ( CASC) ; TEXAS: Erath Co., Happy Valley Estates , 32.164296, -98.287018, May 2023, R. Pfau , Malaise trap, 2m 1f, ( SFC) ; same as previous except 5 June 2023, 1m ( SFC).

Additional records (the following CSCA specimens were determined by Peter Kerr based on photographs of the male terminalia sent by the author). USA: FLORIDA: Wakulla Co., Apalachicola NF, FS366, LLP oak savanna, N30º19.751’, W84º30.309’, Ant Heaven Trap, Malaise ; 15–20 May 2005, Deans, Joshi, Murray coll., CSCA06 LOT 168, 3m ( CSCA; CSCA _06X146) ; Wakulla Co., Apalachicola NF, FS366, LLP savanna, Malaise , N30º19.751’, W84º30.309’, 21–28 May 2005, Wetherby, Murray, CSCA08 L 213, 1m ( CSCA; CSCA _13M992) ; Wakulla Co., Apalachicola NF, FS366, LLP savanna, Malaise , N30º19.751’, W84º30.309’, 21–28 May 2005, Wetherby, Murray, CSCA08 L213, 1f ( CSCA; CSCA _22Q320) .

Description. Male. Body length ca. 7.0 mm (n = 1). Head, yellowish to light brown, area around ocelli black. Antennae with 14 brown, cylindrical flagellomeres plus a small, apical, rounded apicule; flagellomeres 2–13 broader than long, flagellomeres 1 and 14 longer than broad, all without distinct setae. Pedicel, scape, and base of basal flagellomere yellowish. Mouthparts as Fig. 17 ; yellowish and brown, long, terminating near apex of fore coxa. Palps brown, five-segmented. Three centrally-positioned ocelli in a line; median ocellus smaller. Mesonotum cream to yellowish with three broad light brown to brown stripes; lateral stripes anteriorly truncated and median stripe narrowly divided by a narrow darker stripe medially (stripes sometimes merged into a central brown area). Mesonotum with black appressed setae over most of surface except for a pair of bare (asetose) submedian stripes at least anteriorly. Thoracic pleura cream to yellowish; anepisternum, katepisternum, laterotergite, and mediotergite bare. Anterior spiracle without posterior setae. Legs yellowish, becoming slightly darker distally due to density of trichia. Tibial spurs 1:2:2 with inner spurs longer. Fore tibia with apical, triangular sensory area on anterior surface. Hind tibia with trichia irregularly arranged and short black setae in regular rows on all leg surfaces. Wing as Fig 18 ; ca. 5.0–6.0 mm (n = 4), hyaline to slightly brown fumose along wing edge at distal third. Veins brown, anterior and posterior forks and CuP with short, widely-spaced setae on upper surface, especially apically. Anterior veins with more densely-spaced setae except Sc, base Rs, and R 2+3 bare. CuP reaching wing margin. Abdomen yellowish with terminal segments darker; segments 1–4 yellowish with very narrow light brown posterior borders, remaining tergites either dark brown to black with lighter areas laterally or just darker versions of the preceding segments (light brown with dark brown posterior borders). Abdomen with black setae. Male terminalia as Figs. 19–24 . Male tergite 9 posteriorly medially emarginate, posterolateral corners developed into a pair of broad, laterally-compressed, dorsally-hooked lobes. Ventrally, gonocoxites deeply and broadly medially emarginate with only a narrow strap connecting the two halves posteriorly. Lateral lobes of gonocoxites broad, rectangular, apically truncate, without dorsal process dorsomedially. Gonostylus talon-like, apically-hooked and acute, with some strong subapical setae. Sperm pump (possibly fused with parameres?) complex, large and anteriorly elongated, with apodemes reaching into abdominal segments 6–5; notable are two pairs of very long, more laterally-positioned apodemes (one pair more ventral, one pair more dorsal) and an ejaculatory apodeme which is very strongly laterally compressed. The posterior apex of the sperm pump is a pair of laterally flattened lobes that are dorsally connected, forming a U-shaped cradle.

Female. As in male except: Body length ca. 8.0 mm (n = 1). Mesonotum not distinctly striped. Wing ca. 7.0 mm (n = 1) brown fumose along wing margin on distal third; darker anteroapically. Abdomen broader than male; expanding in width posteriorly to segments 4 and 5 then tapering again. Tergites mostly yellowish to light brown with brown posterior borders on tergites 1–3 and tergites 4+ brightest and with the least brown ( Fig. 25 ). Segments beyond tergite 7 strongly telescoped internally. Female terminalia as Figs. 26–27 . Cerci fleshy, setose, oval, pad-like. Sternite 10 broadly rounded to truncate posteriorly.

Etymology. The species epithet is from the Latin flavidus (yellowish) for the predominant pale coloration of the more southern representatives of this species.

Diagnosis. Mouthparts of both sexes ending near apex of fore coxa, male tergite 9 with posterolateral corners developed into a pair of broad (narrow in A. montanum ), laterally-compressed, dorsally-hooked lobes.

Comments. There is significant abdominal color variation in this species described below as a “pale morph” and a “dark morph”. The pale morph (Florida and Georgia) has males with abdominal segments 1–4 yellowish and remaining tergites darker ( Fig. 16 ); female ( Fig. 25 ) with all tergites largely yellowish with brown posterior margins on tergites 1–3 (only one pale female studied so color variation undocumented). One male specimen examined from North Carolina with damaged terminalia (tergite 9 and apices of gonostyli missing) has the apically truncate lateral lobes of the gonocoxites typical of A. flavidum and is thus believed to represent this species. This specimen has the abdominal tergites mostly dark brown with only tergite 4 yellowish; a color pattern unknown from the few specimens examined from further south in Georgia and Florida. However, specimens from Texas with intact male terminalia were also of this darker color morph (all tergites brown except tergite 4 yellowish) which matches abdominal color of some specimens of A. montanum . Females of the darker color morph have abdominal tergites 1–3 brown and remainder yellowish. No morphological differences could be found between the darker and lighter color morphs and while they are considered to be conspecific, the type series is restricted to specimens of the paler form.

Distribution ( Fig. 85 ). Southeastern USA; material was examined from North Carolina Georgia, Florida, and Texas.

Biology. In the Cross Timbers and Prairies Ecological Region of Texas (https://tpwd.texas.gov/landwater/land/ habitats/cross_timbers/ecoregions/cross_timbers.phtml) this species has been collected along an intermittent stream with Cedar Elm ( Ulmus crassifolia Nutt. ) as the primary canopy tree and was observed visiting the flowers of Carolina Buckthorn ( Frangula caroliniana (Walter) A. Gray ) (R. Pfau, pers. comm. Aug. 2023 and iNaturalist observation: https://www.inaturalist.org/observations/161738855).

Figures

FIGURE 85. Distribution map for Asindulum coxale, Asindulum flavidum n. sp., and Asindulum mexicanum n. sp..

FIGURES 16–18. Asindulum flavidum n. sp., holotype male. 16. Habitus, lateral. 17. Head, anterior. 18. Wing. Scale bars = ca. 1.0 mm. Abbreviations: CuP, posterior branch of cubital vein; cx1, coxa 1; lbl, labellum.

FIGURES 19–22. Asindulum flavidum n. sp., male terminalia.19. Dorsal. 20. Ventral. 21. Lateral. 22. Gonostylus, posterolateral (not to scale). Scale bar = ca. 0.5 mm.Abbreviations: ce, cercus; gc, gonocoxite; gs, gonostylus; hp, hypoproct; llgc, lateral lobe of gonocoxite; llt9, lateral lobe of tergite 9; t9, tergite 9.

FIGURES 23–24. Asindulum flavidum n. sp., male terminalia including sperm pump. 23. Lateral. 24. Ventral. Scale = ca. 0.5 mm. Abbreviations: ce, cercus; da, dorsal apodeme; ea, ejaculatory apodeme; gc, gonocoxite; t9, tergite 9 (t9 damaged in this specimen); va, ventral apodeme.

FIGURES 25–27. Asindulum flavidum n. sp., female. 25. Abdomen, posterodorsal. Scale = ca. 1.0 mm. 26. Terminalia, dorsal. Scale = ca. 0.5 mm. 27. Terminalia, ventral. Scale = ca. 0.5 mm. Abbreviations: ce, cercus; s7, sternite 7; s8, sternite 8; s10, sternite 10; t7, tergite 7.