Asindulum mexicanum Fitzgerald, 2023

Fitzgerald, Scott J., 2023, The Nearctic species of Asindulum Latreille and Macrorrhyncha Winnertz (Diptera: Keroplatidae), Zootaxa 5351 (1), pp. 72-106 : 84-87

Asindulum mexicanum Fitzgerald n. sp.

Figs. 28–37 , 85

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Type material. Holotype male ( Fig. 28 ) ( CASC), point-pinned, terminalia dissected: MEXICO: SAN LUIS POTOSI: El Bonito , 7 mi. S. of Ciudad Valles , el. 300’, 20.XII.1970, P.H. & M. Arnaud . Paratypes: same as holotype, 1 female ( CASC) .

Description. Holotype male. Body length ca. 4.5 mm (n = 1). Head, antennae, mouthparts brown. Antennae with 14 cylindrical, barrel-shaped flagellomeres plus a minute, apical, button-like apicule, all without distinct setae. Mouthparts as Fig. 29 ; long, terminating near apex of fore coxa. Palps five-segmented. Three centrally-positioned ocelli in a line; median ocellus smaller. Mesonotum brown with hint of very thin, sparse, greyish pollinosity and short black setae over most of surface except for a pair of bare (asetose) dorsocentral stripes. Thoracic pleura light brown; katepisternum, laterotergite, and mediotergite bare, a single small seta at dorsal edge of anepisternum. Anterior spiracle without posterior setae. Legs light brown, becoming slightly darker distally. 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 a small number of short black setae in regular rows on ventral, anterior, anterodorsal, dorsal, and posterior surfaces. Wing as Fig 28 ; ca. 4.0 mm (n = 1), mostly hyaline except slightly brown fumose along wing margin on 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 brown with short black setae and light brown highlights on anterolateral portions of tergites 4 and 5. Male terminalia as Figs. 30–35 . Male tergite 9 posteriorly medially emarginate, emargination broad v-shaped posteriorly, becoming a narrow notch anteriorly, with posterior edge of tergite 9 forming two very broadly-rounded (nearly truncate) lobes. Posterolateral lobes of tergite 9 somewhat triangular in dorsal and ventral views, not laterally flattened, but with inner surface slightly expanded and sloping into genital chamber. In lateral view, posterolateral lobes of tergite 9, appear apically rounded. Ventrally, gonocoxites medially subdivided with posterior apices forming narrow rounded lobes. In lateral view, lateral lobes of gonocoxites mitten-like, narrowly rounded apically, dorsal edge with a short, thumb-like dorsal process dorsomedially. Gonostylus talon-like, evenly curved, 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 segment 6; 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. At the posterior apex of the sperm pump is a pair of small dorsoventrally flattened, apically rounded, scoop-shaped lobes.

Female. As in male except: Body length ca. 4.5 mm (n = 1). Mesonotum brown laterally and lighter-brown medially forming a light central stripe about 1/3 width of mesonotum. Wing ca. 4.0 mm (n = 1), slightly less brown fumose; fumosity concentrated at anteroapical margin near R 2+3. Abdomen broader than male; expanding posteriorly to segment 5 then narrowing again. Tergites mostly yellowish-brown with brown posterior bands. Female terminalia ( Figs. 36–37 ) retracted into segment 7. Cerci fleshy, setose, oval, pad-like. Sternite 10 broadly rounded posteriorly. Two lightly sclerotized, balloon-shaped spermathecae present.

Etymology. The specific epithet (adjective) is for the type locality in Mexico.

Diagnosis. Mouthparts of both sexes ending near apex fore coxa, posterolateral lobes of male tergite 9 rounded in lateral view (not apically hooked). Only one female specimen known; females possibly distinguished from other Nearctic species by smaller size (wing ca. 4.0 mm) and distribution as indicated in the key.

Comments. One specimen ( CASC) which was collected at the same site and on the same date as the type series is missing the abdomen (sex unknown) and is larger (wing ca. 6.0 mm rather than 4.0 mm); considering it’s condition, it was not included as part of the type series. A damaged specimen (abdomen missing) from Baja California, Mexico ( CASC) with a black thorax may be a dark morph of this taxon or represent an undescribed species; it is the only other Asindulum specimen otherwise known from Mexico.

Distribution ( Fig. 85 ). Known only from the type series collected from San Luis Potosi, Mexico.

Figures

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

FIGURES 28–29. Asindulum mexicanum n. sp., holotype male. 28. Habitus. 29. Head, anterior (not to scale). Scale = ca. 1.0 mm. Abbreviations: cx1, coxa 1; lbl, labellum; lbr, labrum.

FIGURES 30–33. Asindulum mexicanus, holotype male, terminalia. 30. Dorsal. 31. Ventral. 32. Lateral. 33. Gonostylus, posterolateral (not to scale). Scale bar = ca. 0.25 mm. Abbreviations: dp, dorsal process of gonocoxite; gc, gonocoxite; gs, gonostylus; llgc, lateral lobe of gonocoxite; llt9, lateral lobe of tergite 9; t9, tergite 9.

FIGURES 34–35. Asindulum mexicanum n. sp., holotype male, male terminalia including sperm pump. 34. Ventral. 35. Lateral. Scale = ca. 0.25 mm. Abbreviations: da, dorsal apodeme; ea, ejaculatory apodeme; gc, gonocoxite; t9, tergite 9; va, ventral apodeme.

FIGURES 36–37. Asindulum mexicanum n. sp., female terminalia. 36. Dorsal. 37. Posteroventral. Scale = ca. 0.25 mm. Abbreviations: ce, cercus; sp, spermathecae; s7, sternite 7; s8, sternite 8; s10, sternite 10; t7, tergite 7.