Macrorrhyncha vockerothi Fitzgerald, 2023

Fitzgerald, Scott J., 2023, The Nearctic species of Asindulum Latreille and Macrorrhyncha Winnertz (Diptera: Keroplatidae), Zootaxa 5351 (1), pp. 72-106 : 99-101

Macrorrhyncha vockerothi Fitzgerald n. sp.

Figs. 75–83

urn:lsid:zoobank.org:act:98573C85-7462-42F9-B2B3-921D67A5A7CA

Type Material. Holotype male ( CNCI), glued to side of pin, terminalia dissected: CANADA: QUEBEC: Old Chelsea, 30 VIII 1961, J.R. Vockeroth . Paratypes: same as holotype, 2 males ( CNCI) .

Description. Male. Body length ca. 3.5 mm (n = 1). Entirely cream to yellowish in color except, head, antennal flagellomeres, tarsi and apex of abdomen light brown. Head brown, antennae largely brown with base of basal flagellomere and sometimes pedicel and scape cream, mouthparts light brown with palps becoming lighter (cream) distally. Antennae with 14 cylindrical, barrel-shaped flagellomeres plus a minute, apical, button-like apicule, all without distinct setae. Mouthparts as Fig. 76 ; long, terminating approximately at level of apex of fore coxa. Palps five-segmented. Three centrally-positioned ocelli in an arc; median ocellus smaller. Mesonotum cream to yellowish with hint of three broad light brown longitudinal stripes, with short black setae in broad irregular rows medially, dorsocentrally, and laterally. Thoracic pleura bright cream to yellowish with some light brownish coloration; anepisternum, katepisternum, laterotergite, and mediotergite bare. Posterior edge of anterior spiracle with several short black setae. Coxae bright cream to yellowish, remainder of legs cream, becoming progressively more light brown distally (tarsi entirely light brown). 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 anteroventral, anterior, dorsal, posterodorsal, posterior, and posteroventral surfaces. Wing ca. 3.5 mm (n = 1), hyaline. Veins brown, anterior and posterior forks with short, closely-spaced setae on upper surface, especially apically. Anterior veins with closely-spaced setae except Sc, base Rs, and R 2+3 bare. CuP with a few sparse setae, strong basally, but quickly becoming nearly transparent; in some specimens slightly traceable all the way to wing margin as a subtle crease. Halters yellowish to light brown. Abdomen bright cream to yellowish (tergites 1–2 entirely so) with brown tinge over anterior parts of tergites or sometimes over entire tergite with brown coloration becoming more pronounced and darker distally, culminating with tergites 7–9 brown. Male terminalia as Figs. 78–83 . Male tergite 9 reduced, posterior margin with broad v-shaped emargination which nearly or entirely subdivides the sclerite into two small triangular sclerites which are closely appressed to tergite 8. In dorsal view, cerci prominent, triangular, fleshy, setose. Ventrally, gonocoxites with deep, broad u-shaped emargination which nearly subdivides sclerite; a narrow strip of sclerite anteriorly connecting the two halves. Inner process of gonocoxite, short, digitate, bearing a strong apical seta. In lateral view, gonocoxites short, broad, apically truncate, with a narrow, short, ventrally curved, asetose, apically rounded dorsal process that is longer than (i.e. reaches beyond the level of the posterior apex of) the primary lobe of the gonocoxite. Gonostylus cushion-shaped, apically (posteromedial surface) broadly truncate with four strong apically truncate setae. Gonostylus with a minute, nubbin-like basal lobe originating from medial surface; apex of basal lobe with two tiny seta (basal lobe difficult to observe; originates at about same position of origin as inner process of gonocoxite so that it lies hidden between main lobe of gonostylus and inner process of gonocoxite). Sperm pump (possibly fused with parameres?) large and anteriorly elongated, with apodemes reaching into abdominal segment 6; notable are two pairs of long apodemes (one nearly transparent pair more ventral and laterally flattened and the second pair more dorsal and rod-like), an unpaired median ejaculatory apodeme (which is the longest of all the apodemes and the most strongly laterally compressed) and a pair of short, divergent apodemes dorsally. The posterior apex of the sperm pump is difficult to discern, but includes a pair of dorsoventrally-flattened lobes (visible protruding above the thin strap of gonocoxite in Fig. 83 ).

Female. Unknown.

Etymology. This species is named in honor and memory of Richard (Dick) Vockeroth, collector of the types of this species as well as specimens of A. flavidum n. sp. and M. borealis n. sp. While Dick contributed significantly to the study of fungus gnats both through avid collecting and a number of important papers and book chapters, I remember him most for the personal impact he made on me. I first met Dick at the Third International Diptera Congress in Guelph, Canada in 1994. I had just arrived at the dorm after hitchhiking from the airport, duffle bag in hand, and had not even found my room yet, when I met Dick, who had clearly already been out collecting, coming down the hall wearing a belt filled with small aspirator tubes with gnats in all of them. At the time, I was an impressionable student preparing to start a master’s degree program working on Bibionidae ; Dick shared his observations of bibionids and pachyneurids, and encouraged and inspired me to look at fungus gnats as well (which I had largely ignored up to that point). Fast-forward 29 years and I am happy to be able to name this fungus gnat after Dick.

Diagnosis. Dorsal process of gonocoxites well-developed (longer than main lobe of gonocoxite), narrow, apically rounded; gonostylus cushion-shaped with several strong setae and a minute basal process; inner process of gonocoxite short, digitate. The female is unknown, but within the Nearctic Region it should be recognizable by the shorter mouthparts (terminating near apex of fore coxa) and yellowish thorax.

Comments. It is possible that M. vockerothi is the same species that was previously reported from New Hampshire, USA as “ Asindulum flavum Winnertz ” by Johannsen (1910) as it matches Johannsen’s description. Later, Laffoon (1965) records presumably the same taxon (as A. winnertzi (Tarwid) ; now a jun. syn. of “ flavum ”) from both New Hampshire and North Carolina. However, no specimens of Winnertz’s European species, originally described and currently placed in the genus Macrorrhyncha , were found in Nearctic material studied, suggesting that these previous records appear to be based on misidentifications. The only mostly-yellow Asindulum / Macrorrhyncha found in Nearctic specimens studied are A. flavidum n. sp. and M. vockerothi n. sp., both with very different male terminalia from M. flava Winnertz (see Matile 1975). In agreement with Evenhuis (2006), it is the present authors’ conclusion that M. flava is restricted to the Palearctic region. In Palearctic keys, M. vockerothi will key to couplet 15 (does not really fit either choice) in Bechev (2010b) and couplet 6 (does not really fit either choice) in Chandler et al. (2005).

This species is most similar to the Japanese M. circularis Uesugi based on the very similarly-shaped gonostylus, well developed dorsal process of the gonocoxite, and reduced tergite 9, but is easily differentiated by the short inner process of the gonocoxite (inner process very long in M. circularis ; Uesugi 2005).

Distribution. Known only from the type locality in Quebec, Canada.

Figures

FIGURES 75–77. Macrorrhyncha vockerothi n. sp., male. 75. Holotype, habitus. 76. Head and anterior thorax with box indicating area of enlarged anterior spiracle. 77.Anterior spiracle. Scale = ca. 1.0 mm (FIGS. 76–77 not to scale).Abbreviations: asp, anterior spiracle; cx1, coxa 1; CuP, posterior branch of cubital vein.

FIGURES 78–81. Macrorrhyncha vockerothi n. sp., holotype male, terminalia. 67. Dorsal. 68. Ventral. 69. Lateral. 70. Posterior with inset showing enlarged gonostylus (inset not to scale). Scale bar = ca. 0.25 mm.Abbreviations: bl, basal lobe of gonostylus; ce, cercus; dp, dorsal process of gonocoxite; gc, gonocoxite; gs, gonostylus; ip, inner process of gonocoxite; s8, sternite 8; t8, tergite 8; t9, tergite 9.

FIGURES 82–83. Macrorrhyncha vockerothi n. sp., holotype male, terminalia including sperm pump. 82. Lateral. 83. Ventral. Scale = ca. 0.25 mm. Abbreviations: da, dorsal apodeme; ea, ejaculatory apodeme; gc, gonocoxite; t9, tergite 9; va, ventral apodeme;?, short divergent dorsal pair of apodemes (see Discussion).