Research Article |
Corresponding author: Bradley J. Sinclair ( bradley.sinclair@inspection.gc.ca ) Academic editor: Marija Ivković
© 2016 Bradley J. Sinclair, Jeffrey M. Cumming, Scott E. Brooks, Adrian R. Plant, Toyohei Saigusa.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Sinclair BJ, Cumming JM, Brooks SE, Plant AR, Saigusa T (2016) Gondwanamyia, a new empidoid (Diptera) genus of uncertain placement. ZooKeys 621: 137-147. https://doi.org/10.3897/zookeys.621.10115
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A new minute-size empidoid fly genus, Gondwanamyia gen. n. and two new species (G. chilensis Cumming & Saigusa, sp. n., G. zealandica Sinclair & Brooks, sp. n.) are described, illustrated, and their distributions mapped. The family and subfamily assignments remain uncertain, but features of the female terminalia potentially suggest Trichopezinae (Brachystomatidae).
Empidoidea , Brachystomatidae , Trichopezinae , Empididae , Chile, New Zealand, new species, new genus
The higher classification of the exceedingly diverse Empidoidea, commonly referred to as dance flies and long-legged flies, consists of five well-defined families, namely Empididae, Hybotidae, Atelestidae, Brachystomatidae and Dolichopodidae s.l., plus three small unassigned genus-groups (
The genus contains two minute-size new species, one from southern Chile and the other from the North Island of New Zealand. Here we formally describe this new genus and its two included species. The potential phylogenetic placement of this curious Southern Hemisphere group within the Empidoidea, is also discussed.
This study is based on material borrowed from or deposited in the following institutions: Canadian National Collection of Insects, Ottawa, Canada (
Terms used for adult structures primarily follow
G. chilensis Cumming & Saigusa, sp. n.
Body size minute, 1.1–1.4 mm. Arista-like stylus very long, longer than thorax, lacking basal article; males and females dichoptic, eye facets convex, appearing larger than in other empidoids; clypeus strongly convex; mouthparts with large epipharyngeal carina and paired epipharyngeal blades; wing with weakened fold near base, only two longitudinal veins fully developed (R4+5 and M4), R4+5 branched; abdomen with abdominal plaques; male terminalia symmetrical and unrotated, epandrium and hypandrium desclerotized and fused together, epandrial lobe and cercus projected anterodorsally, phallus tubular with or without an elongate apical filament, ejaculatory apodeme slender, rod-like; female terminalia sclerotized, sclerites beyond segment 6 mostly bare; tergite and sternite 8 anteroventrally articulated; female cercus sclerotized, projecting horizontally.
Male.Head: Dichoptic; eye facets convex; some short scattered ommatrichia. Antenna with scape reduced, strap-like with several setulae; pedicel globular, slightly shorter than postpedicel; arista-like stylus longer than thorax, lacking basal article. Ocellar triangle small, not raised, with stout ocellar setae inserted anteriorly, opposite anterior ocellus; several setulae posterior to ocellar triangle; vertical seta lateroclinate; 1 shorter seta between vertical seta and ocellar triangle; several postocular setae present. Mouthparts with swollen or inflated clypeus; epipharyngeal carina elongate and slender, extended well into clypeal region; epipharyngeal blades present at apex of carina, slender and pointed apically; labrum thickly sclerotized laterally; hypopharynx slender, stylet-like; lacinia apparently absent; palpus oval, flattened on inner face, with several long setulae; labellum pointed apically, narrow, without pseudotracheae, apical margin with series of peg-like sensilla.
Thorax: Chaetotaxy well developed and in distinct rows; acrostichals present or absent. Prosternum separated between fore coxae. Dorsal mesepimeral pocket present; metasternal furca tapered to narrow apex, lacking apical projections. Laterotergite bare. Fore leg simple, not raptorial; tibia without basal gland. Mid femur with row of stout posteroventral setae. Hind tibia with posteroapical comb.
Wing: Length: 1.1–1.5 mm. Cuneate and narrowed at base, slightly infuscate; anal lobe and alula not developed. Costa circumambient with basal costal seta and several subequal setae proximal to R1; slender, erect costal setae widely distributed to beyond R4; costal break distal to Sc, continuing posteriorly as weakened transverse fold across cell bm; costa with second break at R1; R1 very short, terminating in basal 0.25 of wing; R2+3 very short, nearly vertical, terminating at apex of R1; two longitudinal veins fully developed (R4+5 and M4); R4+5 branched, with R4 nearly perpendicular to R5; M4 nearly straight, slightly arched toward wing margin; cell dm absent; cell bm quadrate; cell br longer than cell bm; cell cua weakly open parallel to wing margin. Halter long, subequal in length to scutum; shaft with several basal setulae; knob tapered apically.
Abdomen: Abdominal tergites and sternites without modifications, sparsely setose; abdominal plaques present; tergite 8 slender, strap-like; sternite 8 expanded laterally to cradle terminalia, thinly sclerotized medioventrally; posterior marginal setae on sternite 8 distinct and well defined.
Male terminalia: Upright, symmetrical and unrotated; epandrium and hypandrium desclerotized and fused together; gonocoxal apodeme slender, rod-shaped; cercus well developed; phallus tubular with or without elongate apical filament, ejaculatory apodeme slender.
Female terminalia: Sclerotized, mostly bare; tergite 8 shallowly notched posteromedially with four posteromarginal setae; tergite and sternite 8 anteroventrally articulated; tergite ten subtriangular, not divided medially with one pair of posterolateral and one pair of apical setae, apical setae closely approximated; sternite ten triangular, pigmented laterally with pair of lateral setae; cercus thickly sclerotized, similar to sclerite 10, with apex bearing pair of long, stout setae; spermatheca thread-like, extending full length of abdomen.
Named after the southern Mesozoic continent of Gondwana, in reference to the probable age and distribution of this genus of flies on the southern continents of South America and Australasia (Figs
Chile: Los Lagos (Region X), Osorno Province, Puyehue National Park, Antillanca [ca. 40°46'S 72°12'W], 1300 m, Nothofagus, tree line.
Holotype male, pinned. Original label: “CHILE: Osorno, Puyehue/ N.P. Antillanca 1300m/ Feb. 11, 1988/ Nothofagus, tree line/ L. Masner, Chile Exp”; “HOLOTYPE/ Gondwanamyia/ chilensis/ Cumming & Saigusa” [red label] (
CHILE. Los Lagos (Region X). Osorno Province: Puyehue NP, Volcan Casablanca [ca. 40°43'S 71°57'W], 1370 m, nr. snowline, A. Newton & M. Thayer (1 ♂,
This species is distinguished from G. zealandica by the male mid femur and tibia with stout posteroventral setae, mostly membranous epandrium + hypandrium, and long phallic filament.
Male.Head: Ocellar setae stout, reclinate. Arista-like stylus slightly longer than 0.5 mm.
Thorax: Brown, darker than abdomen. Acrostichals absent; six dorsocentral setae; one postpronotal seta, two notopleural setae, upper longer and stouter; one presutural and two postsutural supra-alar setae; one postalar, elongate, subequal in length to apical scutellar seta; two pairs of scutellar setae, lateral pair slender and shorter than apical pair.
Legs: Mid femur with posteroventral row of 10–11 stout setae, longer than width of tibia (Fig.
Gondwanamyia, habitus, wing and mid leg. 1–3 G. zealandica sp. n., holotype ♂ (in ethanol, prior to drying and mounting), habitus 4 G. chilensis sp. n., male wing 5 G. chilensis, male right mid leg, posterior view. Abbreviations: ar styl: arista-like stylus; bm: basal medial cell; br: basal radial cell; clyp: clypeus; CuA: anterior branch of cubital vein; cua: anterior cubital cell; M1, M2, M4: medial veins; R1, R2+3, R4, R5: radial veins; Sc: subcostal vein.
Wing (Fig.
Abdomen: Two pairs of posterior setae on male sternite 8 short and slender. Male terminalia (Fig.
Gondwanamyia, male terminalia in lateral view. 6 G. chilensis sp. n. 7 G. zealandica sp. n. Abbreviations: cerc: cercus; ej apod: ejaculatory apodeme; epand: epandrium; goncx apod: gonocoxal apodeme; hypd: hypandrium; hypd lb: hypandrial lobe; ph: phallus; st: sternite; sur: surstylus; tg: tergite.
Female. Similar to male, except posteroventral row of stout setae on mid femur and tibia absent. See genus description for details of female terminalia (Figs
The species name refers to the country of the type locality.
This species is confined to southern Chile (Fig.
New Zealand: Auckland: Waitakere Range, Matuku Reserve, 25 m, 36.867°S, 174.476°E.
Holotype male, pinned. Original label: “NEW ZEALAND: AK:/ Waitakere Range/ Matuku Reserve, 25 m/ 36.867°S, 174.476°E/ 2–5.iv.2010; L. Masner/ YPT [yellow pan trap] #23”; “HOLOTYPE/ Gondwanamyia/ zealandica/ Sinclair & Brooks” (NZAC).
This species is distinguished from G. chilensis by the less stout posteroventral row of setae on the mid femur and tibia, presence of acrostichal setae, arista-like stylus slightly shorter, posterior setae on male sternite 8 longer and stouter, and phallus without an apical filament.
Male.Head: Ocellar setae stout, reclinate. Arista-like stylus approximately 0.5 mm.
Thorax: Light brown, concolourous with abdomen. Acrostichal setulae present, at least three, uniserial; five dorsocentral setae, anterior seta stouter and laterally offset; one postpronotal seta, two strong, subequal notopleural setae; one presutural and three postsutural supra-alar setae; one postalar; two pairs of scutellar setae, lateral pair slender and shorter than apical pair.
Legs: Mid femur with posteroventral row of pale setae, longer than width of tibia. Mid tibia without posteroventral row of stout setae. Apex of hind tibia slightly expanded with posteroapical comb.
Wing: Length 1.1 mm. Erect costal setae more conspicuous than in G. chilensis; subapical vein streaks present, representing veins M1 and M2.
Abdomen: Four pairs of posterior setae on male sternite 8 long and stout. Male terminalia: Cercus broadly expanded at base, tapered to narrow apex; bearing fine setae. Hypandrium + epandrium with broad ventral connection; slender surstylus with pair of preapical setae; apex arched medially. Hypandrium sheath-like, with two pairs of tapered and apically pointed anterior hypandrial lobes; gonocoxal apodeme very slender, straight, arising on interior of hypandrial sheath. Phallus with hood-like apex, without apical filament; ejaculatory apodeme rod-shaped, very long and slender, running along posterior margin of hypandrium.
Female. Unknown.
The species name refers to the country of the type locality.
This species is known only from the type-locality, on the North Island of New Zealand (Fig.
Members of Gondwanamyia are among the smallest empidoid flies known. Based on the structure of their mouthparts, with free epipharyngeal blades, it is probable that they are predators on tiny arthropods, but nothing is currently known of their habits. Collection dates from both Chile (Dec., Feb., April, June, July) and New Zealand (April) indicate that this is primarily a late flying autumnal genus, apart from the December record. The weather in Chile and New Zealand during these months can be cool to cold. Most specimens were collected using yellow pan traps on the ground, indicating that members of this genus possibly fly low in the forest understory.
The small size of Gondwanamyia has presumably led to reductions in certain features such as wing venation. This has undoubtedly resulted in a loss of informative synapomorphies resulting in some confusion with homologies, creating uncertainty with the family and subfamily assignment of the genus. For example, the homologies of the male terminalia of both species are not completely resolved. The epandrium and hypandrium of G. zealandica appear fused together (Fig.
Gondwanamyia obviously does not belong to the Hybotidae or Dolichopodidae s.l., based on presence of a branched R4+5 wing vein, unrotated male terminalia, and absence of a palpifer and fore tibial gland. It cannot be placed in the Atelestidae based on a branched R4+5 wing vein, setose scape, elongate hypandrium, and presence of female tergite 10. The genus is also clearly not assignable to either the Homalocnemis Philippi, Oreogeton Schiner, or Iteaphila genus (or family) groups.
Gondwanamyia might represent a new lineage of Empididae, although no convincing synapomorphies appear to align it with any included member of that family. The male terminalia of the new genus show some similarities to most Nearctic species of Chelipoda Macquart (Empididae: Hemerodromiinae) (
The form of the female terminalia of Gondwanamyia (only known for G. chilensis) suggests inclusion in the Brachystomatidae based on the anterior articulation of tergite and sternite 8, the more thickly sclerotized terminal segments with absence of micro-setae, and well developed setae at the apex of the cerci and tergite 10 (
We thank Lubomir Masner (