A New Genus of Tachydromiinae from South Africa and Turkmenistan (Diptera: Empidoidea: Hybotidae)

Simple Summary A new hybotid dance fly (or fast-running fly) genus, Parallelodromia is described along with three new species. The new genus is recorded from South Africa and Turkmenistan. Details are provided regarding the morphology of the flies and the wide geographical gap between the species is discussed. Abstract Parallelodromia gen. nov. is described with the inclusion of two new species from South Africa (P. glenlyonensis sp. nov. and P. hantamica sp. nov.) and a new species (P. turkmenistanica sp. nov.) from Turkmenistan. The genus is fully illustrated along with a discussion of its unusual disjunct geographic distribution and its phylogenetic relationship within the Tachydromiinae tribe Drapetidini.


Introduction
In their treatment of the Afrotropical Hybotidae, Sinclair and Cumming [1] referred to a distinctive new genus as "Undescribed genus B" based at the time on one undescribed South African species. Subsequently, a second South African species has been recognized and the third author discovered another new species from Turkmenistan in Middle Asia, which appeared to be congeneric with the two South African species. The purpose of this paper is to describe this new genus along with its three newly included species. The new genus belongs to the Tachydromiinae tribe Drapetidini (corrected spelling of Drapetini, see Sabrosky [2]) as characterized by Sinclair and Cumming [1,3] and Wahlberg and Johanson [4]. The phylogenetic relationship of the new genus to other Drapetidini genera is also briefly discussed along with its unusual disjunct geographic distribution.

Materials and Methods
This study is based on material loaned from or deposited in the following institutions: Canadian National Collection of Insects, Ottawa, Canada (CNC); KwaZulu-Natal Museum, Pietermaritzburg, South Africa (NMSA); Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia (ZISP). Terminology used for adult structures follow those of Cumming and Wood [14]. Label data for primary types are presented exactly as they appear. Data are listed from the top downward on the staging pin, with data from each label enclosed in quotation marks; lines are delimited by a forward slash mark. Additional information is included in square brackets. The repository of each type is given in parentheses. Secondary type data are abridged and listed alphabetically. Photographs were taken with a Leica camera model DFC5400 using Leica Application Suite X or a Nikon SMZ 1500 stereomicroscope equipped with a Nikon D700 digital SLR camera. The distribution map was created with Simplemappr [15].
The South Africa specimens were rather bleached and generally in poor condition due to long storage in alcohol prior to critical-point drying. Consequently, description of leg chaetotaxy was not possible. Recognition. This new genus is distinguished from all other genera of Tachydromiinae by the anteriorly arched wing vein M 1 that parallels vein R 4+5 , eyes without ommatrichia and separated on face, gena distinctly extended below eye, cell br shorter than cell bm at apex, vein CuA+CuP very faint, often apparently detached basally.
Diagnosis. Very small (1.1-1.3 mm) brown to brownish black and densely greyish pruinose flies ( Figure 1A,C). Frons moderately broad just below ocellar triangle (slightly less than width of ocellar triangle), with sides converging to antennae, narrow just above antennae. Eyes narrow, without ommatrichia; facets not enlarged. Face nearly as broad as frons just below ocellar triangle; parallel-sided ( Figure 1B). Vertical setae prominent, 1 pair rather moderately long, inclinate. Ocellar tubercle with 2 pairs of setae, subequally short, anterior pair inclinate, posterior pair lateroclinate. Antenna with pedicel bearing ventral subapical seta, shorter than width of segment; postpedicel short, ovate, with dorsoapical extension; arista-like stylus arising dorsoapically, long and slender. Gena distinctly extended below eye. Occiput broad laterally, somewhat inflated. Palpus fusiform, flattened, with subapical seta. Thorax usually largely densely pruinose, except for shiny katepisternum. Prosternum separated from proepisternum. Proepisternum with 1 short seta just above fore coxa and 1 similar seta on upper part. Postpronotal lobe weakly developed, with postpronotal seta prominent. Lateral mesonotal setae prominent; 2 notopleurals; 0-1 presutural supra-alar; 1 postsutural supra-alar; 1 postalar; 1 apical scutellar pair and 1 shorter subapical scutellar pair; acrostichal setulae biserial, arranged in regular parallel rows, rows divergent on prescutellar depression; dorsocentral setulae (including intra-alars) in 2 or more rows, separated from rows of acrostichals. Legs short, fore tibial gland present; fore femur slightly swollen; mid leg lacking secondary sexual characters in male; tibia with short preapical setae, hind tibia with 1 anteroventral seta; without apical projection. Wings hyaline with short basal costal seta ( Figure 1D); Rs long, originating proximal to middle of cell bm or near middle of R 1 ; R 1 meeting costa near middle of wing; R 2+3 moderately long, meeting costa beyond mid-point of wing; vein M 1 anteriorly arched, running parallel with vein R 4+5 , terminating anterior to wing tip; CuA+CuP present as fold, often apparently detached basally; crossvein CuA 2 absent; crossvein bm-cu oblique; cell br shorter than cell bm at apex; cell bm broader than cell br. Abdomen with tergites 1-7 unmodified; squamiform setae and gland-like intersegmental structures absent. Male terminalia with epandrium completely divided; left epandrial lamella fused to hypandrium; left surstylus differentiated from epandrial lamella, single or paired; right surstylus not differentiated, right epandrial lamella broad and elongate; rod-shaped bacilliform process arising beneath left surstylus; cerci separated, with expanded margins around anus, left cercus enlarged and species specifically modified; hypoproct unmodified; hypandrium with some setae Insects 2022, 13, 171 3 of 10 subapically; phallus long and filamentous (South African species) or short, rather subtubular, well sclerotized (Turkmenistan species); two rod-shaped apodemes (i.e., ejaculatory and ventral apodemes) present, ventral apodeme longer. Female similar to male, except frons slightly broader; segments 7 and 8 greatly reduced and partially retracted into segment 6; terminalia short; tergite 8 separated from sternite 8; syntergite 9+10 divided into pair of small lateral sclerites; cercus rather short, ovate. , x 3 of 10 cercus enlarged and species specifically modified; hypoproct unmodified; hypandrium with some setae subapically; phallus long and filamentous (South African species) or short, rather subtubular, well sclerotized (Turkmenistan species); two rod-shaped apodemes (i.e., ejaculatory and ventral apodemes) present, ventral apodeme longer. Female similar to male, except frons slightly broader; segments 7 and 8 greatly reduced and partially retracted into segment 6; terminalia short; tergite 8 separated from sternite 8; syntergite 9+10 divided into pair of small lateral sclerites; cercus rather short, ovate. Etymology. The genus epitaph is derived from the parallel state of the longitudinal veins M1 and R4+5, and -dromia is a commonly used suffix in Empidoidea, in reference to the running habits of the adults of many genera. The genus name is feminine.   Etymology. The genus epitaph is derived from the parallel state of the longitudinal veins M 1 and R 4+5 , and -dromia is a commonly used suffix in Empidoidea, in reference to the running habits of the adults of many genera. The genus name is feminine.     Recognition. Head, thorax and male terminalia dark brown ( Figure 1A); abdomen and legs pale brown; halter knob brownish; right epandrial lamella (=right surstylus) broad and somewhat pointed apically; male left cercus triangular with prolonged outer corner.

Key to Species of Parallelodromia
Description. Male. Length. Body 1.1-1.3 mm; wing 1.0-1.1 mm. Head. Dark brown in ground-colour with whitish pruinescence; eyes brownish; setation brown. Frons linear, narrower just above antennae, moderately broad (slightly narrower than ocellar triangle) on upper part. Face linear, subequal to width of frons above antennae. Antenna uniformly brown; pedicel with ventral seta subequal to width of segment; postpedicel ovate, slightly longer than pedicel, with short, slender dorsoapical extension; arista-like stylus dorsoapical, about 3 times longer than postpedicel, pedicel and scape combined. Palpus broad, pale brown to yellowish brown, fusiform with slightly shorter pale subapical seta and some setulae. Thorax. Brown in ground-colour, paler than head, clothed in whitish pruinescence; mesonotum without pattern; setation brownish; katepisternum largely shiny, without pruinescence. Legs. Uniformly pale brown to yellowish brown. Femora evenly thickened; most outstanding setae broken off. Wing ( Figure 1D). As in genus diagnosis; faintly infuscate, with largely brown veins; M 4 pale; CuA+CuP faintly visible at certain angles. Halter with brownish knob. Abdomen. Pale brown, with short brown setation. Terminalia (Figure 2A-C). Rather broad in left lateral view, brown, largely subshiny. Cerci with unmodified setation; right cercus short, lobe-like; left cercus triangular more than twice as long, with prolonged outer corner. Epandrium completely divided. Right epandrial lamella (=right surstylus) enlarged, pruinescent, expanded apically and laterally with apex somewhat pointed. Left epandrial lamella fused with hypandrium, bearing several short setae. Left surstylus consisting of one large setose lobe and small protuberance, with several short, unmodified setae. Narrow rod-shaped bacilliform process arising beneath left surstylus. Phallus long and filamentous. Two rod-shaped apodemes present: upper ejaculatory apodeme with expanded apex. Female. Similar to male, except as follows: tergite 8 with deep, broad V-shaped invagination anteriorly; sternite 8 with posterior half more thickly sclerotized, subapical setae with pronounced sockets; syntergite 9+10 broadly divided into pair of small lateral sclerites, bearing pair of setae ( Figure 4A).
Etymology. Named after Glenlyon Farm, an important type locality for various species of insects and vascular plants.
Distribution. Afrotropical Region: South Africa, Northern Cape Province ( Figure 6). Remarks. The Glenlyon Farm, now the Hantam National Botanic Garden (near Nieuwoudtville) is in the winter rainfall region in Western Karoo. The type series was collected in the same Malaise trap as Stuckenbergomyia sp. A [16], a rare hybotid genus endemic to southern Africa.  Recognition. Head, thorax and male terminalia brown; abdomen and legs pale brown to brown; halter knob whitish; right epandrial lamella (=right surstylus) broad, rounded and truncate apically; male left cercus triangular without prolonged outer corner.
Etymology. A name pertaining to Hantam Karoo, a region renowned for its endemic vascular plant flora.
Etymology. The epithet refers to the country of the origin of the new species. Distribution. Palaearctic Region: Turkmenistan ( Figure 6). Remarks. The new species was collected from a spur of the northern part of Kopet Dag Range (or Turkmen-Khorasan Mountain Range), close to the Caspian Sea and the border between Turkmenistan and Iran. The type locality refers to the archaeological place in Turkmenistan (the former city Dahistan/Mishrian).
Insects 2022, 13, x 8 of 10 trochanters brownish; femora extensively brownish, narrowly yellowish apically (somewhat broader on fore femur); tibia entirely yellow; tarsomeres with basitarsi extensively yellow (only apex slightly darkened), tarsomeres 2-5 brownish, becoming gradually darker to tarsomere 5. Femora evenly thickened. Setation almost entirely pale, inconspicuous (except noted), minute. Fore coxa with scattered fine setae anteriorly (more numerous and longer closer to apex). Hind tibia with 1 dark, moderately long, anteroventral seta on about apical 1/4; without apical projection. Wing. As in genus diagnosis; faintly infuscate, with largely pale brown veins; M3 pale; CuA+CuP faintly visible at certain angles. Halter pale yellow. Abdomen. Pale brown in ground-colour, rather densely greyish pruinose, with short pale setation. Terminalia ( Figure 5A-C Figure 6). Remarks. The new species was collected from a spur of the northern part of Kopet Dag Range (or Turkmen-Khorasan Mountain Range), close to the Caspian Sea and the border between Turkmenistan and Iran. The type locality refers to the archaeological place in Turkmenistan (the former city Dahistan/Mishrian).

Discussion
Sinclair and Cumming [1] first recognized Parallelodromia gen. nov. as "Undescribed genus B" in the Tachydromiinae tribe Drapetidini based on a single species from South Africa. Two species (P. glenlyonensis sp. nov. and P. hantamica sp. nov.) are now recognized from the Northern Cape region of South Africa in addition to a single species (P. turkmenistanica sp. nov.) from Turkmenistan in Middle Asia. Despite this strange geographic distribution, the genus appears to be monophyletic based minimally on very distinctive wing venation with an anteriorly arched vein M1 that parallels vein R4+5 and eyes that lack ommatrichia, a reversal that is very rare in Drapetidini [3] (p. 21).
The relationships of Parallelodromia gen. nov. within Drapetidini are presently not evident. As discussed by Cumming [17], a short basal radial cell appears to be a synapomorphy of a clade of approximately 10 drapetidine genera, which would now also include Parallelodromia gen. nov. Cumming [17] suggested that this clade was made up of three lineages (i.e., a Drapetis group of five genera, an Austrodrapetis group of three genera, and Stilpon Loew + Baeodromia Cumming), but that the relationships of these three lineages to each other was uncertain and required further study in particular, of male abdominal glands that occur in different forms in most taxa throughout the clade. Interestingly, Parallelodromia gen. nov. does not possess male abdominal gland-like modifications so its relationships within the short basal radial cell clade remain unclear if it actually belongs there.
The peculiar disjunct geographic distribution of Parallelodromia gen. nov. with two species in the Northern Cape region of South Africa and one species from Turkmenistan in Middle Asia ( Figure 6) with no other species in between, is probably a function of available Mediterranean climate in this area and possibly also a collection artefact. This

Discussion
Sinclair and Cumming [1] first recognized Parallelodromia gen. nov. as "Undescribed genus B" in the Tachydromiinae tribe Drapetidini based on a single species from South Africa. Two species (P. glenlyonensis sp. nov. and P. hantamica sp. nov.) are now recognized from the Northern Cape region of South Africa in addition to a single species (P. turkmenistanica sp. nov.) from Turkmenistan in Middle Asia. Despite this strange geographic distribution, the genus appears to be monophyletic based minimally on very distinctive wing venation with an anteriorly arched vein M 1 that parallels vein R 4+5 and eyes that lack ommatrichia, a reversal that is very rare in Drapetidini [3] (p. 21).
The relationships of Parallelodromia gen. nov. within Drapetidini are presently not evident. As discussed by Cumming [17], a short basal radial cell appears to be a synapomorphy of a clade of approximately 10 drapetidine genera, which would now also include Parallelodromia gen. nov. Cumming [17] suggested that this clade was made up of three lineages (i.e., a Drapetis group of five genera, an Austrodrapetis group of three genera, and Stilpon Loew + Baeodromia Cumming), but that the relationships of these three lineages to each other was uncertain and required further study in particular, of male abdominal glands that occur in different forms in most taxa throughout the clade. Interestingly, Parallelodromia gen. nov. does not possess male abdominal gland-like modifications so its relationships within the short basal radial cell clade remain unclear if it actually belongs there.
The peculiar disjunct geographic distribution of Parallelodromia gen. nov. with two species in the Northern Cape region of South Africa and one species from Turkmenistan in Middle Asia ( Figure 6) with no other species in between, is probably a function of available Mediterranean climate in this area and possibly also a collection artefact. This seems to be a rare biogeographic pattern that is known in a few groups of Diptera [18] and at least one other group of Empidoidea, the Schistostoma albopilosum group of Dolichopodidae, which only contains species in southern Africa and the Mediterranean region [19], plus one species from northern India [20].