﻿A conspectus of Australian Apotropina (Diptera, Chloropidae) with the description of two new species

﻿Abstract The genus Apotropina (Diptera, Chloropidae) has a global distribution with more than 80 valid described species, of which 22 are known to occur in Australia. The Australian Apotropina fauna is poorly studied, with many species known from single type specimens, more with the morphology of the other sex unknown, and there have been no new species descriptions since 1959. Here, we describe two new species from Australia, A.maculigena Riccardi, sp. nov. and A.popeye Ang, sp. nov., and provide an updated illustrated key. We also provide a conspectus of the known Australian Apotropina with images of types and collate all original descriptions and subsequent taxonomic notes of relevance as supplementary information. Finally, we discuss the validity of two known syntype specimens of A.bispinosa due to incongruencies with the species description.

1 Exemplar von Neu-Guinea : Stephansort, Astrolabe Bay (BIRÓ), Ungar.Nat.Museum" Subsequent taxonomic notes in Malloch, 1924: 331 on two Australian specimens determined as aequalis "Very similar to nudiseta in colour, but the wings are greyish hyaline, the cheek is about half as high as the eye, the arista with its longest hairs distinctly longer than its basal diameter, and the outer cross-vein [=dm-m] distinctly longer than its own length from apex of the fifth [=M 4 ].Length, 3-4mm."

Apotropina albiseta (Malloch, 1924)
Original description for Parahippelates albiseta Malloch, 1924: 330 "Male and female.-Headpale yellow, darker on occiput and upper half of frons; ocellar spot [=tubercle], second antennal segment [=pedicel], and entire proboscis black; third antennal segment [=postpedicel] brownish above; arista brown at base, the remainder and its hairs white.Thorax tawny yellow, brownish in places, with whitish pruinescence, most distinct on middle of dorsum when seen from behind, the lateral margins of mesonotum [=scutum] and some patches on pleurae blackish, a central vitta of brownish colour on mesonotum [=scutum] more or less distinct.Abdomen fuscous, apices of the tergites yellowish; male hypopygium tawny yellow.Legs pitchy brown, trochanters and basal three segments of all tarsi yellowish.Wings greyish hyaline, veins blackish.Halteres fuscous or dark brown.Head much as in brunneicosta Malloch, but the arista differently coloured, and the hairs more dense, the longest distinctly longer Supplementary File to Ang et al. ( 2023) A conspectus of Australian Apotropina (Diptera, Chloropidae) with the description of two new species 4 than its basal diameter; the vibrissal angle is slightly produced and the cheek at middle is fully one third of the eyeheight.Thorax as in brunneicosta; scutellum flattened on disc, with two discal hairs, the basal pair of bristles noticeably shorter than the apical pair.Hypopygium of male knob-like.Legs normal, apical spur of hind tibia curved, as long as tibial diameter.Last section of fourth vein [=M 1 ] fully as long as preceding section; outer cross-vein[=dm-m] cross-vein at about 1.75 its own length from apex of fifth [=M 4 ].Length, 3-3.5 mm." Apotropina anomala (Malloch, 1925) Original description for Parahippelates anomala Malloch, 1925: 96 "♀.-Head including antennae rufous yellow, upper half of frons and the occiput fuscous, shining, but with greyish pruinescence, cheeks and face whitish pruinescent; arista fuscous.[=Scutum] and scutellum glossy olivaceous black, with a quite noticeable purplish tinge, two very faint submedian lines and lateral margins broadly grey pruinescent; pleura grey pruinescent.Abdomen varying from brown to fuscous, with grey pruinescence, apices of tergites yellowish.
Legs tawny yellow, mid and hind coxae, at least mid and hind femora, and sometimes fore pair also, largely blackish; same tibiae blackish except basally, apical two segments of all tarsi fuscous.Wings greyish, veins yellowish basally.Calyptra white.Halteres pale.Ocellar bristles of moderate length; arista entirely nude; vibrissal setulae pale and weak; eye distinctly higher than long, more than twice as high as cheek.Dorsocentral thoracic bristles except the hind pair short but distinct; scutellum with basal marginal bristles shorter than apical pair, the discal hairs short.Spur of hind tibia almost indistinguishable from the surrounding hairs.The three principal costal divisions subequal; outer cross-vein This species differs from all the others already described in having the hind tibial spur very minute, in fact in some specimens practically absent.However, it is unmistakably a Parahippelates.The glossy dorsum of thorax with its purplish tinge is quite distinct from the thoracic colour of any other Australian species.
It appears probable to me that pruinosa Thomson and possibly also ornatiforns Meijere belong here.Both have four pairs of dorsocentral bristles, but neither the original describers nor Becker give sufficient details to permit of a definite opinion."Subsequent taxonomic notes in Malloch, 1940: 273, describing sexually dimorphic male wing venation "This quite exceptional species presents a difference in the wing-venation of the sexes that I find in no other species known to me.I had only females before me when I described it, so did not know of the distinction in the sexes.
In the male the marginal cell [=r 2+3 ] of the wing is considerably wider than in the female, the second wing-vein [=R 2+3 ] is more abruptly curved forward at its apex, and the third vein [=R 4+5 ] sweeps downward at its base causing the base of the first posterior cell [m 1 ] to be much narrower than in the female.
Originally described from Blue Mts., N.S.W., and Mt.Eba, S. Australia, I have several male specimens from Mt. Eba, apparently belonging to the same collection as the original type lot from that locality." Apotropina australis (Malloch, 1924) Original description for Ephydroscinis australis Malloch, 1924: 331 "Male and female.Black, opaque, with dense pale grey pruinescence.Frons dark brown, yellow on anterior margin, grey on sides of [ocellar] triangle; face and cheeks yellowish, densely whitish pruinescent; antennae fuscous, third segment [=postpedicel] orange-yellow, except on upper margin; arista pale brown; palpi yellow, proboscis and [=clypeal] margin black.Thorax: with the disc [=scutum] largely fuscous, showing traces of darker vittae, with the lateral margins yellow-grey pruinescent, and the bases of the bristles set in grey pruinose spots; pleura grey; scutellum black on disc, grey on margins.Abdomen with the dorsum blackish-brown, hind margins of the tergites pale grey, a pair of grey spots on hind margin of first visible tergite.Legs fuscous, trochanters, apices of femora, bases and apices of tibiae, and basal two or three tarsal segments tawny yellow, Wings hyaline, veins black.Halteres whitish.
Vertical, post-ocellar, and ocellar bristles distinct, each orbit with about three distinct setulae; interfrontalia setulose; [ocellar] triangle extending almost three-fourths of the way to anterior margin; face slightly concave, vertical; cheek at middle about half as high as eye; two bristles on each anterior [=vibrissal] angle in male, one above the other, only one in female; arista of male and female; eyes bare.Acrostichals very short; scutellum with four bristles.Apical three segments of mid tarsi broadened.Second division [=from h to R 1 ] of costa about 1. 25 as long as third[=from R 1 to R 2+3 ]; first posterior cell [=r1] cell very slightly narrowed apically; outer cross-vein [=dm-m] at a little over its own length from apex of fifth[=M 4 ]; last section of fourth vein [=M 1 ] fully twice as long as preceding section.Length, 3 mm.Type, male, and allotype, Woy Woy, 2 September, 1923 (Mackerras)."
-Abdomen mattglänzend, dunkelbraun, doch 1., 2. und 5. Segment überwiegend gelb.4. und 5. Tergit (besonders seitlich) länger schwarzborstig behaart als die vorderen Tergite.Afterglied des ♂gelb, relativ klein.Afterlamellen des ♀ schwärzlich, apikal wenig länger behaart als basal.-p gelb, nur die 2-3 letzten Tarsenglieder aller p schwarzbraun bis schwarz.Hüften gelb behaart.Beborstung und Behaarung der f wie gewöhnlich.Dorn der t3 subapikal, nicht länger als die t3 unten breit sind.-Flügel gelblich.Adern schwarz.c bis zur m reichend.mg2 länger als mg1 und fast doppelt so lang wie mg3.mg3 fast 3mal so lang wie mg4.R3 gerade oder apikal nur eine Spur aufgebogen.r5 sehr schwach Sförmig gebogen, apikal ein wenig zu m konvergent, der Flügelspitze näher endend als die ziemlich gerade m. ta und tp parallel, ta auf der Mitte der Cd. ta-tp 2½mal so lang wie tp und l ¼-1⅓mal so lang wie der Endabschnitt der cu.Cd Supplementary File to Ang et al. ( 2023) A conspectus of Australian Apotropina (Diptera, Chloropidae) with the description of two new species 7 an der Stelle der basalen Knickung durchquert von einem durch dichte Bereifung erzeugten, ± deutlichen dunklen Streifen, der etwas einwärts der ta endet.-Schwinger rotgelb.-Körperlänge 4-5 mm.Nach 2♂, 3♀ "Cairns, N. Queensland, 1907, Coll. Lichtwardt". " Subsequent taxonomic notes in Malloch, 1936: 23 "A bright orange-yellow to fulvous yellow coloured species, with the mesonotum [=scutum] shining, a dark spot on the ocellar region, and most of the abdominal dorsum and the apical two segments of each tarsus brown.The very high genae of this species, as shown in Figure 7, with the yellow genal hairs, and very short haired aristae, readily distinguish it from the next two dealt with below.The bristle at the lower angle of the back of the head is much less developed than in the other two.The mesonotal [=scutal] bristles are moderately strong, with the acrostichals quite distinct.The hind tibial spur is slightly shorter than the apical diameter of the tibia, but it is strong and slightly curved.The third section of the costa is about 1.5 times as long as the third [it is likely that Malloch meant instead the second section (R 1 to R 2+3 ) to the third (R 2+3 to R 4+5 )], and the outer cross-vein [=dm-m] is about twice its own length from the apex of fifth vein [=M 4 ].The scutellum has normally more than two discal setulose hairs.Length,N. Qld. (coll. Oldenberg;Deutsches Ent. Mus.).This is the type locality." Apotropina costomaculata (Duda, 1934) Original description for Parahippelates costomaculata Malloch, 1924: 329 "Male.-Head yellow, upper occiput and frontal [=ocellar] triangle fuscous, the latter shining, face and cheeks almost white, the latter browned below middle of eye; third antennal segment [=postpedicel] brown at insertion of arista; arista and its hairs fuscous; palpi and proboscis yellow.Thorax and abdomen black, slightly shining, and with thin greyish pruinescence.Legs entirely yellow.Wings hyaline, with a large black spot on costa from a little beyond apex of first Apotropina dasypleura (Malloch, 1928) Original description for Parahippelates (Terraereginia) dasypleura Malloch, 1928: 303 "This species is placed in a separate subgenus, of which it is the only known species, on the character of the finely haired mesopleura [=anepisternum].The dorsocentral bristles are very short and fine except the posterior pair, the acrostichals are represented by microscopic hairs, the scutellum is thicker than in typical Parahippelates.has many microscopic hairs on the disc and on sides, and the basal bristles [of the scutellum] are placed higher than in the other group.The backward inclination of the outer cross-vein [=dm-m] of wing is very pronounced.I do not cite any but the haired mesopleura [=anepisternum] as a subgeneric character.
Female.-Head testaceous, anterior margin of frons more orange-yellow, upper portion of frons, including [ocellar] triangle, brownish-black, shining, distinctly grey dusted, anterior portion of frons, face, and gena anteriorly, yellowishwhite dusted, posterior portion of gena and the occiput densely white dusted, centre of occiput above brownish-black; antennae and palpi orange-yellow, slightly white dusted; arista fuscous.Thorax fuscous, dorsum distinctly shining, slightly brownish-grey dusted and with three rather evident brown vittae; pleura densely greyish-white dusted, and white haired.Abdomen brown, slightly shining, apices of tergites yellowish, and grey dusted.Legs testaceous yellow, coxae greyish, fore pair white dusted, all pale haired; all femora broadly fuscous oh middle, grey dusted, and mostly pale haired, fore and hind tibiae slightly browned centrally, all tarsi with all of fourth and fifth segments, and apex of third, fuscous.Wings clear, veins pale, yellow at bases.Halteres pale yellow.

Supplementary
File to Ang et al. (2023) A conspectus of Australian Apotropina (Diptera, Chloropidae) with the description of two new species 6 1+3 dorsocentrals, acrostichals well developed, divergent posteriorly; scutellum flattened on disc.Spur of hind tibia about as long as tibial diameter, strong.Section of costa before apex of second vein [=R 2+3 ] fully 1.5 times as long as the section beyond it; veins 3 [=R 4+5 ] and 4 [=M 1 ] parallel, last section of 4 [=M 1 ] about 1.75 times as long as preceding section; outer crossvein [=dm-m] at about 1.25 its own length from apex of fifth [M 4 ], the latter not reaching margin of wing.Length, 4 mm.Type, Darwin, Queensland (Gr.F. Hill)" vein [=R 1 ] to just beyond apex of second [=R 2+3 ] and extending on disc to third vein [=R 4+5 ].Halteres whitish.Frons as in the other species of the genus; face almost flat; cheek about as high as width of [postpedicel], and one-fourth as high as eye; vibrissal angle with two bristles; aristal hairs about as long as basal diameter of arista.Thoracic chaetotaxy as in brunneicosta Malloch.Hind tibial spur about as long as tibial diameter.Section of costa in front of apex of second vein as compared to the one beyond [= R 1 -R 2+3 vs. R 2+3 -R 4+5 ] as 7:5 ; veins 3 [=R 4+5 ] and 4 [=M 1 ] parallel, last section of latter about three times as long as preceding section; outer cross-vein[=dm-m] at fully twice its own length from apex of fifth [=M 4 ].Length, 2 mm."