A revision of the Australian genus Pleuroseta Richards (Diptera, Sphaeroceridae) Author Kuwahara, Gregory K. 2E2D313F-7249-4F76-AF5D-615516840188 University of Guelph Insect Collection and Insect Systematics Laboratory, School of Environmental Sciences, University of Guelph, Guelph, Ontario, N 1 G 2 W 1, Canada. gkuwahar@uoguelph.ca Author Marshall, Stephen A. 6C1C1C9E-365F-48BF-B8C7-31163EC5F3A7 University of Guelph Insect Collection and Insect Systematics Laboratory, School of Environmental Sciences, University of Guelph, Guelph, Ontario, N 1 G 2 W 1, Canada. samarsha@uoguelph.ca text European Journal of Taxonomy 2023 2023-12-07 910 69 97 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2361/10335 journal article 281316 10.5852/ejt.2023.910.2361 43a5768f-e8c1-4484-81da-78217a053132 2118-9773 10306494 2B90DE6E-E70A-4199-B485-5A13FDD43056 Pleuroseta monteithi sp. nov. urn:lsid:zoobank.org:act: 9321FA5F-A43E-4B05-8C88-E661260B9E23 Figs 5E , 10–11 , 16B Etymology This species name is in honour of Dr Geoff Monteith, who collected the type specimens of this species as well as most of the other known specimens of Pleuroseta . Material examined Holotype AUSTRALIA • ♂ ; Queensland , Cape Tribulation, transect site 8 ; 16°05' S , 145°26' E ; 18 Nov. 1998 ; G.B. Monteith leg.; dung trap , 6 am –6 pm; QMBA debu00160870 . Paratype AUSTRALIA – Queensland • 1 ♂ ; same collection data as for holotype; DEBU . Description BODY ( Fig. 10A ). As described for P. ingens sp. nov. , except as follows: length 3.7–3.8 mm . Frontal width 2.4–2.5 ×interfrontal height. Gena with 11–14 setulae. First postsutural pair of dorsocentral bristles separated by 9–10 rows of fine acrostichal setulae. Anepisternum with posterodorsal patch of 5–6 setae and 10–12 setulae. Wing pattern ( Fig. 15B ) slightly paler than in P. ingens . CS2 1.3×length of CS3. MALE ABDOMEN ( Figs 5E , 10B–C , 11 ). S5 broad, subrectangular with large, triangular, posteromedial emargination, posterior surface of each lateral lobe with a dense tuft of fine, curved setae. S6+7 large (almost subequal to epandrium) and complex: S6 extending ventrally under (dorsal to) S5 and with dark, T-shaped posterior extension, the apex of which has a rippled margin; dorsal to this lies a tubular, basally constricted sclerite with heavily sclerotized, flattened, disc-like apex; S7 with elongate, dextral extension reaching across to ring sclerite; S8 with dorsal, anteromedial semicircular emargination; ring sclerite well-developed. Epandrium very large (only slightly smaller than head); cercus indistinct from epandrium; subepandrial sclerite thick, X-shaped. Hypandrium triangular, anteromedial apodeme curved upwards anteriorly. Surstylus short and complex: anterior half composed to two lobes: a semicircular dorsal lobe which is bent inwards anterodorsally and a thick, triangular, beak-like, ventrally setose ventral lobe; posterior half subtriangular, bulging laterally, with a broad anterior point, an elongate posterior ‘arm’, and a broad, rounded ventral lobe which has many long setae on the outer surface and a patch of thickened setae along the inner surface. Postgonite elongate, triangular and slightly bent forwards apically into a small hook. Phallapodeme elongate and curved; basiphallus large and saddle-shaped (often visible between surstyli in dried specimens). Distiphallus extremely large (~11% total body length), divided into basal and apical sections: basal section elongate, sclerotized and curved, with small lower knob articulating with apical section and spinose, membranous upper apex; apical section composed of a bent, trough-like, sinuate lower sclerite and a pair of flattened, curved lateral sclerites which fit along inner surface of lower sclerite. Fig. 10. Pleuroseta monteithi sp. nov. A . Male holotype habitus, lateral view (debu00160870). B . Male paratype terminalia, lateral view (debu00160892). C . Male paratype terminalia, posterolateral view (debu00160892). Abbreviations: epa =epandrium; hyp =hypandrium; se =subepandrial sclerite; ss =surstylus. Scale bars: A = 1.0 mm; B–C =0.40 mm. Fig. 11. Pleuroseta monteithi sp. nov. paratype (debu00160892). A . Aedeagus and associated structures, lateral view. B . Male S5–8, ventral view. Abbreviations: bp = basiphallus; dp =distiphallus; pg =postgonite; phal=phallapodeme; rs =ring sclerite. Scale bars: A=0.40 mm; B= 0.60 mm. Fig. 12. Pleuroseta wentworthi ( Richards, 1973 ) . A . Male habitus, lateral view (debu00403539). B . Male terminalia, lateral view (debu00264733). C . Male terminalia, posterolateral view (debu00264733). Abbreviations: epa =epandrium; hyp=hypandrium; se = subepandrial sclerite; ss =surstylus. Scale bars: A =1.0 mm; B–C =0.30 mm. Fig. 13. Pleuroseta wentworthi ( Richards, 1973 ) (debu00264733). A . Aedeagus and associated structures, lateral view. B . Male S5–8, ventral view. Abbreviations: bp = basiphallus; dp =distiphallus; ea= ejaculatory apodeme; pg =postgonite; phal=phallapodeme. Scale bars: A–B =0.30 mm. FEMALE ABDOMEN . Female unknown. Remarks Pleuroseta monteithi sp. nov. is externally almost indistinguishable from, and internally very similar to, P. ingens sp. nov. As such, the male genitalia are required to identify this species: S5 with a triangular posteromedial emargination, S6 with a flattened, T-shaped posterior extension, anterior lobe of surstylus with a more elongate triangular ventral lobe and a semicircular dorsal lobe, postgonite thicker and straighter along the anterior margin, and basal part of the distiphallus more evenly curved without an elongate apical extension. Both known specimens of Pleuroseta monteithi sp. nov. were collected some 150 km north of the northern-most collection locality of the similar P. ingens sp. nov. (from Mount Hypipamee National Park), suggesting that they might be allopatric or parapatric sister species.