Paracacoxenus kaszabi Okada, 1973

Baechli, Gerhard & Vilela, Carlos R., 2020, On the identity of Paracacoxenus kaszabi Okada, with the formal description of a new closely related species (Diptera, Drosophilidae), Alpine Entomology 4, pp. 1-20 : 1

Paracacoxenus kaszabi Okada, 1973

Figs 1 -22

Paracacoxenus kaszabi Okada: Okada (1973: 271) [description, figures]; Máca (1980: 338) [description, figures, distribution, misidentification, see below]; Sidorenko (2001: 219) [key].

Cacoxenus kaszabi (Okada): Bächli (1984: 33) [types]; Toda and Vinokurov (1995: 189) [biology, distribution: Siberia]; Watabe et al. (1995: 199) [distribution: Siberia]; Máca and Barták (2001: 431) [distribution, misidentification, see below]; Vinokurova (2003: 100) [distribution: Siberia].

Cacoxenus (Paracacoxenus) kaszabi (Okada): Tsacas and Desmier de Chenon (1976: 500) [affiliation]; Wheeler (1981: 23) [affiliation]; Bächli and Rocha Pité (1984: 191) [affiliation]; Toda et al. (1996: 466) [key]; Bächli et al. (2004: 52) [key]; Brake and Bächli (2008: 251) [affiliation].

Cacoxenus (Gitonides) kaszabi (Okada): Sidorenko (2002: 10) [phylogeny].

Type locality.

MONGOLIA: Central aimak, Ulan-Baator, Nucht im Bogdo ul [47°54′N, 106°54′E], 1750m.

Material examined.

MONGOLIA: 1 ♂ (Paratype), labelled " Mongolia , Central aimak / Ulan-Baator , Nucht im / Bogdo ul, 1750 m / Exp. Dr. Z. Kaszab, 1966 // Nr. 513 / 10.VI.1966 // ♂ // PARATYPE [white label] // Paracacoxenus / kaszabi Okada / Bächli & Vilela det. 2017" (HNHM). Photomicrographs of holotype slide (HNHM) .

Diagnosis.

Analysis of some male terminalia sclerites is required to tell this species apart from Paracacoxenus macai sp. nov. They are as follows: cerci narrow and bearing a longitudinal row of setae adjacent to inner margins (Figs 13 , 14 ), aedeagus ellipsoid-shaped in dorsal and ventral views (Figs 15 , 16 ), inner paraphyses tribranched (Figs 21 , 22 ), and gonopods smooth (Figs 17 , 18 ).

Description.

♂. Head: Frons (Figs 6 , 8 ) centrally velvety black; all setae black. Frontal length 0.38 mm; frontal index about 1.00, top to bottom width ratio about 1.19. Frontal triangle not distinguishable; ocellar triangle greyish-black, microtrichose, about 40 % of frontal length. Orbital plates greyish-black, microtrichose, about 80 % of frontal length. Orbital setae arranged almost in a row, distance of or3 to or1 about 157 % of or3 to vtm, or1 / or3 ratio about 1.09, or2 / or1 ratio about 0.83; vt index about 1.00, postocellar setae broken or invisible; ocellar setae about 57 %, of frontal length, vibrissa (Fig. 7 ) about 50 % of frontal length. Face black. Carina narrow, slightly prominent. Cheek index about 9. Eye index about 1.26. Occiput black. Antenna black. Flagellomere 1 roundish, length to width ratio about 1.00. Arista microtrichose (Fig. 7 ). Proboscis black. Palpus short, black, with 2 more prominent apical setae. Thorax dull black, length about 1.19 mm, 8 rows of acrostichal setae (Figs 4-6 ), one prominent h. Anterior and posterior dorsocentral setae close together, transverse distance about 6x of longitudinal distance; dc index = 0.38. Scutellar setae nearly equidistant; basal ones divergent; apical scut broken. Haltere whitish. Legs black, knees slightly paler. Wing hyaline, damaged and partly folded, length 1.40 mm (Fig. 3 from holotype). Abdomen dull black (Figs 4 , 9 ). Syntergite 6 + 7 (Fig. 9 ) without a claw-like extension. Terminalia ♂ (Figs 2 [holotype], 9-22): Epandrium microtrichose (Fig. 14 ), except for the anteroventral region, with no ventral, and 1-2 dorsal setae, ventral lobe fused to surstylus. Cercus narrow [wide in Paracacoxenus macai sp. nov.], ventrally positioned, laterally connected to epandrium by membranous tissue, covered with only 8 setae [18-21 in P. macai sp. nov.] organized in a longitudinal row (Figs 13 , 14 ) adjacent to inner margin, microtrichose, without ventral lobe. Surstylus without prensisetae, bearing 3 outer setae (Figs 12 , 13 , 20 ) [2 in P. macai sp. nov.] on central membranous area and no inner seta, not microtrichose, completely fused to ventral lobe of epandrium which is slightly microtrichose in the fusion area (Figs 13 , 14 ). Decasternum divided into two articulate sections connected by a membranous strip, folded over one another (Figs 17 , 18 ); proximal section flattened, anteromedially somewhat projected posterad, medially slightly concave, distally fused to surstyli and laterally connected to hypandrium arms by membranous tissue (Figs 16 , 17 ); distal section [ventral process of Grimaldi (1990): 76, 77 (fig. 424), 78] V-shaped at rest (Figs 17b , 17c , 20 ), proximally bifid, distally flattened, slightly bifid and expanded laterad, marginally non-crested (Figs 17g , 18d ) [widely expanded and marginally crested in P. macai sp. nov.] and fused to dorsomedian region of aedeagus. Hypandrium somewhat square-shaped in posterior view (Figs 2 [holotype], 15, 16, 18), as long as epandrium, anterior margin slightly convex and expanded laterad; posterior hypandrium process absent, "dorsal arch" (see Bächli et al. 2004: 14) formed by a complex, two-sectioned decasternum (Figs 17a-c , 20 ); gonopods fused to each other and to anterior very end of hypandrium, devoid of warts [conspicuously warted in P. macai sp. nov.], bearing 0-1 lateral setula (Figs 17 , 18 , 20 ). Aedeagus reduced to a membranous dorsoventrally flattened bag (Fig. 17 ), ellipsoid-shaped [triangle-shaped in P. macai sp. nov.] in dorsal and ventral views, microtrichose, and dorsally fused to the dorsoventrally flattened end of distal section of decasternum. Two pairs of paraphyses (Figs 19 , 21 , 22 ). Outer paraphysis laterally flattened and tube-shaped, subapically enlarged [triangle-shaped in P. macai sp. nov.], and turned ventrad in lateral view, with two parallel dorsal rows of ca. 4-5 outer setulae per row, articulated both with lateral inner margin (gonopods) of hypandrium medially, and with posterolateral region of aedeagal apodeme (Fig. 19 ). Inner paraphysis slightly shorter than outer paraphysis (Figs 11 , 12 ), strongly sclerotized, bare, mediolaterally fused to aedeagal apodeme, tribranched (Figs 21a-c , 22a-c ) [heptabranched in P. macai sp. nov.]: distal branch long, apically sharp, slightly turned dorsad and inwards, submediodorsal branch wide, triangle-shaped, pointed laterad and dorsad, proximal branches somewhat rectangle-shaped, blunt, pointed dorsalwards and distally connected to each other by a membranous strip embracing submedian region of distal section of decasternum (Figs 10 , 21 ). Aedeagal apodeme shorter than outer paraphysis (Fig. 19 ), dorsoventrally flattened, strongly sclerotized, laterally fused to anterior region of inner paraphysis (Fig. 21 ). Ventral rod apparently absent, probably turned backwards and fused to posteroventral region of aedeagal apodeme (Fig. 11 ).

Distribution.

Mongolia: Okada (1973): 271. Russia, Siberia: Toda and Vinokurov (1995): 189; Watabe et al. (1995): 199; Vinokurova (2003): 100.

Figures

Figure 17. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM); decasternum, hypandrium + gonopods, aedeagus, oblique posterior view. Abbreviations: a = proximal section of decasternum; b and c = distal section of decasternum; d = membranous aedeagus; e = anterior region of hypandrium; f = fused gonopods; g = tip of distal section of decasternum (laterally expanded and fused to dorsal region of aedeagus). Scale bar: 0.1 mm.

Figure 18. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM); decasternum and hypandrium + gonopods. Abbreviations: a = proximal section of decasternum; b and c = distal section of decasternum; d = tip of distal section of decasternum (laterally expanded); e = hypandrium left arm; f = anterior region of gonopods (fused to each other and to hypandrium); g = posterolateral region of left gonopod. Scale bar: 0.1 mm.

Figures 1 - 3. Paracacoxenus kaszabi Okada, ♂ holotype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM) 1 Labels (mislabelled as a female) and slide with wing and terminalia 2 Photomicrograph of terminalia, dorsal view 3 Right wing, dorsal view, distally optically cut. Photos: Z. Soltesz.

Figures 21, 22. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM) 21 Three-branched inner paraphysis, outer paraphysis and aedeagal apodeme, anterior (dorsal) view 22 Three-branched inner paraphysis, outer paraphysis and aedeagal apodeme, oblique posterior view. Abbreviations: a = proximal branch; b = mediodorsal branch; c = distal branch. Scale bar: 0.1 mm.

Figures 13 - 16. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM) 13 Terminalia, dorsal view (in-focus: epandrium, cerci, tips of aedeagus and inner paraphyses) 14 Terminalia, dorsal view (in-focus: all sclerites) 15 Terminalia, posterior view 16 Terminalia, anterior view. Scale bar: 0.1 mm.

Figures 4 - 9. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM) 4 Habitus, left lateral view 5 Habitus, oblique dorsal 6 Habitus, dorsal 7 Head close-up, left lateral 8 Head close-up, dorsal 9 Terminalia close-up, posterior. Scale bars: 0.5 mm (7 - 9); 1.0 mm (4 - 6).

Figures 10 - 12. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM) 10 Terminalia, oblique dorsal view 11 Terminalia, left lateral view 12 Terminalia, oblique ventral view. Scale bar: 0.1 mm.

Figures 19, 20. Paracacoxenus kaszabi Okada, ♂ paratype, Central aimak, Ulan-Baator, Nucht im Bogdo ul, Mongolia (HNHM) 19 Aedeagal apodeme, left inner paraphysis, left outer paraphysis, membranous aedeagus and posterior ejaculatory duct, left lateral view 20 Left surstylus, decasternum, hypandrium, gonopod, aedeagus and posterior ejaculatory duct, lateral view. Scale bar: 0.1 mm.