Rainieria triseta Li, Liu & Yang, 2012

Kim, Wonwoong, Weele, Ruud Van Der & Lee, Seunghwan, 2022, New records of Micropezidae (Diptera, Acalyptratae) from South Korea, with description of a new species of Rainieria Rondani, Zootaxa 5178 (1), pp. 26-40 : 34-35

Rainieria triseta Li, Liu & Yang, 2012

( Figs 1C , 3C–D , 5A , 6C–D , 8C )

Rainieria triseta Li et al., 2012b: 395 . (sp. nov.)

Diagnosis. Total body length 7.5–7.8 mm in males, 7.7–10.2 mm in females; Head black with exception of silvery ventral area of parafacial; frontal vitta velvety black with silvery pruinescence posteriorly; slightly tapering posteriorly and anteriorly; head chaetotaxy: well-developed 1–3 frontal bristles of similar length; 1 orbital bristle slightly longer than the frontal bristle, and strong inner vertical, outer vertical, and postocellar bristles; thorax shining black with anepisturnum and katepisternum covered with short silverly microtrichose; fore coxa brown, becoming pale distally; mid and hind femora dark brown with yellowish brown ring on subapical and extreme base; all tibia and tarsus uniformly dark brown, with the exception of white fore tarsomeres 1–4 and darkened tarsomere 5 ( Fig. 3C–D ); wing membrane uniformly infuscate with distinct discal and apical band ( Fig. 8C ); all tergites and sternites uniformly shining dark brown; bristles on syntergite 1+2 long and light brown, in tergites and oviscape black microsetulose; female S3–4 strongly reduced, proximal part barely visible ( Fig. 6C–D ); pleural membrane uniformly dark brown except distinct triangular white region below T 3–4 in female; female oviscape shiny black with posterior tip reddish brown; male S5 with dense black short, stout setae on inner side of each arm, the arm slightly incurved; basal area of the fork with a shallow cleft ( Fig. 5A ).

Material examined. South Korea: Gyeonggi-do: 2♂, 7♀, Pocheon-si, Yeongjung-myeon, Hoguk-ro 2616 beon-gil, 28-31, on dead Quercus sp. (37°97'55.1"N 127°25'03.2"E), 17.vi.2022, coll. Wonwoong Kim ( SNUM) . Gangwon-do: 1♂, Yanggu-gun , 25.vii.1996, coll. H.K. Lee ( SNUM) ; 1♂, Yanggu-gun , 25.vii.1996, coll. H.K. Lee ( NIBR) ; 1♀, Yangyang-gun, Seo-myeon, Osaek-ri , 460-2 (38°04'40.9"N, 128°26'49.3"E) 28.v.–16.ix.2020, Malaise trap. coll. Duk-Young Park ( SNUM) ; 1♀, Inje-gun, Buk-myeon, Hangye-ri , 854 (38°08'46.5"N, 128°15'47.5"E) 04.vii.2018, coll. Sanghyeok Nam ( SNUM) ; Seoul: 1♀, Gwanak-gu, Daehak-dong, Seoul National University , 30.vi.2014, coll. Chang Eon Lee ( SNUM) ; Gyeongsangnam-do: 1♀, Mt. Jirisan, Sancheong-gun, Sicheon-myeon , Jungsan-ri (35°31'96.5"N 127°75'40.6"E), 20.vi.2022, coll. Wonwoong Kim ( SNUM)

Distribution. South Korea * (Gangwon-do, Gyeonggi-do, Gyeongsangnam-do), China (Northeast: Liaoning, Heilongjiang)

Biology. In our field survey, multiple individuals were found on a bark of recently logged Quercus tree at Pocheon, Gyeonggi-do. Territorial behavior and feeding behavior similar as mentioned above under R. tenebrosa were observed.

Remarks. Li et al. (2012b) mention that the key morphological character of this species is the three frontal bristles, from which the species name triseta was derived. Close examination of the Korean specimens (SNUM) showed that the number of frontal bristles varied between 1–3, even between individuals bearing the same collection data. Accounting for the fact that these specimens with the varying number of frontal bristles shared the same male S5 shape with superficial differences, we conclude that specimens with only 1 or 2 frontal bristles can also be regarded as R.triseta . In addition, the description and the Figure 12 in Li et al. (2012b) shows that the short stout setae of the male S5 are connected at the base of the fork. All Korean specimens dissected in this study showed that the setae of each arm are actually separated by a shallow basal cleft ( Fig. 5A ). Accounting for the general male S5 morphology in subfamily Taeniapterinae ( Marshall 2017, 2022), the basal cleft was most probably overlooked in Li et al. (2012b) ’s drawing.

Based on examinations of the Korean specimens (SNUM) sharing identical morphological features with the original description, it was possible to observe a characteristic desclerotization and reduction of the S3–4 of females ( Figs. 6C–D ). Furthermore, as in the Figure 6 in Li et al. (2012b), distinct triangular white patch of the pleural membrane of female was observed. These characteristics of the female abdomen readily distinguishes R.triseta from its congeners and therefore serves as a useful identification character.

When following the key provided in Krivosheina & Krivosheina (1996) for the genus Rainieria , this species keys out to Rainieria latifrons ( Loew, 1870) due to the presence of yellowish-brown ring of the extreme base of femora, and the uniform length of short, stout setae on the inner side of the arm in male sternite 5. However, examination of the R. triseta specimen collected from Korea revealed that these diagnostic characteristics are shared between the species, thus is not sufficient in distinguishing the two. Furthermore, the interpretation of the ‘ Rainieria latifrons ’ by Krivosheina & Krivosheina (1996) is in discord with the interpretation of this species based on European materials in several studies ( Kurina 2004; van der Weele 1998), especially on the wing coloration. Krivosheina & Krivosheina (1996) have mentioned R.latifrons as having ‘Median band of wing wide, apex of R1 darkened, the band reaching posterior margin of wing,’ which is apparently absent in European latifrons . Since specimens examined by Krivosheina & Krivosheina (1996) are heavily biased on the materials collected from the Russian Far East, we suppose that their interpretation of diagnostic characteristics of ‘ Rainieria latifrons ’ could be a mix of latifrons (Europe) and triseta (Far East Russia). However, since Loew (1870) ’s original description for latifrons is very brief and uninformative, examination of type specimen and specimens from more localities is needed to confirm the exact distribution of R.latifrons and R.triseta across the Palearctic region.

Figures

FIGURE 1. Korean Micropezidae species, live individuals. A, Micropeza soosi, female, on a forest edge; B, ditto, male, on a plastic surface; C, Rainieria triseta, female; D, Mimegralla suzukiana, female [Figures C–D provided by Sangsu Kim]

FIGURE 3. Lateral habitus and spermathecae of Rainieria species. A, Rainieria calceata, male; B, ditto, female; C, Rainieria triseta, male; D, ditto, female; E, Rainieria tenebrosa, holotype male; F, ditto, paratype female; G, ditto, spermathecae and associated structures.

FIGURE 5. Male genital structure of Rainieria species. A, D: Rainieria triseta; B, E: Rainieria tenebrosa; C, F: Rainieria calceata. A–C, Male Sternite V (Genital fork); D–F: Various structures of male terminalia. Abbreviations: aa—phallapodeme; bd—basal distiphallus; c—cercus; dd—distal distiphallus; e—epandrium; ea—ejaculatory apodeme; ed—ejaculatory duct; h—hypandrium; pb—phallic bulb.

FIGURE 6. Female sternite structure of Rainieria species. A, Rainieria calceata; B, Rainieria tenebrosa; C, Rainieria triseta; D, ditto, ventral view of alcohol-preserved specimen. Note the reduction of sternite III–IV.

FIGURE 8. Wings of Korean Micropezidae species. A, Micropeza soosi; B, Compsobata dentigera; C, Rainieria triseta; D, Rainieria tenebrosa; E, Mimegralla suzukiana.