Beris hildebrandtae Pleske, 1930

Lee, Junho & Suh, Sang Jae, 2022, First record of the soldier fly genus Beris Latreille (Diptera, Stratiomyidae) from Korea, with designation of two new synonyms, Biodiversity Data Journal 10, pp. 80487-80487 : 80487

Beris hildebrandtae Pleske, 1930

Beris hildebrandtae Pleske, 1930 - Pleske 1930: 195 (Type-locality: Russia). ♂ Lectotype [ZMAS].

Beris angustifacies Nagatomi and Tanaka, 1972 - Nagatomi and Tanaka 1972: 91 (Type-locality: Japan). ♂ Holotype [KU]. New synonymy.

Beris liaoningana Cui et al, 2010 - Cui et al. 2010: 280 (Type-locality: China). ♂ Holotype [CAU]. New synonymy.

Materials

Type status: Other material. Occurrence : individualCount: 1; sex: 1 male; lifeStage: adult; Taxon : scientificName: Beris hildebrandtae; Location : country: Republic of Korea; stateProvince: Gangwon-do ; locality: Samcheok-si , Hajang-myeon , Galjeon-ri, Mt. Jungbongsan, 37°24'04"N, 128°53'51"E ; Identification: identifiedBy: J Lee; dateIdentified: 2021; Event: samplingProtocol: sweeping; eventDate: VII/26/2018; Record Level: language: en; institutionCode: KNU; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence : individualCount: 6; sex: 1 male, 5 females; lifeStage: adult; Taxon : scientificName: Beris hildebrandtae; Location : country: Republic of Korea; stateProvince: Gangwon-do ; locality: Jeongseon-gun , Yeoryang-myeon , Gujeol-ri, Mt. Sangwonsan, 37°32'18"N, 128°39'1"E ; Identification: identifiedBy: J Lee; dateIdentified: 2021; Event: samplingProtocol: sweeping; eventDate: VIII/10/2021; Record Level: language: en; institutionCode: KNU; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence : individualCount: 5; sex: 5 females; lifeStage: adult; Taxon : scientificName: Beris hildebrandtae; Location : country: Republic of Korea; stateProvince: Gangwon-do ; locality: Pyeongchang-gun , Jinbu-myeon , Jangjeon-ri, Mt. Gariwangsan, 37°28'29"N, 128°31'59"E ; Identification: identifiedBy: J Lee; dateIdentified: 2021; Event: samplingProtocol: sweeping; eventDate: VIII/12/2021; Record Level: language: en; institutionCode: KNU; basisOfRecord: PreservedSpecimen

Description

Male. Body length (excluding antennae): 5.3-5.4 mm; wing length: 5.0-5.1 mm. Head: Black and shining; compound eyes densely covered with black hairs; occiput and vertex with pale recumbent hairs; postocular areas towards lower margin of eye covered with pale yellow hairs; face mixed yellow and black hairs; lower frons with short pale hairs; antennae short, extreme apex of pedicel tinged yellowish-brown, both surfaces of flagellomeres 2-4 and inner surface of flagellomeres 5-6 tinged with yellowish-brown to reddish-brown; flagellum 1.4-1.5 times as long as scape and pedicel combined; basal flagellomeres not abruptly swollen (Fig. 2 C). Thorax: Metallic green, scutum tomentose with yellow hairs; postpronotal lobe tinged with yellowish-brown; central part of anepisternum, katepisternum, except upper part and posterior part of anepimeron, nearly bare. Legs: Mainly yellow, but the following parts tinged dark brown: all coxae, except at extreme apex, fore and mid-tarsomeres 2-5, hind tarsomeres 3-5; all trochanters and basal half of femora pale; hind tarsomere 1 about 1.8-2.0 times wider than hind tibia (Fig. 2 A). Wings: Tinged with brown; base of M1 and M2 separated (Fig. 3 A). Abdomen: Dark brown, lateral margin of tergites mixed with conspicuous long pale yellow and black hairs; sterna wholly densely covered with recumbent yellowish-brown hairs; epandrium broad, anterior margin triangular, posterior margin straight; surstyli absent; cercus parallel-sided and straight; proctiger equilaterally triangular (Fig. 3 C); gonocoxite wider than long, median projection on gonocoxite well-developed, bilobate with deep incision; gonostyli clearly curved inwards, tapering apically (Fig. 3D); phallus comparatively stout, tripartite; lateral lobes fairly divergent and with a short straight and pointed apex, somewhat longer than median lobe; median lobe broader at base, more slender and curved distally (Fig. 3 E and F).

Female. Similar to males, but differing as follows: Body length (excluding antennae): 5.0-5.8 mm; wing length: 4.2-5.0 mm. Head: Hairs on compound eyes relatively shorter and fewer than in males; postocular area with distinct pale pruinosity along towards lower margin of eye; antennae mostly tinged reddish-brown, flagellomeres 6-8 dark brown to black; flagellum 1.7-2.0 times as long as scape and pedicel combined; terminal flagellomere more pointed apically (Fig. 2 D). Thorax: Hairs on side of scutum shorter than in males. Legs: All coxae completely pale to pale yellow; hind tarsomere 1 less swollen than in males (Fig. 2 B). Wings: Tinged with pale yellow (Fig. 3 B). Abdomen: Yellow to yellowish-brown and generally glossy; hairs on lateral margin of tergites shorter than in males; posterior margins of tergites 2-6 with transverse black stripes; middle of tergites 2-6 tinged with brown; sterna normally pale yellow, but middle part of sternites 2-5 sometimes dark brown; sternites wholly densely covered with recumbent pale yellow hairs (Fig. 2 E).

Diagnosis

This species can be distinguished from other congeners by the following key diagnostic characters: legs, except coxae and tarsomeres 2-5, mainly pale yellow to yellow (males) (Fig. 2 A); wings tinged with pale yellow (Fig. 3 B), posterior margin of tergites 2-6 with transverse black stripes (females) (Fig. 2 E) ( Nartshuk and Rozkošný 1975).

Distribution

Korea (new record: Gangwon-do), China (Liaoning), Japan (Hokkaido, Honshu) and Russia (Far East: Siberia).

Taxon discussion

This species was discovered by Pleske in 1930 from the Russian Far East and 45 years later, it was re-described in detail by Russian entomologists, Nartshuk and Rozkošný (1975). It has noticeable intraspecific variations, including sexual dimorphism (see Figs 2 , 3 ). Although there are some variations, i.e. colouration of antennal segments 2-3 and coxae, the Korean specimens collected in Gangwon-do Province highly matched with the original description and re-description ( Pleske 1930; Nartshuk and Rozkošný 1975) and we identified these materials as B. hildebrandtae Pleske. In the case of B. liaoningana Cui, Li and Yang, 2010, this species was described, based on the difference of the phallus structures, i.e. the gap, relative length and divergences of three lobes, in comparison with B. hildebrandtae Pleske. However, in the process of genital examination for Korean materials, we confirmed that the phallus structures of B. hildebrandtae Pleske appeared very similar to the drawing made by Cui et al. (2010) depending on the observation angle in glycerine jelly. When drawing a three-dimensional genital structure like a phallus complex, it often causes some distortions, which leads to the taxonomic problem that the same species are described as different species. Furthermore, the external morphology (except variations) and the other genital characters of this Chinese species significantly agreed with the re-description of B. hildebrandtae Pleske. Therefore, there is no doubt that B. liaoningana Cui, Li et Yang is identical with B. hildebrandtae Pleske. As for B. angustifacies Nagatomi and Tanaka, 1972, it was described, based on specimens from Japan and Russian Far East without comparison with B. hildebrandtae Pleske ( Nagatomi and Tanaka 1972). They also illustrated B. angustifacies as having a bifurcate phallus, which is different from B. hildebrandtae (tripartite phallus). However, Nartshuk and Rozkošný (1975) included the personal communication of Nagatomi that " B. angustifacies Nagatomi and Tanaka is probably separated from B. hildebrandtae Pleske by the female’s abdominal colour ( B. angustifacies more darkened) and these two species are very similar or possibly conspecific". The authors confirmed that the abdomens of several Korean female specimens were also partially yellowish-brown to brown. Moreover, as in the example of Beris clavipes (Linnaeus, 1767), there is a possible intraspecific variation in the colour of the abdomen ( Rozkošný 1982). In other words, the colour of the abdomen is not the main character to distinguish species-level. In conclusion, it is reasonable to treat B. angustifacies as a junior synonym of B. hildebrandtae Pleske.

Notes

The males of this species show intraspecific variations on their thoracic hairs, colour of coxae and tarsi. In the Korean specimens, these features are as follows: thoracic hairs usually pale yellow to yellow; all coxae dark brown to black, but extreme apices yellow, mid-coxa sometimes completely pale; tarsi mainly yellow, but fore and mid-tarsomeres 2-5 and hind tarsomeres 3-5 dark brown. The females of this species also have some variations on their colouration of antennae, darkening on abdomen and wing venation. For Korean materials, the antennae are mostly tinged with yellow to reddish-brown, but flagellomeres 6-8 dark brown to black. Additionally, the following variations are occasionally noted in some individuals from Korea: scape and pedicel tinged with reddish-brown and yellowish-brown, respectively; extreme base of scape dark brown to black; flagellomere 6 orange brown, not darkened like flagellomeres 7-8. The abdomens of Korean materials are mainly yellow to yellowish-brown and middle of tergites 2-7 more darkened; these segments are fully dark brown or pale yellow depending on individuals. Furthermore, M1 and M2 are generally well-separated proximally, but in some individuals, these veins touch at their bases.

Figures

Figure 2. Beris hildebrandtae Pleske, 1930: A Male habitus, lateral view; B Female habitus, lateral view; C Male head, lateral view; D Female head, lateral view; E Female abdomen, dorsal view. Scale bars: A, B = 1.0 mm; C, D = 0.2 mm; E = 0.5 mm.

Figure 3. Beris hildebrandtae Pleske, 1930: A Male wing; B Female wing; C Epandrium, cerci and proctiger, dorsal view; D Genital capsule, dorsal view; E Phallus, dorsal view; F Ditto, lateral view. Scale bars: A, B = 0.5 mm; C-F = 0.1 mm.