Formosargus kerteszi James 1939
Creators: name: Fachin, Diego Aguilar
name: Hauser, Martin
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Stratiomyidae
Formosargus
Formosargus kerteszi

description: Formosargus kerteszi James, 1939
(Figures 3 (a), 5(a–c), 7(a–b), 8(a–b), 15(a), 17(a–b), 18(a), 21–22)
Formosargus kerteszi James, 1939: 36–37 (orig. descr.).
Type locality: Taiwan, Kankau (Koshun). Holotype: ♂ [DEI]; paratypes: 1 ♀, [DEI], 1 ♀, [WSU]; allotype: ♀ [DEI].
Refs: James, 1975: 17 (cat.); Rohlfien and Ewald, 1979: 203 (cat. of types); Zack, 1984: 23 (cat. of types); Woodley, 2001: 190 (cat.); Yang et al., 2014: 416 (com.); Lessard et al., 2020: 28 (com.).
Diagnosis
Upper frons short, wider than long; in males, anterior margin of upper frons inverse-Ushaped at the edge with lower frons (Figure 3 (a)). Scutal medial band narrower on anterior half, wider posteriorly (Figure 7 (a, b)); anepisternum with at least one dark spot. Abdomen yellowish, only males with a transverse dark brown band distally on tergite 1 (Figure 21).
Material examined
Type material. HOLOTYPE (Figures 7 (a), 21(a–f)), ♂ labelled: ‘7.XI. [printed on white paper]’; ‘Kankau (Koshun)/ Formosa /H. Sauter VI 1912 [printed on white paper]’; ‘Coll. DEI/Eberswalde [printed on white paper]’; ‘ N.G. near/ Ptecticus n.sp. [handwritten on white paper]/Det. by T. Shiraki/TAIHOKU, IV, 193 [printed on white paper]’; ‘ Holotypus [printed on red paper]’; ‘ Formosargus / kerteszi / ♂ [handwritten on red paper]/James [printed on red paper]’ (DEI). PARATYPE (Figure 22 (a–d)), ♀ labelled: ‘Kankau (Form.)/H. Sauter IX.12 [1912] [printed on white paper]’; ‘Kertész det. [printed on white paper]’; ‘ Formosargus / kerteszi / ♀ [handwritten on red paper] James/ PARATYPE [printed on red paper]’ (WSU). ALLOTYPE (Figure 22 (e–h)), ♀ labelled: ‘Kankau (Formosa)/H. Sauter VII.1912 [printed on white paper]’; ‘ Formosargus / kerteszi / ♀ [handwritten on red paper] James/ ALLOTYPE [printed on red paper]’; ‘Kertész det. [printed on white paper]’; ‘ ALLOTYPUS [printed on red paper]’ (DEI).
Additional material. 1 ♀ (genitalia dissected and stored in microvial with glycerine), PHILIPPINES, [Eastern Samar], Calicoan PI [Calicoan Island], 10 August 1945, F.F. Bibby, no. 397, fermenting banana plant (USNM). 1 ♂, PHILIPPINES, Laguna, Calamba, Putting Lupa, 30 November 1976, kaingin, Malaise trap, UPLBMNH, DIP-002490 (UPLB).
Redescription.
Female. Length (n = 1): body, 5.5 mm; wing, 5.0 mm. Head (Figures 3 (a), 5(b, c)). Vertex area longer than ocellar tubercle, less than twice. Upper frons shortened, twice wider than long, at least twice shorter than lower frons; black lateral area nearly as wide as ocellar tubercle width, with short yellowish pilosity; upper frons anterior margin weakly convex. Fourth flagellomere rounded, as wide as each previous flagellomere alone or slightly wider. Face twice shorter than lower frons. Thorax (Figure 7 (a)). Medial dark brown band narrower on anterior part of scutum, wider on posterior half, at about twice its anterior width; one-third of scutellum dark brown; pleuron pale yellow, with only small dark brown macula on anepisternum. Tarsomeres yellowish. Wing. R2+3 originating slightly before r– m, curved on basal third and nearly straight on apical two-thirds. Abdomen. Entirely pale yellow to yellow, without dark markings. Terminalia (Figures 15 (a), 17(a, b)). Genital fork widest medially; anterior half clearly triangular; posterior bridge bilobed; posterolateral process wider on approximate basal half, narrowing into a rounded end; genital opening roughly oval.
Geographic distribution.
Oriental Region. Taiwan (Pingtung), Philippines (Eastern Samar: Calicoan Island; Laguna) (Figure 26).
Comments
James’s description of Formosargus kerteszi is based on one male and three females (allotype and two paratypes). The additional male specimen herein presented from the Philippines conforms with the male holotype because both have a pair of diffuse black markings on the anepisternum, and a black mediotergite (Figure 21 (a)). The females from the same site as the male holotype and one additional female from the Philippines (Calicoan Island), however, differ from them by the presence of a single and small spot on the anespisternum and, strangely, their mediotergites are completely yellow. The two Australian species, F. lineatus and F. melanogrammus, also have a yellow mediotergite and similar scutal medial band to those of the females of F. kerteszi (see Figure 18 (a and d) for comparison), but, in contrast, both anepisterna are entirely yellow. Formosargus mangoleensis sp. nov., from Indonesia, is the only species sharing with the females of F. kerteszi one small spot on the anepisternum and a yellow mediotergite (Figure 20 (a)). It is interesting that they also have a rather similar scutal medial band, although in F. mangoleensis sp. nov. it is broader and does not reach the extreme anterior margin of the scutum (Figure 7 (g)). The fact is that these females of F. kerteszi tentatively do not fit in any other species and we do not have enough evidence to propose them as a separate species as well. Our data shows that each species has a distinct genital fork (Figure 17); however, only the female from Calicoan Island has the genital fork illustrated, so a possible confirmation of these females as a separate species from the males would demand the examination of the genital fork of the allotype and paratypes of F. kerteszi, which was not performed in this study.
The holotype male genitalia is currently lost. We only have an additional male of F. kerteszi, which is without the terminal part of the abdomen including the genitalia, so it could not be illustrated and described. On the other hand, one available photograph of the male genitalia of the holotype (Figure 21 (e)) shows that F. kerteszi is similar to F. lineatus, particularly due to the presence of long inner projections of the synsternite (Figure 11 (a)).
description: Published as part of Fachin, Diego Aguilar & Hauser, Martin, 2022, Revision of Formosargus James, 1939 (Diptera: Stratiomyidae): five new species in an otherwise rare genus and Amsaria Adisoemarto, 1974 as a generic synonym, pp. 1513-1562 in Journal of Natural History 56 (37 - 40) on pages 1528-1534, DOI: 10.1080/00222933.2022.2117107, http://zenodo.org/record/7318178