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

description: Formosargus lineatus (de Meijere, 1913)
(Figures 2 (a, b), 3(b, c), 5(d, e), 7(c), 8(c–e), 9(a), 10(a, b), 11, 15(b), 17(c, d), 18 (b–e), 23)
Chrysochlora lineata de Meijere, 1913: 318 (orig. descr.).
Type locality: Indonesia, Irian Jaya, Alkmaar. Holotype: ♀ [ZMAN].
Refs: Brunetti, 1923: 158 (list); Lindner, 1957: 194 (suppl. descr. of male); Woodley, 1989: 316 (cat.); Woodley, 2001: 175 (cat.); Hauser et al., 2017b: 950 (com.); Lessard et al., 2020: 27 (comb. nov.), 28–29 (com.).
Diagnosis
Species very similar to F. kerteszi, but differs from it by pleuron completely yellowish in both sexes, without dark markings over anespisternum and mediotergite. Upper frons shortened as in other species, but roughly four times shorter than lower frons (Figure 5 (d, e)). Scutal band clearly more homogeneous in width, only slightly wider about at level of transverse suture (Figure 7 (c)), while in F. kerteszi, it is wider on posterior half (Figure 7 (a)). Abdomen in males only with a pair of dark brown spots on tergite 1 (Figure 18 (b)); completely yellowish in females as in F. kerteszi, while in F. melanogrammus, it has spots on tergites 2–5.
Material examined
Type material. HOLOTYPE (Figure 23 (a–c)), 1 ♀, INDONESIA, Irian Jaya [West Papua Province], Alkmaar (ZMAN).
Additional material. 1 ♂ (left antenna slide-mounted; genitalia dissected and stored in microvial with glycerine), INDONESIA, [West Papua Province] Neth. Ind.- American, New Guinea Exped. [Expedition], Araucaria Camp 800 m, [- 3.5°S 139.183333°E], 09 March 1939, L.J. Toxopeus (RMNH). 1 ♀, N. Dutch New Guinea [= Indonesia], Waigeu [West Papua Province, Waigeo], Camp. Nok., 2500 ft. [feet], April 1938, L.E. Cheesman, B.M. 1938–593 (NHMUK). 2 ♀ (1 ♀ with left antenna and wing slide-mounted, genitalia dissected and stored in microvial with glycerine), PAPUA NEW GUINEA, Bulolo [Morobe Province], Rifle range LA, 23 February 1983, sp. no. 2014, Pandanus sp., H.R. Roberts, C. IE A14858 (NHMUK). 1 ♀, Morobe Province, Tekadu, - 7.633333°S 146.566667°E, 09 February 2000, T. A Sear and Binatung, brigade MT (UCD).
Redescription
Male. Length (n = 1): body, 6.5 mm; wing, 6.0 mm. Head (Figure 3 (b), 5(d)). Vertex area slightly longer than ocellar tubercle. Upper frons very reduced, twice wider than long, roughly four times shorter than lower frons; black lateral area of upper frons much narrower, short yellowish pilosity; anterior margin of upper frons inverse-U-shaped, pointing towards ocellar tubercle. Fourth flagellomere rounded, as wide as each previous flagellomere alone or slightly wider (Figure 2 (a)). Face three times shorter than lower frons. Thorax (Figure 7 (c)). Medial scutal band dark brown, homogeneous in width along extension, with a subtle enlarging at level of transverse suture; pleuron entirely yellow. Mid leg with a curled modified structure at apex of first tarsomere (Figure 8 (c–e)); tarsomeres yellowish. Wing (Figure 9 (a)). R2+3 originating slightly before r–m, weakly sinuous. Abdomen. Mostly yellowish in background, with a pair of subrectangular dark brown maculae on tergite 1. Terminalia (Figures 10 (a, b), 11). Ventral margin of genitalia with a median bilobed and acuminate projection; synsternite with a pair of well-developed and long inner projections, curved at base, parallel on distal two-thirds, with strong bristles on last third, slightly exceeding distal margin of genitalia. Phallus exceeding gonocoxal bridge distally; parameral sheath as long as gonostylus, subrectangular. Gonostylus wide in lateral view, bilobed.
Female. Similar to male, except as follows: Length (n = 4): body, 5.5–9.0 mm; wing, 5.5– 8.0 mm. Head (Figures 3 (c), 5(e)). Lower frons and face white. Thorax. Medial band narrower than in males (Figure 18 (d)). Abdomen. Homogeneously yellow, without dark markings on tergites. Terminalia (Figures 15 (b), 17(c, d)). Genital fork equally wide on distal two-thirds, lateral margins projected backwards; basal third abruptly narrowing into a very thin, roughly straight and pointed anterior end; posterior bridge bilobed; posterolateral nearly parallel, with basal two-thirds enlarged, gradually narrowing into a rounded apex.
Geographic distribution
Australian Region. Indonesia (West Papua), Papua New Guinea (Morobe) (Figure 26).
Comments
Formosargus lineatus was originally described in Chrysochlora based on a female and only reported again by Lindner (1957) from a male from Indonesia (West Java) collected in 1939, which is here examined. The species was recently transferred to Formosargus (Lessard et al. 2020, referred to as Formosargus lineata), but images of the holotype are only now provided with the redescription of the species.
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 1534-1536, DOI: 10.1080/00222933.2022.2117107, http://zenodo.org/record/7318178