Formosargus mangoleensis, Fachin & Hauser, 2022

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, Journal of Natural History 56 (37 - 40), pp. 1513-1562 : 1554-1555

Formosargus mangoleensis sp. nov.

( Figures 4 (c), 6(c), 7(g), 16(a), 17(i–j), 19(f), 20(a))

Diagnosis (female)

Medial band on scutum narrow, not reaching the extreme anterior end of scutum ( Figure 7 (g)), wider posteriorly. Vertex at least twice the length of the ocellar tubercle ( Figure 4 (c)); upper frons shortened, nearly three times shorter than lower frons ( Figure 6 (c)). Mediotergite completely yellow; anepisternum with a small subrectangular dark spot ( Figure 20 (a)). Abdomen entirely pale yellow.

Material examined

HOLOTYPE, 1 ♀ (genitalia dissected and stored in microvial with glycerine), INDONESIA, [North Maluku Province], Sula Isl. [ Island] Mangole , 2 km W. Mandafuhi Camp, Mal. [ Malaise ] trap 19, c 70 m, 07–24 March 1995, C.v. Achterberg and Y. Yasir ( RMNH) . PARATYPE, 1 ♀, INDONESIA, [North Maluku Province], Mangole, Mandafuhi Camp , 05 March 1995, along road, C.v. Achterberg, RMNH 95’ ( RMNH) .

Description

Female. Length (n = 2): body, 10.0 mm; wing, 9.0 mm. Head ( Figures 4 (c), 6(c)). Vertex area twice longer than ocellar tubercle. Upper frons shortened, twice wider than long, nearly three times shorter lower frons; upper frons black lateral area nearly as broad as ocellar tubercle width, with short brownish pilosity; anterior margin nearly straight at the edge with lower frons, only medially pointing towards antennal insertion. Fourth flagellomere rounded, as wide as each previous flagellomere alone or slightly wider. Face three times shorter than lower frons. Thorax ( Figure 7 (g)). Medial dark brown band covering less than one-third of scutum width, not reaching extreme anterior end of scutum, wider on posterior half and scutellum; pleuron pale yellow, with only a small subrectangular dark brown spot on anepisternum. Wing. R2+3 originating slightly before r–m, weakly curved on basal third, straight on apical two-thirds. Abdomen. Completely yellow; pilosity yellow. Terminalia ( Figures 16 (a), 17(i, j)). Genital fork wider at posterior half at level of posterior bridge; anterior half gradually narrowing into a long and curved anterior end; posterior bridge bilobed; posterolateral process parallel, slightly wider at base, gradually narrowing towards a rounded apex; genital opening roughly circular.

Male

Unknown.

Etymology

The specific epithet, mangoleensis , refers to the collection site of the holotype of the new species, the island of Mangole , in the Sula Islands, Indonesia.

Geographic distribution

Oriental Region. Indonesia (North Maluku: Mangole Island) ( Figure 26 ).

Comments

This species, as mentioned, shares with the females of F. kerteszi a small dark spot on the anepisternum and mediotergite completely yellow. However, it is distinguished from F. kerteszi by a vertex area twice the length of the ocellar tubercle ( Figure 6 (c)); also, in F. mangoleensis sp. nov., the upper frons is relatively shorter than that in F. kerteszi (see Figures 5 (b, c) and 6(c) for comparison) and it has a medial band slightly wider, that does not reach the extreme apex of the anterior part of scutum (see Figures 7 (b) and 7(g) for comparison). Besides these features, F. mangoleensis sp. nov. is so far the only species reported within the limits of Wallacea ( Figure 26 ) – the area between Wallace’s Line and Lydekker’s Line – while F. kerteszi is found more to the north, beyond Wallace’s Line. The nearest species in geographical proximity to F. mangolensis sp. nov. is a record of F. lineatus from the Island of Waigeo, Indonesia, near the north-west boundary of Lydekker’s Line, which is in the Australian Region.

Figures

Figure 4. Heads of Formosargus species, dorsal view. (a) F.berezovskiyi sp. nov., female, paratype. (b) F. borneensis sp. nov., female, holotype. (c) F. mangoleensis sp. nov., female, holotype. (d–e) F. trivittatus sp. nov. (d. male, holotype; e. female, paratype). (f) F. woodleyi sp. nov., male, holotype.

Figure 5. Heads of Formosargus species, frontal view. (a–c) F. kerteszi (a. male, Philippines; b. female, Allotype [DEI], Taiwan; c. female, Philippines). (d–e) F. lineatus (d. male; e. female). (f) F. sagittocerus, male. Arrow: anterior margin of the upper frons at the edge with lower frons.

Figure 6. Heads of Formosargus species, frontal view. (a) F. berezovskiyi sp. nov., female, paratype. (b) F. borneensis sp. nov., female, holotype. (c) F. mangoleensis sp. nov., female, holotype. (d–e) F. trivittatus sp. nov. (d. male, holotype; e. female, paratype). (f) F. woodleyi sp. nov., male, holotype. Arrow: anterior margin of the upper frons at the edge with lower frons.

Figure 7. Thorax of Formosargus species, dorsal view. (a–b) F. kerteszi (a. male, holotype [DEI]; b. female, Philippines). (c) F. lineatus, male; arrow: medial band. (d) F. sagittocerus, male. (e) F. berezovskiyi sp. nov., female, paratype; arrow: mediotergite. (f) F. borneensis sp. nov., female, holotype; arrow: notopleural macula. (g) F. mangoleensis sp. nov., female, holotype; arrow: mediotergite. (h) F. trivittatus sp. nov., male, holotype; arrow: anterior lateral band. (i) F. woodleyi sp. nov., male, holotype.

Figure 16. Female terminalia of Formosargus species, dorsal view. (a) F. mangoleensis sp. nov, holotype. (b) F. trivittatus sp. nov., paratype (cerci lost). Abbreviations: cerc, cercus; st, sternite; tg, tergite.

Figure 20. Habitus of Formosargus species.(a) F. mangoleensis sp. nov., female, holotype, lateral. (b–d) F. trivittatus sp. nov. (b–c. male, holotype, dorsal and lateral, respectively; d. female, paratype, dorsal). (e–f) F. woodleyi sp. nov., male, holotype, dorsal and lateral, respectively.

Figure 26. Geographic distribution of Formosargus. Squares represent holotypes records; circles represent paratypes, and additional material. Three of the ‘lines’ of faunal division are shown: 1. Wallace’s Line; 2. Weber’s Line; 3. Lydekker’s Line. ‘Wallacea’ is the area that lies between Wallace’s Line and Lydekker’s Line.