Formosargus borneensis, 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 : 1552-1553

publication ID	https://doi.org/ 10.1080/00222933.2022.2117107
publication LSID	lsid:zoobank.org:pub:A6F9B9FB-D3F9-49F2-8FC1-5E6A5E0AB3B1
DOI	https://doi.org/10.5281/zenodo.7324778
persistent identifier	https://treatment.plazi.org/id/D4B99C35-6994-422E-9EEB-18D3C56E4CB6
taxon LSID	lsid:zoobank.org:act:D4B99C35-6994-422E-9EEB-18D3C56E4CB6
treatment provided by	Plazi
scientific name	Formosargus borneensis
status	sp. nov.

Treatment

Formosargus borneensis View in CoL sp. nov.

( Figures 4 View Figure 4 (b), 6(b), 7(f), 15(d), 17(g–h), 19(d–e))

Diagnosis (female)

Species distinctly reddish in colour. Medial band on scutum slightly wider on posterior half ( Figure 7 View Figure 7 (f)), with a narrowing at level of the transverse suture and yellow one-third of scutum as wide as in F. berezovskiyi sp. nov., but differs from it by a pair of anterior lateral dark brown maculae over notopleuron ( Figure 19 View Figure 19 (d)). Abdominal tergites with subtle brownish markings, mostly conforming with the background colour ( Figure 19 View Figure 19 (e)).

Material examined

HOLOTYPE, 1 ♀ (genitalia dissected and stored in microvial with glycerine), MALAYSIA, B. [British] N. [Northern] Borneo, [Sabah], Mt. [Mount] Kinabalu, Kamborangah , 7000 ft. [feet], 18 April 1929, [coll. H. M. Pendlebury] ( NHMUK).

Description

Female. Length (n = 1): body, 10.0 mm; wing, 9.0 mm. Head ( Figures 4 View Figure 4 (b), 6(b)). Vertex area twice longer than ocellar tubercle. Upper frons as wide as long, twice longer than lower frons; upper frons black lateral area broader than ocellar tubercle width, with short dark brownish pilosity; anterior margin of upper frons with a median triangular projection pointing towards antennal insertion. Fourth flagellomere rounded, as wide as each previous flagellomere alone or slightly wider. Face nearly as long as lower frons. Thorax ( Figure 7 View Figure 7 (f)). Medial scutal band dark brown, nearly as wide as one-third of scutum, with a subtle narrowing at level of transverse suture, wider posteriorly, weakly discontinued at base of scutellum; a subrectangular dark brown macula over notopleuron area, extending over anepisternum proximally; laterotergite reddish yellow, mediotergite with only a small dark brown mark. Basal half of hind femur dark brown. Wing. R2+3 arising slightly before r–m, weakly curved towards R1 on basal third, nearly straight on apical two-thirds. M1 and M3 less faint. Halter mostly reddish yellow, distal half of knob dark brown. Abdomen. Reddish, with a central transverse brownish band, nearly covering entire surface of each tergites 1–5 ( Figure 19 View Figure 19 (d)), conforming in colour with the background; pilosity reddish yellow. Terminalia ( Figures 15 View Figure 15 (d), 17(g–h)). Genital fork wider medially at level of posterolateral process insertion; anterior half subtriangular, narrowing into a relatively slender and rounded anterior end; posterior bridge weakly bilobed; posterolateral process enlarged and rounded at base, much slenderer on next one-third, enlarging on last third towards apex, distal half nearly parallel; genital opening reduced, roughly oval.

Male

Unknown.

Etymology

The specific epithet, borneensis , refers to the collection site of the holotype of the new species, the island of Borneo.

Geographic distribution

Oriental Region. Malaysia (Sabah) ( Figure 26 View Figure 26 ).

Comments

This species is part of a group of species, including F. kerteszi , F. lineatus , F. berezovskiyi sp. nov., F. mangoleensis sp. nov. and F. melanogrammus , that share the presence of a single medial dark brown band on the scutum (see Figure 7 View Figure 7 (a–c, e, g)) and a rounded fourth flagellomere (see Figure 2 View Figure 2 (a, b)). Formosargus borneensis sp. nov., however, has a pair of additional subrectangular dark markings laterally on the anterior part of the scutum, mostly over the notopleuron ( Figure 19 View Figure 19 (e); see couplets 1 and 2 in the key). This feature indeed has similarities to the condition seen in the three-striped species, for example to that of F. trivittatus sp. nov. ( Figure 20 View Figure 20 (c)). The difference is that in F. trivittatus sp. nov. and in the other species related to it, the lateral macula is not only over the notopleuron but also extends over the anterior part of the scutum (see Figure 7 View Figure 7 (h)).