Poecilosomella borboroides ( WALKER, 1860 )

Papp, L., 2002, Eighteen New Oriental Species Of Poecilosomella Duda (Diptera: Sphaeroceridae), Acta Zoologica Academiae Scientiarum Hungaricae 48 (2), pp. 107-156 : 110-114

Poecilosomella borboroides ( WALKER, 1860)

( Figs 1–5 )

Ephydra borboroides : WALKER 1860: 171. Holotype female (BMNH): Celebes, Makessar [now Sulawesi, Ujungpandang].

The original description says: “Length of the body 1 1/2 line; of the wings 3 lines” [that would be 7.62 mm], which must be an overstatement.

Mr NIGEL WYATT (The Natural History Museum London) examined the only type specimen and he wrote: “I have examined the holotype of Poecilosomella borboroides WALKER and it seems to belong to your ‘species 2’ [my term to differentiate the two forms I saw]. There are no ventral or anteroventral setae on the mid tibia except for the ventral seta at the apex.” This piece of information is critically important in arbitration of the closely related P. ornata , which was formerly erroneously placed into synonymy with P. borboroides (see below).

Material studied: 3 males, 7 females: MALAYSIA: Sabah, G. F. Hevel & W. E. Steiner 1983 ( NMNH, 1 male, 1 female in HNHM): 1 km S Kundasang, el. 1530 m, 6 Aug; Kinabalu National Park , Poring , el. 570, 8 Sept., ibid., Summit trail below Carson Camp , 1980–2700 m, 16 Sept., Telipok , 12 August. 1 male ( ROM): INDONESIA, Sumatra, W. Sumatra: Kerinci-Seblat Nat. Pk., trail to L. Tujuh, 14 SEP 1989. B Hubley, DC Darling, ROM 893074 – 1 ° rainforest, 1640 m, screen sweep, 1°42’N, 101°19’E. 1 male, 2 females ( HNHM): India, leg. Topál.

Male abdominal sternite 5 strongly asymmetrical, sternite 6 contiguous with 2 asymmetrical median lobes and a broad lobe on the left side ( Fig. 1 ). Subepandrial sclerite ( Fig. 2 ) with a broad paired, apically rounded process (characteristic for this species group), whose hairlike setae are longer than in the species from the Philippines. Surstylus ( Figs 4–5 ) apically with 6 thick black teeth (prensisetae). Postgonite ( Fig. 3 ) less broad medially than in the Philippines form, apex more demarcated. There are slight variations in the fine details of the surstylus among specimens from different localities ( Fig. 4 , vs Fig. 5 ) but I think this normal.

2–5

It is useless to say that any specimens identified as P. borboroides before (incl. by myself before 2000) are doubtful. I hope colleagues will not regard my decision to select this biological species for the name P. borboroides (WALKER) just as an arbitrary decision. The form fixed by Figs 1–5 seems to be the widespread one, and I also found specimens collected rather close to its type locality (Sulawesi (Celebes) vs. Borneo, Sabah). A dissection of the female holotype of P. borboroides (being a female) would not get closer to a better solution.

mm for Figs 6–8

In the last phase of work on the Oriental Poecilosomella , I managed to study the type of P. picturata ( MALLOCH, 1913), described from the Philippines and formerly regarded as a junior synonym of P. borboroides . Based on a study of its genitalia, I would like to remove it from synonymy (see also below)

Poecilosomella ornata (DE MEIJERE, 1908) , sp. restit.

( Figs 10–13 )

Limosina ornata : DE MEIJERE 1908: 177.

Originally two syntypes were known from Java, Semarang. It was proposed as synonymous erroneously on two different occasions for two different species (DE MEIJERE 1918, HACKMAN 1977)

Dr. HERMAN DE JONG (Amsterdam) sent me the following information: “ DE MEIJERE (1918; Tijdschrift voor Entomologie 60: 323) regarded his ornata as a variety of venalicia OSTEN SACKEN. According to DE MEIJERE, both should differ in the extent of the dark coloration of the wing membrane.

The single remaining type specimen of ornata was placed under ‘ venalicia ’ in our collection. It has the legs folded and closely appressed to the body. Nevertheless it is clear that the right t2 carries a strong (antero) ventral bristle near midlength. I could not find a ventro-apical bristle on either t2, although the view of both legs is quite obscured.”

Material studied: 2 males ( HNHM) : TAIWAN: Pingtung Hsien, Kenting, Heng-Chun Trop. Botanical Garden – forest undergrowth, Oct 5, 2000, leg. L. PAPP, No. 19. 2 males, 1 female ( ROM, 1 male in HNHM) : INDONESIA: Sumatra, Aceh, Gunung Leuser Nat. Pk., Ketambe Res. Sta., 9–21 SEP 1989, DC Darling, ROM 893087 – 1 ° rainforest. Young forest , Terrace 3, closed canopy, 350 m, 3°41’N, 97°39’E, Malaise traphead; 1 female ( ROM) : ibid., 3–10 SEP, B Hubley, DC Darling, ROM 893027 ; 1 female ( ROM) : ibid., 7 SEP, ROM 893059 – 1 ° rainforest, 350 m, 3°41’N, 97°39’E. Screen sweep; 1 female : INDONESIA: E. Kalimantan, Kac. Pujungan, Kayan-Mentarang Nat. Reserve, Jun-Aug. 1993, DC Darling, Rosichon U. IIS 930596 – lowland diptero.[Dipterocarpus] forest, WWF Station, Lalut Birai, vicinity of Base Camp. Log emergence traps, 2°52’N, 115°49’E, 378 m.

Male sternite 5 ( Fig. 10 ) less asymmetrical than in its relatives, there are 3 wide (long) rows of comparatively long hairs on the sternite 5 & 6 complex medially ( Fig. 10 ), setae on sternite 5 long and comparatively thick. Ventral process of subepandrial sclerite ( Fig. 11 ) long, comparatively thin, finger-like. Sursylus ( Fig. 12 ) with only 1 thick black tooth but there is a dentate process behind it. Postgonite ( Fig. 13 ) rather curved with definitely demarcated dentiform apex. See more in the key below.

postgonite, lateral view. Scales: 0.2 mm for Figs 10–11 , 0.1 mm for Figs 12–15

Figures

Figs 1–5. Poecilosomella borboroides (WALKER), male postabdomen and genitalia. 1 = sternite 5 and 6, ventral view, 2 = right half of subepandrial sclerite, caudal view, 3 = postgonite, 4 = surstylus, lateral view (Sabah), 5 = apical part of surstylus (India). Scales: 0.2 mm for Fig. 1, 0.1 mm for Figs

Figs 6–9.Poecilosomella borborus sp. n., paratype male, postabdomen and genitalia. 6 = right half of subepandrial sclerite, caudal view, 7 = surstylus, lateral view, 8 = postgonite in widest extension, i.e. not lateral view, 9 = sternite 5 and pregenital sternites, ventral view. Scales: 0.2 mm for Fig. 9, 0.1

Figs 10–15. Poecilosomella spp.males.10–13 =P.ornata (DE MEIJERE), Taiwan: 10 = sternite 5 and 6, ventral view, 11 = left half of subepandrial sclerite, caudal view; 12 = surstylus, lateral view, 13 = postgonite, lateral view. 14–15 = P. meijerei (DUDA): 14 = surstylus, true lateral view, 15 =