Pachylophus tschirnhausi, Deeming, 2018

Deeming, John C., 2018, A revision of the Afrotropical species of Pachylophus Loew (Diptera: Chloropidae) and some related Ovoviviparous genera, Zootaxa 4482 (1), pp. 1-51 : 23

Pachylophus tschirnhausi sp. n.

( Plate 16 , Figs 78, 79)

Diagnosis. A slender black species, dirty yellow on face, gena, palpus and legs, but femora infuscate, becoming paler apically, and tarsi more or less darkened, antenna also dirty yellow on basal segments, and on postpedicel on lower one third of height of outer (true posterior) surface and on all but apical angle of inner surface and frons obscurely paler on extreme anterior margin. Dusting grey, darker on occiput and dorsum of thorax and abdomen, paler on paler parts of head and pleura inclusive of notopleuron, but frontal triangle, propleuron and anepisternum completely undusted, palest on a narrow, almost silvery line bordering eye on frons; wing greyish hyaline with blackish brown veins; squamal margin and fringe dark and haltere dark throughout.

Description. Male. Ratio of length: width: depth of head 26:31:24, of length:width at mid length of frons 20:12, of length of first: second: third segment of arista 3:6:12, of length: greatest depth of hind femur 26:7; frontofacial angle c. 85°; outer vertical seta undeveloped, the inner vertical as long as postpedicel is deep; frontal triangle with straight sides; occiput strongly convex; projection on inner surface of pedicel minute; scutum rather flat, slightly longer than wide, extending almost to base of antenna; scutellum short, triangular, with apical marginal setae that are longer than the distance separating their bases, all other setae apart from these and the inner vertical weak and short.

Length about 2.5mm, of wing 2.3mm.

Female resembling male in all but structures of the postabdomen.

Material: Holotype ♂, MADAGASCAR: Southern Bank of Mangoky River, Bevoay , 21°50'S 43°53'E, 19.ii.1984, M. v. Tschirnhaus (X1181) ( ZSM) ; Paratypes, 1♂ 4♀, same data as holotype ; 4♂ 6♀, Andasibé (= Perinet ), 18°55'S 48°25'E, 29.ii.–4.iii.1984, M. von Tschirnhaus (X1187) (all in ZSM apart from 2♀ in NMWC) ; 2♂ 3♀, River Hazovotsy (= Ihazovotsy) 13km. WSW of Ihosy, c. 22°25'S 46°00'E, 11.ii.1984, M. v. Tschirnhaus (X1176) ( ZSM).

A dissected female from Andasibé was found to contain a well-segmented larva with the cephaloskeleton evident and encapsulated in egg chorion, and which was in length two thirds of the mother's abdomen.

This species is closely related to P. varipes Adams , which has, in addition to key characters cited, the entire frons with the exception of the frontal triangle yellow, the knob of the haltere creamy white, the dusting of the thorax uniformly paler grey and the inner vertical seta very short and weak and not larger than the marginal setae of the frontal triangle and the ratio of length of the three aristal segments as 5:8:13.

Figures

PLATE 16. Figs 78–83. Pachylophus spp. 78, P. tschirnhausi sp. n., frons; 79, same, habitus; 80, P. varipes Adams, frons; 81, same, habitus; 82, P. splendidus Adams, frons; 83, same, habitus.