Silba spiculata, Macgowan, Iain, 2015

Macgowan, Iain, 2015, A review of the Silba admirabilis McAlpine species group (Diptera: Lonchaeidae) with descriptions of thirteen new species from the Afrotropical region, Zootaxa 4032 (5), pp. 515-534 : 525-527

Silba spiculata sp. nov.

Description. Male: Head: Eyes bare. Frons 0.6 width of an eye, subshining black, frontal and interfrontal setulae not more than 0.25x length of orbital setae. Orbital plate bare apart from orbital setae. Lunule with ground colour dark, slightly silver dusted as are face and parafacials. Anterior genal setulae short, in a single row of 4–5 along the mouth margin. Antennae; 1st flagellomere black apart from a hint of orange-brown at extreme medial base, length to depth ratio 2.5:1. Arista plumose, ratio of plumosity at maximum extent to depth of 1st flagellomere 1:1.

Thorax: mesonotum, pleura and scutellar dorsum subshining black. Anepisternum with 2 strong anterior setae and 3 strong posterior setae, remainder of sclerite with scattered setulae which are more than 0.5x length of the setae. Katepisternum with 2 setae, the posterior markedly stronger than the anterior. Proepimeron and proepisternum each with 1 seta. Scutellum on margin between lateral and apical setae with 2 small setulae on right, 1 on left, none between the apical setae. Calypteres whitish with a white fringe. Wings clear, wing length 3.5mm. Legs black, basal tarsomeres yellow, becoming slightly more darkened apically.

Male terminalia (Figs. 1–2 & 21–22): epandrium and associated structures of the standard S. admirabilis group type. Phallus: in lateral view an open U-shape, basally with a group of small spicules, ventral plate as long as phallus slightly thickened at apex, spicules visible on apical half. Basal plate, in ventral view Y -shaped, at apex forming two rounded processes separated by a rather open U-shaped incision, numerous small spicules scattered across ventral surface and lateral margins.

Type material. Holotype ♂. MADAGASCAR; 30Km W. Sambavana, 13.iv.1991, A. Freidberg & Fini Kaplan.

Paratypes. Madagascar; 35Km. E. Ranomafana, 21º20’S 47º43’E, 500m, 28.x.2007, A. Freidberg, 3♂.

Specimens in TAUI.

Etymology. The specific epithet refers to the spicules on the basal plate of the phallus.