Lonchaea tanna, MacGowan, 2021

Macgowan, Iain, 2021, The Lonchaeidae of Vanuatu (Diptera: Schizophora), Zootaxa 4926 (3), pp. 342-362 : 354-355

Lonchaea tanna sp. nov. (Figures 31, 32).

IGURES 31 & 32. Lonchaea tanna sp. nov. 31. Epandrium and associated structures, ventral view (phallus removed and pregonites shaded to define their shape). 32. Phallus, lateral view.

Description. MALE: Body length 2.3mm.

Head: Eyes bare. Frons sub-shining black, dulled by fine microsculpture. Frontal and interfrontal setulae very short approximately 0.1x length of orbital seta, becoming longer near anterior margin. Orbital plates shining black, bare apart from orbital seta. Lunule intensely silver pollinose, parafacials and face slightly silver dusted. Antennae black, postpedicel medial surface orange on basal quarter, length to depth ratio 2.8:1. Anterior genal setulae short, forming a single row along mouth margin.

Thorax: Scutum shining black, covered with short setulae approximately 0.2x length of orbital seta. 1 seta on both proepimeron and proepisternum. Thoracic sclerites shining black. Anepisternum and katepisternum with most setae missing due to damage. Scutellum. sub-shining black, covered with slight grey pollinosity, disc bare, margin bare apart from four lateral setae. Legs black, t1 yellow, apical segments darkened. Calypteres pale with a brown margin, fringe yellowish brown. Wing length 2.2mm, wing membrane slightly fumose.

Male terminalia: Epandrium spherical in shape. Surstyli, simple elliptical lobes extending postero-ventrally from epandrium. Cerci approximately same height as epandrium, a large hooded structure covered externally with short setulae, attached to remainder of terminalia by a narrow basal section which bears a row of strong setulae on ventral margin. Pregonites long and blade-like, equal in length, left slightly broader with a small process half way along its medial surface, right pregonite thinner and simple. In ventral view central plate (lying immediately anterior to the base of the cerci) broadly Y-shaped, with a single medial tooth. Phallus J-shaped, long, thin and sinuous with a slightly flared apex.

Type material. Holotype ♂: VANUATU: Tanna , Lenakel, iii.1981, N. L. H. Krauss, BMNH.

Paratypes: Tanna, Lenakel, 0-100m, iii.1970, N. L. H. Krauss, 1♂; Lenakel, 0-200m, i.1981, N. L. H. Krauss, 1♂ (both BPBM) .

Etymology. The specific epithet is derived from the island of Tanna on which the holotype was captured. Noun in apposition.

Remarks. this is another member of the Lonchaea impressifrons species-group with a bare scutellum and long stalked cerci is close to such species as L. efate described above and L. minuta de Meijere, 1910 . Specific identification is based mainly on pregonites, which although they can vary slightly in shape, are much shorter than in these other species.