Neosilba bifida, Strikis, P. C. & Prado, A. P., 2005

Strikis, P. C. & Prado, A. P., 2005, A new species of the genus Neosilba (Diptera: Lonchaeidae), Zootaxa 828, pp. 1-4 : 2-4

Neosilba bifida n. sp.

Material examined: Holotype: male, deposited in the Museu de Zoologia da Universidade de São Paulo, SP. Brazil; reared from Eriobotryia japonica (Thumb.) Lindl. (nêspera) São Bento do Sapucai­SP, Brazil, 31/01/1996, collected by Miguel de Souza Filho, kept in alcohol. Paratypes: 2, one kept in alcohol another mounted in microscope slide deposited in the Museum cited as above, derived from the same sample as the holotype.

Description Male: body size 5.0 mm. Frons narrowed toward lunule. Head length/ width ratio 1.17. Lunule with 8 setulae 4 at each side; ocellar plate with 5 strong bristles, and 2 strong inter ocellar bristles below ocellar plate and 2 others above ocellar plate. Antenna with one prominent bristle in the second segment, first flagelomere with length/ width ratio 3.72 (0.82 mm: 0.22 mm); arista long and plumose (1.05 mm), longer than first flagelomere; arista length/first flagelomere length ratio 1.28. Palpus large and broad.

Thorax: Mesonotum 1.6 mm long; anepisternum with 5 strong bristles and a cluster of 3 setae below the bristles. Scutellum margin bare, with 2 strong marginal basal bristles and 2 apical marginal bristles and a cluster of 4 marginal setae at each side and 2 setae between apical bristles; dorsum of thorax setulose with 12 strong bristles.

Wings: 4.7 mm long, hyaline, with brownish veins and microtrichias; length/width ratio 2.30; calypteres white with white fringes and with about 12 long blackish setae at fold.

Male terminalia: Epandrium short; as long as wide (1:1); in lateral view surstylus is not visible, and has 6 prensisetae. Aedeagus filament fine and slender after “C” shaped base until apex, ending just after prensisetae and evenly tapered to apex ( Fig.1 ). “C” shaped base of aedeagus with no spicules but with a remarkable spine­like left bended structure in ventral view, arising from the distal portion of convex side of the “C” shaped base of aedeagus ( Fig.2 and 3 ). There may be some variation in length of the spine­like structure

Female: unknown.

Diagnosis: the most remarkable character in identifying N. bifida n. sp. is the spinelike structure, which is easily seen in ventral or lateral view of male terminalia.

Taxonomic discussion: N. bifida n. sp. is very similar to N. glaberrima McAlpine & Steyskal externally, but lacks the hair arrangement in the last abdominal tergite; we believe it belongs to a group of undescribed species that has a complex structure in the convex side of the “C” shaped base of aedeagus, ending with the formation of a well defined spine­like structure.

Distribution: Only known from São Bento do Sapucai, São Paulo, Brazil; this locality situated over 900 meters height.

Biology: This species has been reared from Eriobotryia japonica (nêspera), and just a few individuals were collected from this fruit.

The inclusion of N. bifida in McAlpine’s (1982) key to Neosilba species is suggested as follow:

6. Aedeagus short and broad, (Figs. 29–30, 34–35). Prosternum usually setulose .......... 7 Aedeagus slender. Prosternum always bare ................................................................. 8 8 Aedeagus with a median lobe or a pair of teeth on thicker basal section, apex of filament not swollen or strongly S shaped ........................................................................ 9 8’ Aedeagus with a spine­like structure arising from the distal portion of the convex side of the “C”shaped base, short and slender and two times as long as the “C” shaped base ...................................................................................................................... bifida n. sp.

8’’ Adeagus without a median of lobe or a pair of teeth on thicker basal section, apex of filament frequently swollen, flared or S shaped ......................................................... 11

Figures

FIGURES 1 – 3: 1, Male terminalia in lateral view. 2, Male terminalia in ventral view. 3, Detail of male terminalia showing spine­like structure in ventral view.