Fergusonina williamensis

Nelson, Leigh A., Scheffer, Sonja J. & Yeates, David K., 2011, Three new species of Fergusonina Malloch gall-flies (Diptera: Fergusoninidae) from terminal leaf bud galls on Eucalyptus (Myrtaceae) in south-eastern Australia, Zootaxa 3112, pp. 36-48: 42-44

publication ID

http://doi.org/ 10.5281/zenodo.207304



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scientific name

Fergusonina williamensis


Fergusonina williamensis   Nelson and Yeates sp. nov.

( Figs 1 View FIGURE 1 , 3 View FIGURE 3 a–h, 6 a–c)

Holotype. 3. AUSTRALIA.: Victoria: Grampians National Park, Mt William (- 37.293267 °, 142.599817 °, elev. 1137 m), L.A. Nelson & D.K. Yeates, 27.x. 2010, from terminal leaf bud gall collected from E. baxteri   complex.

Paratypes. 2 Ƥ. All same label data as holotype (dried type material lodged: ANIC, Canberra).

Diagnosis. Adult. Small (average wing length 2.45 mm), yellow mesopleuron and almost entirely yellow thorax with the exception of small greyish-brown markings on either side of the midline of the scutum. Larva. Dorsal shield with transverse sclerotised bands on each of the mesothorax and metathorax and abdominal segments 1–7. The strongest band is on abdominal segment 1 and prominent dark sclerotised spicules are present on each band.

Description. Adult ( Fig. 3 View FIGURE 3 a–h, Table 1 View TABLE 1 ). Head as in Figs. 3 View FIGURE 3 a and b. General colour yellow with black markings on abdominal tergites; anterior wall of thorax between postpronotal lobes with a pair of black ‘spots’ separated medially by yellow; basal segment of arista light brown, remainder grey; eyes reddish with iridescent green highlights; ocellar triangle brown-orange with dark brown surrounding each ocellus; thorax entirely yellow except for darkening on the subscutellum and indistinct darker markings laterally on the mesonotum posterior to the suture extending to the intraalar seta, sometimes accompanied by similar-coloured smaller markings (one third the size of the former) anteromedially; abdominal tergites grey-brown, remainder yellow; dark markings on tergites 1 and 2 divided in midline; one third of tergite 5 dark, remainder yellow. Presutural mesonotum yellow; scutum yellow; scutellum yellow; margins and midline of subscutellum dark grey, remainder orange; dorsum of abdomen dark grey and margins yellow; thoracic pleurites yellow, mesopleuron yellow; abdominal sternites yellow; male epandrium light brown.

Setation (all setae black). One pair of short postocellar setae as long as inner vertical seta; outer vertical seta twice as long as inner vertical seta; two differentiated reclinate orbital setae, dorsal one as long as inner vertical seta; most ventral orbital seta two-thirds the length of the dorsal one; parafacial setae short, 20–27 setae on genae per side; one pair of vibrissae twice as long as parafacial setae. Mesonotum with many short setae; posterior two acrostichal setae and intraalar setae differentiated, each about equal in length, but considerably shorter than posterior dorsocentral and posterior supraalar setae; posterior two dorsocentral setae differentiated, with posterior seta longest; posterior supraalar setae long, about same length as posterior dorsocentrals (about 8 × length of undifferentiated mesonotal setae) (following measurements ditto), about same length as posterior dorsocentrals; anterior supraalar seta shorter (3 ×), a little shorter than presutural seta (as long as intra-alar seta), anterior notopleural seta (1.5 × length of supraalar seta), about same length as posterior notopleural seta; differentiated humeral seta as long as anterior notopleural seta; humeral lobe with one long and 3–5 undifferentiated short setae; mesopleuron with 8– 15 undifferentiated setae and one long differentiated seta as long as differentiated humeral seta; sternopleuron with 1 long differentiated seta posteriorly and a row of 3–5 undifferentiated setae along dorsal margin; scutellum with two pairs of marginal setae comprising a pair of very long apical setae, and a pair of subapical setae about 0.5 × length of apical setae. Abdominal tergites with black setae, longest on lateral margin of each tergite, longest on margins of tergite 5 (as long as subapical scutellar setae); sternites with short black setae in two submedial fields: sternite 2 (6 on each field) 3 (7 on each field), 4 (10 on each field) and 5 (23 on each field). On sternite 5 there are two larger differentiated setae lateral to the submedial field of setae.

Wing ( Fig. 3 View FIGURE 3 e, Table 1 View TABLE 1 ) distinctly light grey in colour; broadly elongate oval; costa bearing differentiated setae to little beyond R 2 + 3; costa very feint beyond R 4 + 5; veins R 2 + 3 and R 4 + 5 divergent to mid-length, parallel beyond; anterior cross vein r-m short, posterior cross vein slightly angled mid-length.

Male postabdomen ( Figs. 6 View FIGURES 5 – 7. 5 b and c). Epandrium with 23 pairs of setae (including one pair of large differentiated dorsal setae; telomeres hook-shaped; cerci small and articulating with the ventral margin of the epandrium; postgonites with one large distal tooth and approximately 5 submedial setae.

Variation. Male mesonotal markings variable from almost completely yellow to feint markings as described; some males with lateral markings but lacking medial ones. Female as in male, with exceptions: thorax entirely yellow-orange (lacking darkened markings); female abdomen similar to male except for elements of the ovipositor (segment 6 to end; Fig. 6 View FIGURES 5 – 7. 5 a); anterior two thirds of segment 6 largely dark brown-black grading posteriorly to orange; apex of segment 6 with a row of 6 dorsal, and a row of 6 ventral setae; segment 7 short, with 4 scattered dorsal and 4 ventral setae.

Mature third instar larva ( Fig. 3 View FIGURE 3 g). Similar to other Fergusonina larvae   . Length 1.60–2.90 mm, width 1.20– 2.60 mm (n = 3, specimens in ethanol); shape ovate-pyriform; cephalothorax strongly sclerotised, anterior and posterior spiracles strongly sclerotised, abdomen with 9 visible segments; dorsal shield comprising separate transverse sclerotised bands on each of the mesothorax and metathorax and abdominal segments 1–7. The bands vary in width and degree of sclerotisation with the strongest band on abdominal segment 1. Prominent dark sclerotised spicules are present on the transverse sclerotised bands.

Puparium ( Fig. 3 View FIGURE 3 h) Puparium barrel-shaped, smooth, brown, annulated, bearing dorsal shield (see description of larva). Measurements as in Table 1 View TABLE 1 .

Etymology. This species is named after Mt William, the type locality.


Australian National Insect Collection