Fergusonina nodulosa Taylor, sp. nov.

(Figs 1–14, Tables 1–5)

Holotype. AUSTRALIA, South Australia: 1♂ (dried) Ambleside, 2 km NE Verdun, 35°00.28’S 138°48.38’E, G.S. Taylor, 10.x.1999, from (bagged) woody, axial leaf-bud gall on E. camaldulensis (SAM).

Paratypes. AUSTRALIA, South Australia: 4 ♂, 14 ♀, 6 galls (dried) same data as holotype, WINC 003305– 003306 (SAM, WINC); 1 ♂ (dried) Ambleside, 2 km NE Verdun, 35°00.28’S 138°48.38’E, G.S. Taylor, 7.x.2001 from E. camaldulensis, WINC 003303 ; 8 ♂, 10 ♀ (slide) Ambleside, 2km NE Verdun, 35°00.28’S 138°48.38’E, G.S. Taylor, 13.x.2001, from axial leaf-bud (stem) galls on E. camaldulensis (em. in lab from 22.x.2001) WINC 040190 (ANIC, WINC) ; 13 ♂, 11 ♀, 2 galls (dried) same data, except WINC 040192; 4 larvae (ethanol) Hazelwood Park, 34°56.20’S 138°39.36’E, K.A. Davies, 23.viii.1998, axial stem gall on E. camaldulensis, WINC 004203 ; 1 ♂ (ethanol) Hazelwood Park, 34°56.20’S 138°39.36’E, K.A. Davies, 02.viii.2001, from axial stem gall on E. camaldulensis WINC 003316 ; 8 galls (dried) Kensington Park, 34°55.35’S 138°39.1’E, K.A. Davies, 18.x.2003, from axial ‘stem’ galls on E. camaldulensis; 8 ♂, 4 ♀, 9 galls (dried) Morialta Conservation Park, 34°54.15’S 138°42.11’E, G.S. Taylor, 14.ix.1999, from nodular/woody axial leaf bud gall on E. camaldulensis, WINC 003307–003311 ; 5 pupae (ethanol) same data, WINC 003302; 3 ♂, 4 ♀ (ethanol) Waite Inst., 34°58.1’S 138°38.7’E, K. Davies, 5.x.1995, ex galls on E. camaldulensis, WINC 004921 ; 3 ♂ (dried) Waite Arboretum, 34°58.2’S 138°37.48’E, K.A. Davies, 24.v.2001, from stem gall (2 or 3 locules) on E. camaldulensis, WINC 003318 ; 3 larvae (slide) Waite Campus arboretum, K.A. Davies, 24.v.2001, from stem galls on E. camaldulensis, WINC 003317 ; 1 larva, 1 gall (ethanol) 1 km S Wistow, Mt. Barker–Strathalbyn Rd., 35°07.03’S 138°53.26’E, G.S. Taylor, 25.vii.1999, from leaf bud gall on E. camaldulensis, WINC 004924 ; 4 ♂, 17 ♀ (dried), 8 ♂, 6 ♀ (ethanol), 16 galls (dried) Mt Barker–Strathalbyn Rd., 35°07.03’S 138°53.26’E, G.S. Taylor, 13.x.2005, from ‘stem’ galls on E. camaldulensis; 2 ♂, 13 ♀, 8 galls (dried) River Rd. Hahndorf., 35°1.51’S 138°47.20’E, J. Bellati, 1.ix.2005, ex. E. camaldulensis; 1 ♂, 1 ♀ (dried), 7 ♂, 5 ♀ (ethanol) Mt Barker, 35°05.09’S 138°51.86’E, G. Taylor & B. Hyder, 19.ix.2014, nodular stem gall on E. camaldulensis, Em. 30–31.ix.2014 (ANIC – dried, WINC) ; 1 ♀ (dried) same data, except Em. 30.ix–1.x.2014; 3 ♂, 1 ♀ (ethanol), same data, except B. Hyder, 28.ix.2014, Em. 1–2.x.2014; 4 ♀ (dried), 1 ♂, 1 ♀ (ethanol) same data, except Em. 2–3.x.2014; 7 ♂, 12 ♀ (dried) same data, except Em. 7–8.x.2014 (ANIC); 2 ♂, 6 ♀ (dried) same data, except Em. 11–13.x.2014 (ANIC); 1 ♂ (ethanol) same data, except Em. 14–15.x.2014; 2 ♀ (ethanol) same data, except Em. 18–20.x.2014; 1 ♀ (ethanol) Mt Barker Laratinga Wetlands, 35°04.33’S 138°53.15’E, G. Taylor & B. Hyder, 19.ix.2014, nodular stem gall on E. camaldulensis, Em. 25–26.ix.2014 ; 1 ♀ (dried), 2 ♂, 4 ♀ (etha- nol) same data, except Em. 27–29.ix.2014; 3 ♂, 1 ♀ (dried), 2 ♂, 4 ♀ (ethanol) same data, except Em. 2–3.x.2014 (ANIC – dried, WINC); 2 ♂, 2 ♀ (ethanol), same data, except Em. 4–6.x.2014; 1 ♂ (dried), 1 ♀ (ethanol) same data, except Em. 7–8.x.2014; 3 ♂, 1 ♀ (ethanol), same data, except Em. 9–10.x.2014; 1 ♀ (ethanol), same data, except Em. 11–13.x.2014; 1 ♂ (ethanol) Torrens River Linear Park, 34°55.06’S 138°35.81’E, G. Taylor & B. Hy- der, 12.viii.2014, nodular stem gall on E. camaldulensis, Em. 4–5.ix.2014 ; 1 ♀ (ethanol) same data, except Em. 11–13.x.2014; 1 ♂ (dried), 2 ♂ (ethanol) same data, except 18.viii.2014, Em. 1.ix.2014; 1 ♂ (dried), same data, except Em. 2–3.ix.2014; 2 ♀ (ethanol) same data, except B. Hyder, 22.viii.2014, Em. 1.ix.2014; 1 ♂, 1 ♀ (dried), 1 ♂, 1 ♀ (ethanol) same data, except Em. 3.ix.2014; 2 ♀ (dried), same data, except Em. 4–5.ix.2014; 1 ♀ (ethanol), same data, except 3.ix.2014; 1 ♀ (ethanol) same data, except 22.ix.2014, Em. 27–29.ix.2014; 1 ♂ (ethanol) same data, except 7.x.2014, Em. 14–15.x.2014; 1 ♂, 2 ♀ (ethanol) same data, except Em. 21–22.x.2014; 1 ♂ (ethanol), same data, except 14.x.2014, Em. 18–20.x.2014 . AUSTRALIA: Victoria: 1 pupa (ethanol), 3 galls (dried) near Hamilton, 37°40.65’S 142°00.01’E, K. A. Davies, 23.x.2001, from stem galls on E. camaldulensis, WINC 003315 ; 10 ♂, 6 ♀ (ethanol), 11 galls (dried) Grampians, Victoria Valley roadside, 37°29.15’S 142°20.03’E, K. A. Davies, 25.x.2001, Collection 12 from stem galls E. camaldulensis saplings, WINC 003312 ; 10 ♂, 9 ♀ (slide) roadside near Cavendish, 37°40.65’S 142°00.01’E, K.A. Davies, Collection 14 from stem galls on E. camaldulensis, WINC 002231 ; 4 ♂ (ethanol) same data, except WINC 003313 .

Description. Adult. Measurements as in Table 1. Habitus as in Figs 1–4. General colour yellow with dark brown to black markings; head and antennal segments yellow, all setae black, arista yellow-brown; eyes red-brown with green iridescence; ocellar triangle dark-brown to black; presutural mesonotum with 2+2 dark brown longitudinal vittae, lateral broadest; postsutural mesonotum with 1+1 medial vittae short, lateral vittae split into 2+2 longitudinal markings beyond suture (i.e. 3+3 dark brown longitudinal vittae beyond suture); scutellum yellow-brown; subscutellum dark-brown to black; general colour of thoracic pleurites yellow, although with distinct dark-brown marking across basal half of mesopleuron and basal two-thirds of sternopleuron; dorsum of abdomen with broadly striped appearance; first abdominal tergite yellow-brown with lateral margins darker; abdominal tergites 2–4 yellow with transverse, anterior brown margins; tergite 5 with dappled brown markings medially; in male, postabdomen (genital capsule) dark-brown, in female, cylindrical segment 6 shiny, dark-brown, slightly paler posteriorly; segment 7 sclerotised, shiny, dark-brown to black.

(2.52–2.86) (2.17–2.66) - - (0.46–0.45)

Wing (Fig. 8) elongate oval; costa bearing differentiated setae to just beyond R2+3; costa very faint beyond, appears to terminate at R4+5; veins R2+3 and R4+5 parallel from apical half with slight apical convergence; anterior cross vein r–m short posterior cross vein m–cu about 1.5x longer, the distance between them greater than length of posterior cross vein.

Setation. One pair of ocellar setae 4 times the relative lengths to undifferentiated parafacial setae (4x), one pair of postocellar setae (4x), one pair of inner vertical setae (5x), one pair of outer vertical setae (6x), two pairs of reclinate orbital setae, upper orbital (4x), lower orbital (3x); interfrontal and parafacial setae short, 15–20 (relatively few) short setae on cheek (genae).

Mesonotum with many short setae; acrostichals not clearly differentiated; posterior three dorsocentral setae differentiated, with posterior seta longest (7x) (relative lengths to undifferentiated mesonotal setae, in parenthesis); intra-alars not clearly differentiated; posterior supra-alar setae long (6x); differentiated humeral setae and anterior notopleural setae (5x) about equal in length; posterior notopleural setae, presutural setae, anterior supra-alar and intra-alar setae (4x) about equal in length; humeral lobe with 4–5 setae (one long and 3–4 short setae); mesopleuron with 11–16 setae (one long and 10–15 short setae); sternopleuron with 3–7 setae (mostly 4–5) (one long posterior seta and 2–6 shorter anterior setae) (Table 2); scutellum with a pair of very long marginal subapical setae (8x) and a pair of shorter marginal basal setae (5x).

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First abdominal tergite of female with 16–22 short setae in two submedial fields (range 7–12 per field); second to fifth abdominal tergites with short setae with posterior and lateral setae longest; fifth (pregenital) sternite with 54–71 short setae (lateral pair longest) in two submedial fields (range 27–36 per field) (Table 3).

Male postabdomen (Figs 9–10). Epandrium with 21–24 pairs long setae (including one pair of differentiated dorsal setae); telomeres as short distally rounded structures, articulating from ventrolateral margin of epandrium with 4 small setae on inner surface apically (Fig. 9); cerci as a quadrate lobe lateral to hypoproct and associated with a row of 3–4 internal setae; intromittent organ as in Fig. 10; aedeagal orifice oval; postgonites with one large distal tooth and an ovoid subapical lobe with two lateral setae; aedeagal mantle with 4–5 lateral setae (Table 3).

Female postabdomen (Figs 11–13). Postabdomen short, sparsely setose. Segment 6 with a row of 4 apical setae dorsally, and a row of 4 apical setae and a row of 3–4 subapical setae ventrally (one specimen with a single row of four ventral apical setae only); segment 7 with 2 apical and 2 subapical setae dorsally, and 2 apical and 2 subapical setae ventrally (Table 3). Measurements as in Table 4.

Larva. Third (final) instar larvae (Fig. 5) white, elongate. Measurements as in Table 5. Dorsal shield comprises broad transverse bands of individual raised spicules on thoracic segments 1–3 and abdominal segments 1–7, minute spicules distributed evenly over segments 8–9.

Puparium. Barrel-shaped, matt dark brown with heavily sclerotised integument (Fig. 6). Puparium bearing dorsal shield (see description of larvae), held in spacious gall cavity by a posterior gelatinous attachment.

Gall. Nodular, bulbous, woody, mostly multilocular ‘stem’ galls, 2–8 mm in diameter (Fig. 7). Galls are initiated on axial shoot-tips on host saplings. Number of locules range from 1–16 (mean = 4.4 ± 0.18 SE (n = 245) (Fig. 14).

Diagnosis. Fergusonina nodulosa sp. nov. can be separated from all other species of Fergusonina by the following unique combination of characters: the adult fly has dark brown to black markings on the mesopleuron and sternopleuron; male postgonites with one large distal tooth and an ovoid subapical lobe with two lateral setae; female postabdomen short, sparsely setose; larvae produce nodular axial shoot bud galls along stems of E. camaldulensis; the larva is elongate, its dorsal shield comprising broad transverse rows of raised spicules on thoracic segments 1–3 and abdominal segments 1–7; the puparium is dark matt brown bearing the dorsal shield; it is associated with the nematode Fb. camaldulensae . The structure of the shield most closely resembles that of F. evansi Tonnoir but galls, host and adult morphology differ (Currie 1937).

Notes. Oviposition and flight behaviour of F. nodulosa sp. nov., as “an undescribed species of Fergusonina that forms nodular woody axial leaf bud galls, with few cavities, along the stems of E. camaldulensis ”, was recorded in Taylor & Davies (2010).

Host plant Association. Recorded from Eucalyptus camaldulensis Dehnh., River Red Gum.

Etymology. Named after the nodular appearance of the galls.

Phylogenetic relationships. Bayesian analysis using 665 bp of the mitochondrial COI gene showed F. nodulosa sp. nov. (FC 736, fly species #14 from multilocular shoot bud galls on E. camaldulensis in Scheffer et al. 2017), as sister to an undescribed species of fly (FC 740, fly species #15 from multilocular shoot bud galls on E. camaldulensis in Scheffer et al. 2017). Fergusonina nodulosa sp. nov. is associated with the nematode, Fb. camaldulensae (Davies et al. 2012) . The undescribed sister species of fly is associated with the nematode Fb. schmidti Davies & Bartholomaeus (Davies et al. 2014a) . The two species of fly are separated by 13.83% COI pairwise differences corroborating them as distinct species (Scheffer, pers, com. 2019). Together they form a clade with two undescribed species of fly (FC 746, fly species #55 from flower bud galls on Eucalyptus sp. and FC 738, fly species #50 from unilocular ‘pea galls’ on E. viminalis in Scheffer et al. 2017). Interestingly, two species of fly within this small clade initiate galls on axial shoot buds, namely F. nodulosae sp. nov. (this study) and FC 738 fly species #50 (Scheffer et al. 2017). Bayesian analysis inferred from combined 983 bp ribosomal D2/D3 LSU and 618 bp mitochondrial COI gene showed Fb. camaldulensae (Voucher No. 54 and 311 in Ye et al. 2007) to be sister clade to nematodes from galls on Angophora, Corymbia, Eucalyptus, Metrosideros and Syzygium, that combined, was sister to the basal clade from galls on Melaleuca (Ye et al. 2007) .

In about half of the recorded collections from axial, unilocular and small leaf galls (Davies et al. 2012, 2014a, b, c), the dorsal shields of the third stage fly larvae are of the ‘transverse bars’ form described and illustrated here. Dorsal shields of this form have also been collected from leaf bud galls, flower bud galls, ‘leafy’ leaf bud galls, and flat leaf galls (Davies et al. 2012; 2013a, b; 2014 a, b, c). Purcell et al. (2016) demonstrated a monophyletic clade for larvae bearing dorsal shields of the ‘transverse bars’ form from shoot bud galls on Eucalyptus, subgenus Eucalyptus . Flies having larvae with dorsal shields of the transverse bars form have also been recovered from Eucalyptus (including sub-genera Eucalyptus and Symphyomyrtus), Corymbia, Leptospermum, Melaleuca and Syzygium (Currie 1937, Davies et al. 2010; 2014c; 2018; Purcell et al. 2016). Interestingly, they have not been collected from Angophora (Davies et al. 2014d) . It is likely that this transverse bars form of the dorsal shield has evolved multiple times (Ye et al. 2007, Scheffer et al. 2017).