Melaleuca

Davies, Kerrie A., Ye, Weimin, Giblin-Davis, Robin M., Taylor, Gary S., Scheffer, Sonja & Thomas, W. Kelley, 2010, The nematode genus Fergusobia (Nematoda: Neotylenchidae): molecular phylogeny, descriptions of clades and associated galls, host plants and Fergusonina fly larvae 2633, Zootaxa 2633 (1), pp. 1-66 : 42-45

publication ID	https://doi.org/ 10.11646/zootaxa.2633.1.1
persistent identifier	https://treatment.plazi.org/id/FB74996E-9E0B-FFA9-ACA8-FDBBFC9DD1FA
treatment provided by	Felipe
scientific name	Melaleuca
status

Treatment

Genus Melaleuca View in CoL View at ENA

1. M. leucadendra clade

M. argentea W.V. Fitzg. (voucher specimen no 469); associated with an unknown species of Fergusonina . Clade 17 in Fig. 78.

F. cajuputiae (voucher specimen no 46); from M. cajuputi Powell associated with Fn. purcelli . Clade 17 in Fig. 78.

F. dealbatae (voucher specimens nos 18, 19, 352, 331); from M. dealbata S.T. Blake associated with Fn. makinsoni . Clade 17 in Fig. 78.

F. quinquenerviae (voucher specimens nos 22, 23); from M. fluviatilis Barlow associated with Fn. turneri . Clade 16 in Fig. 78.

F. leucadendrae (voucher specimens nos 461, 451); from M. leucadendra (L.) L. associated with Fn. centeri . Clade 17 in Fig. 78.

F. nervosae (voucher specimen no 49); from M. nervosa (Lindl.) Cheel SBG associated with Fn. schefferae ( Fig. 18 View FIGURES 1–22 ). Clade 17 in Fig. 78.

Fergusobia sp. , from M. nervosa PG (voucher specimen no 47); associated with Fn. goolsbyi . Clade 17 in Fig. 78.

F. quinquenerviae SBG (voucher specimens nos 341, 342, 421, 336, 333, 338, 432); from M. quinquenervia (Cav.) S.T. Blake associated with Fn. turneri ( Figs 17 View FIGURES 1–22 , 39 View FIGURES 23–43 , 59 View FIGURES 44–61 ). Clade 16 in Fig. 78.

Fergusobia sp. , from M. stenostachya (voucher specimen no 48); associated with an unknown species of Fergusonina . Clade 17 in Fig. 78.

F. viridiflorae from M. viridiflora (voucher specimen no 21); associated with Fn. burrowsi . Clade 17 in Fig. 78.

Form of gall. Terminal and axial shoot bud galls from M. quinquenervia ( Fig. 81 View FIGURES 80–88 ), dealbata , fluviatilis ,

leucadendra View in CoL and viridiflora ( Giblin-Davis et al. 2004a) View in CoL . As in other galls induced by the fly/nematode association, the locules within the galls were lined with hypertrophied cells, each with a granular appearance, and one enlarged nucleus with a large nucleolus. A variant, collected from M. stenostachya View in CoL and described as a

‘leaf gall’, contained one central locule surrounded by layers of leaf material, formed as a result of extensive leaf folding, back and forth on itself ( Giblin-Davis et al. 2004a). In this form, eggs and nematodes were apparently deposited between the leaves of a developing bud.

Giblin-Davis et al. (2001) described the development of shoot bud galls on M. quinquenervia . Flies deposit their eggs into the youngest part of the shoot including apical meristematic cells associated with leaf or inflorescence primordia. The first evidence of bud swelling and primordial leaf fusion occurred 35 days after deposition of eggs and nematodes. Hypertrophied parenchymal cells and nematode juveniles were present at this time. The first parthenogenetic females were seen in galls dissected after 44 days. By 66 days, the fly eggs had hatched, and galls had primordial leaf fusion and proliferation of parenchymal cells with formation of elliptical shaped locules. The locules were lined with callus-like cells.

Morphology of nematodes. Parthenogenetic female small; arcuate to open C-shape; medium to enormous oesophageal gland, with flexure in some species; tail short, conoid, varying from relatively slender to bluntly rounded to broadly rounded tip. Infective female small to medium; arcuate to open C-shape; oesophageal gland medium to large; cylindroid, maximum width at mid-body; tail conoid, with bluntly or broadly rounded tip. Male small to large; arcuate to J-shape; oesophageal gland medium to enormous; spicule variable; bursa variable (30% to arising near head) ( Davies & Giblin-Davis 2004).

Morphology of dorsal shield. Associated Fergusonina fly larvae described in Taylor (2004). Dorsal shield of fly larvae comprises narrow to broad black sclerotised plates. Morphology ranges from: shield with 5 to 7, narrow to broad, black sclerotised plates (simplest) to shield with 6 to 7, narrow to broad, black sclerotised plates; with prominent rugose nodules on anterior portion of plates AS 1–2 or 1–3 (most elaborate).

Possible relationships. There was support for Clade 17 of Fergusobia associations from broad leaf melaleucas from analyses of sequences of both D2/D3 and COI (Fig. 78), although it was not strong (93%). The clade was also supported by analyses reported for Fergusobia in Ye et al. (2007b) and for Fergusonina in Scheffer et al. (2004).

In this clade, nematodes and flies appear to have co-evolved with their host species. There is molecular evidence for cryptic species in both F. quinquenerviae and F. dealbatae ( Ye et al. 2007b) (Fig. 78), which is supported by evidence from sequencing of COI for cryptic species in Fn. turneri , respectively developing on M. quinquenervia and M. fluviatilis ( Scheffer et al. 2004) .

Interestingly, F. quinquenerviae is commonly collected from SBG on M. quinquenervia in the southern part of its range, but not from northern QLD. However, it is frequently collected from similar galls on M. fluviatilis in northern QLD (M. Purcell, pers. com., K.A. Davies and RM Giblin-Davis, unpub. data). This was confirmed by sequences from both D2/D3 and COI ( Ye et al. 2007b, Fig. 11 View FIGURES 1–22 ). The lack of F. quinquenerviae on M. quinquenervia in the north while it flourishes there on M. fluviatilis suggests that, over time, something changed with the association on M quinquenervia and that a host-switch to M. fluviatilis allowed the species to survive. However, why F. quinquenerviae does not re-colonise M. quinquenervia in the north is unclear.

2. from M. nervosa

Fergusobia voucher specimen no 47 ( Davies & Giblin-Davis 2004); associated with Fn. goolsbyi Taylor 2004 View in CoL ( Fig. 29 View FIGURES 23–43 ).

Clade 17 in Fig. 78.

Form of gall. ‘Basal rosette’ (pea) axial stem galls. Giblin-Davis et al. (2004a) examined the histology of the galls from M. nervosa . Galls form at the base of the stem below an apical bud, and contain 1 to 5 locules. The gall is formed in ground meristem or pith tissue below the bud, and there is no distinct difference between cells of the gall and surrounding plant tissues. As in other gall forms, hypertrophied cells surround the lumen of the locules.

Morphology of nematodes. Only parthenogenetic females collected ( Davies and Giblin-Davis, 2004). Small, open C-shape; greatest width in posterior half of body; oesophageal gland large; tail short, conoid, tip rounded.

Morphology of dorsal shield. Associated with Fn. goolsbyi ( Taylor 2004) . Shield comprises rows of raised spicules on TS 1 and TS 2, three broad sclerotised plates (as two confluent areas) on TS 3 and AS 1 and 2. Lacks raised sclerotised nodules.

Possible relationships. Clade 18 comprised these nematodes from M. nervosa and also from SPG on M. nodosa . Analyses of sequences from D2/D3 provided weak (70%) support for this grouping of nematodes (Fig. 78). With analyses of sequences from COI (Fig. 79), the nematodes grouped together but without support. The gall forms from which the nematodes were collected were similar. Coming from broad-leaved and narrow-leaved groups of Melaleuca , the host plants were genetically disparate, and their distributions are unlikely to overlap. While nematodes from M. nodosa were not available for comparison, the dorsal shield of the fly larvae was similar to that of Fn. purcelli from M. cajuputi ( Taylor 2004) .

3. From M. quinquenervia (voucher specimen no 357)

Fergusobia voucher specimen no 357; associated with an unknown species of Fergusonina ( Figs 19 View FIGURES 1–22 , 40 View FIGURES 23–43 , 60 View FIGURES 44–61 ). Unplaced in Fig. 78.

Form of gall. ‘Basal rosette’ terminal and axial stem galls from M. quinquenervia . Superficially at least,

‘basal rosette’ stem galls on M. quinquenervia and M. nervosa are similar. Both occured at the base of the stem below the apical bud, and contained 1 to 5 locules. Fly eggs and nematodes were apparently deposited in ground meristem below the apical bud ( Taylor, 2004).

Morphology of nematodes. Parthenogenetic female small size, arcuate in shape; broad; oesophageal gland medium; uterus non-extensile; tail short, conoid, bluntly rounded tip. Infective female small, arcuate shape; relatively slender. Male small, arcuate shape; tail short, conoid; broadly rounded tip; spicule angular to arcuate, bent at about 40% of length, with manubrium and shaft longer than blade; bursa ca 40 – 50% body length.

Morphology of dorsal shield. (WINC 063820). Shield comprises a few sparse sclerotised spicules medially on TS 3, followed by a broader band of spicules on posterior margin of TS 3. There is an additional band of spicules medially on AS 1, and a thin indistinct band on the anterior margin of AS 2. In some specimens, this is followed by a very indistinct narrow medial band of spicules on AS 2.

Possible relationships. These nematodes from RBG from M. quinquenervia did not group with any other Fergusobia species. From analyses of D2/D3 sequences, they placed basal in the tree, but without support (Fig. 78). From COI analyses, they grouped with Fergusobia from M. nodosa and Met. excelsa .

4. From Narrow leafed Melaleucas

(a) Unilocular terminal shoot bud galls, from M. armillaris (Sol. ex Gaertn) Smith.

Fergusobia Morphospecies 19 (voucher specimens nos 410, 405) associated with Fergusonina sp. ( Taylor 2004) . Clade 2

in Fig. 78.

Form of gall. Unilocular terminal shoot bud galls; with form resembling a spear head.

Morphology of nematodes. Parthenogenetic female medium, arcuate; large oesophageal gland; short conoid tail; extensile uterus with up to 5 eggs. Infective female small, arcuate, tail conoid with broadly rounded tip; oesophageal gland small. Male small, arcuate, tail barely concave on dorsal side, tip bluntly rounded; relatively large oesophageal gland; angular spicule with rounded manubrium; smooth bursa arises at 60% body length or near head.

Morphology of dorsal shield. (WINC 004407). Collected Sydney ( Taylor 2004). Shield comprises bands of raised spicules, widest and most prominent on TS 3 and AS 1 to AS 4 (5 bars), with a narrow dense band between them (4 bars); all bars situated mid-segment.

Possible relationships. Clade 2 comprised Fergusobia from similar gall forms on M. armillaris and M. linariifolia . It was inferred with 100% support from analyses of sequences of D2/D3 (Fig. 78). Its grouping with F. magna , however, was not well-supported (62%). From analysis of COI sequences (Fig. 79), Fergusobia from M. armillaris grouped with those from M. decora but with poor support, and those from M. linariifolia were grouped with nematodes from E. camaldulensis SBG again with poor support.

While the relationship of the two Melaleuca hosts is unknown, both belong to the group of narrow-leaved melaleucas, and their distributions overlap. Both fly/nematode associations induce unilocular galls. The associated fly larvae have similar shield forms.

Parthenogenetic females from F. magna , M. armillaris , M. linariifolia , and E. camaldulenis SBG all have extensile uteri. This is unusual in Fergusobia (K.A. Davies, unpub. obs.) and suggests that nematodes with this particular morphology could have a common origin. More sampling is needed to understand the relationships of these nematodes.

(b) from M. linariifolia Smith

Fergusobia Morphospecies 20 (voucher specimen no 412), associated with an undescribed species of Fergusonina . Clade 2 in Fig. 78.

Form of gall. Unilocular axial bud galls from M. linariifolia . Stalked, with form resembling a spear head.

See Fig. 86 View FIGURES 80–88 , from M. decora , for photograph of a similar gall form.

Morphology of nematodes. Parthenogenetic female medium, arcuate; relatively large oesophageal gland;

short conoid tail; extensile uterus with up to 5 eggs. Infective female small, arcuate; oesophageal gland small;

tail conoid with broadly rounded tip. Male small, arcuate; relatively large oesophageal gland; tail barely concave on dorsal side; tip bluntly rounded; relatively large oesophageal gland; angular spicule with rounded manubrium; smooth bursa arises at 60% body length or near head.

Morphology of dorsal shield. (WINC 004401). Dorsal shield comprising 6 or 7 transverse bands of raised sclerotised spicules. First a short, broad, band on TS 2; then a broader band on TS 3; followed by prominent transverse ridges of raised sclerotised spicules on AS 1–4. Each of these is situated mid-segment, and that on AS 2 is most prominent. AS 5 has a transverse band of a few raised spicules.

Possible relationships. Grouped in Clade 2; see discussion under M. armillaris .

Fergusobia voucher specimen no 411; associated with an unknown species of Fergusonina . Clade 17 in Fig. 78. See Fig. 18 View FIGURES 1–22 for drawing of a similar nematode.

Form of gall. Unilocular basal shoot bud galls on M. nodosa (voucher specimen no 411). Galls occur at the base of the stem below an apical bud, and prevent expansion of the shoot bud, which appears to be com-

pressed length-wise.

Morphology of nematodes. No nematode morphological voucher material available, only material sequenced.

Morphology of dorsal shield. (WINC 004406). No larval material available. On pupa, shield weakly sclerotised. Comprising three confluent areas of sclerotised cuticle; the first a transverse band on posterior margin of TS 3, the second occupying the full length of AS 1, and the third the anterior margin of AS 2; with an additional band of sclerotised cuticle on the anterior margin of AS 3. A few sclerotised spicules occur on posterior margin of TS 2 and anterior margin of AS 1. Similar to that of Fn. purcelli Taylor 2004 from M. cajuputi ( Taylor 2004) .

Possible relationships. Grouped in Clade 17; see discussion under M. nervosa BSG.

(d) from M. decora

Fergusobia voucher specimen no 462; associated with an unknown species of Fergusonina . Did not sequence for D2/D3.

Form of gall. Unilocular axial bud galls from Tea Gardens/Hawks Nest, NSW; similar to those described for M. linariifolia .

Morphology of nematodes. Parthenogenetic female small; arcuate shape; relatively slender; oesophageal gland large; tail broadly conoid to sub-cylindrical with broadly rounded tip. Infective female arcuate shape, small; relatively broad; tail short with broadly rounded tip. Male straight to arcuate shape, small; tail conoid with broadly rounded tip; spicule arcuate; bursa ca 30–50% body length.

Morphology of dorsal shield. (WINC 004402). Shield comprises a short, broad band of raised sclerotised spicules on TS 2; followed by a short narrow band between TS 2 and 3; a short broad lightly sclerotised band on TS 2 with sparse raised sclerotised spicules laterally; a short narrow patch between TS 3 and AS 1; a long, broader sclerotised patch between AS 1 and 2; a short narrow sclerotised patch mid-AS 2 with sparse raised sclerotised spicules laterally; a short narrow sclerotised patch between AS 2 and 3; a weak sclerotised patch mid-AS 3 with sparse sclerotised spicules laterally; a weak sclerotised spot between AS 3 and 4; and a transverse band of sparse sclerotised raised spicules on AS 4.

Possible relationships. Fergusobia from M. decora did not sequence for D2/D3, but with COI a group of these nematodes and those from M. armillaris was inferred (Fig. 79). While gall forms and shield morphology of the associated fly larvae from the two samples were similar, nematodes from M. decora appeared to lack the extensile uterus found in those from M. armillaris .