Fergusobia armillarisae, Davies, Kerrie A., Giblin-Davis, Robin M., Ye, Weimin, Taylor, Gary S., Makinson, Jeff & Purcell, Matthew, 2014

Davies, Kerrie A., Giblin-Davis, Robin M., Ye, Weimin, Taylor, Gary S., Makinson, Jeff & Purcell, Matthew, 2014, Nematodes from galls on Myrtaceae. X. Fergusobia from galls on narrow-leaved Melaleuca spp. in Australia, with descriptions of three new species, Zootaxa 3889 (2), pp. 237-258 : 239-243

Fergusobia armillarisae n. sp. Davies

( Figs 1 , 4 A)

= Fergusobia MSp 18 apud Davies et al. (2012a)

Measurements. Table 2 .

Material examined. The description presented here is based on measurements of 16 parthenogenetic ♀s, 2 infective ♀s and 19 ♂ s; Illalong Bay, Kuringai Chase, Sydney, NSW, Australia (33°38.17´S 151°13.32´E). Taken from unilocular pea galls on Melaleuca armillaris (Sol. ex Gaertn) Smith 1797 . Collected by R.M. Giblin-Davis, K.A. Davies, Zeng Qi Zhao & Ian Riley, 4.vii.2004.

Holotype: One parthenogenetic female, together with an infective female and a male, on a slide deposited in the ANIC, Canberra, ACT, Australia; collection data as above.

Paratypes: Vouchers (collection data as above) deposited at the WINC, The University of Adelaide, SA, Australia, 5 parthenogenetic females, 1 infective female and 8 males on slides numbered WINC 004345–47 (WNC 2372); at the Australian National Museum, Sydney, NSW, Australia, 7 parthenogenetic females and 8 males on slides; and at the USDA Nematode Collection, Beltsville, MD, USA 3 parthenogenetic females and 2 males on slides.

Description. Parthenogenetic female. Body shape variable, arcuate to open C-shaped, dorsally curved with ventral side convex and most curvature in tail region; relatively small; relatively broad; similar in size to amphimictic pre-parasitic females and smaller than males; body narrows behind vulva to form a conoid tail. With light microscope, cuticle appears smooth, sub-cuticle with strong longitudinal striae. Lateral fields not seen.

Cephalic region ~ 70% diameter of body at anterior end, offset, 2 µm high, unstriated; rounded outline in lateral view, circum-oral area flat or slightly raised. Amphids not seen. Stylet well sclerotised with cone occupying ~ 50% of stylet length, basal knobs just higher than wide, 2–3 µm wide at base, rounded.

Orifice of dorsal pharyngeal gland 1–2 µm posterior to stylet knobs. Anterior fusiform part of digestive tract occupying 38–66% (mean 50%, n = 11) of body diameter, length 2–3 times diameter; lumen of tract broadens at distal end of dorsal pharyngeal gland. Pharyngeal glands extending over intestine, occupying 50–76% (mean 65%) of body diameter, length from head to end of glands being 37 (30–50)% of total body length. Gland nucleus large, with medium-sized nucleolus.

Holotype Partheno Parthenogenetic Males Infective females

genetic female females

Spicule length 18.4±0.8 (17–19)

Tail length 28 24±3.2 45±3.6 22

(18–32) (37–48) (21-23) Secretory/excretory pore opens anterior to nucleus of pharyngeal gland; secretory/excretory cell not seen. Hemizonid not seen.

Reproductive tract variable in length, extending to secretory/excretory pore, part-way along pharyngeal gland or to nerve ring; flexed in 6/ 15 specimens examined; oviduct usually with two oocytes in a row; quadricolumella with clustered cells, uterus extensile, containing 1– 5 eggs; vulva a simple transverse slit with protruding rounded lips in some specimens; no vulval plate. Anus pore-like, opening in cuticular depression. Tail relatively short, conoid, concave on dorsal side; length 1.3–2.2 times anal body diameter; tip bluntly rounded.

Infective pre-parasitic female. Arcuate shape when heat-relaxed; relatively broad; maximum body diameter at mid-body length; body tapers gradually in tail region. Cuticle obscurely annulated, less than 1 µm wide; longitudinal striae apparent with light microscope; lateral fields not seen.

Cephalic region just offset, dome-shaped; circum-oral area rounded; stylet slender, weakly sclerotised with basal knobs being higher than wide; ~ 2µm wide; cone ~ 40% of stylet length.

Orifice of dorsal pharyngeal gland 1–2 µm posterior to stylet knobs. Anterior fusiform part of digestive tract little expanded, occupying ~ 50% of body diameter, length 2.0 –2.5 times diameter. Pharyngeal glands occupying ~30% of body diameter, extending over intestine, length from head to end of glands being ~30% of total body length.

Secretory/excretory pore opens behind pharyngeal glands; duct obscure; ellipsoid secretory/excretory cell ~ 7 µm long. Hemizonid not seen.

Uterus ~ 70% of total gonad length in uninseminated females, packed with sperm in inseminated females; vagina at right angle to body axis; reproductive tract extending to dorsal pharyngeal gland; hypertrophy of length of tract in some specimens. Vulva a transverse slit, vulval lips not raised, no vulval plate present. Anus an obscure pore. Tail relatively short, sub-cylindroid; length 1.3–1.5 times diameter at anus, tip broadly rounded.

Male. Body arcuate when relaxed by heat, tail region slightly curved ventrally. Cuticle clearly annulated, annuli ~1µm wide at mid-body length; strong longitudinal striae apparent with light microscope; lateral fields ~5µm wide, lacking prominent lateral ridges, having broken diagonal striae.

Cephalic region occupying ~ 70%–90% anterior body diameter, offset, ~ 2 µm high; circum-oral area slightly raised, with lightly sclerotised framework; stylet well sclerotised with cone 30% of length, stylet knobs higher than wide, 2–3 µm wide, rounded. Anterior fusiform part of digestive tract occupying 52–70% of body diameter, length 2–3 times diameter. Orifice of dorsal pharyngeal gland ~ 2 µm behind knobs. Pharyngeal glands occupying 65 (47–82)% of body diameter, extending over intestine, length from head to end of glands being 33 (23–48)% of total body length. Lumen of intestinal tract broadens behind pharyngeal gland.

Secretory/excretory pore opens opposite nucleus of pharyngeal gland; duct obscure; secretory/excretory cell ~ 5µm long. Hemizonid lens-like, extending over two annules, 8 annules in front of secretory/excretory pore.

Reproductive tract with single testis, variable in length, usually extending to nerve ring but may overlap dorsal pharyngeal gland; may be reflexed; testis, seminal vesicle and vas deferens not clearly differentiated. Bursa peloderan but may appear to be leptoderan, smooth; may be prominent or obscure; arises 50% – 80% along length of body. Spicules paired, angular at about half length, moderately sclerotised; with manubrium wider than shaft, may or may not be offset; blade narrows irregularly to bluntly rounded tip with concavity on distal edge; opening subterminal. Inconspicuous muscles associated with cloaca. Tail arcuate, ventrally concave, conoid; length 2.2–2.9 times diameter at cloaca; bluntly rounded tip.

Molecular phylogenetic relationships. For molecular analysis, the partial SSU (V 410: FJ393268 ), the D2/ D3 expansion segments of LSU (V 405: FJ386994 : V 410: FJ386995 ) and mtCOI (V 405: FJ386964 ) of F. armillarisae n. sp. were sequenced. Based on the LSU, V 405 and V 410 are close to each other and sister to V 412 ( M. linariifolia n. sp.) ( Davies et al., 2010a, Fig. 78). A phylogenetic tree inferred from COI placed V 405 with V 462 ( M. decora n. sp.) in a clade and in a basal position with many other Fergusobia species collected from Melaluca ( Davies et al., 2010a, Fig. 79). The blastn search of SSU of V 410 (1686 bp sequenced) revealed it has 7 to 11-bp differences (99% identity) from some Fergusobia species. The blastn search of LSU of V 410 (880 bp sequenced) revealed it has 9-bp differences (94% identity) and 3 gaps with V 405 and 40-bp differences (95% identity) and 16 gaps with V 412 ( FJ386996 ) ( M. linariifolia n. sp.). The blastn search of COI of V 405 (618 bp sequenced) revealed the highest match was with V 462 ( FJ386982 ) ( M. decora n. sp.) with 52-bp differences (92% identity). These large sequence divergences supported Fergusobia armillarisae n. sp. as a unique species.

Diagnosis and relationships. Fergusobia armillarisae n. sp. is morphologically characterized by the combination of a medium-sized, arcuate parthenogenetic female with an extensile uterus, a narrow conoid tail; an arcuate, relatively broad, infective female with an almost hemispherical tail tip; and a small arcuate male with an angular spicule having an offset manubrium, and bursa arising at 50%–80% of body length. Morphologically, F. armillarisae n. sp. is similar to F. linariifoliae n. sp., but lacks the swollen cuticle of the latter.

The parthenogenetic female of F. armillarisae n. sp. (arcuate shape) differs from F. brevicauda Siddiqi, 1994 , F. brittenae Davies, 2010 (in Taylor & Davies 2010), F. cosmophyllae Davies 2013b (in Davies et al. 2013b), F. diversifoliae Davies 2013 (in Davies et al. 2013b), F. fasciculosae Davies 2012 (in Davies et al. 2012b), F. floribundae 2013 (in Davies et al. 2013b), F. gomphocephalae Davies 2014 (in Davies et al. 2014c), F. indica ( Jairajpuri, 1962) Siddiqi, 1986 , F. leucoxylonae Davies 2014 (in Davies et al. 2014c), F. magna Siddiqi 1986 sensu Davies 2010 (in Davies et al. 2010b), F. microcarpae Davies 2013 (in Davies et al. 2013a), F. minimus Lisnawita 2013 (in Davies et al. 2013b), F. morrisae Davies 2012 ( Davies et al. 2012b), F. pimpamensis Davies 2013 (in Davies et al. 2013b), F. planchonianae Davies 2014 (in Davies et al. 2014b), F. porosae Davies 2013 ( Davies et al. 2013a), F. ptychocarpae Davies, 2008 ( Taylor & Davies 2008) , F. viminalisae Davies 2014 (in Davies et al. 2014b), and F. viridiflorae Davies & Giblin-Davis, 2004 (C-shape). The presence of an extensile uterus in the parthenogenetic female of F. armillarisae n. sp. separates it from that of F. cajuputiae Davies & Giblin-Davis, 2004 , F. colbrani Davies 2014 (in Davies et al. 2014a), F. dealbatae Davies & Giblin-Davis, 2004 , F. delegatensae Davies 2013 (in Davies et al. 2013b), F. eugenioidae Davies 2012 (in Davies et al. 2012b), F. fisheri Davies & Lloyd, 1996 , F. leucadendrae Davies & Giblin-Davis, 2004 , F. nervosa Davies & Giblin-Davis, 2004 , F. philippinensis Siddiqi, 1994 , F. schmidti Davies 2014 (in Davies et al. 2014c), F. quinquenerviae Davies & Giblin-Davis, 2004 , F. ro s et t a e Davies 2013 (in Davies et al. 2013f), F. rileyi Davies 2011 (in Davies et al. 2011a), F. sporangae Davies 2014 (in Davies et al. 2014c), F. tolgarae Davies 2014 (in Davies et al. 2014d), F. tumifaciens ( Currie 1937) Wachek 1955 sensu Davies 2014 (in Davies et al. 2014b), and F. decorae n. sp., which do not have extensile uteri. In having cuticle that does not swell upon fixation, it differs from F. jambophila Siddiqi 1986 , F. linariifoliae n. sp. and F. pohutukawa Davies 2007 (in Taylor et al. 2007), in which it does. Having a flat or slightly raised circum-oral area separates the parthenogenetic female of F. armillarisae n. sp. and that of F. camaldulensae Davies 2011 (in Davies et al. 2011a), in which it is distinctly raised. The stylet (9–12 µm) of this parthenogenetic female is longer than in F. curriei Fisher & Nickle 1968 (5–8 µm) and F. juliae Davies 2012 (in Davies et al. 2012b) (5–7 µm). In having enormous oesophageal glands (b’ 1.5–2.2), it is similar to F. quinquenerviae but lacks the extra lobe or flex found in the gland of the latter.

Infective females of F. armillarisae n. sp. have an arcuate shape, differing from that of F. diversifoliae , F. fasciculosae , F. gomphocephalae , F. leucadendrae , F. nervosae , F. pimpamensis , F. philippinensis , F. rosettae , F. sporangae , F. tolgarae , and F. viminalisae (open C-shape). With body length ranging from 279–291 µm, it is smaller than the female of F. brittenae (375–550 µm), F. colbrani (369–405 µm), F. cosmophyllae (374–448 µm), F. curriei (417–489 µm), F. dealbatae (307–347 µm), F. delegatensae (375–452 µm), F. eugenioidae (438 µm), F. floribundae (357–450 µm), F. juliae (396–550 µm), F. linariifoliae n. sp. (347–384 µm), F. magna (537–633 µm), F. microcarpae (302–341 µm), F. morrisae (322–395 µm), F. pimpamensis (369–443 µm), F. philippinensis (290–370 µm), F. planchonianae (303–339 µm), F. ptychocarpae (387–471 µm), F. sporangae (289–353 µm), and F. viminalisae (334–437 µm). In having a flat circum-oral area, the infective female of F. armillarisae n. sp. differs from those of F. camaldulensae , in which it is raised. It has a longer stylet than F. minimus and F. schmidti (respectively, 11–14 vs 4–5.5 and 5–10 µm). It has a short sub-cylindroid tail (21–23 µm) with an almost hemispherical tip, separating it from F. brevicauda (24–30 µm), F. d ec o r a e n. sp. (13–18 µm), F. f i s he r i (21–49 µm, mean 30 µm), F. leucoxylonae (11–18 µm), F. rileyi (40–50 µm with a bluntly rounded tip), and F. porosae and F. tolgarae in which the tip is bluntly rounded. Given that only two specimens of the infective female of F. armillarisae n. sp. were examined, it is difficult to separate it from the same stage collected from various broadleaved melaleucas. However, it appears to be shorter than F. viridiflorae (321 µm); and to have a more anterior secretory/excretory pore than F. cajuputiae and F. quinquenerviae (anterior end to secretory/excretory pore 47 µm vs 53–78 and 71–91 µm).

In shape (arcuate), the male of F. armillarisae n. sp. differs from that of F. brittenae , F. curriei , and F. fasciculosae (J-shape), F. pimpamensis , F. schmidti (J or C-shape), F. magna , F. planchonianae , F. ptychocarpae , and F. viridiflorae (with strongly curved posterior). In length (302–400 µm), it is smaller than the male of F. diversifoliae (413–459 µm) and F. floribundae (403–570 µm). The male of F. armillarisae n. sp. has a flattened circum-oral area, but it is raised in F. camaldulensae , F. colbrani and F. jambophila . In length (9–12 µm), the stylet is shorter than in F. leucoxylonae (10–13 µm) and longer than in F. minimus (4–7 µm). The shape of the tail (arcuate with a bluntly rounded tip) differs from that of F. philippinensis (truncate tip). Spicule length (17–19 µm) is shorter than in F. juliae (20–27 µm). The shape of the spicules in F. armillarisae n. sp. (angular to arcuate) differs from those of F. brevicauda , F. cajuputiae , F. dealbatae , F. delegatensae , F. eugenioidae , F. gomphocephalae , F. leucadendrae , F. microcarpae , F. morrisae , F. pohutukawa , F. quinquenerviae , and F. viminalisae , in which it is clearly angular. In the male of F. armillarisae n. sp., the bursa arises at ~ 50%–80% of the body length, separating it from those of F. cosmophyllae (~ 10%–40%), F. decorae n. sp. (~ 30%–50%), F. f i s h e r i (~ 20%), F. linariifoliae n. sp. (80%–90%), F. nervosae (~ 50%), F. pohutukawa (~ 90%), F. porosae (15%–33%), F. rileyi (90%–95%), F. rosettae (~ 40%–50%), F. sporangae (10%–40%) and F. tumifaciens (18%–22%).

Etymology. Named after M. armillaris , the plant species from which the nematodes were collected.

Figures

FIGURE 1. Fergusobia armillarisae n. sp. (all in lateral view): A, Entire parthenogenetic female; B, Head of parthenogenetic female; C, Habitus; D, Tails of parthenogenetic females; E, Entire infective female; F, Head of infective female; G; Habitus; H, Tails of infective females; I, Entire male; J, Head of male; K, Habitus; L, Tails of males; M, lateral lines. Scale bars: A, E, I = 50 Μm. B, F, J, M = 5 Μm. Tails not drawn to scale.

FIGURE 4. Spicules from Fergusobia spp. collected from galls on narrow-leaved Melaleuca spp.: A, from M. armillaris; B, from M. decora; C, from M. linariifolia. Scale bar = 5 µm.

Tables

TABLE 2. Measurements (µm) of Fergusobia armillarisae n. sp. from Melaleuca armillaris. (Mean ± standard deviation, with range in brackets).

N	16	19	2
Length 331	318±30.4 (265–368)	343±23.1 (302–400)	285 (279–291)
a 9.4	8.8±0.6 (7.5–10.0)	11.8±1.1 (9.6–13.6)	10.0 (8.9–11.2)
b’ 2.8	2.7±0.3 (2.0–3.2)	3.3±0.6 (2.1–4.4)	3.4
c 11.9	13.4±2.0 (9.6–16.5)	7.7±0.6 (6.8–9.2)	12.8 (12.6–13.1)
c’ 1.9	1.7±0.2 (1.3–2.2)	2.6±0.2 (2.2–2.9)	1.4 (1.3–1.5)
V or T% 92	86.6±2.8 (84–94)	74.4±5.0 (56–80)	82.8 (82–84)
Body diameter 37	36±2.7 (32–41)	29±3.6 (24–39)	29 (26–32)
Stylet length 10.6	10.9±0.8 (9–12)	10.2±0.8 (9–12)	8
Ant. end to SE pore 48	47±7.4 (39–61)	88±8.2 (74–98)	47