Fergusobia pimpamensis, Davies, Kerrie A., Giblin-Davis, Robin M., Ye, Weimin, Taylor, Gary S. & Thomas, W. Kelley, 2013

Davies, Kerrie A., Giblin-Davis, Robin M., Ye, Weimin, Taylor, Gary S. & Thomas, W. Kelley, 2013, Nematodes from galls on Myrtaceae. V. Fergusobia from large multilocular shoot bud galls from Angophora and Eucalyptus in Australia, with descriptions of six new species, Zootaxa 3741 (1), pp. 101-140 : 126-130

Fergusobia pimpamensis n. sp. Davies

( Figs 8 , 9 B, 10B)

Measurements. Table 7.

Holotype Parthenogenetic females Males Infective females

Parthenogenetic

female

n 22 20 22 Length 429 379±28.5 (313–429) 467±38.6 (407–525) 408±21.6 (369–443) a 11.0 9.3±1.0 (7.3–11.0) 10.8±1.5 (7.6–13.3) 10.3±1.1 (8.3–12.0) b’ 2.5 2.7±0.3 (2.1–3.3) 5.1±1.3 (3.3–8.5) 4.3±0.6 (3.5–5.3) T% 78.6±6.6 (61.2–86.4)

Material examined. 22 parthenogenetic ♀, 22 pre-parasitic infective ♀, and 20 ♂; roadside vegetation, Pimpama, Queensland, Australia (27°49´S 153°18´E). Taken from multilocular shoot bud galls on Angophora near woodsiana . Collected KA Davies, 9.vi.2002.

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

Paratypes: (collection data as above) deposited at the WINC, The University of Adelaide, SA, Australia, 10 parthenogenetic ♀, 10 pre-parasitic infective ♀, and 8 ♂; the Queensland Museum, South Brisbane, QLD, Australia, 10 parthenogenetic ♀, 10 pre-parasitic infective ♀ and 10 ♂; and at the USDA Nematode Collection, Beltsville, MD, USA 1 parthenogenetic ♀, 1 pre-parasitic infective ♀, and 1 ♂.

Description. Parthenogenetic female. From multilocular shoot bud galls on A. near woodsiana . Body shape variable, usually dorsally curved with ventral side convex to form open C-shape, occasionally more tightly curved; similar in size to amphimictic pre-parasitic females and smaller than males; body tapers gradually posterior to the vulva to form a relatively elongate tail. Cuticle with obscure annules, spacing not measured; longitudinally striated. Lateral fields seen only with SEM, 4–5 µm wide at mid-body length, with 6 incisures.

Cephalic region diameter ~65% of body diameter immediately posterior, offset, frequently retracted when heat killed, unstriated; rounded outline in lateral view, circum-oral area flat or with small central elevation. With SEM, cephalic region retraction obvious ( Fig. 4 A), 8 sectors around slightly elevated circum-oral area, four rounded sectors alternating with four flatter sectors, dorsal and ventral sectors slightly narrower ( Fig. 4 A). Amphids not seen.

Stylet with cone ~40% of total length, basal knobs well defined, ~2µm across at base, round.

Orifice of dorsal pharyngeal gland ~2 µm posterior to stylet knobs. Anterior fusiform part of digestive tract diameter 43–62% of body diameter, length 1.3–2.8 times diameter. Lumen of tract broadening at ~70% length of dorsal pharyngeal gland. Pharyngeal glands large, occupying ~50% of body diameter, extending 30–42% (mean 38) of total body length.

Secretory/excretory pore with obscure duct; secretory/excretory cell not seen. Hemizonid 4 or 5 annules anterior to secretory/excretory pore.

Reproductive tract variable in length, extending part-way along dorsal pharyngeal gland or to nerve ring; outstretched or singly reflexed; oviduct with oocytes not in rows; uterus containing no eggs or occasionally one egg (in 2 of 24 specimens); vulva with lips protruding or flat, or a depressed slit. With SEM, anterior lip of vulva overlap of posterior lip visible at lateral edges (suggesting that posterior lip is depressed for egg deposition). Tail tapering, often arcuate; length 1.6–2.5 times anal body diameter, tip rounded.

Infective pre-parasitic female. From multilocular shoot bud galls on A. nr. woodsiana . Infecting mature larval stage of Fergusonina sp. or pupa. Body arcuate to open C-shape when relaxed by heat, greatest curvature in tail region with ventral side convex; maximum body diameter in posterior half of body, or at vulva; body narrowing gradually posterior to vulva. Cuticle with obscure annules, width not measured; longitudinal striations apparent when viewed with light microscope; lateral fields not seen.

Cephalic region diameter 65% of body diameter immediately posterior, offset, 1.5–3 µm long; circum-oral area flat or slightly raised; stylet slender, weakly sclerotised with small round basal knobs ~1.5 µm across; cone 40– 50% of total length.

Orifice of dorsal pharyngeal gland ~2 µm posterior to stylet knobs; pharyngeal glands occupying 18–31 (mean 27) % of body diameter, extending over intestine to average 23 (19–29) % body length. Anterior fusiform part of digestive tract diameter 43–71 (mean 54) % of body diameter, length 2.7–4.4 times diameter.

Secretory/excretory pore with obscure duct; secretory/excretory cell not seen. Hemizonid extending over 2 annules, immediately anterior to secretory/excretory pore.

Uterus 70% of body length in uninseminated females, packed with sperm in inseminated females; vagina perpendicular to longitudinal body axis, plugged with refractive material; reproductive tract extending to nerve ring, length hypertrophied in some specimens. Vulval lips broad and barely raised. Tail broad, arcuate; length 0.5– 1.3 times diameter at anus, tip hemispherical.

Male. From multilocular shoot bud galls on A. nr. woodsiana . Body arcuate to C-shaped when relaxed by heat, tail region more or less curved ventrally. Cuticle with obscure annules ~1 µm wide; strong longitudinal striations apparent when viewed with light microscope; lateral fields not seen.

Cephalic region diameter 75 % of body diameter immediately posterior, offset, often retracted when fixed; circum-oral area flat, with lightly sclerotised framework; stylet with cone 40% of total length, round stylet knobs ~2 µm across. Anterior fusiform part of digestive tract occupying 44–68 % of body diameter, length 1.9–2.9 times diameter. Orifice of dorsal pharyngeal gland ~2 µm posterior to stylet knobs. Pharyngeal glands occupying ~30–50 % of body diameter, extending over intestine to 12–30 (mean 20) % of total body length. Lumen of intestinal tract broadening halfway along gland.

Secretory/excretory pore opening at ~50–100% of length of pharyngeal gland; duct obscure, secretory/ excretory cell not seen. Hemizonid not seen.

Reproductive tract with single testis, variable in length, sometimes extending to nerve ring but usually overlapping dorsal pharyngeal gland; outstretched or reflexed; testis, seminal vesicle and vas deferens not clearly differentiated. Bursa peloderan; smooth or crenate; prominent or obscure; arising 61 – 80 % along length of body from tail tip. Spicules paired, arcuate, moderately sclerotised; manubrium similar width to shaft, continuous or offset; blade broad, notched on anterior edge near tip; opening unclear. Inconspicuous muscles associated with cloaca. Tail straight or ventrally curved; length 1.5–2.6 times diameter at cloaca; tip bluntly rounded.

Diagnosis and relationships. Fergusobia pimpamensis n. sp. is morphologically characterized by the combination of an open C- to C-shaped parthenogenetic female with a narrow conoid tail, an arcuate to open Cshaped infective female with a hemispherical tail tip, and arcuate to C-shaped males with arcuate spicules and long, crenate, peloderan bursa.

Morphologically, all stages are similar to those of F. floribundae n. sp.

From phylogenetic analyses based on sequences of D2/D3 and COI, F. pimpamensis n. sp. is genetically close to F. floribundae n. sp.

Parthenogenetic females of F. pimpamensis n. sp. have an open C to C-shape differing from that of F. rileyi (almost straight to arcuate). Parthenogenetic females of F. pimpamensis n. sp. (313–429 µm), are shorter than F. indica (525–626 µm) and F. magna (418–780 µm), and longer than F. cajuputiae (221–273 µm), F. fasciculosae (237–285 µm), F. fisheri (228–305 µm), F. jambophila (195–300 µm), F. leucadendrae (205–303 µm), F. nervosae (245–309 µm), and F. philippinensis (229–310 µm). The circum-oral area in the parthenogenetic female of F. pimpamensis n. sp. is flat, thus differing from F. camaldulensae , F. eugenioidae , F. indica , F. jambophila , F. magna , F. morrisae , and F. pohutukawa , in which it is raised. The stylet length (7–9 µm) is shorter than in F. camaldulensae (11–13 µm), F. pohutukawa (10–11 µm), and F. r i l e y i (10–13 µm). In having large to enormous pharyngeal glands (b’ 2.1–3.3), it is similar to most described species, but differs from F. brevicauda , which has smaller glands. The slender, arcuate shape of the body posterior to the vulva and bluntly rounded tail tip differs from that of F. diversifoliae n. sp. (body narrowing sharply), F. porosae (shorter); F. juliae , F. microcarpae , F. quinquenerviae , F. tumifaciens , and F. viridiflora (tail tip more broadly rounded); and F. curriei (a broader cone). The tail length (20–41 µm) is longer than in F. delegatensae n. sp. (14–18 µm). The ratio c’ (1.6–2.7) is greater than in F. brevicauda (0.9–1.1). The hemizonid in parthenogenetic females of F. pimpamensis n. sp. is 4–5 annules anterior to the excretory/secretory pore but 1 annule anterior in F. floribundae n. sp., 0 annules anterior in F. ptychocarpae , and 8–9 annules anterior in F. brittenae . The anterior fusiform part of the digestive tract occupies 43–62 % of body diameter in F. pimpamensis n. sp. but 62–80 % in F. cosmophyllae n. sp. The stylet length (7–9 µm) is mostly shorter than in F. dealbatae (9–10 µm).The cephalic region is retracted in heat-relaxed F. pimpamensis n. sp. but not in F. minimus n. sp.

The body shape of the infective female of F. pimpamensis n. sp. (arcuate to open C) differs from that of F. magna , F. brittenae , and F. curriei (open C-shape), from that of F. eugenioidae , F. juliae , F. morrisae , and F ptychocarpae (strongly curved in posterior region), and from that of F. rileyi (almost straight). It is shorter (369– 443 µm) than F. magna (537–633 µm) and longer than F. cajuputiae (239–309 µm), F. dealbatae (307–347 µm), F. fasciculosae (268–332 µm), F. leucadendrae (227–291 µm), F. porosae (277–300 µm), and F. quinquenerviae (259–325 µm). The ratio a (8.3–12) is larger than in F. cosmophyllae n. sp. (4–6.8). The stylet is longer (6–10 µm) than in the infective female of F. minimus n. sp. (4–5 µm). Shape of the body posterior to the vulva (curved, with hemispherical tip) differs from that of F. rileyi (straight and more slender), from that of F. brevicauda , F. camaldulensae , F. cosmophyllae n. sp., F. delegatensae n. sp., F. diversifoliae n. sp., F. microcarpae , and F. viridiflorae (straight), from that of F. fisheri and F. nervosae (broadly rounded tips), and from that of F. philippinensis (truncate tip). The position of the hemizonid (immediately anterior to the excretory/secretory pore) differs from F. floribundae n. sp. (4–5 annules anterior).

The male body shape of F. pimpamensis n. sp. (arcuate to C), differs from that of F. brittenae , F. curriei , F. juliae , and F. ptychocarpae (J-shape); from F. fasciculosae and F. tumifaciens (barely J); and from F. cosmophyllae n. sp., F. jambophila , F. porosae , and F. rileyi (straighter shape). The arcuate spicule differs from all other described species in which the spicule is angular, except for F. jambophila and F. rileyi . The body length (407–525 µm, mean 467) is longer than in F. cajuputiae (286–364 µm), F. fasciculosae (274–336 µm), F. jambophila (200– 390 µm), F. nervosae (277–312 µm), F. philippinensis (280–390 µm), F. p o ro s a e (270–326 µm), and F. quinquenerviae (256–329 µm); and mostly longer than F. morrisae (347–413 µm, mean 384). The tail shape (arcuate, with a bluntly rounded tip) differs from that of males of F. magna (more slender); and F. philippinensis (truncate tip). The tail is longer (41–57 µm), than in F. brevicauda (28–35 µm). The spicule is longer (19–24 µm) than in F. leucadendrae (14–17 µm). The bursa of F. pimpamensis n. sp. is medium in length (arising at ~ 70% of body length), and differs from that of F. delegatensae n. sp., F. pohutukawa , F. rileyi , and F. viridiflorae (in which it arises at 80% or more of body length); and from F. brevicauda (~33%) F. brittenae (~20%), F. cosmophyllae n. sp. (10–40%), F. curriei (~20%), F. eugenioidae (~25%), F. fisheri (20–50%), F. floribundae n. sp. (23–55%), F. juliae (23–39%), F. minimus n. sp. (12–28%), F. porosae (15–33%), F. tumifaciens (~40%), and F. quinquenerviae (30–50%), in which it is shorter. In having a crenate bursa, F. pimpamensis n. sp. differs from all described species of Fergusobia , except F. delegatensae n. sp. and F. tumifaciens .

Etymology. Named after Pimpama, the area of the Gold Coast, south-eastern Queensland, where the nematodes were collected.

Figures

FIGURE 4. Scanning electron micrographs of Fergusobia spp. from large multilocular shoot bud galls. A, B F. pimpamensis n. sp.; C, D F. delegatensae n. sp. A, Head (en face); B, vulva and lateral field; C Head (en face); D, Head (lateral view). Scale bars: A, C = 2 µm; B = 10 µm; C = 5 µm.

FIGURE 8. Fergusobia pimpamensis n. sp. ex A. nr. woodsiana (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. Scale bars: A, E, I = 50 µm. B, F, J = 5 µm. Tails not drawn to scale.

FIGURE 9. Habitus drawings of Fergusobia spp. collected from large multilocular leaf bud galls: A— F. floribundae n. sp. from Angophora floribunda; B— F. pimpamensis n. sp. from Angophora sp; C—undescribed species from E. nr. acmenioides; D—undescribed species from E. amygdalina; E— F. delegatensisae n. sp. from E. delegatensis; F—undescribed species from E. pauciflora; G—undescribed species from E. racemosa; H—undescribed species from E. obliqua; I— F. diversifoliae n. sp. from E. diversifolia; J—undescribed species from E. blakelyi; K— F. brittenae from E. camaldulensis; L—undescribed species from E. dealbata; M— F. minimus n. sp. from E. tereticornis; N— F. cosmophyllae n. sp. from E. cosmophylla; O—undescribed species from E. robusta; P—undescribed species from Eucalyptus sp. at Woodburn, NSW. Scale bars = 50 µm.