Biodiversity Data Journal : Taxonomic Paper
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Taxonomic Paper
Description of Hoplolaimus bachlongviensis sp. n. (Nematoda: Hoplolaimidae) from banana soil in Vietnam
expand article infoTien Huu Nguyen, Quang Duc Bui, Phap Quang Trinh
‡ Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi, Vietnam
Open Access

Abstract

Background

The genus Hoplolaimus Daday, 1905 belongs to the subfamily Hoplolaimine Filipiev, 1934 of family Hoplolaimidae Filipiev, 1934 (Krall 1990). Daday established this genus on a single female of H. tylenchiformis recovered from a mud hole on Banco Island, Paraguay in 1905 (Sher 1963​, Krall 1990). Hoplolaimus species are distributed worldwide and cause damage on numerous agricultural crops (Luc et al. 1990Robbins et al. 1998​). In 1992, Handoo and Golden reviewed 29 valid species of genus Hoplolaimus Dayday, 1905 (Handoo and Golden 1992). Siddiqi (2000) recognised three subgenera in Hoplolaimus: Hoplolaimus (Hoplolaimus) with ten species, is characterized by lateral field distinct, with four incisures, excretory pore behind hemizonid; Hoplolaimus (Basirolaimus) with 18 species, is characterized by lateral field with one to three incisures, obliterated, excretory pore anterior to hemizonid, dorsal oesophageal gland quadrinucleate; and Hoplolaimus (Ethiolaimus) with four species is characterized by lateral field with one to three incisures, obliterated; excretory pore anterior to hemizonid, dorsal oesophageal gland uninucleate (Siddiqi 2000). Since then, Hoplolaimus puriensis Ali, Shaheen & Pervez, 2009 has been described (​Ali et al. 2009). Up to now, there have been two species of genus Hoplolaimus reported in Vietnam, viz H. seinhorsti and H. chambus (Nguyen and Nguyen 2000).

New information

Hoplolaimus bachlongviensis sp. n. was isolated from banana soil in Bach Long Vi Island, Vietnam. The female of this species is described and illustrated below. Some diagnostic characters of this species include body slightly curved ventrally, offset lip region exhibiting three to four annules, lateral field reduced, pharyngeal glands with six nuclei, excretory pore anterior to hemizonid, epiptygma absent, intestine not overlapping rectum and male was not found.

Keywords

bananas, Hoplolaimus, new species, Tonkin Gulf, Vietnam

Introduction

In many surveys of plant parasitic nematodes on bananas in agriculture and natural forest systems in mainland of Vietnam, only two species Hoplolaimus seinhorsti Luc, 1958 and H. chambus Jairajpuri & Baqri, 1973 were recorded (Nguyen and Nguyen 2000). During a survey of plant parasitic nematodes in Bach Long Vi Island (located about 130 km off the mainland of Vietnam), a Hoplolaimus sp. was collected which was morphologically different from other known species. Herein this species is morphologically characterised and described as Hoplolaimus bachlongviensis sp. n.

Materials and methods

The nematodes were detected from banana soil samples in Bach Long Vi Island, Vietnam (20°07'52.8" N, 107°43'56.6" E). Soil nematodes were extracted using the decanting and modified Baermann tray method (Whitehead and Hemming 1965). Measurements were made on permanent slides of heat-killed nematodes with fixative TAF and ethanol-glycerin dehydration according to the method described by Seinhorst (1959) and modified bySeinhorst (1959), De Grisse (1969). For morphological examination, nematodes were observed through the Olympus BX-51 light microscope, and photographed with an Olympus U-TV 0.5xC-3 digital camera.

Taxon treatment

Hoplolaimus bachlongviensis, sp. n.

Materials    Download as CSV 
Holotype:
  1. family:
    Hoplolaimidae
    ; genus:
    Hoplolaimus
    ; island:
    Bach Long Vi
    ; stateProvince:
    Hai Phong
    ; county:
    Vietnam
    ; verbatimCoordinates:
    20°07'52.8"N, 107°43'56.6"E
    ; sex:
    female
    ; behavior:
    migratory ectoparasite on banana roots
    ; identificationID:
    BLV-4050-1
Paratype:
  1. family:
    Hoplolaimidae
    ; genus:
    Hoplolaimus
    ; island:
    Bach Long Vi
    ; stateProvince:
    Hai Phong
    ; county:
    Vietnam
    ; verbatimCoordinates:
    20°07'52.8"N, 107°43'56.6"E
    ; sex:
    female
    ; behavior:
    migratory ectoparasite on banana roots
    ; identificationID:
    BLV-4050-2

Description

Females

(Table 1; Figs 1, 2, 3)

Morphometrics of Hoplolaimus bachlongviensis sp. n. (all measurements in µm, as mean ± standard deviation (range).

Measurements

Holotype female

Paratype females

n

1

8

Body length

1439

1405 ±78.2 (1247-1493)

Stylet cone length

26

25.5±1.1 (24-27)

Stylet knob length

7

7.2±0.7 (6-8)

Stylet length

50

47.1±2.2 (44-50)

Lip region height

9

8.8±0.6 (8-9)

Lip region diam.

18

18.1±1.0 (17-20)

Anterior end to nerve ring

147

126.5±11.9 (108-147)

Anterior end to excretory pore

154

144.2±8.6 (131-154)

Anterior end to end of pharyngeal glands

248

207.5±22.2 (175-248)

DGO

6

4.2±1.2 (3-6)

Anterior end to intestine-pharyngeal valve

170

154.6±13.2 (137-174)

Anterior phasmid of body length (%)

34

34.7±4 (29-38)

Posterior phasmidof body length (%)

80

78.6±4.5 (74-84)

Max body diam.

58

58.0±4.2 (51-66)

a

24.7

24.3±1.6 (22-27)

b

5.8

6.8±0.6 (6-8)

c

53.2

55.9±5.1 (48-64)

c’

0.7

0.7±0.1 (0.6-0.8)

V

56

56.7±1.7 (53-59)

Anal body diam.

33

36.1±2.3 (33-40)

Tail length

27

25.2±1.6 (23-27)

Tail annules

13

11 ±1.6 (9-13)

Figure 1.

Light micrographs of Hoplolaimus bachlongviensis sp. n. (Scale bar = 40 μm).

aAnterior end
bExcretory pore (arrow 1) and hemizonid (arrow 2)
cVulva region in ventral view
dVulva region in lateral view
ePosterior phasmid position (arrow 2) and lateral field in lateral view (arrow 1)
fPosterior end, intestine (arrow 1) and rectum (arrow 2)
Figure 2.

Spermatheca and posterior end of Hoplolaimus bachlongviensis sp. n. (Scale bar = 40 μm).

aSpermatheca
bPosterior end in ventrosublateral view
Figure 3.

Diagnostic drawings of Hoplolaimus bachlongviensis sp. n. (Scale bar = 50 μm).

aAnterior end
bLip region
cVulva region (ventral view)
dPosterior phasmid.
ePosterior end (ventrosublateral view)
fPosterior end (lateral view)

Body slightly curved ventrally, rarely C-shaped, cylinder, vermiform, tapering slightly at both ends. Lip region offset, usually bearing 4 distinct annuli, sometimes 3 annuli, basal ring of lip region with 6 longitudinal striations (Figs 1a, 3a, b). Cuticular annulation prominent. Lateral field reduced and represented by the interruption of body annuli as a single incisures, but often indistinct (Figs 1e, 3d). Stylet large and strong with prominent tulip-shaped basal knob represented by three anterior projection, DGO about 4 µm behind spear base (Figs 1a, 3a). Metacorpus ovate with well-developed, sclerotized valve. Pharyngeal glands with 6 nuclei (Fig. 3a). Distinct nerve ring encircling isthmus. Excretory pore situated within range from level of nerve ring to level of esophago-intestineal valve or even somewhat more posterior. Hemizonid distinct large, two annules in length, located about seven annules behind Excretory pore (Figs 1b, 3a). Hemizonion located 8-10 annules posterior to hemizonid. Phasmids (scutella) anterior and posterior to vulva, large and conspicuous (Figs 1e, 3d). Vulva prominent, transverse slit at mid-body; epiptygma absent (Figs 1c, d, 3c). Ovaries two, outstretched (amphidelphic), spermatheca empty (Fig. 2a). Intestine not overlapping rectum (Figs 1f, 3e, f). Tail short, rounded, shorter than the anal body diameter, usually with 9-13 annuli (Figs 1f, 2b, 3e, f).

Diagnosis

Hoplolaimus bachlongviensis sp. n. is characterized by lip region set off, lateral field reduced, represented by a single incisure on the body, but often indistinct, Pharyngeal glands with six nuclei, excretory pore prominent and located seven annules anterior to hemizonid, epiptygma absent, intestine not overlapping rectum, male absent.

Etymology

The species is named after the geographic location, Bach Long Vi Island of Vietnam.

Notes

Males: Unknown

Type material

Female holotype and seven female paratypes deposited in the nematode collection of the Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet str., Hanoi, Vietnam. Accession numbers: IEBR.Nema4050-1 (one female hoplotype); IEBR.Nema4050-2 (8 female paratypes).

Discussion

Hoplolaimus bachlongviensis sp. n. is similar to Hoplolaimus seinhorsti, H. chambus, H. columbus Sher, 1963 and H. pararobustus (Schuurmans Stekhoven & Teunissen, 1938) Sher, 1963 by having excretory pore anterior to hemizonid, lateral field reduced, represented by interruptions of annules as a single incisure, often indistinct, pharyngeal glands with six nuclei (Handoo and Golden 1992). However, H. bachlongviensis sp. n. differs from H. seinhorsti by epiptygma absent vs present and number of longitudinal striations on basal ring 6 vs 8-12. It differs from H. chambus by male absent vs present, epiptygma absent vs present, intestine not overlapping rectum vs overlapping rectum. Hoplolaimus bachlongviensis sp. n. differs from H. columbus in having fewer tail annuli 9-13 vs 16-22; a=22-27 vs a=30-38; b=6-8 vs b=9.1-12.4; DGO=3-6 vs DGO=9-13; epiptygma absent vs present; hemizonid located about 7 annuli behind excretory pore vs 2-5 annuli and intestine not overlapping rectum vs overlapping rectum. Hoplolaimus bachlongviensis sp. n. differs from H. pararobustus by male absent vs present, intestine not overlapping rectum vs overlapping rectum, epiptygma absent vs present and sperm absent vs present.

Hoplolaimus bachlongviensis sp. n. is distinguished from H. sheri Suryawanshi 1971 by having lateral field reduced and represented by the interruption of body annuli as a single incisures vs two incisures in lateral field; having longer stylet 44-50 vs 40-45; having fewer longitudinal striations on basal ring 6 vs 20; hemizonid is conspicuous vs obscure; a=22-27 vs a=26-30; b=6-8 vs b=9.7-11.5.

Hoplolaimus bachlongviensis sp. n. differs from H. puriensis by lateral field reduced, represented by a single incisure on the body, but often indistinct vs four lateral lines, longer stylet 44-50 µm vs shorter stylet 32-35 µm.

Acknowledgements

This research was supported by Project code VAST.NĐP.01/14-15. The authors would like to thank Dr. Le Hung Anh and Mr. Dang Huy Phuong for their help in sampling.

References