Discolaimus

Discolaimus	Contents	Rev 06/16/2023
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Discolaimus Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Qudsianematidae Menu	Feeding	References
	Go to Nemaplex Main Menu	Go to Dictionary of Terminology

Classification:

Enoplea

Dorylaimia
Dorylaimida

Qudsianematidae (see also family Discolaimidae)

Discolaimus Cobb, 1913

Recent literature lists around 47 species (Wu et al., 2016)

List of species (2016)

Morphology and Anatomy:

Large nematodes: 0.8-4.3 mm
Cuticle smooth
Lateral chords with a series of glandular bodies and pores.
Labial region wide, discoid configuration, with small inner liplets. Easily recognized by this feature.
Odontostyle strong, shorter than labial diamter with aperture occupying about half its length.
Prectum 2.5 x anal body diameter.
Female diovarial, amphidelphic.
Vulva transverse, not sclerotized.
Males rare. 4-18 ventromedial supplements.
Tail conoid, curved or bluntly rounded; similar in both sexes.

Ref: Andrassy (2009)

Female:

Anterior Photographs by Ferris; Drawings by Wu et al. (2016)		Diovarial, amphidelphic gonads
Males:

Body size range for the species of this genus in the database - Click:

Key to the species of Discolaimus (adapted from Wu et al., 2016)

1	Average body length > 24 mm	2
	Average body length < 24 mm	6
2	Average body length > 4 mm	D alborossicus
	Average body length < 4 mm	3
3	Odontostyle long, ≥45 µm	D magnistylus
	Odontostyle shorter, <45 µm	4
4	Odontostyle23-25 µm	D mariae
	Odontostyle >25 µm	5
5	Odontostyle aperture 155-18 µm, c=90-120	D curvus
	Odontostyle aperture 20-29µm, c=65-81	D krugeri
6	Tail length longer, c' average >15, perioral liplets present	D labiatus
	Tail length shorter, c' average ≤15, perioral lipletsabsent	7
7	Body length average < 07 mm	D pygmaeus
	Body length average > 07 mm	8
8	Large, muscular, trapezoidal vaginal structure present	D trapezoides
	Trapezoidal vaginal structure absent	9
9	Basal enlarged portion of esophagus offset by a constriction	10
	Basal enlarged portion of esophagus not offset by a constriction	11
10	L=125-13 mm, c=50-57, V=53-57	D conicus
	L=168-246 mm, c=58-81, V=54-62	D constrictus
11	c >90	D pakistanense
	c <90	12
12	Basal enlarged portion of esophagus with conspicuous sheath	13
	Basal enlarged portion of esophagus without conspicuous sheath	14
13	L=18-21 mm, c=68-71, odontostyle = 23 µm	D bicorticus
	L=08-11 mm, c=40-52, odontostyle = 15-16 µm	D laksi
14	Body conspicuously tapered from middle of esophagus forward, male with 18 supplements	D acuticapitatus
	Body not conspicuously tapered from middle of esophagus forward, male with <18 supplements	15
15	Prererctum > 4x abd	16
	Prerectum < 4x abd	17
16	L=13 mm, prerectum 5-7x abd	D intermedius
	L=16-18 mm, prerectum >12x abd	D lahorensis
17	Odontostyle average length < 16 µm	18
	Odontostyle average length > 16 µm	25
18	V <50	19
	V >50	21
19	Odontostyle length 115-13 µm; aperture about 2/3 its length	D microdorus
	Odontostyle length > µm; aperture about 1/2 its length	20
20	V=37-45; odontostyle length 14-16 µm	D texanus
	V=43-47; odontostyle length 12-145 µm	D monoplanus
21	Tail length <1x abd	22
	Tail length >1x abd	23
22	Body with three complete rows of lateral pores	D elegans
	Body without three complete rows of lateral pores	D pizai
23	L=08-085 mm, odontostyle = 11 µm	D gossypiorum
	L=>1 mm, odontostyle >12 µm	24
24	L=12 mm, c=55, c'=11, 53-55	D affinis
	L=10-12 mm, c=40-46, c'=15, 50-54	D tenax
25	L=18-11 mm	D rotundicaudatus
	L>10 mm	26
26	Anterior portion of esophagus with two swellings	27
	Anterior portion of esophagus without two swellings	35
27	Two conspicuous speramthecae in each female gonad	D levinae
	Generally one speramtheca in each female gonad	28
28	Body length average <14 mm	29
	Body length average >14 mm	32
29	Odontostyle 28-30 µm; c' <1	D pernis
	Odontostyle <20 µm; c' >1	30
30	V=44-47	D omanensis
	V>50	31
31	L=11-12 mm, c' =12-13; odontostyle 16-17 µm	D paratenax
	L=12-13 mm, c' =10-11; odontostyle 18-19 µm	D dhanachandi
32	c=44-49	D papulus
	c<50	33
33	Basal portion of esophagus expanding gradually	D similis
	Basal portion of esophagus expanding abruptly	34
34	Lip region with six sectors separated by Y-shaped radial grooves, posterior portion of esophagus with a sheath	D anemaqen
	Lip region with six wedge-shaped; posterior portion of esophagus with irregular sheath	D major
35	V<50	36
	V>50	38
36	L = 19Ã¯Â¿Â½20 mm, a = 41Ã¯Â¿Â½47, V = 41Ã¯Â¿Â½42	D neomajor
	L < 18 mm, a < 40, V > 43	37
37	Odontostyle 21Ã¯Â¿Â½23 μm, a = 28Ã¯Â¿Â½32, V= 45Ã¯Â¿Â½48	D agricolus
	Odontostyle 25 μm, a = 27, V = 44	D auritus
38	Odontostyle >20 μm	39
	Odontostyle <30 μm	41
39	L=19 mm; odontostyle length 25 μm	D perplexans
	L<19 mm; odontostyle length <24μm	40
40	a=37-42; c=48-57; c'=13-14; V=51-53	D silvicolus
	a=52; c=78; c'=10; V=54	D zicsii
41	L = 16 mm, a = 32, c'=10	D discocephalus
	L = 17-19 mm, a = 44-47, c'=12-13	D papillatus

Feeding:

Categorized as a predator (Yeates et al., 1993) and studied as a predator (Bilgrami and Gaugler (2005).

The prey cuticl;e is penetrated by thrusts of the odontostyle. Body contents of the prey are ingested throught the odontostyle (Bilgrami, 2008).

Feeding activities of the predatory nematodes Laimydorus baldus and Discolaimus major preying on Hirschmanniella oryzae were studied under laboratory conditions.

Discolaimus major killed more prey, and fed and aggregated longer than L. baldus.
Predator activities at the feeding site were greatest at 30◦C.
Predators starved for 6 days detected prey rapidly and aggregated at the feeding site longest. Predators were increasingly efficient at finding prey as prey density increased.
Prey search and predation abilities of L. baldus and D. major are regulated by temperature, prey density, starvation and prey incubation (Bilgrami and Gaugler, 2005).

Life Cycle:

For Ecophysiological Parameters for this genus, click

Species of Discolaimus are assumed to be sexually reproducing where males are present and there are spermathecae in the female genital tract.

Ecosystem Functions and Services:

References:

Andrassy, I. 2009. Free-living Nematodes of Hungary III. Hungarian Natural History Museum, Budapest. 608p.

Bilgrami, A.L. and Gaugler, R. 2005. Feeding behaviour of the predatory nematodes Laimydorus baldus and Discolaimus major (Nematoda: Dorylaimida). Nematology 7:11-20.

Bilgrami, A.L. 2008. Biocontrol potentials of predatory nematodes. Chapter 1 in Ciancio, A. and Mukerji, K.G. (eds).Integrated Management and Biocontrol of Vegetable and Grain Crops Nematodes pp3-28.

Thorne, G. 1939. A monograph of the nematodes of the superfamily Dorylaimoidea. Capita Zool. 8: 1-263.

Wu, W-J, Yan, L, Xu, C-L., Wang, K., Jin, S-Y., Xie, H. 2016. A new species of the genus Discolaimus Cobb, 1913 (Nematoda: Dorylaimida: Qudsianematidae) from Qinghai, China. Zootaxa 4088: 129-138.

Yeates, G.W., T. Bongers, R. G. M. De Goede, D. W. Freckman, and S. S. Georgieva. 1993. Feeding habits in soil nematode families and genera—An outline for soil ecologists. Journal of Nematology 25:315-331.

Back to Top

List of species of the genus Discolaimus Cobb, 1913

(from Wu et al., 2016)

D. acuticapitatus Furstenberg & Heyns, 1965

D. affinis Loof, 1964

D. anemaqen n. sp.

D. agricolus Sauer & Annels, 1985

D. alborossicus Merzheevskaya, 1951

D. auritus Lordello, 1955

D. bicorticus Furstenberg & Heyns, 1965

D. conicus Siddiqi, 2005

D. constrictus Heyns, 2001

D. curvus Siddiqi, 2005

D. dhanachandi Gantait, Bhattacharya & Chatterjee, 2009

D. discocephalus Tulaganov, 1949

D. elegans Sauer & Annels, 1985

D. gossypiorum Karimova, 1957

D. intermedius Heyns & Lagervey, 1965

D. krugeri Furstenberg & Heyns, 1965

D. labiatus Pena-Santiago, Torres, Liebanas & Abolafia, 2002

D. lahorensis Khan, 1998

D. laksi Khan & Laha, 1982

D. levinae Furstenberg & Heyns, 1965

D. magnistylus Siddiqi, 2005

D. major Thorne, 1939

D. mariae Pena-Santiago, Torres, Liebanas & Abolafia, 2002

D. microdorus Siddiqi, 2005

D. monoplanus Heyns, 1963

D. neomajor Siddiqi, 2005

D. omanensis Siddiqi, 2005

D. pakistanense Nasira, Shahina & Erum, 2008

D. papillatus Khan, Ahmad & Jairajpuri, 1994

D. papulus Jain & Saxena, 1994

D. paratenax Siddiqi, 2005

D. pernix Siddiqi, 2005

D. perplexans Siddiqi, 1964

D. pizai Monteiro, 1970

D. pygmaeus Siddiqi, 2005

D. rotundicaudatus Khan & Laha, 1982

D. silvicolus Sauer & Annels, 1985

D. similis Thorne, 1939

D. tenax Siddiqi, 1964

D. texanus Cobb, 1913

D. trapezoides Siddiqi, 2005

D. zicsii Andrassy, 1968

The following species are junior synonyms or inquirenda:

D. arenicolus Yeates, 1967 = D. major

D. paremajor Coomans, 1966 = D. major

D. brevis Siddiqi, 1964 = D. monoplanus

D. monhystera Thorne, 1939 = D. texanus

D. otiosus (Kirjanova, 1951) Andrassy, 1967

Discolaimus

Contents

Classification:

Back to Top

Morphology and Anatomy:

Key to the species of Discolaimus (adapted from Wu et al., 2016)

Back to Top

Distribution:

Back to Top

Feeding:

Back to Top

Biology and Ecology:

Back to Top

Life Cycle:

Back to Top

Ecosystem Functions and Services:

Back to Top

Management:

Back to Top

References:

Back to Top

Copyright © 1999 by Howard Ferris.
Revised: June 16, 2023.

Discolaimus

Key to the species of Discolaimus (adapted from Wu et al., 2016)

Copyright © 1999 by Howard Ferris. Revised: June 16, 2023.

Copyright © 1999 by Howard Ferris.
Revised: June 16, 2023.