FRESHWATER NEMATODES FROM LOCH NESS 



15 



Fig. 20 Ditylenchus sp. A-D, male. A, oesophageal region; B, spicular 

 region: C. habitus; D. lateral field. Scale bars a = 20 pm. b = 10 pm. c ■■ 

 100 pm. 



Geocenamus cf. nanus (Allen, 1955) Brzeski, 1991 



(Fig. 21) 



Material examined. River Oich: 0.31 m; core 31, 19. 



Female. (n= 1). L = 510pm;a = 26.5;b = 6.3;c = ll;c' = 3.5; 



V = 54; tail/ V-a = 0.24; tail annules 54; tail = 44.8 ujn. 



Head slightly narrower than adjacent body with 5 or 6 fine 

 annules; labial frame work weak. Spear 12 um long with backward- 

 sloping knobs, 2.5 um wide. Cuticle annules fine and moderately 

 distinct, about 0.9 um wide at mid-body. Lateral fields with 6 lines 

 at mid-body, inner lines faint and not always evident throughout the 

 entire length of the lateral fields. Deirid at level of excretory pore. 

 Excretory pore 77 um from anterior. Oesophagus (possibly con- 

 tracted) 80 um long; median bulb ovoid, valve weak at 49.5% of 

 oesophageal length. Vulva and vaginal structures poorly defined. 

 Genital branches stretched out; anterior and posterior branches do 

 not extend into the oesophageal or anal regions respectively. Phasmids 

 at 40% of tail length. Tail annules continue almost to terminus. 



Distribution and habitat. Originally described from the 

 Netherlands with further records from Iran, Turkey, Belgium, and 

 Poland. Terrestrial, in soils around roots of various plants (Saltukoglu 

 et ai, 1976); also in meadow and peat soils (Brzeski, 1991a). 



Remarks. Provisionally identified as G. nanus on account of the 

 number of tail annuli and the value of ratio c'. Other very similar 

 species have fewer tail annules and ratio c' is generally lower, but 

 observed values overlap. For a discussion on relationships between 

 G. nanus (Allen, 1955), G. alboranensis (Tobar Jimenez, 1970) and 

 G. microdorus (Geraert, 1966) see Brzeski ( 1991a). 



Tylenchorhynchus sp. 



Material examined. Fort Augustus Bay: 105 m; Core 7, 1 

 juvenile. Foyers Plateau: 157 um; core 16. 1 juvenile. 



Helicotylenchus pseudorobustus (Steiner, 1914) Golden, 

 1956 



(Fig. 22) 



Material examined. Fort Augustus Bay: 9 1 m; core 2, 1 9. River 

 Oich: 0.33 m; core 35. 1 9. 



FEMALES, (n = 2). L = 800, 830 um; a = 26.6. 34; b = 6.8. 6.9; b' 

 = 5.0, 5. 1 ; c = 43.2, 37; c' = 1 .3, 1 .4; V = 60, 62; tail = 1 8.5, 22.4 um. 

 Head hemispherical 6.4, 7.0 um wide with 4-5 annules. Spear 

 27.5, 26.8 um long, with distinct knobs about 6.0 um wide. Cuticle 

 annules about 1.6 um wide at mid-body. Lateral field with 4 lines, 

 outers weakly crenate. Dorsal oesophageal gland opening 9.6, 10.0 

 um behind spear knobs. Excretory pore 110 um from anterior. 

 Oesophagus 160, 162 urn long. Spermathecae offset without sperm. 

 Phasmid 6-8 annules before anus. Tail with 12 ventral annules, 

 dorsally convex and terminating in a long projection that has a fine 

 irregular outline. 



Distribution and habitat. 

 also fresh water. 



Cosmopolitain; found in soils and 



Fig. 21 Geocenamus cf. nanus (Allen. 1955). A-C, female. A, 



oesophageal region; B, tail; C. habitus. Scale bars a = 20 pm, b = 100 

 pm. 



Remarks. These females are in close agreement with descriptions 

 of//, pseudorobustus by Sher (1966) and Siddiqi (1972). 



Meloidogyne ardenensis Santos, 1968 



(Fig. 23) 



Material examined. Borlum Bay (1992 collection): 0.18 m; 

 core 4, second-stage juvenile. 



