FRESHWATER NEMATODES FROM LOCH NESS 



A/1 

 ill 1 



Fig. 5 Coslenchus sp. 2. A-E, female. A, oesophageal region: B. lateral 

 field; C, vulval region; D. tail; E. habitus. Scale bars a = 20 pm. b = 100 

 pm. 



rounded about 2.6 um wide. Oesophagus 1 36 um long; median bulb 

 ovoid, valve well developed at 45.5% of oesophageal length. Vulva 

 with lateral vulval membranes, 7.6 um long or about 3 annules wide; 

 vagina slightly inclined anteriorly with thickened walls; postuterine 

 sac short; spermatheca empty. Distance from vulva to anus 91 um. 

 Tail damaged, but annules up to finely rounded terminus. 



Remarks. Although the tail of this specimen is damaged, it is 

 clearly different from the other species of Coslenchus found in Loch 

 Ness. Ratios effected by this damage are considered to be close to 

 measurements that would have been obtained had the specimen been 

 undamaged. It keys out close to C. pastor Andrassy, 1982, but the 

 morphometries are a poor fit. 



Filenchus cf. discrepans (Andrassy, 1954) Raski & 

 Geraert, 1987 



(Fig. 6) 



Material examined. Fort Augustus Bay: 98, 102 m; cores 5, 6; 



2 99. Deep South Basin: 196, 204 m; cores 8. 10; 2 99. Foyers 

 Plateau: 158,-160m; cores 14, 15, 18; 3 99. Deep North Basin: cores 

 20, 22; 2 1 1 m. 2 99. River Foyers: 0.25-0.39 m; cores 4 1 , 42, 44; 1 6, 



3 99. 



Horizon. Core 14, (1-2 cm). 



Females, (n = 10). L = 429 um (337-526); a = 35 (27.0-45.8); b 

 = 5.3 (5.0-6. 1 ); c = 3.8 (3.4-4.5); c'= 14.1 (12.8-17.6); V = 60 (57- 

 64); V = 82.3 (80.5-84); tail/V-a = 2.1 (1.7-2.5); tail = 109 urn 

 (91.4-140). 



Head 3.8-5.0 pm wide at base. Annules 1 .2 um (0.8-1 .6) wide at 



Fig. 6 Filenchus cf discrepans (Andrassy, 1954). A-E, female. A. 

 oesophageal region: B. lateral field; C, reproductive system; D. tail; E, 

 habitus. F, male spicular region. Scale bars a = 20 pm. b = 10 pm, c = 

 50 pm. 



mid-body. Lateral fields with two lines. Spear slender, 6.0-7.6 pm 

 long with small basal knobs, about 1 .2 pm wide. Oesophagus 69-92 

 pm long; median bulb somewhat fusiform, valve weak at 35-42% of 

 oesophageal length. Anterior genital branch 68-156 pm long. 

 Spermatheca axial, oblong with rounded sperms about 1.3 pm in 

 diameter. Postuterine sac 7.0-13.4 pm long. Vagina more or less 

 perpendicular to body axis. 



MALE, (n = 1 ). L = 453 pm; a = 47; b = 5.0; c = 4.5; c' = 14.5; 

 gubernaculum = 3.0 pm; spicules = 13.8 pm; tail =101 pm. 



Similar to female, except body more slender with narrower lateral 

 fields. Testis 152 pm long, occupying 33% of body length. Bursa 

 adanal, 19 pm long. 



Distribution and habitat. Widely distributed in Europe with 

 additional records from Mexico, Russia, USA (terrestrial soils) and 

 New Guinea (terrestrial and fresh water). 



REMARKS. This population keys out to F. discrepans. The mor- 

 phology of the female reproductive system closely resembles that 

 figured for the type specimen, especially in respect of the oblong 

 spermatheca in females. However, the cephalic region is not makedly 

 narrower than the adjacent body region as figured by Andrassy 

 (1954) and described by Troccoli & Geraert (1995). Brzeski (pers. 

 comm..) suggests that these nematodes show affinities to F. misellus 

 (Andrassy, 1958), but in F misellus tail length (28-7 1 pm) and ratio 

 tail/V-a (0.7-1.6) are different (Brzeski, 1979); tail shape also 

 differs. 



