FRESHWATER NEMATODES FROM LOCH NESS 



17 



Head not offset from body, with labial cap and one postlabial 

 annule. Cuticular annulation distinct but fine, about 0.9 urn wide at 

 mid-body. Lateral fields with four lines. Spear slender, 1 1 .5 urn long 

 with small backward-sloping knobs. Dorsal gland opens 5.0 urn 

 behind spear knobs. Length of oesophagus (from anterior to median 

 bulb) 6 1 .4 urn; median bulb more or less ovoid; excretory pore 81.2 

 urn from anterior. Hemizonid immediately anterior to excretory 

 pore. Phasmid not seen. Tail terminus tapers sharply with a short 

 terminal portion ending in a finely rounded tip. Length of hyaline 

 tail terminus 16.5 pm. 



Distribution and habitat. Recorded from Estonia, Russia, Po- 

 land and the United Kingdom, all in wet sandy, peat and silt soils 

 (Karssen & Van Hoenselaar. 1998). 



Remarks. The present second-stage juvenile agrees well with 

 descriptions of the species. 



Criconema annuliferum (de Man, 1921) Raski & Luc, 

 1984 



(Fig. 25) 



Material examined. 



Foyers Plateau: 160 m; core 15, 19. 



Female. (n= 1). L = 598pm;a = 11.2; b = 3.9; c = 25; V = 88; R 

 = 60; Rex = 20; Rvan = 5; Ran = 4; VL/VB = 1 .4; tail = 22.4 um. 

 Labial disc low. Head region offset, collar-like. Annule two 



Fig. 25 Criconema annuliferum (de Man, 1921) A-C, female. A. 

 habitus; B. anterior region; C, posterior region. Criconema sp. D, E, 

 female. D, anterior region; E, posterior region. Scale bars a = 100 um. 

 b = 30 um. 



slightly smaller and narrower than annule three, both distinctly 

 smaller than annules one and four. Annules 10.8 um wide at mid- 

 body, outer edges smooth, rounded or slightly retrorse; interspaces 

 sometimes filled with fine detritus. Spear straight, 101 um long; 

 knobs 11.5 um wide, anterior surfaces indented. Vulva closed, 

 anterior lip well developed, overlapping entire posterior lip. Ovary 

 not reflexed, oocytes arranged in two rows. Spermatheca not 

 observed. Anus inconspicuous. Tail terminus peg-like. 



Distribution and habitat. Throughout Europe, associated with 

 plant roots in both dry and wet soils. 



Remarks. This nematode agrees with descriptions and 

 morphometries presented for C. annuliferum. 



Criconema sp. 



(Fig. 25) 



Material examined. Fort Augustus Bay: 92 m; core 3, 1 9 



Female. (n= 1 ). L = 670 pm; a= 12.3; b = 4.1: c = 21.8; V = 90; 

 R = 65; Rex = 21; Rvan = 3; Ran = 5; VL/VB = 1.5; tail = 30.7. um. 

 Labial disc low. Head region offset, collar-like; annules two 

 and three of equal size, distinctly smaller than annules one and 

 four. Body annules 10.2 um wide at mid-body, outer edges 

 smooth, rounded or slightly retrorse; interspaces with fine scatter- 

 ing of detritus. Spear 120 pm long; shaft gently curved, conus 

 straight; knobs 12.2 pm wide, anterior surfaces indented. Vulva 

 closed, anterior lip well developed, overlapping entire posterior 

 lip. Ovary poorly preserved; oocytes arranged in two rows. 

 Spermatheca not evident. Anus conspicuous. Tail terminus bifur- 

 cate. 



Remarks. Similar to C. annuliferum and keys out to that species 

 (de Grisse & Loof, 1 965 ) but the spear is longer with a gently curved 

 shaft, possibly an artefact; the tail terminus is bifurcate, also the 2nd 

 and 3rd head annules are equal in size. 



Criconema demani (Micoletzky, 1915) Raski & Luc, 1984 

 (Fig. 26) 



Material examined. River Oich: 0.3 1 , 0. 1 8 m; cores 31,33,29 



9. 



Females. (n = 2). L = 401, 417 pm; a = 8.3, 8.7: b = 3.8, 4.0; c = 

 1 0.6. 1 0; V = 84.5, 82.2; R = 73, 7 1 ; Rex (n = 1 ) = 20; Rvan = 5; Ran 

 = 9; VL/VB = 1.7; tail = 37.7, 42.2 pm. 



Labial disc low. Head region offset with second annule broader 

 than first. Annules 5.8, 6.4 pm wide at mid-body; outer edges 

 smooth, rounded or moderately retrorse; with fine, scattered, foreign 

 detritus but nevertheless margins apparently minutely crenate. Spear 

 70.4, 71.6 pm long; knobs 8.3, 8.6 pm wide, anterior surfaces 

 indented. Vulva closed; anterior lip well developed, overlapping 

 entire posterior lip. Ovary reflexed distally. Spermatheca poorly 

 preserved, without sperms. Anus inconspicuous. Tail with terminus 

 straight or curved dorsally. 



Distribution and habitat. Belgium, Denmark, Netherlands and 

 North America. Terrestrial, in moist soils and alongside riverbanks, 

 ditches and lake margins. 



REMARKS. Keys out to C. demani and generally fits in well with 

 descriptions of the species (Taylor, 1936), (Bongers, 1988), (de 

 Grisse & Loof, 1965); except that ratio a is slightly lower, as is V in 

 one specimen. Differences between the tail termini are not consid- 

 ered in this instance to be of specific importance. 



