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Males:
Poland, Tarnów (n = 1). L = 655; oes. = 137; ex. p. =
93; tail = 87; a = 40; b = 4.8; MB = 41; c = 7.6; c' = 6.5; spicule = 17.5;
st. = 7.5.
Poland, Kucharki (n = 2). L = 604, 659; oes. = 118, 124;
ex. p. = 84, 97; tail = 70, 80; a = 32, 36; b = 5.1, 5.3; MB = 42, 46;
c = 8.2, 8.6; c' = 6.0, 6.2; spicule = 16, st. = 7.5, 8.
Poland, Puszcza Bialowieska (n = 1). L = 544; oes. = 112; ex.
p. = 82; tail - 73; a = 35; b = 4.8; MB = 40; c = 7.4; c' = 6.5; spicule
= 17; st. = 8.
Poland, Btonie (n = 4). L = 590 (526-692); oes. = 110
(105-115); ex. p. = 84 (79-94); tail = 72 (67-80); a = 34-36; b = 5.4 (4.8-6.0);
MB = 42-43; c = 8.2 (7.9-8.6); c' = 6.0 (5.2-6.8); spicule = 17 (15-20);
st. = 7-8.
Poland, Kochów (n = 4). L = 771 (719-884); oes. =
144 (140-149); ex. p. = 99 (95-105); tail = 86 (81-94); a = 48-51; b =
5.0-5.6; MB = 39-40; c = 8.8-9.0; c' = 7.5 (7.2-7.8); spicule = 17.5 (16-19);
st. = 8.
Poland, Puszcza Bolimowska (n = 1). L = 982; oes. = 160; tail
= 81; a = 50; b = 6.1; MB = 35; c = 12.1; c' = 6.1; spicule = 18; st. =
8.
Switzerland, Thalwil (n = 2). L = 694, 744; oes. = 129, 140;
ex. p. = 104, 105; tail = 81, 89; a = 37, 38; b = 5.3, 5.4; MB =
41, 46; c = 7.9, 9.1; c' = 5.6, 6.1; spicule = 19; st. = 9.
DESCRIPTION
Female: Body slightly ventrally arcuate to almost straight
when relaxed, more curved in posterior part. Lateral field with four
incisures, occasionally two additional faint lines could be observed at
spermatheca level. Cuticular annuli at mid=body about 1.2-1.6 um
wide. Head low, with one or two annuli usually 6-7 um wide.
Stylet cone about one-third of stylet length, size of knobs somewhat variable
as the longer specimens have larger knobs. Median bulb without lumen
wall thickenings, mostly elongated, fusiform, occaisionally slightly wider
than illustrated. Basal bulb elongated, offset from intestine.
Excretory pore opposite posterior part of isthmus, 78 (67-87) % of oesophagus
length from anterior end. Vulva mostly within limits V = 73-77.
PUS length equals 2.1 (1.3-3.0) VBD or 36 (25-51) % VA. Post-vulval part
of body 14.9 (11.1-22.1) ABD long (71% of females within 13-17). Body width
at vulva 1.5 (1.3-1.8) ABD (68% of females with 1.5-1.6). Tail elongated
conical, tip pointed, dull or rounded.
Male: Similar to female. Gubernaculum 4-5 um. Caudal alae length 2.4 (1.7-3.2) ABD; exceptional male with bursa 4.2 ABD long. Alae extends along 25 (12-41) % of tail length, mostly 18-30%.
HABITATS AND LOCALITIES
Most D. acutus examined were collected in cultivated sandy soils.
One population came from sand of the bottom of temporarily drying ditch.
D. acutus was described from India; many collections from
Poland and one from Switzerland were examined.
DIAGNOSIS AND RELATIONSHIPS
The species is distinct because of four incisures, low head, stylet
mostly 7.5-9 um, non-muscular fusiform median bulb, position of vulva (V
mostly 73-77), PUS length (25-51% VA) and conical tail mostly 5-9 of ABD
long. Medium sized bursa and spicules 15-20 um long further contribute
to species characterization.
The measurements of D. acutus are similar to that
of D. oryzeae and D. attenuatus. The former needs to be restudied
as indicated by Sumenkova (1975), but is drawn with distinctly clavate
tail. The latter differs from D. acutus mainly by having very
long basal bulb of about one-third of total oesophagus length, probably
thiner (sic) body (a = 53-59) and much longer vulva-anus distance in relation
to tail length.
(Description- Brzeski, 1991)