On the “ Paractinolaimus ” genus group (Nematoda: Actinolaimidae), with description of five new and two rare species of Egtitus Thorne, 1967
Author
Andrássy, István
text
Journal of Natural History
2012
2012-02-29
46
7 - 8
453
494
http://dx.doi.org/10.1080/00222933.2011.642415
journal article
10.1080/00222933.2011.642415
1464-5262
5202591
Egtitus remotus
sp. nov.
(
Figures 6A–E
and
7A, B
)
Holotype
female: L
=
2.39 mm
; a
=
40; b
=
3.6; c
=
28;
ć
=
2.6;
V
=
51%.
Paratype
males (
n =
4): L
=
2.18–2.58 mm
; a
=
41–50; b
=
3.6–4.0; c
=
55–76;
ć
=
0.8–0.9.
General characters
Body ventrally curved upon fixation, especially in its posterior third, strongly tapered toward anterior end, 52–60 µm wide at mid-region. Cuticle smooth, 2–3 µm thick on most body regions. Lip region comparatively small, 15–17 µm wide, separated by a weak depression, lips amalgamated. Body at posterior end of pharynx 3.1–3.7 times wider than lip region. Amphids caliciform with apertures nearly half as wide as corresponding body.
Labial chamber less separated, wider (9–11 µm) than dental chamber (8–9 µm). The latter slightly ribbed, without denticles. Onchia simple. Odontostyle 20–22 µm long, 1.2–1.4 times as long as lip region width, 1.6–1.8 µm thick, slightly thicker than cuticle at the same level. Guiding ring double but thin, 6.0–6.5 µm wide, 14–16 µm from anterior end of body. Pharynx tripartite, 590–690 µm long, in three of the
five specimens
occupying more than one-quarter (28%) of body length, expanded at 51–54% of its length. Medial part comparatively short, 80–86 µm, occupying 13–14% of entire length of pharynx. Pharyngeal nuclei rather obscure, D
=
52–56% (14–15% of total body length),
AS
nuclei indistinct, PS
=
72–74%. Glandularium 280–318 µm long. Posterior end of pharynx with a shallow disc, cardia conical. Intestine with wide lumen.
Female
Amphidelphic with short genital branches, each 4.4 body widths long or occupying about 10% of body length. Ovaries extending one-third distance from genital tip to vulva. Vulva longitudinal with well sclerotized inner pieces. Vagina 26 µm, occupying half the body width. Uteri proximally broad, distally narrow. Mature eggs not observed. Distance between posterior end of pharynx and vulva shorter (0.8 times) than pharynx. Rectum 1.4, pre-rectum 2.3 anal body widths long. Vulva–anus distance equal to 12.6 tail lengths. Tail short, 86 µm or 3.6% of entire length of body, conical with very sharp tip.
Figure 6.
Egtitus remotus
sp. nov.
(A) Anterior end; (B) medial part of pharynx; (C) cardial region; (D) vulval region; (E) female tail. Scale bars 20 µm.
Figure 7.
Egtitus remotus
sp. nov.
(A, B) Posterior end of male. Scale bar 20 µm.
Male
Diorchic with well-developed testes packed with fusiform spermatozoa. Spicula 68–70 µm long, nearly twice as long as tail. Ventromedial supplements small, 10 (
two males
) or 11 (
two males
), the posteriormost well before the spicula. Pre-rectum beginning within the range of supplements. Tail 30–40 µm long or occupying 1.2–1.8% of total body length, shorter (0.8–0.9 times) than anal body diameter, conoid with narrowly rounded tip.
Diagnosis and relationships
Size ranging between 2.2 and
2.6 mm
, body strongly tapered in its anterior quarter (neck region), lip region small, odontostyle of medium length, longer than lip region width, pharynx enlarged somewhat posterior to its middle, female gonads short, vulva longitudinal, male supplements 10–11, female tail short with sharp tip, male tail narrowly rounded.
By virtue of the short female tail,
E. remotus
sp. nov.
can be compared with
E. conicaudatus
from
Japan
and
E. shillongensis
from
India
. It differs from
E. conicaudatus
by the longer body (2.2–2.6 versus 1.7–2.0 mm), much narrower lip region (16–18 versus 22–25 µm wide), odontostyle longer than lip width (versus about as long as lip width), and by the very sharply pointed tail. The new species differs from
E. shillongensis
by the much narrower lip region (16–18 versus 23–25 µm wide), shorter odontostyle (19–21 versus 24–26 µm) and shorter tail (86 versus 125–132 µm).
Egtitus remotus
sp. nov.
can be differentiated from the other Papuan species as follows. From
E. neocyatholaimus
in having a shorter odontostyle (19–21 versus 22–24 µm), fewer supplements (10–11 versus 12–13) and a much shorter female tail (2.6 versus 8.0 anal body diameters); from
E. biformis
sp. nov.
in having a shorter odontostyle (19–21 versus 25–26 µm) and a shorter tail (2.6 versus 6–7 anal body diameters); from
E. longicaudatus
sp. nov.
by the much shorter female tail (86 versus 380 µm).
Type specimens
Holotype
female on slide no. 13000.
Paratypes
:
four males
.
All
in the collection of the
Department of Systematic Zoology
of the
ELTE
University
,
Budapest
.
Type habitat and locality
Moss growing on the trunk of a
Podocarpus
sp.
, Kambugomambuno, Mount Wilhelm,
Papua New Guinea
; collected in
August 1968
by J. Balogh and I. Loksa.
Etymology
Latin
remotus
=
remote, concerning the distant Far Eastern occurrence of this species.