Revision of the genus Chordodes (Gordiida, Nematomorpha) from Africa-III: ultrastructural redescription of Chordodes capensis Camerano, 1895, C. clavatus Linstow, 1906, C. digitatus Linstow, 1901, C. tuberculatus Linstow, 1901, and reinterpretation of C. ibembensis Sciacchitano, 1958 and C. uncinatus Sciacchitano, 1958
Author
De Villalobos, Cristina
Author
Zanca, Fernanda
Author
Schmidt‐Rhaesa, Andreas
text
Journal of Natural History
2007
2007-12-31
41
45 - 48
2775
2788
http://dx.doi.org/10.1080/00222930701754855
journal article
10.1080/00222930701754855
1464-5262
5233552
Chordodes digitatus
Linstow, 1901
(
Figures 4
,
5
)
Chordodes digitatus
Linstow 1901
, p 417
, Figure 18.
Material
Holotype
: 1
„
,
Tanzania
,
Unyika
plateau (
ZMB
Vermes 4017)
.
Paratypes
:
2♀♀
, from type locality (
ZMB
Vermes 4017a)
.
Figure 4.
Chordodes digitatus
, holotype, SEM male posterior end. (A) View of the cloacal opening (c) lying on the central cuticular protuberance and surrounded by circumcloacal spines. Lateral to the cloacal opening are two rows of bristles (the bristlefield, arrow); (B) detail of the posterior end. Scale bars: 50 mm (A); 20 mm (B).
Material examined.
Holotype
and
paratypes
, SEM midbody.
Holotype
, SEM posterior end.
Host
Unknown.
Description
The body colour of the male is dark brown. The body length is
110 mm
and
0.5 mm
in diameter. The anterior end is tapered and a dark collar is lacking. The posterior end is undivided and has a median ventral groove (
Figure 4A
). The cloacal opening lies on a central cuticular protuberance and is situated ventrally at about
210 mm
from the posterior margin of the animal. The cloacal opening is oval (
32.4 mm
in length) and surrounded by circumcloacal spines. These spines are about
12.7 mm
long and unbranched. Lateral to the cloacal opening are two straight rows of bristles (
Figure 4A, B
). They reach up to
79 mm
in length. Around the cloacal opening, the cuticle is smooth and contains scattered small bristles spreading over the ventral side (
Figure 4A
).
The cuticle of the male contains five areolar
types
. Simple areoles are the most abundant, they are rounded or oval in shape, low (
6.5 mm
), and have a smooth surface. Irregular minute projections are distributed on the apical surface (
Figure 5A
). Among these are scattered areoles with the same shape but with a tubercle on top (tubercle areoles). The tubercle is about
4.5 mm
long. Another
type
of areole has a solid spine (thorn) on top (thorn areoles). The thorn is longer than the tubercles (
7.6 mm
) and originates in an eccentric depression in the areole, which is round or horseshoe-like in shape (
Figure 5A, B
). Clusters of 11–13 of circumcluster areoles (
8.6–9.5 mm
high) with short filaments on the apex surround three crowned areoles (
Figure 5B
). Crowned areoles (
9.6–10.5 mm
high) have extremely short apical filaments. The interareolar furrow is wide (
2.7–6.4 mm
) and structured into cord-like ridges.
Figure 5.
Chordodes digitatus
. (A, B) SEM male midbody cuticle: (A) cuticle with simple (1), tubercle (2) and thorn areoles; (B) midbody cuticle showing thorn areole (3) and clusters of crowned areoles (4) surrounded by circumcluster areoles (5). (C) SEM of female longitudinal ventral groove: thorn areole (3) and crowned areoles with long filaments (6). Scale bars: 10 mm.
The female body length varies between 120 and
140 mm
, the diameter varies between 0.4 and
0.8 mm
. The anterior end is tapered, a white tip or dark collar are not present. The body colour is brown.
The cuticle contains the same
five types
of areoles as in the male, but on both sides along the ventral midline there is another
type
of crowned areole (
Figure 5C
). These crowned areoles have a crown of long filaments (
78.1 mm
) on top and occur in clusters of three and are surrounded by 9–10 circumcluster areoles.
Comments
In the original description of
Chordodes digitatus
,
Linstow (1901)
provided measurements of the specimens without specifying to which sex each corresponded.
Camerano (1915)
mentioned this fact, noting the importance of this information. The present information by SEM reveal that the
type
specimens of
C. digitatus
correspond to
one male
and
two females
.
Linstow (1901)
described the cuticle of
C. digitatus
with three areolar
types
:
types
1 and 2 correspond to the simple and tubercle areoles, respectively, in the present reinvestigation. The areoles described by
Linstow (1901)
as
type
3 are considered to correspond to circumcluster and crowned areoles.