New species of Raphidascaris (Sprentascaris) (Nematoda: Anisakidae) in Rineloricaria steinbachi (Actinopterygii: Loricariidae) from Northwest Argentina
Author
Ailán-Choke, Lorena Gisela
Author
Ramallo, Geraldine
Author
Davies, Dora
text
Zootaxa
2017
4231
1
129
136
journal article
37068
10.11646/zootaxa.4231.1.10
b9f12d8b-b4f5-47e6-9134-b24e93ea6d94
1175-5326
293599
8D663345-A7C6-4249-86E2-C79FE6D985C6
Raphidascaris
(
Sprentascaris
)
saltaensis
sp. nov.
(
Figs 1–2
)
Type material.
Holotype: female CH-FML # 07663; paratypes: eight males and five females, of which nine specimens were used for SEM, CH-FML # 0 7665.
Type
host.
Rineloricaria steinbachi
Regan
, (
Siluriformes
:
Loricariidae
) (IBIGEO-I # 355–422).
Type
locality.
La Caldera
River
(
24°35´40.07”S
;
65°22´11”W
),
La Caldera Department
, province of
Salta
, Northwest
Argentina
.
Etymology.
The new species is named for its geographical location in the province of
Salta
.
Site of infection.
Intestine.
Infection parameters.
Prevalence: 11.94% (8/67); media intensity: 2.63 per fish.
Measurements.
Table 1
.
General description.
Medium sized nematodes. Cuticle bearing transverse striations. Mouth aperture triangular, two ventrolateral lips and one dorsal lip. Lips well-developed and oval-shaped; dorsal lip slightly smaller than the two ventrolateral ones. Dorsal lip bearing two double papillae, ventrolateral lips with one double papilla, one single papilla and one amphid. Lips with lateral membranous margins forming finger-shaped protrusions at each side. Membranous extensions at base of lips. Interlabia absent (
Figs. 1
A–C; 2A–C). Excretory pore slightly posterior to nerve ring level. Lateral alae present in both sexes, beginning in lateral region below lips and reaching almost to tail tip. Muscular oesophagus short with expanded posterior half. Caudal alae absent in both sexes. Ventriculus shorter than wide, ventricular appendix longer than wide. Both sexes with conical tail, its distal tip slender and sharply pointed.
Adult males (eight specimens): Spicules equal, simple with pointed distal tips. Twenty pairs of caudal papillae. Preanal papillae: Sixteen subventral pairs; counting from cloaca opening, the first until the seventh pair are closer to each other than the remaining pairs. Adanal papillae: only one subventral pair. Postanal papillae: three small subventral pairs. Lateral alae present, without the partition in the caudal region. Caudal alae absent. Conical tail (
Fig. 1
G).
Adult female (six specimens): Vulva preequatorial, posterior to oesophagus end level (
Fig. 1
E). Eggs ovalshaped, with thick and rough shell provided with membranous striations, mature eggs larvated (
Figs. 1
D). Conical tail (
Figs. 1
F; 2D).
FIGURE 1.
Raphidascaris
(
Sprentascaris
)
saltaensis
sp. nov
.
(A) Female, anterior end, lateral view. (B) Male, apical view. (C) Female, head, lateral view. (D) Mature and larvated egg. (E) Female, vulva, lateral view. (F) Female, tail, lateral view. (G) Male, posterior end with spicules and papillae, ventral view.
FIGURE 2.
Raphidascaris
(
Sprentascaris
)
saltaensis
sp. nov.
(SEM micrographs) (A) Male, cephalic end. Lateral alae (black arrow), membranous elevations below lips (discontinuous black arrow). (B) Anterior end of female, dorsal view. Lips with lateral membranous margins forming finger-shaped protrusions at each side (black arrow). (C) Cephalic end of male, apical view. Subdorsal double papillae (black arrow), single papillae (white arrow), amphids (discontinuous black arrow). (D) Female, posterior end, sublateral view. Anus (black arrow), lateral alae (discontinuous black arrow).
Remarks.
Raphidascaris
(
Sprentascaris
)
saltaensis
sp. nov.
is distinguished from their congeners, by possessing 16 pairs of preanal papillae, membranous elevations below the lips, mature eggs with striated shell and the size of spicules (
0.24 mm
). For more detailed description of morphometric differences between the new species and other species of
Raphidascaris
(
Sprentascaris
)
see Table 2.
Raphidascaris
(
S.
)
saltaensis
sp. nov
.
differs from
R
. (
S
.)
mahnerti
and
R.
(
S.
)
lanfrediae
by the absence of caudal alae in the males; but shares this feature with
R.
(
S.
)
pimelodi
,
R.
(
S.
)
hypostomi
and
R.
(
S.
)
marano
. The new species presents lateral alae, which begins in the base of ventrolateral lips and extends almost to tail tip; no partition of this structure is observed, hence caudal alae are not present.
Raphidascaris
(
S.
)
saltaensis
sp. nov
differs from
R.
(
S.
)
pimelodi
and
R.
(S.)
hypostomi
by the presence of lateral alae, and by the number of postanal papillae pairs;
R.
(
S.
)
saltaensis
possess three pairs, while
R.
(
S.
)
pimelodi
and
R.
(
S.
)
hypostomi
present five pairs and lack lateral alae (
Moravec 1998
).
TABLE 1.
Measurements of
Raphidascaris
(
Sprentascaris
)
saltaensis
sp. nov.
Given in mm, mean ± SD (range). (* measurements with a unique value).
| Character |
Holotype |
Paratypes |
| ♀ 1 |
♀ 5 |
♂ 8 |
| Total body length |
6.86 |
6.59±1.37 (5.62–7.56) |
5.65±0.32 (5.12–5.92) |
| Body width |
0.57 |
0.58±0.06 (0.54–0.63) |
0.46±0.15 (0.28–0.67) |
| Lateral alae width |
0.01 |
0.02* |
0.02±0.02 (0.01–0.04) |
| Lips length |
0.06 |
0.05±0.02 (0.04–0.06) |
0.06±0.00 (0.06–0.07) |
| Oesophagus total length |
0.75 |
0.92±0.25 (0.71–1.27) |
0.79±0.09 (0.63–0.88) |
| Oesophagus total width |
0.30 |
0.36±0.06 (0.30–0.43) |
0.22±0.06 (0.14–0.34) |
| Nerve ring—anterior end |
0.29 |
0.37±0.08 (0.32–0.43) |
0.34±0.03 (0.29–0.37) |
| Excretory pore—anterior end |
0.36 |
0.45±0.02 (0.44–0.47) |
0.40±0.05 (0.32–0.47) |
| Ventriculus length |
0.05 |
0.07* |
0.06±0.01 (0.06–0.07) |
| Ventriculus width |
0.13 |
0.13* |
0.19±0.06 (0.15–0.24) |
| Ventricular appendix length |
0.16 |
0.10* |
0.14±0.06 (0.10–0.19) |
| Ventricular appendix width |
0.06 |
0.04* |
0.05±0.00 (0.04–0.05) |
| Ventricular appendix/ oesophagus length ratio |
1: 0.21 |
1:0.13* |
1:0.21 (1:0.12–0.3) |
| Vulva—anterior end |
1.20 |
1.74* |
- |
| Spicules length |
- |
- |
0.24±0.02 (0.22–0.27) |
| Tail length |
0.37 |
0.30±0.13 (0.15–0.39) |
0.25±0.02 (0.22–0.27) |
| Eggs length |
0.07 |
0.06±0.02 (0.04–0.09) |
- |
| Eggs width |
0.04 |
0.03±0.01 (0.03–0.04) |
- |
Raphidascaris
(
S.
)
saltaensis
sp. nov
.
resembles
R.
(
S.
)
marano
, both species have lateral alae and three pairs of postanal papillae; but can readily be distinguished by the number of preanal papillae (16 vs. 22), the shape and size of lips (smaller and different lips with protrusions vs. longer, symmetrical, simple and equal lips), shape of eggs (rough-shelled vs. thin-shelled) and the spicule length (0.24 vs. 0.27) (
Moravec 1998
;
Ramallo 2009
).
Discussion.
Five genera of
Anisakidae
have been reported from the intestine of Neotropical freshwater fishes:
Goezia
(Zeder, 1800)
,
Hysterothylacium
(Ward and Magath, 1917)
,
Terranova
(Leiper and Atkinson, 1914)
,
Raphidascaroides
(Yamaguti, 1941)
and
Raphidascaris
(Railliet and Henry, 1915)
.
Goezia
,
Hysterothylacium
and
Raphidascaris
show a broad geographical distribution including Mexico, Guyana, Venezuela, Brazil, Paraguay, Peru and Argentina;
in contrast
Raphidascaroides
and
Terranova
were only recorded in
Brazil
and
Venezuela
(
Moravec 1998
).
Raphidascaris
has two subgenera:
Raphidascaris
(not in the
Neotropical region
), and
Sprentascaris
whose members are restricted to
South America
and were only reported in freshwater fishes (
Ramallo 2009
). Species of
Raphidascaris
(
Sprentascaris
)
are characterized by possessing a cuticular ring without spines, the presence of small postlabial or interlabial cuticular elevations, absence of true interlabia; the excretory pore slightly posterior to nerve ring level, a muscular oesophagus with ventriculus and ventricular appendix; and no intestinal caecum (
Moravec 1998
).
All species of
Raphidascaris
(
Sprentascaris
)
, except
R.
(
S.
)
lanfrediae
, have
Siluriformes
fishes as hosts.
Raphidascaris
(
S.
)
hypostomi
was isolated from specimens of the subfamilies: Hypostominae and
Ancistrinae
(all
Loricariidae
) (
Moravec 1998
).
Eiras
et al.
(2010)
found nematodes identified as
R.
(
S.
)
hypostomi
and
R.
(
S.
)
mahnerti
in
Metynnis lippincottianus
Cope
(
Characiformes
,
Serrasalmidae
) from
Brazil
.
Raphidascaris
(
S.
)
mahnerti
was also reported in
Loricariidae
fishes; moreover
Moravec
et al.
(1993)
recorded the third larval stage of
Raphidascaris
(
Sprentascaris
)
in the intestine of the cichlid
Geophagus brasiliensis
Quoy & Gaimard
, (
Perciformes
,
Cichlidae
). The larva is probably conspecific with
R.
(
S.
)
mahnerti
and
G. brasiliensis
could be a paratenic host (
Moravec 1998
). This is not the only time
Raphidascaris
(
Sprentascaris
)
was detected in cichlids; Melo
et al
. (2011) reported the adults of
R.
(
S.
)
lanfrediae
in
Satanoperca jurupari
. Possibly, this species share the host spectrum with
R.
(
S.
)
mahnerti
. Both species might be closely related but they can be differentiated by morphological features and their geographical distribution (Melo
et al
. 2011).
Raphidascaris
(
S.
)
pimelodi
is distinguished from other known species of the subgenus, because it was only detected in a pimelodid species.
Although
R.
(
S.
)
marano
and
Raphidascaris
(
S.
)
saltaensis
sp. nov.
have both been recorded in Northwest of
Argentina
, they inhabit different fluvial systems;
R.
(
S.
)
marano
in Marapa River
(basin of
Sali River
, provinces of
Tucumán
and
Catamarca
), and
R.
(
S
.)
saltaensis
sp. nov
.
in
La Caldera
River
(basin of the
Bermejo River
, province of
Salta
)
.
Ramallo (2009)
proposed that
R.
(
S.
)
marano
would be an endemic species in
Argentina
, following the endemic character of its host,
H. cordovae
(Loricariidae)
. However,
H. cordovae
is synonymous of
H. paranensis
, thus the geographical distribution was extended to include
Paraguay
(
Paraguay
River basin, the main tributary of
Paraná River
) (
Ferraris 2007
). The new parasite species was found from
Rineloricaria steinbachi
(Loricariidae)
, whose geographical distribution is limited to
southern Bolivia
and
northwestern Argentina
, including the basins of the Bermejo (Rivers Bermejo, San Andrés,
La Caldera
, Mojotoro and Vaqueros and streams Gallinato and Pucheta), Juramento (Rivers Salado, Piedras, Arias Arenales, Rosario, Aguas Negras and Calchaquí),
Pilcomayo River
, and also the
Dorado River
basin (
La Sala
stream and
Popayan River
).
In this paper, we propose the erection of the sixth species of
Raphidascaris
(
Sprentascaris
)
from the Neotropical region and the second from
Argentina
.
Raphidascaris
(
S.
)
saltaensis
sp. nov
.
differs from all congeners in the number of preanal papillae, the shape and size of lips, the egg’s shell and the spicules length. The new identification key presented in the article incorporates
R.
(
S.
)
lanfrediae
,
R.
(
S.
)
marano
and
R.
(
S.
)
saltaensis
sp. nov.