Comparative Parasitology 67(1) 2000 - Peru State College

90 COMPARATIVE PARASITOLOGY, 67(1), JANUARY 2000
Table 2. Measurements (in micrometers; mean with range in parentheses; n = number of structures
measured) of Sciadicleithrum splendidae Kritsky, Vidal-Martinez, and Rodriguez-Canul, 1994, from 3
species of cichlid fishes from 4 localities (Chiapas, Tabasco, Yucatan, and Quintana Roo) from southeastern
Mexico.
Body length
Pharynx width
Ventral hamuli length
Ventral hamuli width
Dorsal hamuli length
Dorsal hamuli width
Ventral bar length
Dorsal bar length
Hooks
MCOI length
Accessory piece length
Petenia
splendida*
250
20
32
17
40
14
39
37
(15-16)
31 (27-35)
22
n
1
1
1
1
1
1
2
2
6
2
1
Cichlasoma
friedrichstahlrf
621 (406-690)
35 (24-43)
38 (36-38)
16 (15-18)
42 (39-44)
12 (10-14)
50 (42-53)
41 (37-48)
15 (15-16)
44 (42-50)
38 (30-45)
n
8
8
16
16
16
15
8
8
8
9
8
* Original descriptions of S. splendidae by Kritsky et al. (1994).
t Dzaptiin Cenote, Yucatan.
t Cedros River, Chiapas.
§ Mahahual, Quintana Roo.
|| Santa Gertrudis, Tabasco.
1 Male copulatory organ.
In addition, this study expanded the spectrum
of fish hosts of individual Sciadicleithrum taxa
found in southeastern Mexico and Guatemala by
13 new host records. Each of the 4 species of
Sciadicleithrum found in this area exhibits relatively
wide host specificity in the same family,
since they occur in as many as 8 cichlid species
(5. bravohollisae in C. geddesi, C. lentiginosum,
C. managuense, C. pearsei, C. salvini, C. synspilum,
P. splendida, and Cichlasoma sp.).
Three species of Sciadicleithrum found in Yucatan
occur even in members of 2 closely related
genera, Cichlasoma and Petenia. It is also noteworthy
that both P. splendida and C. managuense
from southeastern Mexico harbor as
many as 3 species of Sciadicleithrum, namely,
S. bravohollisae, S. mexicanum, and S. splendi
dae\d S. bravohollisae, S. splendidae, and S
meekii, respectively. In the Terminos Lagoon
(stations El Viento and Santa Gertrudis), 3 species
of Sciadicleithrum (S. bravohollisae, S.
meekii, and S. splendidae) occurred, and all
these species are found on C. managuense. It
can be assumed that horizontal transmission of
these monogeneans to this cichlid occurred in
this locality, with C. helleri probably serving as
a source of S. meeki, and C. pearsei of S. bravohollisae.
Sciadicleithrum splendidae was
Cichlasoma
friedrichstahlij.
—
19 (17-24)
31 (29-34)
14 (12-16)
37 (33-39)
12 (12-14)
38 (36-43)
30 (26-35)
15 (15-16)
40 (31-49)
34 (29-36)
Cichlasoma
friedrichstahn
//§
0
2
22
20
16
10
15
14
26
20
12
Copyright © 2011, The Helminthological Society of Washington
19 (17-20)
29 (22-31)
12 (12-13)
36 (36-37)
13
41 (40-41)
32 (30-33)
16 (15-17)
36 (29-39)
29 (20-39)
n
0
8
6
4
4
2
3
3
13
7
6
Cichlasoma
motaguense\\1
(18-24)
31 (30-32)
16
38 (33-41)
14 (14-15)
43 (40-46)
32 (31-32)
16 (15-17)
38 (27-51)
32 (24-47)
found only on C. managuense at this locality
and may represent the original host of S. splendidae.
This study has also provided new data on intraspecific
variability of Sciadicleithrum species
from a wide spectrum of fish hosts and geographical
regions. It is obvious that the knowledge
of intraspecific morphological and biometrical
variation is necessary to prevent descriptions
of new taxa based only on slight morphological
differences. This is important if the
original descriptions were based on limited numbers
of specimens, as in the case of S. splendidae
(Kritsky et al., 1994).
A species of Sciadicleithrum, S. mexicanum,
is reported from Guatemala for the first time in
this study. However, the occurrence of other
Sciadicleithrum taxa in Guatemala is highly
probable, and we suggest that more studies on
the helminth parasites of freshwater in that
country and Central America in general be carried
out. Investigations into fish helminths, including
gill monogeneans, are therefore needed
for a better understanding of the evolution of
these parasites and their hosts in the transient
area between the Nearctic and Neotropical zoogeographical
regions.
n
0
4
3
1
4
2
3
2
6
4
3