Two new trematode species from freshwater fishes of Peninsular ...

P8l'88it. hung. 17. 1984
Two new trematode species from freshwater fishes
of Peninsular Malaysia
Dr. Susan LIM LEE BONG· -
Dr. Juan I. FURTADO
University Malaya, Lembah Pantai, Kuala Lumpur, Malay8ia
"Two new trematode species from freshwater fishe s of Peninsular Malaysia" -
Lim Lee Hong, S. - Furtado, J.I. - Parasit. "hung., !2.. 37-44.1984.
ABSTRACT. Two new species of trematodes have been obtained from four species
of freshwater fishe s -in Peninsular Malaysia. They are He lostornatis cypri­
~ sp. n. from Labiobarbus festiva and Osteochilus melanopleura and Singhia
kruinensis sp. n. from Notopterus chitala and N. notopterus.
KEY WORDS. Trematoda, Helostomatis cyprinorum sp. n., Singhia kruinensis
sp.n., freshwater fishe s, ecology, Peninsular Malaysia.
INTRODUCTION
There are at present only two recorded species of freshwater fish trematodes from Peninsular
Malaysia: Orientocreadium batrachoides Tubangui, 1931 (Furtado et Lau 1968) and Transversotrema
patialense Soparkar, 1924 (Betterton 1979). These two new species will thus increase
the number of recorded species of trematode to four. Two other trematode species, a
Phyllodistomum species and a Haplorchoides species, were collected from Mystus nemurus
(Bagridae); but due to the low number of specimens collected, these two species will not be
described until more specimens are be obtained.
MA TERIALS AND METHODS
The host species of the two new species were obtained from Tasek Bera, a freshwater inundated
swamp forest in Peninsular Malaysia. The parasites collected were treated for whole
mount morphological studies: they were flattened between a glass slide and coverslip or two
glass slides depending on the size of the trematodes, fixed in Bouin's solution, stored in 70%
alcohol and stained in the laboratory following procedures recommended by FERNANDO et al.
(1972).
AU the measurements are given in millimeter (mm.), with the averages followed by the ranges
in parentheses.
Description
Helostomatis cyprinorum sp. n. (Paramphistomidae) (Fig. 1).
Hosts: Labiobarbus festiva (Heckel) (Cyprinidae) (Type host)
Osteochilus melanopleura (Bleeker) (Cyprinidae)
·Part of the preparation of this report was done by the senior author during her visit to Hungary
in 1979.
37

Locality: Tasek Bera, Pahang.
No. of specimens studied: 10 specimens from L. festiva and 5 specimens from O. melanopleura.
Type specimens: Holotype (UMT 1) and pa ratypes (UMT 1 et 2) are deposited in the Department
of Zoology, University of Malaya, Kuala Lumpur.
Body oval to elliptical, ends bluntly rounded with posterior slightly broade r than the ante rior,
length 1.88 (1.58-2.04) and width 1. 09 (0.89-1.28). Cuticle smooth, without spines. Pha rynx
terminal surrounding mouth, length 0.20 (0.14-0.27) and width 0.20 (0.11-0.21). Acetabuium
posterior, subterminal, larger than oral sucker, length 0.44 (0.35-0.60). width 0.46 (0.29-
0.64). Oe sophagus; length 0.29 (0.21-0.43), width 0.07 (0.05-0.08). On either side of prepharynx
short, stout muscular primary pharyngeal sacs, length 0.24 (0.18-0.27), width 0.08
(0.04-0.11). Extending from the primary pharyngeal sacs blind convoluted diverticular
pouches, length 0.42 (0.32-0.53). width 0.27 (0.21-0.35). filling the space between prepharynx
and esophageal bulb. Esophageal bulb elongated, transversely striated, length 0.50
(0.48-0.53), width 0.14 (0.13-0.16). Intestinal bifurcation beginning at a distance of 0.67
(0.56-0.78) from anterior end. Caeca continuing late rally then posteriorly, resulting in the
caeca having a 3-shaped configuration. Caeca terminate about 0.34 (0.21-0.64) above posterior
end.
Two oval-lobulate testes, situated at 0.96 (0.85-1.01) from anterior, in pre-ovarian field.
Vas efferens not distinct. Single vas deferens opening into cirrus sac just before bifurcation
of intestine. Large cirrus sac situated between genital sucker and bifurcation of inte stine,
length 0. 18 (0.16-0.19), width 0.07 (0.04-0.10). Seminal vesic1e internal and convoluted.
Glandular cells of pars prostatica observed just before gen ital opening. Cirrus opening into
common genital atrium.
Ovary ovoid, situated medially between testes and acetabulum, in posterior one-third of body,
length 0.07 (0.05-0.15), width 0.08 (0.05-0.19). Ootype extending latero-posteriorly, Laurer'
s canal small. Mehlis' gland not distinct. Follicular vitellaria lateral, extracaecal with
vitelline ducts entering ootype laterally. Coiled uterus extending anteriorly in intercaecal
field, ending in an enlarged metraterm which opens into the genital atrium. Eggs embryonated
length 0.13 (0.11-0.14), width 0.07 (0.06-0.08).
Differential diagnosis
This newly described species belon gs to the genus Helostomatis (Fukui 1929) Travassos,1934
(Family: Paramphistomatidae Fischoeder, 1901; subfamily Helostomatinae Skrjabin, 1949).
Hitherto there had been only three species described for this genus: Helostomatis helostoma_
tis (MacCallum 1905) Travassos 1934 from Helostoma temmincki (Sumatra). H. sakrei Bhalerao,
1937 from Labeo calbasu (India) and H. cirrhini Gupta and Kumari, 1970 from Cirrhina
mrigala (India). All these species are parasites of the alimentary system of cyprinids
in the Oriental zoogeographical region.
The present species differs from H. helostomatis in having larger diverticular pouches and
3 -shaped caeca. The 3 -shaped caecal arrangement (after bifurcation caeca curving sinuously
giving a 3 -shaped structure) is recorded in all the specimen s studied. H. sakrei is different
from the present species in having trilobed ovary, straight caeca and smaller diverticular
pouches. H. cirrhini is diffic,ult to analyse because of its incomplete description which is
without drawing (since the description given is only a resumé) (GUPTA end KUMARI 1970"
however it differs from the present new species in the caeca terminating at the level of the
ovary, the testes being diagonal, and the shape of the ovary which is presumably trilobed.
Gupta and Kumari (1970) reported that there is no genital sucker in H. sakrei from Labeo
dero but only a gen ital atrium lined with sphincter muscles.
Based on these differences the present species is considered a new species, and iE. named
Helostomatis cyprinorum because of its occurrence in cyprinid fishes.
38

0.0
O.S
Fig. 1: Composite illustration of Helostomatis cyprinorum sp. n.
39

.The specimens obtained from O. melanopleura are larger and the caecal configuration less
3 -shaped. This may possibly be due to the relaxed state of the worm, however the measurements
obtained for the other features showed that this is not so. Since the Helostomatis species
in both cases are mature specimens, the age of the worm is eliminated as a possible
cause of variation. The differences in size may be due to adaptation to different microenvironment,
especially since Osteochilus melanopleura is a comparatively much larger fish
than Labiobarbus festiva. Except for these differences, the Helostomatis species collected
from O. melanopleura is very similar to those found in L. festiva, and is considered the
same species as Helostomatis cyprinorum sp. n .
Amendments to the genus Helostomatis (Fukui, 1929) Travassos, 1934.
The gene ric (Helostomatis) and subfamilial (Helostomatinae Skrjabin, 1949) characteristics
should be amended in the light of the discovery of the new species, because a few characteristic
s are que stionab1e mo rphologically:
(1) The description of the acetabuium being "wider than posterior end of bOGy proper, with
its aperture drawn out late rally and curved backward" (Y AMAGUTI. 1971 p . 47) should be
deleted because this is not a gene ric characteristics, but rather a specific characteristics
of H. helostomatis, since this feature is not observed in any of the recorded species of
the genus (se e H. sakrei Bhalerao, 1937; H. cirrhini Gupta and Kumari, 1970; and present
species) .
(2) "Oral sucker with long diverticles in the forrn of claviforrn appendages" should be altered.
MacCALLUM (1905) describing the first species mentioned that' each side of the prepharynx
gives off a short muscular tube with circular and radial musc1e fibres and many
glands cella which extend into a blind convoluted sac lying on each side be side the pharynx'
though he did reve rt back now and then to the fact that lateral pouches arose from the
'mouth suckers'. BHALERAO (1937) described it similarly but GUPTA and KUMARI (1970)
described the' pharyngeal sac' or diverticular pouches as arising from' pharynx' (GUP­
TA and KUMARI.1970). The amendment should thus be "large or sman diverticular present,
arising from prepharynx, divided into 2 parts: diverticular lobes and pouches".
(3) Testes of Helostomatis species are not wholly subsymmetrical or symmetrical, therefore
it should be amended as "Testes sub-symmetrical or symmetrica1" or 'Testes variable'.
(4) GUPTA and KUMARI (1970) suggested that there is a genital-sucker surrounding the genital
pore, and that the genital atrium is surrounded by a loose genital sphincter and lined
by genital atrial radial musc1es. However, in H . cyprinorum n. sp. the gen ital atrial
structure is quite distinctly that of a sucker. In order to confirm or refute GUPTA and
KUMARI' s observations, their material needs re-examination and more histological studies
using various microtechniques are required. Until this genital structure is further
studied, the description that' gen ital sucker present' still stands.
Singhia kruinensis sp. n. (Echinostomatidae) (Figure 2)
Host: Notopterus ch itala (Hamilton) (Notopteridae) (Type-host) and N. notopterus (Pallas)
Microhabitat: Intestine
N o. of specimens studied: 6 from N. chitala and 5 from N. notopterus.
Type specimens: Holotype (UMT2) and paratypes (UMT3 and UMT4) deposited in the Department
of Zoology, University of Malaya.
Body nearly spatulate. length 11.64 (10.40-13.20). width l. 71 (l. 32-1.91). Head collar
large, length 0.3B (0.81-1.02). width 1.73 (1.48-1.91), wen constricted from budy, with continuous
row of conical spines. These collar spines can be divided into 3 group S depending on the
position on the collar, viz. corner (C). lateral (L) and median spines (M). Number of spines
varying from 29 to 31 but corner spines and lateral spines are constant, always 4 and 8.
Paired eyelike structure on either side of collar, of size 0.08 (0.03-0.11) x 0.07 (0.03-0.10),
with tubular structure extending posteriorly, possibly an excretory system. Body spinulated,
40

OOO
!
:i
o O~
0.10 A
Fig. 2: Composite illustration of Singhia kruinensis sp. n. (A). Egg of S. kruinensis sp. n. (B)
41

spines extending from neck posteriorly tilI 3/4 of body for distance of 9.71 (9.08-10.80); distance
between spines increasing with distance from anterior, varying between 0.01 to 0.02.
Sizes of spines ranging from 0.01 to 0.04 (increasing in size posteriorly). about 132-135 rows
of spines .present.
Oral sucker terminal to subterminal, slightly inverted-triangular shape, length 0.22 (0.15-
0.27), width 0.38 (0.32-0.46). Acetabuium immediately posterior to gonopore, situated ventrally
at 2.08 (1. 89 -2. 44) from anterior, length 0. 38 (0.37-0.39), width 0.38 (0.3 5-0. 43),
larger than oral sucker. Terminal to subterminal mouth surrounded by oral sucker. Prepharynx
at 0.38 (0.37-0.39) from anterior, length 0.37 (0.21-0.56) width 0.05 (0.04-0.05).
Pharynx muscular, at 0.54 (0.33-0.81) from anterior length 0.23 (0.19-0.26). width 0.19
(0.17-0.21). Esophagus, at 0.79 (0.61-1. 06) distance from anterior. Intestina l bifurcation
beginning at 1.80 (1. 62-2.11) from anterior, terminating at 0.86 (0.53-1. 22) .
Two testes in tandem, situated at 1.44 (1.08-1. 91) and 2.15 (1. 60-2. 54). from posterior end,
respectively, distance between testes 0.20 (0.05-0.34). Vas efferens joining medially, forming
vas defe rens, in preovarian fie1d. Large cirrus sac, at 1.88 (1.71 -2. 19) from anterior,
length O. 37 (0.32 -O. 45), width O. 31 (0.27 -0.32), enc10sing a con vo1uted seminal vesicle, a
striated and spined cirrus and prostrate glands. Terminal genitalia large, with single gonopore
and sphincter muscle, into which cirrus and metraterm enter.
Single spherical ovary, smaller than either testes, length 0.28 (0.21-0.35). width 0.33 (0.23-
0.42). in pretesticu1ar field. Mehlis' gland compact, posterior to ovary. Ootype observed.
Laurer' s cana1 not observed. Two vitelline ducts draining into vitelline reservoir, 1atter
connected to a slightly coiled ootype. ViteHaria follicle-like mainly extracaecal. Uterus extending
anteriorly, in transverse coils, in intercaecal and pretesticular field, opening into
metraterm, which itself opens into common gonopore. Eggs fully embryonated, length 0.10
(0.08-0.11). width 0.05 (0.04-0.06).
Differential diagnosis
This newly described trematode belon gs to the genus Singhia, Yamaguti 1958. There is only
one other species from this genus, S. thapari (Singh, 1953) Yamaguti, 1968 which differs
from the present forms in
(l) the dia gonal arrangement of the two testes (tandem in present species)
(2) a pair of corner spines on each side of collar compared to four in the present species,
(3) extent of body spines to midbody (which is weH beyond midbody in present species),
(4) position of ovary at level with anterior testes.
Based on these differences the present species is considered new and the propo sed name for
this is Singhia kruinensis sp. n. after the locality Tanjong Kruin in Tasek Bera.
Five similar specimens have also been obtained from a related host Notopterus notopterus,
except that they are about half the size of the specimens from N. chitala. The difference in
size may be due to the age of the worms since none of the specimens from N. notopterus possessed
eggs, or to specific host differences (see Discussion).
Amendments to genus Singhia Yamaguti, 1958
The genus Singhia Yamaguti, 1958, as amended by YAMAGUTI (1971) is inadequate to accommodate
S. kruinensis n. sp. because of the features (given above) which distinguish S.
thapari from the present species (see YAMAGUTI, 1971 pp. 209). -
Therefore, the genus Singhia Yamaguti, 1958 (as given in Yamaguti 1971, pp. 209) is amended
with the following additions:
(l) Head collar constricted from body proper, bears dorsally a single almost uninterrupted
row of spines of various sizes, with end group spines of 2 -4 each.
,
42

(2) Testes diagonal or in tandem, in posterior 1/3 of body
(3) Armed or unarmed cirrus
(4) Ovary median to well below submedian, pretesticular, occasionally (or not at aIl) level
with anterior testes.
Since S. thapari (Singh, 1953) Yamaguti, 1958, has been de scribed basal on only two specimens,
it is possible that many features and, certainly specific and gene ric variation have not
been weIl studied. It is probable that S. kruinensis n . sp. is related to S. thapari sinc e they
are from the same host species. However, the present species is presently considered as
distinct on the basis of the above features, and biogeographic differences of the two localities.
DISCUSSION
The present new species constitute the first records of the genera Helostomatis and Singhia
in Peninsular Malaysia. These two new species together with the two undescribed trematode
species (PhyIlodistomum and Haplorchoides) represent the total number of species of trematodes
collected over a period of two years (1976-1978) in Tasek Bera, indicating a pauc it y of
trematodes in that habitat. This may be due to the relatively low mollusc populatio n there,
(the usual intermediate hosts of trematodes), as a result of the low calcium content in the
waters (LIM, 1976).
These trematodes are identified only on the basis of their adult morphology which may possess
variations due either to polymorphism and/or fixation and staining procedures. From
this arises the issue of species validity and biological distinctness; this issue is especially
important in the case of trematodes which are usually not very hóst-specific (i. e. in terms
of their final piscine host). Since polymorphism may be environmentally induced as by different
host species (SHEPPARD, 1958), the H. cyprinorum sp. n. from L. festiva and O.
melanopleura are possibly polymorphs since they are probably from the same cercarial population
as are the ~}linensis n. sp. from N. chitala and N. notopterus; however this issue
of polymorphism meeds experimental verification. Also, even though S. kruinensis sp. n.
appears to be a fairly distinct species on the basis of the differentiation criteria currently in
use, its relationships with S. thapari (Singh 1953) Yamaguti, 1958, within a geographical polytypic
species or gene ric complex is wor.thwhile further investigation.
Parasites can be useful indicators of biological and/or ecological relationships (A UDY, 1960).
Their ability to function as biological indicators is due to their specific ecological requirements.
For example, the presence of trematodes indicates the presence of specific groups of
organisms serving as intermediate and final hosts, as in the projected presence of mollusc
in Tasek Bera in spite of its low calcium content (LIM, 1976). Trematodes can also indicate
different behavioural patterns, habitat .requirements, and food habits: according to YAMA­
GUTI (1979) echinostomatids' life-cycle requires insects as the intermediate hóst; S. kruinensis
sp. n. is associated with insectivorous -carnivorous fish (N. chitala and N. notopteruS).
Similarly Helostomatis species indicates a herbivorous host (see YAMAGUTI 1979p. 15-16)
as is the case of L. festiva and O. melanopleura, while PhyIlodistomum species possibly indicates
the presence of a cosmopolitan molluscan host, and/or a similar urinary system
among the fishes, since they are found in a wide variety of fish species (see FOTEDAR, 1969)
and they do not required a sec ond intermediate hosts (see YAMAGUTI 1979, p. 15-16).
ACKNOWLEDGEMENTS
This work has been made possible by a tutorship award in Zoology to one of us (L.H.S. LIM),
VOTE F. research grant s by the University of Malaya to us (L.H.S. LIM and J.!. FURTADO),
by the typographical assistance of Mrs. S. WONG and by the cooperation of the Semalai people
at Tasek Bera especially NONEK and his family, and the Department of Aboriginal Affairs.
43

LIM LEE BONG, S. - FURTADO, J. 1.: Két új mételyfaj a
Maláj-félszigeti édesvizi halakból
Maláj -félszigeti édesvizi halak parazitológiai vizsgálata során a sze rz6k két, a tudományra
nézve uj mételyfajt találtak. Az uj fajok, a Holostomatis cyprinorum sp. n. (Paramphistomidae)
és a Singhia kruinensis sp. n. (Echinostomatidae) leirását a genusok jellemzése és a
fajok el6fordulására vonatkozó ökológiai m egfigyelések tárgyalása egésziti ki.
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- Unpublished M. Sc. thesis, University of Malaya, Kuala Lumpur, pp. 114.
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Abt. Syst., ~(6): 667-678.
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Received 25 May, 1984
Dr. LIM LEE HONG, S.
Dr. FURTADO. J. I.
University Malaya
Lembah Pantai, Kuala Lumpur,
MALAYSIA
44