On a New Trematode Allocreadium Allocreadium gachuai Sp. Nov. of the Family Allocreadiidae Stossich, 1903 from the Intestine of FreshwaterFish of Jammu, India

Ranvijay Singh¹

¹Dean of Research Studies, Cluster University of Jammu, Jammu, J&K UT, India

Corresponding Author Email: ranvijaysingh172@gmail.com

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Introduction
A number of distinctly allocreadid trematode worms, were found parasitic in the intestines of channa gachua (Ham.) a murrel obtained from a sub- shivalik freshwater lake Mansar in Jammu. These worms were morphological different from all allocreadian species described from fishes in India and therefore, described here as a new species under the genus Allocreadium Allocreadium Looss, 1900, as A. A. gachuai. Materials and Methods The worms were washed in 0.1% saline to clean them of any attached debris before being fixed in acetic-formol-alcohol (1:1:3). Fixing was done on glass slide under cover slip to help flatten the worms in fixation. The fixed specimens were preserved in 70% alcohol for subsequent use. Staining was usually done with freshly fixed specimens with aceto-alum carmine (Gray, 1973) after washing and dehydrating the fixed material in ascending grades of ethanol, cleared in xylene and mounted in D.P.X. All measurements were recorded micrometrically from stained specimens only, given as a mean (with the range in parenthesis) and are in mm unless otherwise stated. Description: (Based on 30 randomly selected stained specimens, Fig. 1& 2). Body: Elongate, aspinose, 2.44 (1.35-3.66) long and 0.54 (0.32-0.75) wide at the widest part. Oral Sucker: Subterminal, facing ventrally, nearly globular, 0.24 (0.18-0.29) long and 0.24 (0.20 -0.29) wide. Prepharynx: Absent. Pharynx: Rounded and well developed, 0.08 (0.06- 0.11) in main diameter. Esophagus: Variable in development mostly indistinguishable (80% specimens), and 0.10 (0.30-0.23) long in about (20% specimens). Caeca: Long,reaching the hind 2 © 2022 Journal of e-Journal of e-Science Letters. All Rights Reserved. Ranvijay Singh., / Journal of e-Journal of e-Science Letters (2022) end of the body. Acetabulum: Pre-equatorially median,spherical in outline, 0.18 (0.12-0.23) x 0.19 (0.12 -0.27) Testes: Two, entire, subspherical to oval in outline and tandem, variable in position, the anterior testis predominantly equatorial in some worms found even pre-or post-equatorial in position; 0.22 (0.15-0.32) long and 0.21 (0.11 – 0.30) wide. The posterior testis in majority of worms postequatorial and equal to or bigger in size than anterior testis, 0.25 (0.17 – 0.38) long and 0.21 (0.11 – 0.32) wide. Cirrus sae: Pyriform median and lying obliquely between intestinalbifurcation and the acetabulum, 0.14 (0.08 – 0.23) long and 0.11 (0.06-0.2) wide. Vesicula seminalis: Unipartite, lies at the basal part of cirrus sac. Ovary: Oval to subspherical, pre-testicular but post-acetabular, nearer toacetabulum than the anterior testis, 0.16 (0.08-0.23) long and 0.15 (0.06 – 0.23) wide. Uterus: Short with only a few turns spread between genital pore and anterior testis. Metraterm: Indistinct. Genital pore: Positioned between intestinal bifurcation and acetabulum, slightly shifted from the median position to the right. Receptaculum seminis: Variable in shape placed between the ovary and anterior testis, 0.12 (0.06-0.18) long and 0.13 (0.06 – 0.21) wide. Vitelline follicles: Numerous, large, extending from ovary to the posterior end of the body, lateral in pre-testicular region covering the intestinal caeca and confluent in the post-testicular region of the worm. Eggs: Oval in shape, few in number and conspicuously large 118.5 (90-135)µ long and 83.25 (75- 105) µ wide. Excretory pore and vesicle not visible. Allocreadium Allocreadium gachuai n. sp. Type-host : Channa gachua type-locality : Mansar lake, Jammu and Kashmir, India. Site of infection : Intestine Type- material : Deposited in the museum of Department of Zoology, University of Jammu. Collector : Ranvijay Singh Discussion The worms under description have been assigned to the genus Allocreadium Looss, 1900 because of (i) a non-appendiculate oral sucker, (ii)a preacetabula post-furcal genital pore, (iii) pretesticulo post acetabula ovary. (iv) pre-testicular uterine coils and (v) vitellaria spread mostly in the hind body, extending only a little into the forebody but no further cephalad of the ovary. Of the 3 subgenera Allocreadium Allocreadium, A. Allocreadiodes and A. Neoallocreadium recognized by Yamaguti (1971) under the genus Allocreadium, the worms described above apparently belong to the subgenus Allocreadium Allocreadium Yamaguti (1971), because of the confinement of uterus to the pre-testicular region, vitellaria to the hindbody and cirrus pouch to pre-acetabular region dorsally. Under Allocreadium Allocreadium Yamaguti (1971) has listed 27 species from different fish species world over, of which 15 are reportedly parasitic in the gut of some freshwater fishes of India. Subsequent to Yamaguti’s (1971) list of species under Allocreadium Allocreadium five more species namely; A. kashmirensis (Fotedar & Dhar, 1974), A. cyprini and A. kawi (Sudan, 1979). A. indicum (Kalyankar and Deshmukh, 1980) and A. fotedari (Dhar and Kharoo, 1984) were added to the tally. It may be mentioned here, in passing, that Fotedar and Dhar (1974) and Dhar & Kharoo (1984) have not assigned their species under any of the three subgenera of Allocreadium. However, in light of the description of the worms, the distribution of vilellaria in their form being close behind the oral sucker to the end of the body,A. kashmirensis (Fotedar & Dhar, 1974) and A. fotedari (Dhar & Kharoo, 1984) can be unhesitatingly placed alongwith subgenus Neoallocreadium. Similarly Sudan (1979) also has not assigned his two species A. cypriniand A. kawi to any of the subgenera under the genus Allocreadium, but the patterns of the distribution of the vitellaria and extension of uterine coils in these two species, warrants their placement with Allocreadium Allocreadium. Thus, of the 30 odd species now known under Allocreadium Allocreadium, 18 are Indian in distribution, of which 3A. A.handiai, A.A. ophiocephali and A.A.kawi have been described from the gut of the freshwater fish Channa punctatus (Ophiocephals punctatus) a congeneric species of the host of the present forms. But in light of the review of the genus Allocreadium by 3 © 2022 Journal of e-Journal of e-Science Letters. All Rights Reserved. Ranvijay Singh., / Journal of e-Journal of e-Science Letters (2022) Kakaji (1969) which has suggested synonymy of A.A. ophiocephali with A.A. handiai,and supported by Yamaguti (1971), only two species A.A. handiai and A.A. kawi remain effectively as parasites so far reported in the gut of Channa punctatus from India. No species of A. Allocreadium has so far been described from the gut of fish Channa gachua. The forms described above stand morphometrically distinct (Table 1) from A.A. handiai in (i) having a relatively smaller body, being almost half in size than A.A. handiai (ii) producing significantly large sized eggs, which are bigger than those of A. A .handiai by a factor of 2.5 and (ii) showing no divisioning of the vesicular seminalis into an external and aninternal portion, unlike the biparatite vesicular seminalis reported in A. A. handiai. These differences are taxonomically important for treating the form under discussion as distinct from A. A. handiai. The present form shows striking differences (Table 1) from A.A. kawialso particularly in (i) the oro-acetabular size ratio, the oral sucker being bigger than the acetabulum and reverse being the condition in A.A. kawi, (ii) the absence of prepharynx which is present in A.A. kawi and (ii) relatively fewer in number and larger in size eggs than in A. A. kawi where the number of eggs per worms is much greater and size of eggs relatively much smaller (Table 1). In view of these differences, together with the fact that the host species(Channa gachua) is different from the host species(Channa punctatus) from where the other two species i.e. A.A. handiai and A.A. kawi have been described, it is felt that the present worms may be treated as new to the science and nominated as Allocreadium Allocreadium guchuai. The suggested species namebeing after the species of the host from where described for the first time. A key to the identification of species of Allocreadium Allocreadium known from Jammu and Kashmir state is presented below. 1). External vesicular seminalis present ……. cyprini Sudan, 1979. External vesicular seminalis absent …….. 2 2). Genital pore prefurcal …….. 3 Genital pore postfurcal …….. 4 3). Genital pore in proximity of pharynx …..nemachilus Kaw, 1950. Genital pore close in front of intestinal bifurcation …..schizothoracis Pande, 1938. 4). Pre-pharynx present ……kawi Sudan, 1979. Pre-pharynx absent ……. gachuai n. sp. Fig. 1: Camera Lucida drawing of Allocreadium Allocreadium gachai n. sp. 4 © 2022 Journal of e-Journal of e-Science Letters. All Rights Reserved. Ranvijay Singh., / Journal of e-Journal of e-Science Letters (2022) Table 1: Showing Morphological difference between the different species of AllocreadiumAllocreadium from the fish Channaspp. Morphological features compaired A.A.gachuai n. sp. (n = 30) A.A. handiai Pande, 1937 (n=?) A.A. Kawi Sudan, 1979 (n = 1) Mean body size Small 2.44 x 0.54 (1.35-3.66) x (0.32-0.75) Large 5.46 x 1.1 (4.42-6.5) x (1.0-1.13) Small 2.58 x 0.60 Prepharynx Absent Absent Present Oro-acetabular sucker size ratios Bigger than acetabulum 1.3 Bigger than acetabulum ? Smaller than acetabulum 0.94 Vesiculaseminalis Unipartite Bipartite Unipartite Egg number & size Few 118.5 x 83.25 (90-135) x (75-105) Few (117-125) x (84 x 100) Numerious (82 x 40) Egg length/body length ratio 0.05 0.02 0.03 Host Channagachua Channapunctatus Channapunctatus Note: n, Parasite number;?, Not Known. (a) (b) Fig 2: Photomicrograph of Allocreadium Allocreadium gachuai n. sp. (a) Entire body (x 100), (b) Oral sucker (x 400) 5 © 2022 Journal of e-Journal of e-Science Letters. All Rights Reserved. Ranvijay Singh., / Journal of e-Journal of e-Science Letters (2022) Acknowledgements The author is highly grateful to Council of Scientific and Industrial Research (C.S.I.R.) Govt. of India for providing financial assistance. 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