Boletín chileno de parasitología
Print version ISSN 0365-9402
Bol. chil. parasitol. vol.56 no.3-4 Santiago July 2001
Rhabdochona indiana n. sp. (Nematoda: Rhabdochonidae) from the intestine of
B. Bharata Lakshmi
Department of Zoology, Andhra University, Waltair - 530 003, A. P., India
Rhabdochona indiana n. sp. (Nematoda: Rhabdochonidae), del intestino de Pempheris vanicolensis.
Rhabdochona indiana es una nueva especie obtenida desde el intestino de Pempheris vanicolensis (Cuvier), un pez marino procedente de Poodimadaka, Andhra Pradesh. Esta especie difiere de otras en el número y distribución de las papilas caudales, largo de las espículas, solevantamientos que sirven de apoyo a la cápsula bucal y medidas corporales.
Key words (Palabras clave): Rhabdochona indiana n. sp.; intestinal nematode (nematode intestinal); Phempheris vanicolensis; India.
In the course of a survey of the parasites of marine fishes of Poodimadaka (Andhra Pradesh) a new species Rhabdochona indiana was obtained from the intestine of Pempheris vanicolensis (Cuvier). This paper gives the description and status of the new species.
The host Pempheris vanicolensis (Cuvier) was obtained from Poodimadake, Bay of Bengal and also from local fish markets.
The nematodes were fixed in hot 70% alcohol and preserved in 10% glycerine alcohol. These specimens were cleared in lacto phenol for appropriate observations. For enface - veiw study, the head of parasite was cut with a sharp blade and brought into the desired position under the cover glass in lacto-phenol on the slide.
|Family||: Rhabdochonidae Skrjabin, 1946.|
|Genus||: Rhabdochona Railliet, 1916.|
|Rhabdochona indiana, n.sp. (Fig. and 1 Fig. 2).|
|Material||: 2 male, 2 females.|
|Host||: Pempheris vanicolensis (Cuvier).|
|Locality||: Poodimadake, Andhra Pradesh, India.|
|specimen||: Holotype and paratype specimens will be deposited in the Department of Zoology, Andhra University, Waltair, India.|
| ||Fig. 1. Rhabdochona indiana n.sp. Drawings: a) Anterior region of male. b) Posterior region of female. c) Posterior region of male|
| ||Fig. 2. Rhabdochona indiana n.sp. Photographies: a) Anterior region of female. b) Posterior region of female. c) Posterior region of male.|
Elongated, thread like and whitish worms. Mouth bounded by inconspicuous lips. Head truncated, somewhat rounded and smooth. Prostome small and barrel shaped, inner surface strengthened by longitudinal ribs anteriorly projecting out to form four small teeth. Mesostome long, narrow with cuticular transverse striations. Cervical papillae absent. Oesophagus divided into and anterior muscular and posterior glandular portion. A valvular apparatus present at the junction of oesophagus and intestine. Intestine long. Caudal end of the male curved ventrally and straight with a spike at the end in female. Cuticle thin and smooth.
Male: Body measures 24-25 x 0.108 - 0.144.
Prostome 0.012-0.015. Mesostome 0.1244 x 0.012. Muscular oesophagus 0.336 x 0.038 and glandular oesophagus 2.01 x 0.144. Nerve ring at 0.168 from anterior end. Caudal papillae nine pairs and all are sessile. Five pairs preanals and four pairs are postanals. Spicules two, unequal and dissimilar. Right spicule short, thick, broader proximally and 0.168 in length, left spicule long, thin 0.408 in length. Gubernaculum absent. Caudal end curved ventrally. Caudal alae narrow. Tail 0.096 long with a spike.
Female: Body measures 20-30 in length, 0.144 in width. Prostome 0.012-0.018. Mesostome 0.18 x 0.012. Muscular oesophagus 0.228-0.312 x 0.066, glandular oesophagus 1.628-2.032 x 0.132. Nerve ring at 0.18 from anterior end. Vulva 6-8 from posterior end, postequatorial in position. Uteri opposed, oviparous. Eggs embryonated at deposition, non-filamentous, 0.048 x 0.012. Tail 0.168 long with a spike.
In having non-alate spicules and postequaotorial vulva the present species resembles, R. ghaggari Sood, 1972; R. labeonis Kalyankar, 1972; R. chhapprai Gupta and Srivastava, 1982; and R. nemacheli Rautela and Malhotra, 1982 but differs from all these species in the number and arrangement of caudal papillae, length of spicules and presence of a broad ala. In the present species caudal papillae are 9 pairs (5+0+4) spicule lengths 0.168 and 0.408 versus 15 pairs (7+0+8) caudal papille, spicules 0.1- 0.12 and 0.55-0.57 in R. ghaggari 17 pairs (9+0+8) caudal papille, spicules 0.12 and 0.57 in R. labeonis, 20 pairs (13+0+7) caudal papillae, spicules 0.30, 0.50 in R. chhaprai and 11 pairs (6+0+5) caudal papillae, spicules 0.07-0.098 and 0.24-0.378 in R. nemecheli.
Both the present species and R. dasi Sahay and Prasad, 1965 have nonbifurcated spicules but the former differs in the number and arrangement of caudal papillae (9 pairs vs 15 pairs) length of spicules (0.168, 0.408 vs 0.098, 0.21-0.27 presence of narrow caudal alae and a broad ala throughtout the body.
The present species differs from Rhabdochona marina Lakshmi and Sudha (1999) collected from the same host Pempheris vanicolensis in the number and arrangement of caudal papille, length of spicules and body measurment.
In view of these differences the present form is erected as a new species to accommodate under the genus Rhabdochona and named it as Rhabdochona indiana n.sp.
Comparision of the present species with R. marina is given in Table I.
Detailed study of the present material reveals that it belongs to the genus Rabdochona, Railliet, 1916. The genus Rhabdochona includes a large number of species from all over the world. The genus was erected by Railliet in the year 1916 with R. denudata from Cyprinus eurytharophthalmus as the type species. Sahay (1971) revised the genus Rhabdochona with a key to the Indian species. Moravec (1972, 1975, 1978) extensively studied the genus Rhabdochona. Sood (1988) provided key to the species of Rhabdochona Railliet, 1916 from fishes in south Asia. Yamaguti 1961 listed about 30 species under the genus Rhabdochona Railliet, 1916 from different hosts from various parts of the world. All these parasites were recovered from fresh water fishes. The present species differs from all known species described from various parts of the world. This genus is represented in India by 32 species.
The present species resembles R. cavasius Rehana and Bilquees, 1973 in having non bifurcated, non alate spicules and post equatorial vulva but differs in the number of longitudinal ridges supporting buccal capsule, length of spicules, number and arrangement of caudal papillae (4 ridges supporting buccal capsule, spicules length 0.168 and 0.408, caudal papillae 9 pairs 5+0+4 versus 3 ridges supporting buccal capsule, spicules lengths 0.12 and 0.042, caudal papillae 14 pairs 9+0+5, R. cavasius).
Acknowledgements. The author is grateful to Prof. K. Hanumantha Rao for his help and encouragement and thankful to the University authorities and the head of the Department of Zoology for the facilities privided to carry out the work successfully.
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