Folia Parasitologica 58[4] 279-288 (2011) | DOI: 10.14411/fp.2011.028

Ritacestus gen. n. (Cestoda: Proteocephalidea) and redescription of R. ritaii comb. n., a parasite of Rita rita (Siluriformes) in India

Alainde Chambrier¹, Tomáš Scholz², Anirban Ash², Pradip Kumar Kar³

¹ Department of Invertebrates, Natural History Museum, P.O. Box 6434, CH-1211 Geneva 6, Switzerland

² Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic & Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic

³ Jhargram Raj College, Jhargram, Paschim Medinipur, West Bengal 721507, India

A new genus, Ritacestus, is proposed to accommodate Ritacestus ritaii (Verma, 1926) comb. n. (syn. Proteocephalus ritaii), a parasite of the catfish Rita rita (Hamilton) in India. The new genus, which is placed in the Gangesiinae, is characterized by (i) a small, subspherical scolex formed by four large lobes separated from one another by longitudinal grooves, with a large, widely oval to pyriform rostellum-like apical organ, larger than suckers and possessing an apical hemispherical depression; (ii) paramuscular and cortical position of some vitelline follicles (most follicles are situated medullary); (iii) ventral and dorsal bands of vitelline follicles usually uninterrupted ventral to terminal genitalia and reaching to the posterior margin of proglottides; (iv) the vagina always anterior to the cirrus-sac; (v) a large size of the body (length up to 51 cm); and (vi) development of the uterus of type 2. In its morphology, especially shape of the scolex and apical organ, and paramuscular and cortical position of some vitelline follicles, Ritacestus resembles Postgangesia Akhmerov, 1969, but differs in the presence of a genital atrium (both genital pores of Postgangesia are separate), the anterior position of the vagina (almost always posterior in the latter genus), position of vitelline follicles in cross sections (dorsal and ventral bands in Ritacestus versus only a lateral band in the latter genus), and dorsal excretory canals indistinguishable in mature and gravid proglottides of R. ritaii (well developed in Postgangesia spp.). The type and only species of the genus, R. ritaii, is redescribed on the basis of new material from the type host from the Ganges River basin in India and its neotype is designated.

Keywords: morphology, taxonomy, neotype, Eucestoda, Gangesiinae, freshwater fish, Ganges River, India

Received: May 9, 2011; Accepted: July 14, 2011; Published: November 16, 2011  Show citation