North-East India Helminth Parasite Information Database

Explanatum explanatum (Fukui Fukui) Creplin 1847 Back


Platyhelminthes »
       TREMATODA »
              Digenea »
                     Paramphistomidae Fischoeder, 1901 »
                            Paramphistominae Fiscoeder, 1901 »
                                   Explanatum (Fukui, 1929) Eduardo, 1984 »
                                           Explanatum explanatum (Creplin 1847), Fukui 1929


(Paramphistomum fraternum Stiles et Goldberger 1910; P. siamense Stiles et Goldberger, 1910)


Bos (indicus), Bubalus (bubalis)


Bile duct


Guwahati (Assam), Silchar (Assam), Shillong (Meghalaya), Nongstoin (Meghalaya), Jowai (Meghalaya), Aizawl (Mizoram), Agartala (Tripura)


Body large, tapering anteriorly, curved ventrally, 8.13-10.30 mm in length, 4.74-5.65 mm in width; ratio of body width to body length 1:1.53-1.2. Acetabulum sub-terminal, 3.57-4.52 mm in external diameter; ratio to body length 1:1.87-1:2.50, of explanatum type (sensu Näsmark, 1937) in median sagittal section; units of circular muscles on lateral sides as follows : d.e.c.m.1. 26-30, d.e.c.m. 2.22-33, d.i.c.rn. 39-44, v.e.c.m. 20-28, v.i.c.m. 41-48, m.e.c.m. 5-8. Pharynx 0.58-1.03 mm in length, 0.67-0.99 mm in breadth; ratio to body length 1:8.15-1:14.79, to diameter of acetabulum 1:3.72-1:6.15; of explanatum type (sensu Näsmark, 1937) in median sagittal section; internal surface lacking papillae. Oesophagus 0.27-0.54 mm long, no bulb or posterior sphincter. Caeca lateral, wavy, reaching to acetabulum. Testes obliquely or directly tandem; anterior testis 1.17-2.16 mm in length,. 1.8-3.11 mm in breadth; posterior testis 1.13-1.85 mm in length, 2.07-3.16 mm in breadth. Seminal vesicle thin walled, coiled, pars musculosa weakly developed, pars prostatica moderate. Ovary 0.40-0.63 mm by 0.72-0.90 mm, posterior to testes. Laurer's canal crossing excretory vesicle or duct, opening dorsally posterior to excretory pore. Vitellaria in lateral fields, extending from level of pharynx to acetabulum. Eggs 0.090- 0.135 mm by 0.063-0.081 mm. Terminal genitalium of explanatum type (sensu Näsmark, 1937) in median sagittal section, opening at level of pharynx.


Stiles and Goldberger, (1910) described two species,Paramphistomum fraternum and P. siamense and differentiated them from P. explanatum only on the basis of differences in the relative position of the body organs. After re-examination of the type specimens of these species deposited in the United States National Parasite collection, Eduardo,(1984) opined that they were identical and synonymous with P. explanatum (= E. explanatum). E. explanatum is a widely distributed species in cattle, buffaloes and goats in India. However, it has previously been reported or recorded as Gigantocotyle explanatum (see Mukherjee and Chauhan, 1965; Gupta, 1966) or as P. explanatum (see Mehra, 1980).

Helminthological collections record

NEHU/Z - TM/10

Specimen Type

Holotype: W7772/1 in Zoological Survey of India, Kolkata.


Stiles, C. W. and Goldberger, J. (1910). A study of Watsonius (n.g.) watsoni of man and of allied species of mammalian trematode worms of the superfamily Paramphistomidea. Bulletin of the Hygienic Laboratory , Public Health and Marine- Hospital Service of the United States. No.60, pp 259.

Eduardo ,S. L. (1984). The taxonomy of the family Paramphistomidae Fischoeder, 1901 with special reference to the morphology of species occurring ruminants. IV. Revision of the genus Gigantocotyle N?â?ñsmark, 1937 and elevation of the sub-genus Explanatum Fukui, 1929 to full generic status. Systematic Parasitology. 6:pp 3-32.

Mukherjee, R. P. and Chauhan, B. S. (1965) Studies on the trematode fauna of India. Part V. Sub-class Digenea: Paramphistomidae Fischoeder (1901). Journal of the Zoological Society of India. 17:pp 151-225.

Gupta, S. P. (1966). On Gigantocotyle explanatum (Creplin, 1847 ),an amphistomid parasite of cattle. Research Bulletin (N.S.) of the Panjab University. 17:pp 77-80.

Mehra, H. R. (1980). The fauna of India and the adjacent countries. Edited by the Director, Zoological Survey of India. pp 418.