Mesocoelium gonocephali Singh 1967
Creators: name: Dronen, Norman O.
name: Calhoun, Dana M.
name: Simcik, Steven R.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Trematoda
Plagiorchiida
Mesocoeliidae
Mesocoelium
Mesocoelium gonocephali

description: Mesocoelium gonocephali   
(Table 16)  
 Type host: Gonocephalus grandis (Gray), sailfin or crested river dragon (Squamata: agamidae).   
 Type locality: Malaysia.   
 Site: Intestine.   
 Specimen examined: Paratype (1) BMNH 1972.4.7. 1.   
 Description of paratype specimen: Based on one adult specimen. With characteristics of genus. Body leiperi type, relatively large, elongate with slightly rounded ends, body spinose, 2,900 by 913; body spines not observed; forebody 670 long, 23% of body length. Mouth subterminal; oral sucker spherical to subspherical, 310 by 275, prepharynx short; pharynx wider than long, 100 by 110; esophagus longer than prepharynx, 105 long; cecal bifurcation ½ distance down forebody; ceca reaching well posterior to ovary, terminating about midlevel of body, occupying 15% of length of postovarian space. Ratio of widths of oral sucker and pharynx 1:2.5. Ventral sucker located upper ¼ of body, smaller than oral sucker, 210 by 230. Ratio of sucker widths 1:1.2.   
Testes smooth, slightly diagonal, overlapping posterior ½ of ventral sucker. Right testis 153 by 135; left testis 150 by 163. Cirrus sac medial, situated immediately postbifurcal, well anterior to ventral sucker, enclosing short cirrus, reduced par prostatica, short ejaculatory duct surrounded by prostate cells and bipartite seminal vesicle, 190 (7% of body length) by 63. Genital pore immediately postbifurcal, median.  
Ovary smooth, posttesticular, situated immediately posterior to right testis, 193 by 233, removed from posterior end by some distance; postovarian space 1,925 long, 66% of body length. Seminal receptacle spherical, located immediately sinistral to ovary. Laurer’s canal present, opening not observed. Vitelline fields distributed along ceca from level of pharynx posteriorly to midlevel of body, terminating a short distance posterior to cecal ends; vitelline follicles 46 (30–55) by 43 (32–60) (n = 5). Uterus occupies most of hindbody, largely postacetabular. Eggs operculate, 35 (32–38) by 23 (22–24) (n = 20).  
Excretory vesicle Y-shaped with poorly developed arms; excretory pore slightly subterminal.  
 Remarks: This specimen (BMNH 1972.4.7.1) has moderately long ceca, and a genital pore that is postbifurcal and median, placing it in the leiperi body type. The posterior extent of the vitelline fields surpass the cecal ends posteriorly, the anterior extent of the vitelline fields reach anteriorly to the level of the pharynx, the ratio of the width of the ventral sucker to the width of the oral sucker is 1:1.2, the ceca occupy 15% of the postovarian space, the ratio of the width of the pharynx to the width of the oral sucker is 1:2.5, the cirrus sac comprises 7% of the body length and the eggs are 32–38 by 22–24, placing it in M. gonocephali. This specimen was apparently fixed without coverslip pressure and because this paratype specimen was of marginal quality it was not illustrated.   
 Mesocoelium carli as originally described and illustrated by André (1915) (Figure 49)— Not redescribed herein
description: Published as part of Dronen, Norman O., Calhoun, Dana M. & Simcik, Steven R., 2012, Mesocoelium Odhner, 1901 (Digenea: Mesocoelidae) revisited; a revision of the family and re-evaluation of species composition in the genus 3387, pp. 1-96 in Zootaxa 3387 (1) on pages 88-90, DOI: 10.11646/zootaxa.3387.1.1, http://zenodo.org/record/5253926