Gangafaustula, Dronen & Blend & Mohammed & Bannai, 2021

Dronen, Norman O., Blend, Charles K., Mohammed, Essa T. & Bannai, Majid, 2021, Reconsideration of the species assigned to Faustula Poche, 1926 (Digenea: Microphalloidea) with the proposal of five new genera in the Faustulidae Poche, 1926, Zootaxa 5027 (2), pp. 231-253 : 244-245

Gangafaustula n. gen.

( Fig. 8 )

Type species: Gangafaustula makundai ( Agarwal & Verma, 1981) n. comb. Type and only species.

(Syn. Faustula makundai Agarwal & Verma, 1981 )

Diagnosis: Body small, broadly elliptical to somewhat pyriform; anterior extremity markedly tapered to form relatively narrow end; posterior extremity more broadly tapered to form a bluntly pointed end; tegument aspinose. Forebody occupies less than one-half of body length. Oral sucker muscular, globose, somewhat subterminal. Ventral sucker muscular, globose, near midlevel of body, slightly smaller than oral sucker. Prepharynx absent. Pharynx elliptical (elongate-spherical), muscular. Esophagus relatively short. Intestinal bifurcation about midway between suckers. Ceca short, terminate posterior to midlevel of body. Testes 2, entire, symmetrical, near midlevel of body; anterior extent may overlap midlevel of anterior aspect of ventral sucker. Cirrus sac claviform to retort-shaped, anterior one-third proceeds across body from about level of anterior one-third of left cecum to about midline of body, curves posteriorly and slightly overlaps right margin of ventral sucker, terminates about level of posterior margin of ventral sucker or slightly more posteriorly; sac encloses short, narrow ejaculatory duct, modest tubular pars prostatica and relatively large, saccate, naked (not surrounded by glandular cells) seminal vesicle; no large glandular cells apparent around pars prostatica or upper aspect of seminal vesicle. Genital pore immediately postbifurcal, distinctly submedian, sinistral, opens just short of midway between midline of body and body wall. Ovary with 4 lobes, median, anterior one-half occupies about posterior one-third of intertesticular space. Seminal receptacle immediately posterolateral of ovary. Uterus largely posterior to gonads, filling most of posttesticular space. Vitellarium composed of few (approximately 6–10), relatively large follicles linearly organized near lateral margins of body from about level of posterior margin of intestinal bifurcation nearly to posterior margin of testes. Eggs small, operculated. Excretory vesicle V-shaped, extent of excretory arms unknown; excretory pore nearly terminal. Reported as intestinal parasite of species of clupeid fishes in the Ganges River (River Ganga ), India.

Etymology: The genus is named after the river in India where the type species was originally collected (“ Ganga ”) and its probable assignment within the faustulid trematodes ( Faustula ).

Remarks: Gangafaustula makundai is similar to species of Faustula by having ceca that are relatively short, terminating at about the level of the posterior margin of the testes or slightly more posterior; a submedian, claviform cirrus sac that lies along the left margin of the ventral sucker, sometimes overlapping it to some extent dorsally and terminating at about the level of the posterior margin of the sucker; symmetrical testes that overlap the posterior end of the ventral sucker laterally to some extent; a median or nearly so, lobed ovary that is primarily posttesticular, but that may extend anteriorly into the posterior aspect of the intertesticular space to some extent and a uterus that is largely posttesticular and mainly in the hindbody. Gangafaustula makundai differs from species of Faustula by having the ventral sucker somewhat smaller than the oral sucker and more posteriorly positioned about the midlevel of the body; a simple saccate seminal vesicle where large glandular cells are not apparent in the cirrus sac vs a winding tubular seminal vesicle that is at least partially embedded in large glandular cells; a distinctly submedian genital pore; few (6–10/ side), large vitelline follicles that are linearly arranged in the lateral fields, 1 line on each side of the body and restricted to the region from the level of the posterior margin of the intestinal bifurcation to near the level of the posterior margin of the testes vs follicles being relatively small, more numerous and arranged in compact masses where their anterior extent surpasses the intestinal bifurcation anteriorly being distributed from about the midlevel of the esophagus to the anterior aspect of the posttesticular space of the hindbody or more posteriorly; gonads that are located posterior to the midlevel of the body and an ovary with 4 lobes vs 8 or more lobes as seen in species in the genus (e.g., F. basiri , F. brevichrus , F. keksooni ).

Figures

FIGURES 7–8. Diagrammatic illustrations of faustulids (ventral views): 7. Schellitrema gasterostei (Schell, 1973) n. comb. based on Schell (1973); representative of Schellitrema n. gen. 8. Gangifaustula makundai (Agarwal & Verma, 1981) n. comb. based on Agarwal & Verma (1981); representative of Gangafaustula n. gen.