Faustula Poche, 1926

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 : 233-234

Faustula Poche, 1926 (sensu stricto)

(Syn. Orientophorus Srivastava, 1935 )

Type species: Faustula keksooni ( MacCallum, 1918) Poche, 1926

(Syn. Eurema keksooni MacCallum, 1918 nec Hübner, 1820)

Museum specimen: USNM 1337171.

Emended diagnosis: Body small, oval, elliptical (elongate-oval) to lingulate (see fig. 43 of McCallum 1918 and fig. 3 of Price 1938), spinose (type species F. keksooni originally described as aspinose, but apparently body spines were lost during fixation). Forebody occupies less than one-half of body length. Oral sucker subterminal, sometimes approaching terminal. Ventral sucker muscular, about same size to slightly larger than oral sucker, located some distance anterior to midlevel of body. Prepharynx short to absent. Pharynx small, muscular, oval to elliptical, somewhat globular. Esophagus relatively long. Intestinal bifurcation in forebody about one-half distance from anterior end and ventral sucker or slightly more posterior, well anterior to midlevel of body. Ceca relatively short, blind, terminate about midlevel of body. Testes 2, entire, symmetrical (opposite, side by side) or nearly so, largely intercecal, located about level of ventral sucker or slightly more posterior. Intertesticular space generally wide. Cirrus sac generally claviform (somewhat retort-shaped in F. keksooni , may be a product of the poor condition of the single specimen used to establish the species), encloses short invaginable cirrus (documented in some species); short ejaculatory duct with few prostatic glands that surround it posteriorly; short pars prostatica and long tubular seminal vesicle that spirals through posterior two-thirds of cirrus sac, at least partially embedded in numerous large glandular cells. Genital pore median to somewhat submedian, often posterior to intestinal bifurcation, sometimes bifurcal or prebifurcal. Genital atrium small, sometimes indistinct. Ovary multilobate (8 or more distinct lobes), usually slightly submedian, located short distance posterior to testes and ventral sucker, far removed from the posterior extremity, larger than either. Laurer’s canal present, relatively long, opens dorsally close to posterior extremity where known. Canalicular seminal receptacle present, formed as dilation of proximal end of Laurer’s canal where documented. Vitelline follicles distributed in 2 clusters, 1 on each side of body from about level of intestinal bifurcation or somewhat more anterior to about level of ovary or somewhat more posterior. Uterus occupies bulk of hindbody, extends from level of ovary posteriorly to near posterior extremity. Eggs numerous, relatively small, operculate. Excretory vesicle V-shaped, may approach Y-shaped with short stem; excretory arms reach anterior to about level of posterior margin of pharynx; excretory pore terminal to somewhat dorsal. Most commonly intestinal parasites of clupeid fishes in India (rivers) and northern Indian Ocean.

Remarks: Despite the damage apparent in the specimen representing the type species (“Specimen was mutilated, anterior end being torn off and the body partly crushed. The crushing apparently resulted from over flattening and was sufficient to rupture the intestinal ceca and force a part of the ingesta into the tissues, thereby causing outpocketings which were regarded by McCallum as openings of vaginae” [see pp. 9–10 of Price 1938;] and generally confirmed in examination of the type specimen by NOD in the present study), NOD also noted that the specimen had been rolled. However, despite the apparent fixation-induced variability of many specimens used to describe subsequent species, some species are easily assigned to Faustula based on morphology (e.g., F. basiri [see fig. 1 of Hafeezullah & Siddiqi 1970], F. brevichrus [see fig. 1 of Srivastava 1935], and F. gangetica [see fig. 2 of Srivastava 1935 and fig. 1 of Garner et al. 2019]). Of these 3 species, we consider F. gangetica to be the most fully documented species.