Faustula basiri Hafeezullah & Siddiqi, 1970

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 : 238

Faustula basiri Hafeezullah & Siddiqi, 1970

(Syns. Faustula hilsai Rizvi, 1971 ; Faustula rahemii Al-Daraji, 2004 )

( Fig. 2 )

Type host: Toli shad, Tenualosa toli (Valenciennes) (Clupeidae) .

Type locality: Off Veraval , India .

Remarks: Faustula basiri differs from F. keksooni by having a longer forebody relative to body length (42– 49% vs about 30%); a somewhat longer esophagus (240–456; 11–18% of the body length) and a somewhat shorter egg (maximum length 18 vs 20). Faustula basiri somewhat resembles F. gangetica by having a terminal oral sucker (as originally described for both species); relatively long ceca that surpass the testes posteriorly, terminating near the level of the ovary; a median genital pore that opens immediately posterior to the intestinal bifurcation and vitelline fields that are extensively distributed in the lateral fields of the body. Faustula gangetica differs from F. basiri by having a smaller body (1,340 –1,650 × 790–970 vs 2,140 –2,580 × 1,030 –1,100); a shorter forebody (410; 30% of body length vs 912–1,158; 42–49%); a shorter esophagus (160–180; 10–12% vs 240–456; 11–18%); a shorter cirrus sac (360–400; 24–27% vs 408–528; 19–21%) that surpasses the ventral sucker posteriorly, extending some distance into the hindbody where it approaches the ovary vs being confined to the region from immediately posterior to the intestinal bifurcation to about the anterior margin of the ventral sucker; a shorter postovarian space (355; 26% vs 660; 30%) and longer eggs (16–25 vs 12–18). In the original description of F. basiri the oral sucker is illustrated as being slightly subterminal (see fig. 1 of Hafeezullah & Siddiqi 1970).

Although there are some 13 species of Faustula generally recognized, a little-known potential species, Faustula rahemii Al-Daraji, 2004 , was described from the intestine of the Hilsa shad, T. ilisha (Syn. C. ilisha ), from the Khor Al-Zubair lagoons by Al-Daraji (2004). Mhaisen et al. (2018) included this species in their checklist of parasites from marine fishes from Iraq, but based on the lack of recognition of this species in existing literature and its omission from any records of being synonymized with other species of Faustula , these authors suggested that it likely should be considered an invalid species. Our literature search of species of Faustula also yielded no published evidence of recognition of this species beyond Mhaisen et al. (2018) and the related information provided by these authors. Al- Daraji (2004) separated F. rahemii from all other species based on the location of the cirrus sac being preacetabular. However, as Mhaisen et al. (2018) pointed out, Al-Daraji (2004) had not compared his species to at least 10 other recognized species. There are 3 similar species like F. rahemii by having the cirrus sac anterior to the ventral sucker: F basiri ; F. hilsai as described by Rizvi (1971) and F. clupeae . Unlike F. clupeae , both F basiri and F. hilsai are also like F. rahemii by having unusually extensive vitelline fields that extend from about the level of the esophagus to near the level of the ovary and the ovary positioned some distance posterior to the ventral sucker; F. hilsai has been synonymized with F. basiri (e.g., see WoRMS 2021a). Al-Daraji (2004) recognized the similarities between F. basiri and F. rahemii and provided a comparative table for these two species, which like Table 1 herein, does not conclusively distinguish F. rahemii . In the comparative table Al-Daraji (2004) further asserts that F. rahemii differs from F. basiri by having the ventral sucker “equal or larger than oral sucker”; however, the sucker ratios of these 2 species are similar (1: 0.91–1:0.97 vs 1:0.87–1:0.90, respectively), and both have the ventral sucker smaller than the oral sucker. The genital pore of F. rahemii was illustrated in fig. 1 by Al-Daraji (2004) as being located at the level of the anterior extent of the intestinal bifurcation, which is most similar to F. clupeae . The specimens of F. rahemii used in this description were fixed between 2 microscope slides and given that species of Faustula tend to be somewhat fragile and susceptible to possible fixation-induced alterations of some characteristics, the subtle difference in the position of the genital pore in F. rahemii compared to that in F. basiri (just posterior to the intestinal bifurcation) may not represent a creditable difference. Faustula rahemii is most similar to F. basiri and was described from T. ilisha , the most common fish wherein species of Faustula have been reported from generally the same geographic region, and it is our opinion it should be synonymized with F. basiri .

Figures

FIGURES 1–2. Diagrammatic illustrations of faustulids (ventral views): 1. Faustula keksooni (MacCallum, 1918) Poche, 1926 largely based on Price (1938); type species of Faustula Poche, 1926. 2. Faustula basiri Hafeezullah & Siddiqi, 1970 based on Hafeezullah & Siddiqi (1970). Abbreviations: C, cecum; E, esophagus; F, vitelline follicles; G, genital pore; L, large glandular cells in cirrus sac; O, ovary; OS, oral sucker; P, pharynx; S, seminal vesicle; T, testes; U, uterus; V, excretory vesicle; VS, ventral sucker.