Kalipharynx Boeger & Thatcher, 1983

Karar, Yasser F. M., Blend, Charles K., Dronen, Norman O. & Adel, Asmaa, 2023, Towards resolving the problematic status of the digenean genus Astiotrema Looss 1900: Taxa excluded from Astiotrema (sensu stricto) with special reference to plagiorchioid genera closely related to the restricted concept of Astiotrema, Zootaxa 5284 (3), pp. 445-495 : 469

Genus Kalipharynx Boeger & Thatcher, 1983

( Fig. 21 )

Kalipharynx was erected by Boeger & Thatcher (1983) for its type-species, Kalipharynx piramboae Boeger & Thatcher, 1983 , to accommodate specimens collected from the intestine of a freshwater fish, the South American lungfish, Lepidosiren paradoxa Fitzinger (Ceratodontiformes: Lepidosirenidae ), from Xiborena Hole, off Manaus, Amazonas, Brazil. Boeger & Thatcher (1983) emphasized the similarity of their new genus to Heterorchis Baylis, 1915 from which it differs mainly by possessing a unipartite sacciform seminal vesicle and a submedian genital pore (see Boeger & Thatcher 1983) whereas Heterorchis is characterized by its bipartite seminal vesicle and submarginal genital pore (see Baylis 1915; Pojmańska et al. 2008). Although Heterorchis underwent some taxonomic displacements between the Plagiorchiidae ( Baylis 1915; Prudhoe & Bray 1982) and the Fellodistomidae Nicoll, 1909 ( Vassiliades & Richard 1970; Yamaguti 1971), which settled on allocating Heterorchis to the Plagiorchiidae, Boeger & Thatcher (1983) seemed unaware of the opinion of Prudhoe & Bray (1982) and placed Kalipharynx in the Fellodistomidae based on its close morphology with Heterorchis . Pojmańska et al. (2008) considered Kalipharynx and Heterorchis as incertae sedis in the Plagiorchioidea (sensu lato) on the basis of an absence of information on the structure of the excretory vesicle in the former (see Boeger & Thatcher 1983) and the highly unusual organization of the excretory vesicle observed in the type-species of the latter, Heterorchis crumenifer Baylis, 1915 (see Baylis 1915).

As stated earlier, the change in nature of the seminal vesicle (unipartite vs bipartite; saccate vs tubular; straight vs coiled) represents a strong morphological character for differentiating taxa not only at the genus level but also at family and even superfamily levels. Accordingly, we believe Heterorchis and Kalipharynx do not represent members in the same group. Thus, Heterorchis probably represents a member of the Plagiorchiidae or a closely related family, whereas, Kalipharynx is apparently closer to that group of genera that have a unipartite, sacciform seminal vesicle: Astiotrema (sensu stricto), Homeoastiotrema , Ichthyastiotrema , Longigula and Plesioastiotrema . Kalipharynx easily can be characterized by the combination of the following features: ventral sucker large, about three times size of oral one; ceca overlap ventral sucker dorsally; pharynx papillate; posterior extent of cirrus-pouch does not surpass ventral sucker level; posterior extent of vitelline fields extends well into post-testicular area; esophagus extremely short; genital pore submedian, extracaecal; and its ovary is equatorial. In addition, Plesioastiotrema is morphologically closest to Kalipharynx , particularly in that both share in having an extracaecal genital pore. However, the former differs by having (i) a ventral sucker of roughly equal size with the oral one or slightly smaller, (ii) the intestinal bifurcation overlaps the ventral sucker dorsally, (iii) a pharynx that is not papillate, (iv) the posterior extent of the cirrus-pouch exceeds the ventral sucker, reaching ovarian level, (v) the posterior extent of the vitellarium never surpasses the testicular zone, (vi) an esophagus that is fairly long, (vii) a median genital pore (viii) a pre-equatorial ovary, (ix) and records of Plesioastiotrema are from reptilians and not from fish.

Figures

FIGURES 21–23. Kalipharynx piramboae Boeger & Thatcher, 1983 and intra-specific variation observed in Pseudoparamacroderoides seenghali Gupta & Agrawal, 1968. 21. K. piramboae Boeger & Thatcher, 1983, ventral view, redrawn from Boeger & Thatcher (1983, fig. 1). 22. P. seenghali, ventral view, redrawn from Gupta & Agrawal (1968, p. 71). 23. P. seenghali (syn. Pseudoparamacroderoides vittati Kakaji, 1969), dorsal view, redrawn from Kakaji (1969, fig. 10). Abbreviations: AT, anterior testis; BS, body spines; Ce, cecum; CP, cirrus-pouch; ED, ejaculatory duct; EP, excretory pore; Es, esophagus; EV, excretory vesicle; GP, genital pore; LT, left testis; MG, Mehlis’ gland; OS, oral sucker; Ov, ovary; PC, prostatic cells; Ph, pharynx; PP, pars prostatica; PT, posterior testis; RT, right testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VD, vitelline duct; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 21 = 500 µm; Fig. 22 = 500 µm; Fig. 23 = 500 µm.