Alloglossidium raychaudhurii ( Agarwal & Kumar, 1983 ) Karar & Blend & Dronen & Adel, 2023

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 : 477

Alloglossidium raychaudhurii ( Agarwal & Kumar, 1983) n. comb.

( Fig. 26 )

(Syn. Pseudoparamacroderoides raychaudhurii Agarwal & Kumar, 1983 n. syn.)

Record. 1. Agarwal & Kumar (1983).

Agarwal & Kumar (1983) described P. raychaudhurii from three specimens collected from the intestine of the striped dwarf catfish, M. vittatus , within the Varuna River, a tributary of the Ganges River Basin, Varanasi, northern Uttar Pradesh, India. Pseudoparamacroderoides raychaudhurii was differentiated from the original description of P. seenghali by the former possessing a prepharynx, an ovary well-separated from the ventral sucker, a coiled seminal vesicle, and a different vitellarium extent. In addition, they distinguished P. raychaudhurii from P. vittati (= P. seenghali ) by the difference in sucker ratio, a shorter length of the esophagus, the greater extent of the excretory vesicle and the shape of the seminal receptacle. Truong et al. (2021) referred to the dubious state and weak differentiation of the aforementioned features for distinguishing P. raychaudhurii from P. seenghali , and this is what led them to consider these descriptions as strikingly similar to each other. We concur with Truong et al. (2021) in their evaluation of these features except for the coiled nature of the seminal vesicle; they considered the illustrations by Agarwal & Kumar (1983, figs. 1A & 1B) of this feature to be “medially constricted”. Truong et al. (2021) regarded species of Pseudoparamacroderoides as possessing a unipartite seminal vesicle, yet the obvious coiled (bipartite) nature of this feature in P. raychaudhurii apparent in illustrations of this species (see Agarwal & Kumar 1983, figs. 1A & 1B; Fig. 26 of current study) represents a strong morphological character for distinctly separating P. raychaudhurii from this genus. Our findings suggest that P. raychaudhurii belongs to an alloglossidiid genus (see Hernández-Mena et al. 2016), Alloglossidium , based on the combination of the following characteristics: body spines dense in anterior extremity, decreasing in number at mid-level of hindbody; oral sucker spherical, with subterminal aperture; ventral sucker well-developed, with lumen, in anterior half of body, approximately equal in size to oral sucker; testes post-equatorial; cirrus-pouch curved, not completely anterior to ventral sucker but partially dorsolateral to it with a bipartite seminal vesicle; genital pore median, immediately anterior to ventral sucker; ovary submedian, entire, between ventral sucker and testes, closer to ventral sucker; uterine seminal receptacle present; vitelline follicles form continuous lateral fields not confluent anteriorly and posteriorly, extend anteriorly beyond level of ventral sucker; excretory vesicle I-shaped; excretory pore terminal; and ceca terminate in post-testicular space, extending to near posterior end of body ( Font & Lotz 2008; Hernández-Mena et al. 2016). Accordingly, we move P. raychaudhurii into Alloglossidium as Alloglossidium raychaudhurii ( Agarwal & Kumar, 1983) n. comb., and, thus, it now represents the first record of an Indian alloglossidiid species. This species is characterized from other congeners by the more posterior extent of its vitellarium into the post-testicular zone and its record from a different group of freshwater fish, the bagrid catfishes, Bagridae .

Figures

FIGURES 26 & 27. Alloglossidium raychaudhurii (Agarwal & Kumar, 1983) n. comb. and Anomalomacroderoiditrema keni (Agarwal & Agarwal, 1984) n. gen., n. comb. 26. Al. raychaudhurii (syn. Pseudoparamacroderoides raychaudhurii Agarwal & Kumar, 1983), ventral view, redrawn from Agarwal & Kumar (1983, fig. 1A). 27. An. keni (syn. Pseudoparamacroderoides keni Agarwal & Agarwal, 1984), dorsal view, redrawn from Agarwal & Agarwal (1984, fig. 1A). Abbreviations: AT, anterior testis; BS, body spines; Ce, cecum; CP, cirrus-pouch; ED, ejaculatory duct; Eg, egg; EP, excretory pore; Es, esophagus; EV, excretory vesicle; GP, genital pore; LC, Laurer’s canal; OC, ôtype complex; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; Pr.Ph, prepharynx; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VD, vitelline duct; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 26 = 500 µm; Fig. 27 = 300 µm.