Astiotrema Looss, 1900

Karar, Yasser F. M., Blend, Charles K., Dronen, Norman O. & Adel, Asmaa, 2021, Towards resolving the problematic status of the digenean genus Astiotrema Looss 1900: An updated concept and revision of species composition for Astiotrema (sensu stricto), Zootaxa 4991 (1), pp. 36-72 : 59-60

Key to species of Astiotrema Looss, 1900 (sensu stricto)

1a. Cecal ends either not reaching significantly into or do not exceed testicular zone.................................. 2.

1b. Cecal ends extending deeply into post-testicular zone....................................................... 5.

2a. Cecal ends and posterior vitellarium extent exceed level of anterior testis; parasitize non-amphibian hosts.............. 3.

2b. Cecal ends and posterior vitellarium extent do not exceed level of anterior testis; parasitize amphibian hosts........................................................ Astiotrema ranarum ( Mehra & Negi, 1926) Fotedar, 1971 ( Figs. 12–14 ).

3a. Anterior extent of vitellarium does not exceed bifurcal level; ovary distant from ventral sucker and closer to anterior testis.................................................................................................... 4.

3b. Anterior extent of vitellarium pre-bifurcal and can reach to pharyngeal level; ovary contiguous with or very close to ventral sucker and more distant from anterior testis............... Astiotrema impletum ( Looss, 1899) Looss, 1900 ( Figs. 6–11 ).

4a. Anterior extent of vitellarium bifurcal; oral sucker distinctly larger than ventral sucker; parasitizes marine turtles........................................... Astiotrema karachiensis Bilqees, Khatoon & Khan, 2002 n. comb. ( Figs. 26 & 27 ).

4b. Anterior extent of vitellarium post-bifurcal; suckers roughly equal in size; parasitizes freshwater turtles and fish...................................................................... Astiotrema odhneri Bhalerao, 1936 ( Figs. 17–20 ).

5a. Anterior extent of vitellarium pre-ovarian but does not reach pre-bifurcal level, posterior extent terminates anterior to cecal ends.............................................................................................. 6.

5b. Anterior extent of vitellarium pre-bifurcal, posterior extent terminates at cecal ends or slightly further posteriorly........................................................................ Astiotrema fotedari Dhar, 1977 ( Figs. 23–25 ).

6a. Genital pore immediately anterior to ventral sucker; ventral sucker relatively close to intestinal bifurcation............. 7.

6b. Genital pore anterior to ventral sucker by a distinct distance; ventral sucker distant from intestinal bifurcation...................................................................... Astiotrema cyclemysi Siddiqi, 1965 ( Figs. 21 & 22 ).

7a. Esophagus distinct, long; anterior extent of vitellarium does not reach anterior to ventral sucker; ovary smaller than testes.......................................... Astiotrema reniferum ( Looss, 1898) Looss, 1900 [type species] ( Figs. 1–5 ).

7b. Esophagus indistinct or very short; anterior extent of vitellarium reaches anterior to ventral sucker and is confluent medially in pre-acetabular region; ovary and testes roughly equal in size........... Astiotrema emydis Ejsmont, 1930 ( Figs. 15 & 16 ).

Figures

FIGURES 12–14. Astiotrema ranarum (Mehra & Negi, 1926) Fotedar, 1971 revealing some slight intra-specific variations. 12. A. ranarum (Syn. Centrovitus pentadelphi Bhalerao, 1926), dorsal view, redrawn from Bhalerao (1926, fig. 1). 13. A. ranarum (Syn. Tremiorchis ranarum Mehra & Negi, 1926), dorsal view, redrawn from Mehra & Negi (1926, fig. 2). 14. A. ranarum (Syn. Tremiorchis mehrai Rai, 1962), dorsal view, redrawn from Rai (1962, p. 382).Abbreviations: AT, anterior testis; Ce, cecum; Ci, cirrus; CP, cirrus-pouch; ED, ejaculatory duct; EP, excretory pore; Es, esophagus; EV, excretory vesicle; GP, genital pore; MG, Mehlis’ gland; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VD, vitelline duct; VF, vitelline follicle; VR, vitelline reservoir; VS, ventral sucker. Scale bars: Fig. 12 = 500 µm; Fig. 13 = 500 µm; Fig. 14 = 500 µm.

FIGURES 6–8. Intra-specific variations observed in Astiotrema impletum (Looss, 1899) Looss, 1900. 6. A. impletum (Syn. Astiotrema varanum [Verma, 1930] Mukherjee & Ghosh, 1970), dorsal view, redrawn from Verma (1930, fig. B). 7. A. impletum, dorsal view, redrawn from El-Naffar et al. (1984, fig. 2a). 8. A. impletum (Syn. Astiotrema sudarshani Mukherjee & Ghosh, 1970), ventral view, redrawn from Mukherjee & Ghosh (1970, fig. 1). Abbreviations: AT, anterior testis; Ce, cecum; CP, cirrus-pouch; EA, excretory arm; EP, excretory pore; Es, esophagus; EV, excretory vesicle; GP, genital pore; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 6 = 500 µm; Fig. 7 = 1,000 µm; Fig. 8 = 500 µm.

FIGURES 9–11. Intra-specific variations observed in Astiotrema impletum (Looss, 1899) Looss, 1900 from the present study. 9. Voucher specimen of A. impletum, ventral view. 10. Voucher specimen of A. impletum, ventral view. 11. Voucher specimen of A. impletum, dorsal view.Abbreviations:AT, anterior testis; Ce, cecum; CP, cirrus-pouch; EP, excretory pore; Es, esophagus; GP, genital pore; MG, Mehlis’ gland; OD, ovarian duct; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 9 = 500 µm; Fig. 10 = 500 µm; Fig. 11 = 500 µm.

FIGURES 26 & 27. Astiotrema karachiensis Bilqees, Khatoon & Khan, 2002 n. comb. 26. A. karachiensis, dorsal view, redrawn from Bilqees et al. (2002, fig. 1). 27. A. karachiensis, ventral view, redrawn from Bilqees et al. (2002, fig. 3). Abbreviations: AT, anterior testis; Ce, cecum; CP, cirrus-pouch; Es, esophagus; GP, genital pore; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 26 = 500 µm; Fig. 27 = 500 µm.

FIGURES 17–20. Intra-specific variations observed in Astiotrema odhneri Bhalerao, 1936. 17. A. odhneri (Syn. Astiotrema reniferum of Odhner, 1911 nec Looss, 1898), ventral view, redrawn from Yeh & Fotedar (1958, fig. 5) after Odhner (1911). 18. A. odhneri (Syn. Astiotrema hanumantharai Dhanumkumari, 1999), ventral view, redrawn from Dhanumkumari (1999, fig. 1). 19. A. odhneri (Syn. Astiotrema nathi Gupta, 1954), ventral view, redrawn from Gupta (1954, fig. 1). 20. A. odhneri (Syn. Astiotrema sudanensis Khalil, 1959), dorsal view, redrawn from Khalil (1954, fig. 1). Abbreviations: AT, anterior testis; Ce, cecum; CP, cirrus-pouch; Es, esophagus; GP, genital pore; MG, Mehlis’ gland; Oo, oötype; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VD, vitelline duct; V-D, vasdeferens; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 17 = 1,000 µm; Fig. 18 = 1,000 µm; Fig. 19 = 500 µm; Fig. 20 = 500 µm.

FIGURES 23–25. Intra-specific variations observed in Astiotrema fotedari Dhar, 1977. 23. A. fotedari, ventral view, redrawn from Dhar (1977, fig. 1). 24. A. fotedari, ventral view, redrawn from Dhar (1977, fig. 2). 25. A. fotedari (Syn. Gauhatiana fusiformis Wang, 1981), dorsal view, redrawn from Wang (1981, fig. 7). Abbreviations: AT, anterior testis; Ce, cecum; CP, cirrus-pouch; Eg, eggs; Es, esophagus; GP, genital pore; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SV, seminal vesicle; Ut, uterus; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 23 = 500 µm; Fig. 24 = 500 µm; Fig. 25 = 500 µm.

FIGURES 21 & 22. Astiotrema cyclemysi Siddiqi, 1965. 21. A. cyclemysi, ventral view, redrawn from Siddiqi (1965, fig. 1). 22. A. cyclemysi (Syn. Astiotrema lissemydis Agrawal, 1966), ventral view, redrawn from Agrawal (1966a, fig. 11). Abbreviations: AT, anterior testis; Ce, cecum; CP, cirrus-pouch; EP, excretory pore; EV, excretory vesicle; GP, genital pore; OD, ovarian duct; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior 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.

FIGURES 1–5. Astiotrema reniferum (Looss, 1898) Looss, 1900 revealing some intra-specific variations in esophagus extension, vitellarium distribution and maturation, testes configuration, and ovary shape. 1. A. reniferum (Syn. Distomum unicum Looss, 1896 nec Molin, 1859), ventral view, redrawn from Looss (1896, fig. 20). 2. A. reniferum (Syn. Astiotrema giganticum Tiwari, 1958), dorsal view, redrawn from Tiwari (1958, fig. 1). 3. A. reniferum (Syn. Astiotrema thapari Gupta, 1954), ventral view, redrawn from Gupta (1954, fig. 4). 4. A. reniferum (Syn. Astiotrema loossii Mehra, 1931), dorsal view, redrawn from Mehra (1931b, p. 187). 5. A. reniferum (Syn. A. loossii), ventral view, redrawn from Dwivedi (1966, fig. 2). Abbreviations: AT, anterior testis; Ce, cecum; CP, cirrus-pouch; Eg, eggs; EP, excretory pore; Es, esophagus; EV, excretory vesicle; GP, genital pore; LC, Laurel’s canal; Oo, oötype; OS, oral sucker; Ov, ovary; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VD, vitelline duct; V-D, vas-deferens; VF, vitelline follicle; VS, ventral sucker. Scale bars: Fig. 1 = 1,000 µm; Fig. 2 = 2,000 µm; Fig. 3 =2,000 µm; Fig. 4 = 500 µm; Fig. 5 = 1,000 µm.

FIGURES 15 & 16. Intra-specific variations observed in Astiotrema emydis Ejsmont, 1930. 15. A. emydis, dorsal view, redrawn from Ejsmont (1930, fig. 1). 16. A. emydis, ventral view, redrawn from Modrzejewska (1938, fig. 1). Abbreviations:AT, anterior testis; Ce, cecum; CP, cirrus-pouch; EP, excretory pore; Es, esophagus; EV, excretory vesicle; GP, genital pore; OD, ovarian duct; OS, oral sucker; Ov, ovary; P.Ph, prepharynx; Ph, pharynx; PP, pars prostatica; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; Ut, uterus; VD, vitelline duct; V-D, vas-deferens; VF, vitelline follicle; VR, vitelline reservoir; VS, ventral sucker. Scale bars: Fig. 15 = 500 µm; Fig. 16 = 500 µm.