Trematodes from Red Sea fishes: On the validity of Helicometra marmoratae Nagaty et Abdel-Aal, 1962 and the description of H. aegyptense sp. nov. (Opecoelidae Ozaki, 1925)

Abstract

Specimens of the fishes Siganus spinus L. (Siganidae) and Sargocentron spiniferum ForsskDl (Holocentridae) were caught in the Red Sea off the coast of Sharm El-Sheikh, South Sinai, Egypt. Twenty-three (46%) and 12 (20%) of these fishes, respectively, were found to harbour intestinal trematodes. Siganus spinus was parasitized by Helicometra marmoratae Nagaty et Abdel-Aal, 1962 (Opecoelidae Ozaki, 1925 and S. spiniferum by Helicometra aegyptense sp. nov. (Opecoelidae Ozaki, 1925). Based on a large number of specimens collected from its type host and locality, H. marmoratae is broadly redescribed for the first time, and its type specimen is re-examined. The validity of this species is discussed and considered a new synonym of H. fasciata (Rudolphi, 1819) Odhner, 1902 (type species of the genus). Helicometra aegyptense sp. nov. is similar to H. equilata (Manter, 1933) Siddiqi et Cable, 1960, H. nasae Nagaty et Abdel-Aal, 1962, H. pteroisi (Gupta, 1956) Fischthal et Kuntz, 1965 and H. interrupta Hassanine, 2005 in having a short forebody and a long cirrus sac extending posterior to the ventral sucker, but differs significantly from them or unique in having a distinctly elongate pharynx, a larger sucker ratio and vitelline follicles grouped in small clusters arranged in two lateral rows on each side of the body. The valid species of Helicometra are listed in four principal groups.

Digenetic trematodes from siganid fish Amphacanthus sigan at Macady Bay, Southern Hurghada, Red Sea, Egypt

“…On the other hand, Hassanine (2007) revised the proposed groups into four groups including all species of Helicometra possessing a terminal, infundibuliform oral sucker. These groups are re-described as follows: Group I includes: Species having a sub-terminal oral sucker, a short cirrus sac with a posterior-most extent lightly posterior to the ventral sucker, and vitelline follicles extending into the region of ventral sucker or into the forebody such as: H. fasciata (Rudolphi, Odhner, 1902, H. mutabilis Stossich, 1902(Stosscich, 1903, H. flava Stosscich, 1903, H. gobii Stossich, 1883; H. labri (Stosscich, 1886) Isaichikov, 1928, H. epinepheli Yamaguti, 1934, H. hypodytis Yamaguti, 1934, H. markewitschi Pogorel.tseva, 1954, H. dochmosorchis Manter and Pritchard, 1960, H. marmoratae Nagaty and Abdel-Aal, 1962, and more than 15 species of the same characters.…”

“…From the point of view of these differences, the present sample is considered as a new species. Generally, five species of Helicometra are so far known from the Red Sea fishes: H. fasciata [described as H. hypodytis Yamaguti, 1934by Nagaty (1956, as H. epinepheli Yamaguti, 1934by Ramadan (1986 and as H. marmoratae Abdel-Aal, 1962 by Nagaty andAbdel-Aal, 1962], H. equilata [described as H. boseli Nagaty, 1956by Nagaty (1956], H. nasae Nagaty and Abdel-Aal (1962), H. interrupta Hassanine 2005 and H. aegyptense [described by Hassanine (2007)]. …”

“…The collected samples of parasitic trematodes were identified according to Yamaguti (1971) and some of the available recent publications (e.g., Al-Jahdali, 2012; Al-Jahdali and Hassanine, 2012;Hassanine, 2007;Hassanine and Al-Jahdali, 2007;Mohamed and Abdel-Latif, 2007). All measurements are in millimeters (mm) except eggs in lm.…”

“…Many other studies on the trematodes of fishes had been carried out including the examination of fishes infested by helminth parasites in the Red Sea (started by Nagaty, 1930till Ali, 2005 who revealed the existence of more than 89 trematode species were under more than 47 genera from which at least 14 species were new. Many other studies had been done on the Red Sea fish parasites by Hassanine (1995Hassanine ( , 2005Hassanine ( , 2007. On the other hand, Nagaty (1956) described Gyliauchen volubilis from the small intestine of Amphacanthus sigan, called ''sigan'' from Sharm El-Naga in Hurghada.…”