THREE NEW SPECIES OF LIGOPHORUS (MONOGENEA: DACTYLOGYRIDAE) ON THE GILLS OF MUGIL CEPHALUS (TELEOSTEI: MUGILIDAE) FROM THE JAPAN SEA^*

Abstract

Comparative morphology and multivariate morphometric analysis of monogeneans collected on flathead mullets Mugil cephalus from 2 Russian localities of the Japan Sea revealed the presence of 3 new species of Ligophorus, namely, L. domnichi n. sp., L. pacificus n. sp., and L. cheleus n. sp., which are described herein. So far, only 1 species of dactylogyrid monogenean identified as Ligophorus chabaudi was known on flathead mullets in this sea, but after comparison with the present material, we propose that this form actually represents L. domnichi n. sp. Results support previous zoogeographical evidence, suggesting that flathead mullets from different seas harbor different species complexes of Ligophorus. One interesting finding is that the 3 new species have a U-shaped ovary, whereas ovate ovaries have been reported in previous descriptions of species of the genus, e.g., L. vanbenedenii, L. parvicirrus, L. imitans, and L. chongmingensis. The U-shaped ovary was revealed only when the worms were observed in lateral view. The additional examination of L. vanbenedenii, L. parvicirrus, L. imitans, and L. pilengas specimens from our collections also revealed a U-shaped ovary in these forms as well. Further studies should establish whether or not this character is shared by all members of the genus.

Ligophorus species (Monogenea: Ancyrocephalidae) from Mugil cephalus (Teleostei: Mugilidae) off Morocco with the description of a new species and remarks about the use of Ligophorus spp. as biological markers of host populations

“…6 -entity 3): L. huitrempe Fernandez, 1987; (ii) Northwest Atlantic ocean ( Balbuena et sarabeev, 2007;L. domnichi rubtsova, Balbuena et sarabeev, 2007;L.…”

Ligophorus uruguayense sp. nov. (Monogenea, Ancyrocephalidae), a gill parasite from Mugil platanus (Mugiliformes, Mugilidae) in Uruguay

“…Additionally, Ligophorus uruguayense differs from L. euzeti Dmitrieva et Gerasev, 1996, L. gussevi, L. llewellyni Dmitrieva, Gerasev et Pron'kina, 2007, and the three recently described species from the Japan Sea by Rubtsova et al (2007): L. domnichi, L. cheleus and L. pacificus, mainly in the shape of the accessory piece of the penis, the host species and the geographic distribution.…”

“…A total of twenty-five characters of sclerotized structures were measured, of which twenty-two were defined by Mariniello et al (2004), Rubtsova et al (2007), and the remaining three are defined here, namely distance between upper and lower lobe of the penis ac-Gabriela Failla Siquier and Margarita Ostrowski de Núñez 96 cessory piece; the vaginal plate (corresponding to the saucershaped opening); and the vaginal ring (corresponding to transverse annulations at the distal end). All these structures were measured on fixed and live specimens, except the vaginal plate and the vaginal ring, which were measured on live specimens only.…”

“…mediterraneus Sarabeev, Balbuena et Euzet, 2005 cited for the Mediterranean Sea, from specimens formerly assigned to L. mugilinus by Euzet and Suriano (1977); and (3) L. vanbenedenii Parona et Perugia, 1890 cited for the Japan Sea, was first transferred to L. chabaudi by Euzet and Suriano (1977), and then described as a new species, L. domnichi Rubtsova, Balbuena et Sarabeev, 2007 (see Sarabeev andSarabeev et al 2005;Balbuena et al 2006;Rubtsova et al 2006Rubtsova et al , 2007.…”

“…The genus Ligophorus was established for species recovered from Mediterranean mugilids. In the Northern Hemisphere, new species of Ligophorus were found parasitizing mugilid species from the Black Sea, Azov Sea, Mediterranean Sea, North Atlantic Ocean, and Pacific Ocean (Dmitrieva and Gerasev 1996;Sarabeev and Balbuena 2004;Sarabeev et al 2005;Rubtsova et al 2006Rubtsova et al , 2007Dmitrieva et al 2007). In the Southern Hemisphere the only species so far described is L. huitrempe Fernández Bargiela, 1987 from a mugilid in the Chilean coast, Pacific Ocean.…”