Description and Morphometrical Variability of a New Species of Ligophorus and of Ligophorus Chabaudi (Monogenea: Dactylogyridae) on Mugil Cephalus (Teleostei) From the Mediterranean Basin

Abstract

A comparative morphological study of specimens of Ligophorus spp. from Mugil cephalus in western Mediterranean and the Black Sea localities has been carried out, indicating the presence of 2 distinct forms, i.e., Ligophorus chabaudi and Ligophorus cephali n. sp. A detailed description of the latter and an up-to-date redescription of L. chabaudi are provided. The existence of these 2 morphological species was additionally supported by principal component analysis based on 19 metric characters of 87 specimens arranged in samples defined by parasite species and geographical locality. The analysis indicated consistent differences between species but not between localities; this pattern was well supported by jackknife procedures. Linear discriminant analyses showed that the main metric differences between the 2 species were attributable to the lengths of the dorsal and ventral bars and to the uncinulus length; use of the first 2 variables was enough to allocate all specimens studied to either form. The erection of L. cephali n. sp. raises the number of sympatric Mediterranean species of Ligophorus on M. cephalus to 3. The known geographical ranges of these species are compared.

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

“…Based on the features mentioned above, L. uruguayense differs from the following Mediterranean species described by (1) Euzet and Suriano (1977): L. szidati, L. chabaudi, L. macrocolpus, L. acuminatus, L. minimus, L. heteronchus, L. angustus, L. imitans, L. confusus;(2) Euzet and Sanfilippo (1983): L. parvicirrus; (3) Sarabeev et al (2005): L. mediterraneus; and (4) Rubtsova et al (2006): L. cephali, on the basis of the shapes of the ventral bar and anchors, the accessory piece of the penis and the vaginal aperture, the host species and the geographic distribution. 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.…”

“…The distance between the membranous processes of the ventral bar is not a reliable measurement because it differed between mounted and live specimens or the membranous processes could not be seen clearly. In contrast to Rubtsova et al (2006), no difficulty was found in obtaining an accurate measurement of the whole length of the penis either for live or mounted specimens.…”

“…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.…”

Phenotypic plasticity in haptoral structures of Ligophorus cephali (Monogenea: Dactylogyridae) on the flathead mullet (Mugil cephalus): a geometric morphometric approach

“…Slides were then mounted in Kaiser's glycerol-gelatin and examined under a microscope at 100× magnification. The specimens were identified as L. cephali on the basis of morphological traits (haptoral and copulatory structures) based on Rubtsova et al (2006), Dmitrieva et al (2009 and Sarabeev et al (2013).…”