Nudaciraxine imperium sp. n. (Monogenea: Axinidae) from the gills of Mediterranean needlefish Tylosurus acus imperialis (Teleostei: Belonidae)

Abstract

Nudaciraxine imperium sp. n. (Monogenea: Axinidae) is described from the gills of the needlefish Tylosurus acus imperialis (Rafinesque) caught in the gulf of gabès, Tunisia. This new species mainly differs from both previously described species, Nudaciraxine gracilis (Linton, 1940) Price, 1962 from Strongylura marina (Walbaum) and Nudaciraxine cabosanlucensis Payne, 1990 from Ablennes sp., by having more testes (42 vs. 20-22 and 32, respectively). Nudaciraxine imperium also differs from N. gracilis by having a median vaginal pore (submedian in N. gracilis), narrower clamps (52-70 µm vs. 75-100 µm) and differently shaped haptoral lateral hamuli. From N. cabosanlucensis it can be distinguished by a J-shaped rather than U-shaped ovary, a longer cirrus pouch (125-190 µm vs. 64-70 µm), an oesophageal bifurcation slightly anterior to genital complex (immediately after pharynx in N. cabosanlucensis) and a wider guard on the lateral hamuli. In agreement with Payne (1990), the diagnosis of the genus Nudaciraxine Price, 1962 is amended as follows: vaginal pore dorsal, median to submedian, armed or not with horn-like spines. This is the first report of the genus Nudaciraxine in the Mediterranean Sea. The potential use of axinid monogeneans as biological tags for subspecies of belonid fishes is discussed. During a recent parasitological study on fishes in the gulf of gabès (Tunisia), three species of Monogenea were collected from T. a. imperialis: Aspinatrium gallieni Euzet et Ktari, 1971 (Microcotylidae) on the inner side of the operculum and also two additional previously undescribed axinid species on the gills. In this paper we describe one of these, the most abundant axinid monogenean, as a new species of Nudaciraxine. The potential use of axinid monogenean as biological tags for subspecies of belonid fishes Tylosurus is discussed. Keywords MAteRIALs AND MethoDsBetween May and July of 2004, 2006 and 2007, 74 specimens of T. a. imperialis caught in the gulf of gabès (Tunisia) by local fishermen using gill nets were examined. This fish inhabits offshore waters, but can be found in coastal waters during spring and summer. Specimens were identified using Bauchot (1987).Fish were dissected and examined a few hours after capture. The operculum and gill arches were separated and placed in Petri dishes with filtered seawater using filter paper. Monogeneans were detected using a stereomicroscope, detached from the gills and operculum and then transferred to a dish containing filtered seawater. They were studied either alive or fixed between slide and coverslip in 70% alcohol. Fixed specimens were stained with Semichon's acetic carmine. Other specimens were double-stained with light green and Semichon's acetic carmine to study the morphology of the clamps. After dehydration

Diversity of monogenean parasites in belonid fishes off the Mediterranean Sea with redescription of Aspinatrium gallieni Euzet and Ktari, 1971 and Axine belones Abildgaard, 1794

“…During parasitological survey on various species of belonids along Tunisian coast, several Polyopisthocotylean monogeneans were recovered. We recently described monogenean species Nudaciraxine imperium Châari, Derbel and Neifar, 2010 (N. imperium) from the gills of Tylosurus acus imperialis Rafinesque, 1810 (T. a. imperialis) [18]. This paper enhances the current knowledge of monogeneans from belonid hosts off Tunisian waters.…”

“…In Tunisia, several studies on the monogenean parasites of fishes have been made [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Concerning those of belonid fishes, only two records have previously shown presence of Axine belones Abildgaard, 1794 (A. belones) on Belone belone Lowe, 1839 (B. belone) [20] and Aspinatrium gallieni Euzet and Ktari, 1971 (A. gallieni) on Strongylura acus Lacépède, 1803 (S. acus) [3].…”

Sclerodistomoides pacificus Kamegai, 1971 (Sclerodistomoididae Gibson & Bray, 1979) and Tetrochetus coryphaenae Yamaguti, 1934 (Accacoeliidae Odhner, 1911), two rarely reported digeneans from Tylosurus acus imperialis (Rafinesque) (Belonidae), and a list of helminth parasites of Tylosurus acus (Lacépède)

“…Raibaut et al (1998) listed the copepods of T. a. imperialis from the Mediterranean Sea. In a study on the biodiversity of parasite communities in T. a. imperialis off the Tunisian coast, we recently described the monogenean Nudaciraxine imperium Châari, Derbel & Neifar, 2010 and two digenean species, Lecithostaphylus tylosuri Châari, Derbel & Neifar, 2013 and Oesophagotrema mediterranea Châari, Derbel & Neifar, 2011(see Châari et al, 2011, 2013. The present paper deals with redescriptions of two other poorly known digenean species, Sclerodistomoides pacificus Kamegai, 1971 andTetrochetus coryphaenae Yamaguti, 1934.…”

Parasitic infections in the Mediterranean needlefish Tylosurus acus imperialis (Teleostei: Belonidae) off Tunisian coast

“…Raibaut [6][7][8]. However, the quantitative aspect of parasites of T. acus imperialis has not previously been studied.…”