| Popis: |
Plerocercus larvae of Callitetrarhynchus parvus sp. nov. (Trypanorhyncha: Lacistorhynchidae) were collected from commercially exploited fish, the black Scorpionfish Scorpaena porcus Linnaeus, 1758, the white grouper Epinephelus aeneus (Geoffroy Saint-Hilaire, 1817) and the dusky grouper Epinephelus marginatus (Lowe, 1834) from Tunisian waters. The prevalence of plerocerci larvae recorded in the three hosts were low 1.4%, 9.4% and 12.5%, respectively. The blastocysts were found attached to the external stomach wall of infected fish. Light and scanning electron microscopical observations of larvae showed a scolex with two bothria, a poeciloacanthous atypical, heteromorphous metabasal armature, with 7 hooks, one intercalary hook and one chainette. Hook 7(7') was unicate with an anterior extension at the base (BR = 3.86-6.38:1). Molecular characterization of the rDNA regions (SSU, LSU and ITS) confirmed that the species was included in the genus Callitetrarhynchus. The phylogenetic analysis carried using the SSU rDNA and LSU rDNA concatenated complement the characterization of the new species by defining its phylogenetic position among the species of the family Lacistorhynchidae Guiart, 1937. Molecular analysis revealed a high genetic distance between C. parvus sp. nov. and its congeners from the Callitetrarhynchus genus. |
