Обнаружение и морфология личиночных стадий трематоды Gymnophallus rebecqui (Bartoli, 1983) (Trematoda: Gymnophallidae) в двустворчатых моллюсках у Черноморского побережья Крыма

Abstract

The purpose of the research description of larvae Gymnophallus rebecqui (Bartoli, 1983) morphology from bivalve mollusks Abra segmentum Recluz, 1843 and Cerastoderma glaucum Poiret, 1789 in the Black Sea; to study seasonal abundance of G. rebecqui in the Black Sea. Materials and methods . During 2011–2012 years, 875 samples of bivalves A. segmentum and 440 samples of C. glaucum were investigated from two biotopes Sevastopol water area. The samples were selected every month. All mollusks tissues were investigated for parasites with a compressor method over binocular at increase × 98. The detected cercarias and metacercarias were fixed for life and dyed with acetous carmine, and after dehydration in a series of alcohol and clarification in clove oil were placed in Canada balsam. One of the generally accepted systems of trematodes measuring was used in the work. Measurings were made on microscope XY-B2 with с a film camera at increase × 1000. The images were made in redactor of vector graphics Inkscape 0.48.2-1. Results and discussion . For the first time, at the estuary of the river Chernaya and in the Black Sea, larvae of trematodes G. rebecqui have been found in mollusks A. segmentum and C. glaucum. A. segmentum has appeared to be not only the second intermediate host for such trematode in the studied ecosystem but also parthenitas G. rebecqui were detected in it. According to the main diagnostic and morphological features, the analyzed larvae of trematodes were identified as G. rebecqui: the Y-shaped secretory cyst without diverticula in cercarias, and the absence of the ventral hole and of accumulation of prostatic cells over the ventral sucker at the metacercaria stage. The morphometric features of the cercarias and metacercarias of trematodes G. rebecqui, which were studied by us, are within the boundaries known for larvae of this type parasitizing in mollusks A. segmentum and C. glaucum off the coasts of France, Great Britain and the Black Sea. An infection peak of mollusks C. glaucum with metacercarias G. rebecqui was observed in late summer and early autumn in both regions.