Metacercariae of Galactosomum lacteum (Jägerskiöld, 1896) Looss, 1899 (Heterophyidae) from marine teleosts in the Gulf of Cagliari (southern Sardinia, Italy).

Abstract

Galactosomum lacteum (Jägerskiöld, 1896) Looss, 1899 metacercariae, encysted on the optic nerve, on the brain and/or on the muscle and the connective of the pharynx and oesophagus, were found in Spicara maena L., S. flexuosa Rafinesque, 1810, S. smaris L. (Centracanthidae), Gobius cruentatus Gmelin, 1789 (Gobiidae), Symphodus tinca L., S. mediterraneus L. (Labridae), Serranus cabrilla L. (Serranidae), Diplodus sargus L. and D. annularis L. (Sparidae) caught in the Gulf of Cagliari (southern Sardinia, Italy). Excysted specimens were identified by some distinctive morphological features: more or less expanded forebody, depending on whether the specimens were living or fixed; tubular excretory bladder extending to the posterior border of the ovary; two-chambered seminal vesicle; asymmetrical and parenchymatous ventral sucker with lines of spines within its cavity; and unarmed gonotyle. Comparison has been made with the congeneric species metacercaria, G. timondavidi Pearson & Prévot, 1971, also registered in the Mediterranean Sea.