Within the genus Prochilodus Agassiz, 1829, five species are known to carry B chromosomes, i.e. chromosomes beyond the usual diploid number that have been traditionally considered as accessory for the genome. Chromosome microdissection and mapping of repetitive DNA sequences are effective tools to assess the DNA content and allow a better understanding about the origin and composition of these ...

The present work studied the prevalence and histopathology of Neoechinorhynchus curemai Noronha, 1973 (Acanthocephala; Neoechinorhynchidae) from curimbatá, Prochilodus lineatus Valenciennes, 1836. Eighteen fishes with averages of 46.7 +/- 1.1 cm length and 1,674.8 +/- 75.6 g weight were collected with net, bimonthly from December 1995 thru December 1996 in the hydroelectric power station of Vol...

The ultrastructural organization of the mature spermatozoon of the digenean Atractotrema sigani (from Siganus lineatus off New Caledonia) was investigated by transmission electron microscopy. The male gamete of A. sigani exhibits the general morphology described in digeneans with the presence of two axonemes of different lengths showing the 9 + "1" pattern of the Trepaxonemata, a nucleus, two m...