Metazoan parasites of white mullet Mugil curema Valenciennes, 1836 (Mugiliformes: Mugilidae) and new records of occurrence in the western Atlantic, Brazil.

Mugil curema is a pelagic fish species and it is considered the most common species of the Mugilidae family on the Brazilian coast. The objective of this study was to compile the existing information on the metazoan parasites of this host, as well as including new records from specimens captured in the Cabedelo city, state of Paraíba, Brazil. In the present study, we listed 81 taxa belonging to ten groups previously recorded for the host M. curema, and included 16 species recorded in the Cabedelo region. Eight out of 16 parasite taxa found in the Cabedelo region are first host records for M. curema: Ligophorus brasiliensis, Ligophorus sp.1, Ligophorus sp.2 (Monogenea), Fellodistomidae gen. sp., Bucephalidae gen. sp. (Digenea), Pharyngodonidae gen. sp. (Nematoda), Piscicolidae gen. sp. (Hirudinea) and Lernaeopodidae gen. sp. (Copepoda). Monogenea was the most abundant taxonomic group, followed by Copepoda. Despite the number of existing parasitological studies on this host species, new records of occurrence were made for the Cabedelo region and for the host, indicating that the knowledge about the parasites associated with this fish species is still under construction, especially because of its wide geographic distribution.

The ultrastructure of the spermatozoon of the lizard Iguana iguana (Reptilia, Squamata, Iguanidae) and the variability of sperm morphology among iguanian lizards.

The spermatozoon of Iguana iguana is filiform and resembles that of other iguanian lizards, being most similar to Tropidurus. All sperm synapomorphies of Tetrapoda, Amniota and Squamata are present in the sperm of Iguana iguana. By reconstructing the evolution of 30 sperm characters we identified a novel synapomorphy of Iguania: the presence of a well-developed acrosomal ridge at the level of the epinuclear lucent zone. Because of the poor topological resolution among iguanian clades we could not discount the possibility of convergence or neutral selection as determinant of the variability in characteristics of the sperm cell. In agreement with previous studies, we identified heterogeneous rates of evolution among the three main regions of the sperm cell, namely the head, midpiece and tail.