Multiple Chromosome Fissions, Including That of the X Chromosome, in Kaup (Coleoptera, Passalidae) from New Caledonia: Characterization of a Rare but Recurrent Pathway of Chromosome Evolution in Animals.

The male karyotype of Kaup 1868 (Coleoptera, Scarabaeoidea, Passalidae, Aulacocyclinae) from New Caledonia contains an exceptionally high number of chromosomes, almost all of which are acrocentric (53,X1X2Y). Unlike the karyotypes of other species of the pantropical family Passalidae, which are principally composed of metacentric chromosomes, this karyotype is derived by fissions involving almost all the autosomes after breakage in their centromere region. This presupposes the duplication of the centromeres.

Structure and ultrastructure of the ovary in the South American Veturius sinuatus (Eschscholtz) (Coleoptera, Passalidae).

The morphoanatomy of the ovary in Veturius sinuatus (Eschscholtz) was studied by light and transmission electron microscopy. Data from the female gonad of this species provide more extended and precise knowledge regarding the organization of the ovary in Passalidae. Ovaries are composed of a pair of long telotrophic meroistic ovarioles, with some differences compared to the bauplan of this ovary type in Polyphaga (Coleoptera).

Parthenogenetic reproduction demonstrated in the diploid Spasalus puncticollis (Le Peletier & Serville 1825), n. stat., from the Antilles (Coleoptera, Scarabaeoidea, Passalidae).

Only females were observed in Spasalus crenatus (Mac Leay 1819) in the Antilles, from Puerto Rico to Saint-Vincent, whereas both sexes are in Trinidad and on the continent. No difference in endo- and ectodermic female genitalia could be noticed between the two populations. Chromosomes of specimens from Guadeloupe reveal a 26,XX karyotype, as in females of various sexual species of Passalini, which demonstrates its diploidy.