title: Karyological analysis of Cylindera trisignata (Latreille & Dejean, 1822) from Portugal (Coleoptera, Cicindelidae).
abstract: Cellular suspensions of germinal tissues of Cylindera trisignata provided the definition of its karyotype: 2n = 23 and 2n = 26 for the males and females respectively. This Palearctic species has a sex chromosome system of the X1X2X3X4Y/X1X1X2X2X3X3X4X4 type, only found until now in Cicindela maroccana pseudomaroccana. The heterosomes are not well-differentiated from the general morphological standpoint. To explain the origin of the 4X condition, a mechanism of dissociation of the X chromosomes rather than an incorporation of autosomal segments is proposed. However, based on the occurrence of distinct ploidy levels, both in male and female cells, with a relatively high incidence for the tetraploid condition with regular autosomal bivalents, the hypothesis of a possible evolutionary role of polyploidy is suggested.
authors.affiliation: Departamento de Zoologia e Antropologia, Faculdade de Ciências, Lisboa-Portugal.
authors.forename: M J
authors.initials: MJ
authors.lastname: Collares-Pereira
authors.forename: A R
authors.initials: AR
authors.lastname: Serrano
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000235:genetics*; D005260:Female; D007621:Karyotyping; D008297:Male; D008938:Mitosis; D009867:Oogonia / Q000166:cytology; D013093:Spermatogonia / Q000166:cytology; D014960:X Chromosome