Cytogenetics of four species of Spirostreptidae (Diplopoda, Spirostreptida).

Considering an estimated number of millipedes of approximately 80,000, cytogenetic studies on these animals are rare, as only a total of 70 species have their karyotypes described. The present study reports on the chromosomal number of four Brazilian diplopods of the family Spirostreptidae: Urostreptus atrobrunneus with 2n=24, XY; Gymnostreptus olivaceus 2n=12, XY and Alloporus araraquarensis and A. principes, 2n=18, XY.