A karyological study of the spirurid nematode Mastophorus muris (Nematoda: Spirocercidae).

The karyotype of Mastophorus muris (Gmelin, 1790) comprises four pairs of small autosomal chromosomes and two larger sex X chromosomes in females or one X chromosome in males (2n = 8 + XX/XO). All pairs of chromosomes possess rather uniform morphology without distinct primary or secondary constrictions. No heterochromatin bands were found by C-banding analysis. The absolute chromosome length ranges from 4.02 to 2.24 microns. The mean total length of the haploid complement is 14.34 microns. The course of gametogenesis represents a typical pattern common in the order Spirurida. The recently available karyotypes of spirurid nematodes have been reviewed.