Molecular evidence for cryptic species within Cylicostephanus minutus (Nematoda: Strongylidae)

Abstract

The nucleotide sequences of the first and second internal transcribed spacers of nuclear ribosomal DNA were determined for adults of Cylicostephanus minutus from different geographical origins. The lengths of first and second internal transcribed spacer sequences ranged from 370 to 372 bp and 215 to 216 bp, respectively. Pairwise sequence comparisons revealed that some individuals of C. minutus had identical first and second internal transcribed spacer sequences, whereas others differed by 3.0% and 7.4% in their first and second transcribed spacers, respectively. Some individuals with sequence differences originated from the same host. The levels of difference within C. minutus were higher t..