MORPHOMETRIC VARIATION AND JUVENILE STAGES OF SOME LONGIDORID NEMATODES FROM BULGARIA WITH COMMENTS ON THE NUMBER OF JUVENILE STAGES OF LONGIDORUS AFRICANUS, L. CLOSELONGATUS AND XIPHINEMA SANTOS
The morphometric variability of six species of longidorid nematodes occurring in south west Bulgaria is discussed. It is suggested that Longidorus distinctus, Xiphinema italiae and X. vuittenezi may have three or four juvenile stages, L. euonymus and L. latocephalus have three and X. pachtaicum four juveniles stages. L. closelongatus from Crete and L. africanus from Egypt and X. santos from Egypt and Portugal must be regarded as populations with only three juvenile stages. The evidence of scatter diagrams of body length and stylet measurements for each of the species is discussed in relation to the possibility that in some there may be two juvenile forms with similar stylet measurements but differing in body length.