Computerized identification of species of the genus Radopholus ( Tyienchida : Pratylenchidae )

A polytomous identification key for 24 species of Radopholus was constructed using the computer software packages EXCEL 5.0., spreadsheets and BIKEY 7 (©Lobanov & Dianov, 1994). Specimen identification is based on the principle that the initial set of taxa can be investigated interactively and reduced by different filters (i.e. character states) in several steps of identification. Quantitative characters are best utilised by EXCEL which can filter, using "Autofilter", "Advanced Filter" or "Sort", initial assemblages of taxa by a set of several characters at each step. Conversely, BIKEY has preferences to utilise qualitative characters and uses images during selection of character states, with text explanations providing only an auxiliary aid. This package provides a list of characters, arranged in descending order depending on their diagnostic value (not at random). In constructing the identification key for Radopholus it was determined that 20 characters are sufficient to identify the 24 species, with an average identification path of only 5.196 steps. The most important characters are: number ofincisures from phasmid to tail terminus, sperm shape, tail terminus shape, tail terminus annulation, relative width of the central band in lateral field, number of cephalic annules, number of incisures in lateral field, and difference in size between the anterior and posterior spermatheca.