A note on Xiphinema inaequale (khan et Ahmad) and X. saopaolense Khan et Ahmad

Abstract

Khan and Ahmad described in 1975 a new species of Xiphinema Cobb from India: X. neoamericanum. At that time they were unaware that a species had been described under the same name in 1973, also from India, by Saxena, Chhabra and Joshi. These two species are clearly different, the odontostyle being 70-72 [Lm and the ({ c» value 27-29 for Saxena's et al. specimens but 98-105 [Lm and 49-69 respectively for those of Khan et Ahmad. However, the illustration 1D of Saxena et al. shows a tail of about 30 [Lm, which would give a ({ c» value of 53-68. Recently Khan and Ahmad (1977) renamed their species X. inaequale (Kahn et Ahmad, 1975) which in the original description is considered different from X. brevicolle Lordello et Da Costa 1961 because of the longer tail (c = 49-69 viz. 63-93 and c' 1 viz. < 1) and the longer basal portion of the oesophagus (2 neck widths viz. 1.5). We have studied populations of X. brevicolle of different geographical origin (Table 1) and have noted that the tail length is a variable character comprising in its range the 30 [Lm long tail of Fig. 1 D in the original description and the 26 [Lm long tail of the para type of X. inaequale which we have examined. Moreover, the ratio oesophageal bulb: neck width varies in the Brazilian population of X. brevicolle from 1.8 to 2, being almost the same as that of X. inaequale. Finally, we have observed that the lip region of the two species is identical in shape: offset from the rest of the body by a slight depression. We suggest, therefore, that X. inaequale and X. brevicolle are probably identical.