Rotylenchus elisensis - New species associated with soybean roots

Abstract

In a study of soybean varieties devoted to encouragement of its cultivation by the growers of the State of São Paulo, we had the opportunity to examine soil samples to identify parasitic nematodes. From one of these samples we found a tylenchoid parasite that called our attention because of the particularity of males being more numerous than females. As we could not take this material for a careful investigation on this parasite at that time, we kept it in slide preparation for later examination. A recent study of this material provided the following characteristics. Body in spiral shape, cylindrical, tapering gradually from base of oesophageal region to lip region and sharply from anus to terminus. Cuticle annulated. Lateral fields more or 1ess one third as wide as body diameter. Phasmid in posterior region of the anus. Male and female tails arcuate ventrally and the terminus of it is like that of Paratylenchus macrophallus. The male tail is enveloped by a rudimentar bursa. Lip region continuous with the neck contour and marked by four or five transverse striae. Cephalic papillae and amphids not seen. Buccal stylet 21 to 24 microns long, with strongly developed basal knobs. Vestibulum wall thickened, forming a cylindrical guide for stylet. Outlet of dorsal oesophagus gland about one fourth the length of buccal stylet behind the latter. Oesophageal bulb spheroid with small sclerotized valvular apparatus, Junction of oesophagus with the intestine obscure, but certainly the three oesophageal glands are not joined to form a basal bulb as in Tylenchorhynchus. Intestine opaque. Rectum and anus obscure. Branches of amphidelphic sexual apparatus of female outstretched, not so long. The posterior one reaching to near the rectum. Vulva post-equatorial. Male spicula 24 microns long, arcuate as the tylenchoids. Testis single, long as half the length of the body. Rotylenchus elisensis is different from all described species by the male and female tail end, which is like that of Paratylenchus macrophallus.