Female – body worm-like in shape, tapering to both extremities, more abruptly posteriorly to a blunt tail. Lip region slightly set off from neck, bearing three annules (2 striations). Cuticle marked by fine transverse striation. Lateral fields showing four lines. Outer margin of cephalic framework normal.
Stylet strong, with round knobs and well developed protrudor muscles. The distance between the opening of the dorsal oesophageal gland and the stylet knobs is about 3.0 microns. Anterior conical portion of stylet as long as or a little longer than the cylindrical basal extension. Middle bulb of oesophagus slightly elongate (10.0-13.8 x 9.2-12.2 microns). Excretory pore well defined, located at the latitude of the oesophageal glands, immediately behind the hemizonid; excretory duct almost perpendicular to the ventral surface of body.
Oesophageal glands forming a broad, thick lobe overlapping beginning of intestine. Intestinal cells filled with coarse refractive granules. Anus and rectum rather obscure, invisible in some individuals.
Ovary outstretched (in one specimen the ovary was reflexed), quite developed, the anterior end commonly reaching the latitude of the oesophageal glands. Most oocytes are in tandem arrangement. Oviduct thinly walled. Eggs in uterus 68.8-70.4 microns long and 23.0 microns wide. Spermatheca not present. Apparently, the eggs are deposited before segmentation. Vulva small compared to the size of the eggs. Vagina occupying about one third of the body width. Posterior uterine branch as long as or a little longer than the width of the body. Distance from vulva to anus equal to about 3.5 times the tail length. The cuticular annulation does not follow the tail end. Phasmids small, located anteriorly to middle of tail.
Male – Unknown.
Type Host and Type Locality- As given for Nacobbus serendipiticus
bolivianus n. subsp.
Type Host (from Nacobbus serendipiticus bolivianus) – Potato, Solanum andigenum Juz. & Buk. The following varieties were found attacked by N. s. bolivianus, the numbers cited in parenthesis referring to the potato collection of the Departamento de Botanica Aplicada, Universidad Mayor de San Simon, Cochabamba, Bolívia: Añahuayu (n.o 34) from Potosi, Tinguipaya, alt. 3,800 m; Huila pallalla (n.o 134), from Tacacoma, La Paz, alt. 3,700 m; Chiar huayli (n.o 139) from Tacacoma, La Paz; Chacapa (n.o 140), from Tacacoma, La Paz; Alkañahui (n.o 372), from Potosi-Puna, alt. 3,800 m; Ch de M.-11 (n.o 329), from La Molina Exp. Station, Peru; n.o 392 (53-52-38-1) and n.o 397 (53-90-4), two hybrids from Tibaitatá.
All the potato varieties listed above were identified as Solanum andigenum, except var. 140, which is to be referred to as Solanum sp., and vars. 392 and 397, which are hybrids of not mentioned species.
Solanum andigenum was known to be attacked only by Ditylenchus dipsaci (Kuehn, 1857) Filipjev, 1936 (Seinhorst & Dunlop, 1945), and by Heterodera rostochiensis Wollenweber, 1923 (Ellenby, 1945).
Type Locality (from Nacobbus serendipiticus bolivianus) – Koari, a farm located 85 km far from Cochabamba, Bolívia, alt. 3,200 m above sea level.
Diagnosis – P. andinus has been compared with P. tumidiceps Merzheevskaya, 1951, and with the species studied in the revision published by Sher & Allen (1953), as well as with those described later by Lordello, Zamith & Boock (1954), Taylor & Jenkins (1957), Luc (1959), Seinhorst (1959) and Loof (1960).
The species most closely resembling P. andinus is P. penetrans (Cobb, 1917) Sher & Allen, 1953, from which it differs in having: a) no Spermatheca; and, b) ovary extending to the oesophageal glands.
Redescription of P. andinus Lordello, Zamith & Boock, 1961 (Nematoda: Pratylenchidae) by D.C.M. Corbett