Abstract
Ph.D. (Nematology)
This thesis consists of three parts: the first and major part dealing with
Xiphinema species from southern Africa. the second shorter part with
Xiphinema species from the Aldabra Atoll. and the last part with aspects of
the ultrastructure of Xiphidorus balcarceanus Chaves & Coornans, 1984
from Argentina.
Nine new Xiphinema species are described from southern Africa. The
three new species X. erriae, X. ripogranum and X. lacrimaspinae are all related
to X. meridianum Heyns. 1971. but can be differentiated by the nature
of the uterine spines and inclusions in the pseudo-Z-organ. tail shape.
ovejector shape and the presence or absence of males. Two new longtailed
species related to X. fJagellicaudatum Luc, 1961. viz. X. judex and X.
dracomontanum, can be distinguished by body length. tail length and
shape. the nature of the pseudo-Z-organ and presence or absence of
males. Three new species with digitate or subdigitate tails are described,
viz. X. capriviense from South West Africa-Namibia, which is characterised
i.a. by peculiar inclusions in the uterus. X. pongolense from northern Natal
which is quite similar to X. umobae Heyns & Spaull, 1979. and X. simplex from
the Transkei, in which the uterus is devoid of any inclusions. The last new
species to be described is X. ometizulu, which belongs to the X. zulu Heyns,
1965 and X. mampara Heyns, 1979 species complex.
The abovementioned species complex was studied in detail, and X.
mampara was found to consist of three different forms, one amphimictic,
which is herein called X. mampara f. bisexuale. and two parthenogenetic
forms. called X. mampara f. major and X. mampara f. minor.
Redescriptions based on new populations are given for X. clavatum
Heyns, 1965 and X. imitator Heyns, 1965. and additional information is also
offered for X. umobae.
A dichotomous key is presented for the identification of the 54 species
of Xiphinema recorded from southern Africa. and the known distribution of
these species is shown in a series of maps.
X. brevicolle Lordello & Da Costa. 1961. X. italiae Meyl. 1953 and X.
malagasi tuc, 1973 are reported from the Aldabra Atoll. All three species
are described and figured, and compared with previous descriptions.
The ultrastructure of the cuticle and feeding apparatus of Xiphidorus
ba/carceanus was studied and compared with some other Longidoridae
species.