Abstract:
The nematode genus Bursaphelenchus is a highly divergent group. This genus mainly consists of mycophagous entomophilic species, but some species have specialized as obligate
or facultative plant parasites, facultative insect parasites, or exhibit feeding dimorphism
(phenotypic plasticity) leading to mycophagous and predatory forms. In the present study, a
new Bursaphelenchus species, B. suri n. sp. was isolated from fresh syconia (figs) of Ficus
sur and is described and illustrated based on its typological characters and molecular phylogenetic status. The new species is characterized by its highly derived feeding structures
found in obligate plant parasites, lip possessing a labial disc and a long and thick stylet with
a long conus and extremely well-developed basal swellings. In addition, slender body of
both sexes is characteristic of the species. The new species is phylogenetically and typologically closely related to B. sycophilus, i.e., these two species share the characteristic feeding
structures and form a well-supported clade within the B. fungivorus group in the genus. Biologically, these two species are both isolated from fresh figs of the section Sycomorus. However, the new species differs from B. sycophilus by the length of the female post-uterine sac
and the shape of the male spicule, i.e., the new species has a long post-uterine sac and
spicule condylus without dorsal recurvature. Thus, the new species is the second obligate
fig parasite of the genus, and the evolutionary relationship between the B. suri n. sp. and B.
sycophilus clade and section Sycomorus figs is hypothesized as an example of adaptive
radiation with more species to be discovered.
