Sumario: |
A new dagger nematode, Xiphinema tica n.
sp., is described and illustrated from several populations extracted from soil associated with several crops and wild plants in Costa Rica. The new dagger nematode is
characterised by a moderate body size (3276–4240 μm),
a rounded lip region, ca 13.5 μm wide, separated from
body contour by a shallow depression, amphidial fovea
large, stirrup-shaped, a moderately long odontostyle ca
135 μm long, stylet guiding ring located at ca 122 μm
from anterior end, vulva almost equatorial (50–54%),
well-developed Z-organ, with heavy muscularised wall
containing in the most of specimens observed two moderately refractive inclusions variable in shape (from
round to star-shaped), with uterine spines and crystalloid
bodies; female tail short, dorsally convex-conoid, with
rounded end and a small peg, with a c’ ratio ca 0.8,
bearing two or three pairs of caudal pores and male
absent. The unique and novel uterine differentiation
based on the coexistence of a well-developed Z-organ
mixed with uterine spines and crystalloid bodies in
Xiphinema prompted us to update and include this
combination of characters in the polytomous key of
Loof and Luc (1990). Integrative diagnosis was completed with molecular data obtained, using D2-D3 expansion segments of 28S rDNA, ITS1-rDNA, partial
18S–rDNA and the partial mitochondrial gene cytochrome c oxidase subunit 1 (coxI). The phylogenetic
relationships of this species with other Xiphinema spp.
indicated that X. tica n. sp. was monophyletic to the
other species from the morphospecies Group 4,
Xiphinema oleae.
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