Morphological and molecular characterisation of Californian species ...

Studies on Metaporcelaimus
Table 2. Morphometric data of female Metaporcelaimus ovogranulosus
sp. n. All measurements are in μm except L in mm,
and in the form: mean ± s.d. (range).
Character
El Dorado County
Salix sp. and other trees
Holotype
Paratypes
n – 18
L 1.96 1.75 ± 0.12 (1.54-1.96)
a 40 36.2 ± 1.5 (34-39)
b 3.6 3.9± 0.2 (3.6-4.2)
c 49 43.7 ± 3.5 (39-52)
c ′ 1.5 1.5 ± 0.1 (1.4-1.6)
V 51 49.9 ± 0.9 (48-51)
Lip region diam. 19 18.2 ± 0.6 (17-19)
Odontostyle length 18 18.6 ± 0.4 (17-19)
Odontophore length 34 32.9 ± 1.7 (27-35)
Guiding ring from ant. end 8.5 8.7 ± 0.3 (8.0-9.5)
Neck length 539 448 ± 23.0 (415-480)
Pharyngeal expansion length 275 230 ± 13.8 (213-253)
Diam. at neck base 47 45.6 ± 3.7 (38-53)
at mid-body 49 49.0 ± 3.6 (42-56)
at anus 28 26.9 ± 1.6 (24-30)
Prerectum length 79 83.3 ± 32.4 (53-161)
Rectum length 35 32.4 ± 2.2 (27-35)
Tail length 40 40.4 ± 2.6 (35-44)
occasionally visible but poorly developed. Lip region offset
by deep constriction, 2.8-3.1 times as broad as high
and one-third to one-half (35-46%) of body diam. at neck
base, lips angular and moderately separated, labial papillae
slightly protruding. Amphid fovea funnel-shaped, its
aperture 9.0-9.5 μmorca one-half (47-54%) of lip region
diam. Cheilostom nearly cylindrical, lacking any differentiation.
Odontostyle typical of genus, 4.9-5.4 times as
long as wide, 0.9-1.0 times as long as lip region diam., and
0.9-1.14% of body length, aperture 11-14 μm long or occupying
up to three-fourths (70-74%) its length. Guiding
ring plicate. Odontophore linear, rod-like, 1.5-1.9 odontostyle
lengths long. Anterior region of pharynx enlarging
very gradually; basal expansion 6.7-9.1 times as long
as wide, 4.7-5.8 times as long as body diam., occupying
49-53% of total neck length, pharyngeal gland nuclei
apparently located as follows: DN = 58-61, DO-DN =
21 μm (n= 1), S 1 N 1 = 64% (n = 1), S 1 N 2 = 71-72%
(n = 3), S 2 N = 86-89% (n = 3). Nerve ring located at
136-161 μm from anterior end or 30-34% of total neck
length. Cardia conical, (14-17) × (10-14) μm, its junction
with pharyngeal base surrounded by weak ring-like
structure, visibly asymmetrical as dorsal surface is larger
than ventral, dorsal cellular mass present at level of anterior
end of intestine in some specimens. Genital system
didelphic-amphidelphic, with both branches equally
and moderately developed, anterior 118-229 μm or7-
13% of body length (178-261 μm long or 11-14% of body
length with an egg inside), and posterior 113-190 μm or
7-11% of body length (178-253 μm long or 10-13% of
body length with an egg inside). Ovaries comparatively
large, anterior 64-204 μm and posterior 69-239 μm long,
oocytes arranged first in two or more rows, then in a single
row. Oviduct 66-119 μm long or 1.4-2.3 times corresponding
body diam., consisting of slender part with prismatic
cells and a very poorly developed pars dilatata with
very narrow lumen. Oviduct-uterus junction barely perceptible.
Uterus a simple tube 27-41 μm long or 0.6-0.8
times corresponding body diam. Uterine eggs ovoid, (88-
103) × (33-37) μm, 2.4-2.8 times as long as wide, its shell
bearing small but abundant granular bodies. Vagina extending
inwards 19-24 μm, occupying two-fifths to onehalf
(38-52%) of body diam., pars proximalis 11-17 ×
13-19 μm, with somewhat sigmoid walls and surrounded
by weak musculature, pars refringens with two adjacent
triangular to rounded pieces measuring (5.5-7.5) × (4-
5) μm, combined width of 7.5-10.5 μm, pars distalis 1.5-
2.5 μm long. Vulva a nearly equatorial, transverse slit.
Prerectum 2.0-3.6, rectum 1.0-1.5 anal body diam. long.
Tail conical with rounded tip, ventrally straight, dorsally
convex or with a weak concavity at terminus, inner core
somewhat sunken at both sides and forming a digitate,
terminal extension nearly reaching tail tip, hence hyaline
portion of tail is very short. Two pairs of caudal pores,
subdorsal, at middle of tail.
Male
Unknown.
TYPE LOCALITY AND HABITAT
American River Parkway, River Bend Park, El Dorado
County, California, USA, where the new species was
collected in association to willow (Salix sp.) and other
trees.
TYPE MATERIAL
Female holotype and 16 female paratypes deposited in
the nematode collection of the University of Jaén, Spain.
Two female paratypes deposited with USDA Nematode
Collection, Beltsville, MA, USA.
Vol. 00(0), 2012 11