Morphological and molecular characterisation of Californian species ...

S. Álvarez-Ortega et al.
Metaporcelaimus subhasi comb. n.: The conical elongate
tail with finely rounded or acute tip of this species
supports its inclusion in Metaporcelaimus. Its original description
is of poor quality, lacking many relevant morphological
details. It is very similar, if not identical, to M.
chauhani, a widely distributed species in India, and might
be its junior synonym.
Key to species
1. Pars refringens vaginae absent...................2
Pars refringens vaginae present, with two well developed
sclerotised pieces . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2. Lip region 12-13 μm wide; odontostyle 14 μm long
.............................cylindricus comb. n.
Lip region > 14 μm wide; odontostyle > 15 μm long
...............................................3
3. Lip region 20-22 μm wide; odontostyle 20-21 μm
long; V = 59-61.................shamimi comb. n.
Lip region < 20 μm wide; odontostyle < 19 μm
long; V 58...................................4
4. Body 2.6-3.1 mm long; neck 700-760 μmlong.....
.......................................oceanicus
Body < 2.5 mm long; neck < 550 μmlong.......5
5. Lip region offset by more or less marked depression;
tail lacking any dorsal concavity . . . . . . . . . . . . . . . . . 6
Lip region offset by constriction; tail bearing a more
or less developed dorsal concavity . . . . . . . . . . . . . . . 7
6. Body 2.40-2.45 mm long and more slender (a = 49-
50); pharyngeal expansion occupying 56-57% of total
neck length; uterus > 2 body diam. long . . . . . . . . . . .
.................................indicus comb. n.
Body 1.51-2.09 mm long and more obese (a = 30-
40); pharyngeal expansion occupying 48-56% of total
neck length; uterus < 1.5 body diam. long . . . . . . . . .
................................insignis comb. n.
7. Body more slender (a = 38-51); comparatively
shorter neck (b = 4.3-4.8); pharyngeal expansion occupying
45-52% of total neck length; male present . .
....................................ahmadi sp. n.
Body more obese (a = 32-33); comparatively longer
neck (b = 3.8-4.1); pharyngeal expansion occupying
53-55% of total neck length; male absent . . . . . . . . . .
.......................................coomansi
8. Female tail conical with subacute or acute tip . . . . . 9
Female tail conical with more rounded terminus . . 11
9. Vulva more anterior, V 54; shorter neck, 1.5 mm long (including A. parangalitzi, 1.44-
1.99 mm long) and more slender (a 26). . . . . . . .12
12. Odontostyle up to 20 μmlong..................13
Odontostyle > 20 μm long (including A. capitatus
19-23 μm long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
13. Longer body, L > 2.50mmlong................14
Shorter body, L < 2.50 mm long . . . . . . . . . . . . . . . . 18
14. Female tail shorter, c ′ = 1.0-1.3.................15
Female tail longer, c ′ 1.4.....................16
15. Vulva more anterior, V = 49-53; 10-12 regularly
spaced ventromedian supplements, the posteriormost
one or two lying within range of spicules. . . . . . . . . . .
......................................romanicus
Vulva more posterior, V = 58; 8-9 regularly spaced
ventromedian supplements lying outside range of
spicules..........................thornei comb. n.
16. Body distinctly narrowing at level of odontophore
base; odontostyle 14-16 μmlong..........labiatus
Body not distinctly narrowing at level of odontophore
base; odontostyle 19-20 μmlong...............17
17. Body 2.8-2.9 mm long; neck 644-705 μm long; male
absent......................donghwaens comb. n.
Body 3.1-3.2 mm long; neck 711-721 μm long; male
present...............................sublabiatus
18. Female tail shorter, c ′ = 1.1-1.2.................19
Female tail longer, c ′ 1.3.....................20
19. Body 2.0 mm long; smaller odontostyle aperture
(occupying ca 66% of total length); tail 50 μm long
...............................raniensis comb. n.
Body 1.8 mm long; larger odontostyle aperture (occupying
ca 75% of total length); tail 36 μm long. . . .
........................................efficiens
20. Lipregion12μm wide; pharyngeal expansion occupying
53-57% of total neck length . . . . . . . . . . . . . . . . .
............................parangalitzi comb. n.
Lip region > 14 μm wide; pharyngeal expansion
occupying