Crassolabium vietnamense, Vu & Ciobanu & Abolafia & Peña-Santiago, 2010
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publication ID |
https://doi.org/ 10.1080/00222933.2010.481055 |
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persistent identifier |
https://treatment.plazi.org/id/E759B624-FFCD-4B1A-4E97-E4DD76ADFEC6 |
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treatment provided by |
Felipe |
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scientific name |
Crassolabium vietnamense |
| status |
sp. nov. |
Crassolabium vietnamense sp. nov.
( Figures 4–6 View Figure 4 View Figure 5 View Figure 6 )
Material examined
Ten females and four males in acceptable state of conservation.
Measurements
See Table 2.
Description
Adult. Moderately slender to slender nematodes of medium size, 1.55–1.88 mm long. Body cylindrical, tapering towards the anterior end. Habitus more or less curved ventrad upon fixation, adopting an open C-shape in females, and most curved ventrad in posterior body region of males. Cuticle with very fine transverse striations, sometimes difficult to appreciate, 3.0–4.0 µm thick in anterior region, 3.0–4.5 µm at mid-body and 5.5–7.5 µm on tail; it is three-layered, especially noticeable at tail, where the inner layer appears very distinct and thicker than the intermediate and the outer layer. Lateral chord 6.0–9.0 µm wide at mid-body, occupying less than one-fifth (11–17%) of corresponding body diameter at mid-body. Two dorsal and one ventral body pores are usually present at cervical region. Lip region angular, offset by marked constriction; it is 2.6–3.0 times as broad as high and more than one-third (33–42%) of body diameter at neck base; lips moderately separated, distinct; labial and cephalic papillae protruding. Amphid fovea cup-shaped, its opening occupying 9.0–10.0 µm or hardly more than half of lip region diameter. Cheilostom 10.0–11.0 µm long, with slender walls. Odontostyle relatively slender, little wider than cuticle at its level; 1.1–1.3 times the lip region diameter long, 5.4–7.2 times as long as wide and 1.1–1.4% of body length;
Notes: Scale bars, (A) 200 µm; (B, C, E, G, H–K) 10 µm; (D, E) 50 µm.
aperture occupying 42–50% of total length. Guiding ring thin, simple, plicate, located at 0.7–0.8 times the lip region diameter from anterior end. Odontophore rod-like, 35.0–39.0 µm long, 1.6–1.9 times the odontostyle; its inner lining usually somewhat irregular or folded at its anterior part. Pharynx consisting of a slender but muscular anterior portion enlarging gradually; basal expansion 8.2–10.2 times as long as
Notes: Scale bars, (A–C, F, G) 10 µm; (D) 200 µm; (E) 20 µm.
broad, 3.9–5.4 times longer than body diameter at neck base, and occupying about half (47–56%) of total neck length; pharyngeal gland nuclei not always well perceptible, located as follows: DO = 55–58, DN = 59–64, S 1 N 1 = 69–73, S 1 N 2 = 75–78, S 2 N = 90–94. Nerve ring located at 117.0–159.0 µm from anterior end or 28–36% of total neck length. Cardia conical, 10.0–20.0 µm wide×10.0–12.0 µm long; a ring-like structure is surrounding its junction to pharyngeal base; a dorsal cellular chord is very distinct at level of cardia or anterior intestine in most specimens examined.
Female. Genital system didelphic-amphidelphic. Ovary reflexed, moderately developed, sometimes reaching and surpassing the sphincter level, the anterior 78.0–118.0 µm, the posterior 88.0–97.0 µm long; oocytes arranged first in several rows and then in single row. Genital tract often convoluted, so morphometrics provided, particularly of uterus, might not be very precise. Oviduct joining ovary subterminally, 65.0–100.0 µm long or 1.2–1.8 body diameters, and consisting of a tubular part and a welldeveloped pars dilatata. Distinct sphincter separating oviduct from uterus. Uterus very long, tripartite, i.e. consisting of a wider proximal region with distinct lumen, a more slender and rather long intermediate section with narrow lumen, and a welldeveloped, spherical, distal part; it is 148.0–224.0 µm long or 2.9–3.9 times as long as corresponding body diameter. Uterine eggs not observed. Vagina extending inwards 26.0–35.0 µm long, occupying more than half (52–57%) of corresponding body diameter; pars proximalis nearly as long as wide, 9.0–15.0×11.0–13.0 µm, with sigmoid walls and surrounded by moderately developed musculature; pars refringens with two distinct, triangular to trapezoidal, close together pieces, measuring 5.0–6.0×4.0–5.5 µm, and with a combined width of 7.5–12.0 µm; pars distalis short, measuring 3–4 µm. Vulva a postecuatorial transverse slit, which appears in every specimen of type locality covered by a more or less developed plug of translucent material, but lacking or being less developed in specimens of the other locality. Ovoid spermatozoa, 4.0–5.0 µm long present within genital tract. Pre-rectum 1.1–2.3 anal body diameter long. Rectum 1.1–1.3 times anal body diameter. Anus also covered by a more or less developed plug of translucent material, which lacks in specimens of the non-type locality. Tail rounded, slightly less convex ventrally; two pairs of caudal pores at the middle of tail, one subdorsal, other lateral.
Male. Genital system diorchic, with opposite testes. In addition to ad-cloacal pair, there is a series of eight to nine widely separated (7.0–36.0 µm apart) ventromedian supplements, the two most posterior of which are within the range of spicules; ad-cloacal pair situated at 9.0–11.0 µm from cloacal aperture; hindermost ventromedian supplement located at 16.0–22.0 µm from ad-cloacal pair. Spicules quite robust, 1.3–1.5 anal body diameters long, 4.4–4.8 times as long as wide. Lateral guiding pieces cylindrical, 15.0–16.0 µm long, 5.3–6.4 times as long as wide. Pre-rectum 3.2–4.0, cloaca 1.2–1.3 times the anal body diameter long. Cloacal aperture covered with a more or less developed plug of translucent material, which lacks in specimens of non-type locality. Tail more conoid than that of female, ventrally somewhat more straight. Two pairs of caudal pores, one subdorsal, the other lateral.
Diagnosis
This species is characterized by its body, 1.55–1.88 mm long, lip region offset by constriction and 17.0–19.5 µm wide, odontostyle 19.5–22.0 µm long with aperture occupying 42–50% its length, neck 370.0–455.0 µm long, pharyngeal expansion 173.0–246.0 µm long or occupying 47–56% of total neck length, female genital system amphidelphic, uterus very long and tripartite, pars refringens vaginae with two close together sclerotized pieces, V =55–59, vulva transverse and usually covered with a plug, tail short and rounded (19.0–25.0 µm, c =69–86, c’ = 0.6–0.8 in females), spicules 53.0–55.0 µm long, and eight to nine spaced ventromedian supplements, two of them within the range of spicules.
Relationships
This species is unique within the genus Crassolabium in usually having a plug covering the vulva, the anus and the cloacal aperture, and in lacking hiatus or pre-cloacal space. With its medium size, comparatively long odontostyle and short tail, it resembles C. australe Yeates, 1967 , C. diversum (Ciobanu, Popovici, Abolafia and Peña-Santiago, 2007) , C. lautum (Andrássy, 1959) and C. rhopalocercum (de Man, 1876) . The new species can be distinguished from C. australe by its larger size (vs. body 0.9–1.5 mm long), transverse (vs. longitudinal) vulva, longer spicules (vs. 34.0–38.0 µm), and fewer (vs. 11–14) and spaced (vs. nearly contiguous) ventromedian supplements; from C. diversum by its more offset lip region (vs. marked by depression or weak constriction), longer odontostyle (vs. 15.0–17.5 µm), uterus tripartite (vs. long but a simple tube), more rounded (vs. more conoid) female tail, and fewer (vs. 4–7) ventromedian supplements; from C. lautum (only known from males) by its lip region angular (vs. rounded) and offset by constriction (vs. continuous), more slender odontostyle, and fewer (vs. 13) and spaced (vs. nearly contiguous) ventromedian supplements; and from C. rhopalocercum by its lip region offset by constriction (vs. nearly continuous) and wider (vs. 13.0–14.0 µm), more posterior vulva (vs. V = 44–49), female tail rounded but not clavate (vs. clavate), and male present (vs. absent).
With its guiding ring plicate and the “three-layered” cuticle at tail, the new species also resembles some (atypical) members of Aporcelaimellus with short odontostyle aperture (less than half its length), in particular A. baqrii Ahmad and Jairajpuri, 1982 and A. medius Andrássy, 2002 from which it can be separated by the presence of a plug covering the vulva, the anus and the cloacal aperture, and the absence of hiatus of precloacal space. Moreover, it differs from A. baqrii in its shorter body (vs. body 1.81–2.05 mm long), shorter odontostyle (vs. 24.0–26.0 µm), uterus tripartite (vs. a short, simple tube), shorter female tail (vs. 27.0–30.0 µm), shorter spicules (vs. 63.0 µm), different arrangement of the ventromedian supplements (vs. 12 irregularly spaced) and from A. medius by having shorter neck (vs. 460.0–510.0 µm), more posterior vulva (vs. V = 52–54), comparatively longer female tail (vs. c’ = 0.4–0.5) which lacks a slight dorsal concavity, shorter spicules (vs. 72.0 µm) and different arrangement of ventromedian supplements (vs. 10 supplements out of the range of spicules, the most posterior 3 being almost contiguous).
Remarks
The most remarkable character of this new species is the absence of hiatus or precloacal space in the series of ventromedian supplements, a very unusual feature in rounded-tailed members of Qudsianematidae , although a distinctive character of the conical-tailed genus Allodorylaimus Andrássy, 1986 . Ahmad and Sturhan (2000b) described the genus Sphaeroamphis , being rounded-tailed and lacking hiatus, but, in other respects, the new species herein described does not fit the general pattern of this genus.
Type habitat and locality
Forest soil collected at about 350 m a.s.l. within the Phuoc Binh National Park (geographical coordinates: 11º 59′ N and 108º 44′ E), Ninh Thuan province, Vietnam GoogleMaps .
Other localities
Forest soil collected at 650 m a.s.l. within the Phuoc Binh National Park (geographical coordinates: 12º 00′ N and 108º 46′ E), Ninh Thuan province, Vietnam GoogleMaps .
Type material
Female holotype, two female and two male paratypes on slide 0507 deposited in the nematode collection of Departamento de Biología Animal , Biología Vegetal y Ecología, University of Jaén, Spain ; four female paratypes and one male paratype on
slide [DQ-03], deposited in Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi, Vietnam.
Etymology
The specific epithet refers to geographical origin of the new species.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.