Paraxonchium laetificans (Andrassy, 1956) Altherr & Loof 1969
Creators: name: Pedram, Majid
name: Pourjam, Ebrahim
name: Vinciguerra, Maria T.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Adenophorea
Dorylaimida
Aporcelaimidae
Paraxonchium
Paraxonchium laetificans

description: Paraxonchium laetificans (Andrássy, 1956) Altherr & Loof, 1969   
(Fig. 3 & 4)  
 Syn. Dorylaimus laetificans Andrássy, 1956   
 Aporcelaimus laetificans ( Andrássy, 1956) Andrássy, 1958 Drepanodorus laetificans ( Andrássy, 1956) Andrássy, 1958 Paraxonchium striatum Krall, 1958   
 Paraxonchium magnidens Thorne, 1974   
Females Males  
n 2 4  
L (1.48, 1.55) 1.54±0.06 (1.46–1.62) a (23.1, 23.2) 21.5±1.5 (20.5–23.5) b (3.3, 3.4) 3.5±0.2  
(3.2–3.6) c (34.5, 42.0) 38.5±2.0 (35.5–40.5) c`(0.8, 1.0) 0.8±0.1  
(0.7–0.9) V or T (61.5, 62.0) 49.5±3.0 (47.0–52.5) Anterior end to vulva (915, 925) -  
Diam. at neck base (59, 63) 67±4  
(61–70) – at mid-body (64, 65) 72.0±2.5 (69–75) – at anus (42, 43) 49.0±4.5 (46–55) Lip region diam. (8.5, 9.0) 9.0±0.0  
(9–9)  
Lip region height (4.5, 5.0) 5.0±0.0  
(5, 5)  
Odontostyle length (15, 15) 15.0±0.0 (15–15) Odontostyle width at base (3, 3) 3.0±0.3 (2.5–3.0) Odontostyle length / Odontostyle width (5.0, 5.0) 5.5±0.5  
(5–6)  
Neck length (432, 460) 455.5±7.0 (455–460)  
Cardia length (16, 21) 14±1  
 (13–15) Cardia width (13, 15) 13.5±1.0 (13–15) Prerectum length (102, 113) 141.0±7.5 (132–145) Rectum length (40, 43) 53.5±3.0 (50–55) Tail length (36, 43) 40.0±2.5 (37–43) Spicule length - 64.5±2.0 (63–67) Ventromedian supplements - 16.5±0.5 (16–17) Lateral accessory pieces - 14.5±0.5 (14–15) Material examined: Two females and four males from forests of Kelardasht, northern Iran; in good condition.   
 Measurements: See Table 2.   
 Morphological description. MALE. Body slightly curved ventrad, L shaped. Body strongly tapering anteriorly, mainly in anterior half of neck. Cuticle 2–3 µm at odontostyle level, varying to 3–5 at mid-body and 5–7 µm on tail, distinctly divided into two layers. Lateral hypodermal chords 15.5–21.5% of corresponding body width. Lip region rounded to moderately angular, 1.6–2.0 times as wide as high, separated from the rest of body by a constriction. Amphidial fovea cup-shaped with slit-like opening, occupying 72–75% of lip region width. Odontostyle 5–6 times longer than wide, with the aperture 54–60% of its length; odontophore rod-shaped, its base not clearly visible. Nerve ring located at 130–156 µm from anterior end. Pharynx composed of a slender but well muscled anterior part expanding gradually into a basal expansion occupying 42–45% of total neck length. Cardia conical, its length 0.8–1.0 times its width. Reproductive system diorchic, dorylaimoid, occupying ca 30.5% of body length. Spicules dorylaimoid, well sclerotised, moderately slender, 5–6 times longer than wide. Lateral guiding pieces present in two of the four males, more or less cylindrical, with bifurcate tip, ca 15×3 μm sized or 5 times longer than wide. Adcloacal pair of supplements located at 9–13 μm from cloacal opening; 16–17 spaced ventromedian supplements running anteriorly, the supplements row ca 120 μm long, the posteriormost located at 70–75 μm from adcloacal pair. Rectum ca 2.5 times longer than prerectum. The latter starts in the range of the supplements row. Tail asymmetrically conical with flat ventral side and a subdigitate mucro, bearing four pores in each side (n=1).   
 FEMALE. General morphology similar to that of male except for its habitus straight after heat relaxation. Genital system didelphic-amphidelphic, identical to that described in Iranian population by Baniyamuddin et al. (2010).   
 Remarks. P. laetificans was originally described on a single male found in Hungary (Andrássy, 1956). Heyns (1988) redescribed the species reporting data of numerous populations from Europe and Iraq mostly composed by females only, with the exception of a population from Switzerland composed by ten females and a male. In this paper Heyns observed that only one female of the Swiss population was impregnated while none of the other females, in the same and in the other populations observed, most of which were gravid, contained sperm. Moreover he stated that the male spicules lacked the lateral accessory pieces commonly present in dorylaimoid spicules, confirming what originally observed by Andrássy in the type specimen. In a recent study, Baniyamuddin et al. (2010) revised the family Paraxonchiidae and reported a population of this species from Shahrekord, Iran, also in this case composed by females only. The small population object of our study, otherwise, is clearly amphimictic, with males relatively abundant and females containing sperm in their uterus. The morphology and morphometric data of this population agree well with those given in the original description except that for odontostyle length, which, both in males and females, is greater compared to that in the original description (15 µm vs. 11.7 μm); but the data given for the other European populations by Heyns (1988) range from 10.5 to 13 µm and those of the Iranian population reported by Baniyamuddin et al., (2010) from 13 to 14 μm. It is noteworthy that the males in our population may possess (in two males) or lack (in two males) the lateral accessory pieces that usually accompany the spicules; it is possible that these structures are initially present in all males, as usual also in this species, but that they can be lost during the animal's life.
description: Published as part of Pedram, Majid, Pourjam, Ebrahim & Vinciguerra, Maria T., 2012, Description of a new species of the rare genus Epacrolaimus Andrássy, 2000 (Dorylaimida, Aporcelaimidae) and new data on male of Paraxonchium laetificans (Andrássy, 1956) Altherr & Loof, 1969 (Dorylaimida, Paraxonchiidae) from Iran, pp. 53-61 in Zootaxa 3327 on pages 57-59, DOI: 10.5281/zenodo.210470