Paradorylaimus flagellicaudatus, Orselli, Lara, Clausi, Mirella & Vinciguerra, Maria Teresa, 2012

Orselli, Lara, Clausi, Mirella & Vinciguerra, Maria Teresa, 2012, The genus Paradorylaimus Andrássy, 1969 (Nematoda: Dorylaimida) with description of three new species from Ecuador, Zootaxa 3302, pp. 25-43 : 34-39

Paradorylaimus flagellicaudatus n.sp.

( Figs. 4 and 6 A–D ; Table 3 )

Female. Body ventrally curved in fixed specimens. Cuticle 2–3 µm thick at midbody and 1–2 µm at level of odontostyle. Lateral chords occupying about one third of maximum body diameter. Two ventral and two dorsal body pores clearly visible in all specimens at odontostyle level. Lip region truncate, practically continuous with adjoining body, two times as wide as high. Lips amalgamated, rounded, with inner and outer papillae only slightly protruding and not interfering with the lip region profile, their arrangement obscure. Amphidial fovea cup-like; its aperture about 60% of corresponding body diameter. Odontostyle dorylaimoid, straight, protruded in all specimens, ten–twelve times as long as wide, extending 1.8–2.5 times the lip region diameter; its aperture 31–35 % of its length. Guiding ring appearing double, fixed ring located 13–14.5 µm from anterior end. Odontophore linear, 2.4– 2.7 lip region diameters long. Expanded part of pharynx about 50% of its total length. In the pharynx glandularium subventral nuclei small and hardly visible. The location of pharyngeal gland nuclei, according to Andrássy’s formula, is as follows: (n=1): DN = 58.4; AS 1 = 24.8; AS 2 = 42.9; PS1 = 68; PS2 = 71.9. Cardia composed of a disc-like and a conoid part. Nerve ring encircling the slender part of pharynx at 28.7–31.9% of its length. Reproductive apparatus didelphic-amphidelphic. The reflexed ovaries are generally long, occupying 56–92 % of each genital branch, extending to trespass the junction oviduct-uterus, sometimes reaching the vagina. Oocytes in a single row except that at the ovary tip. Oviduct a simple tube, 1.5–3.4 body diameters long, ending in a short pars dilatata (15.5–24 µm long); a sphincter is present at the junction oviduct-uterus. Uterus in two parts, 4.3–4.8 body diameters long, Its distal part, 24–31 µm long, is characterised by a very thick wall; the proximal part, 68–87 µm long, has wider lumen and thinner wall and it contains small oval spermatozoa 1–2 µm long and one or two eggs, 49–68 µm long and 21.5–26.5 µm wide. The vulva is the opening of a funnel-shaped depression not clearly oriented when observed from a lateral view (apparently elongated longitudinally) but the opening of pars refringens vaginae is a transverse slit between the sclerotized pieces. Vagina extending inward for about half body diameter; pars proximalis vaginae cylindrical, measuring 13–15.5 Μm; pars refringens vaginae, measuring 2.5–3.5 µm, constituted by two strongly sclerotized pieces which in lateral view appear continuous; pars distalis vaginae 2.5–3.5 µm deep. Pre-rectum short, 1.8–2.6 anal body diameters long; rectum 1.8–2 anal body diameters long. Tail very long, gradually narrowing till becoming filiform, 25–26 anal body diameters long; the hyaline part representing 16–23 % of tail length. A dorsal and two ventral pairs of caudal pores are present.

Male. Similar to female in general morphology. A series of 10 contiguous ventral pre-anal supplements is present in addition to the adanal pair. The distance between the latter and the most posterior supplement is about 37 Μm. 6–7 sub-ventral papillae are visible at the sides of supplements series. Spicula dorylaimoid, 1.7 anal body diameters long; lateral guiding pieces 12–17 Μm long. Pre-rectum short, 2.4 anal body diameters long, starting at level with the series of supplements. Rectum 1.6 anal body diameters long. Tail very short, conoid, dorsally convex and ventrally straight, with blunt terminus. A subventral and two subdorsal pairs of caudal pores are present.

Differential diagnosis. The new species is characterized by 1.65 1.73 mm long female body, lip region continuous with adjoining body, odontostyle 19–24 Μm long; pre-rectum short, 1.8–2.6 anal body diameters long in female and 2.4 in male; spicules 45 µm long; 10 ventral supplements. Female tail elongate-filiform, 25–26 anal body diameters long, the hyaline part representing 16–23 % of tail length; male tail short, conoid, 0.8 anal body P. flagellicaudatus sp. n., with its very long tail, can easily be distinguished from most species of Paradorylaimus and compared to P. wilhelmschneideri , to P. tenuistriatus and to P. longicaudatus . It can be distinguished from P. wilhelmschneideri by the shorter female tail (vs. c’ = 50) and the smaller body (vs. L = 2.8 mm); from P. tenuistriatus by its smaller body (vs. L= 2.5–3.1 mm) and by the shorter odontostyle (vs. 34–36 µm); from P. longicaudatus it mainly differs in the longer female tail (vs. c’ = 11–16) and in the shorter odontostyle (vs. 30–32.5 µm).

Type habitat and locality. Forest litter. Natural reserve of Otonga, S. Francisco de Las Pampas, Cotopaxi, Ecuador.

Type specimens. Holotype female and 1 paratype male deposited in the nematode collection of the Department of Biological, Geological and Environmental Sciences, University of Catania ( Italy); 1 paratype female deposited in the collection of Prof. I. Andrássy, University of Budapest ( Hungary); 1 paratype female deposited at USDA collection, Beltsville, MD, USA.

Etymology. The name refers to the very long and filiform female tail.

Absolute measurements in µm, except for L in mm. Values in the form of Mean ± SD (range).

(41–48)

continued on next page Female. Body ventrally curved in fixed specimens. Cuticle 3.5 µm thick at midbody and 2.5 µm at level with odontostyle. Lateral chords occupying about one third of maximum body diameter. Two ventral and two dorsal body pores clearly visible in both specimens at odontostyle level. Lip region truncate, practically continuous with adjoining body, about three times as wide as high. Lips amalgamate, rounded, with inner and outer papillae slightly protruding. Amphidial fovea cup-like; its aperture corresponding to about 60% of corresponding body diameter. Odontostyle dorylaimoid, straight, protruded in all the specimens, with ratio width/length 12 %, extending 2.5 times the lip region diameter; its aperture 28–32 % of its length. Guiding ring appearing double; fixed ring located 18 µm from anterior end. Odontophore linear, 2.6–2.7 lip region diameters long. Pharynx extended part occupies about 55% of pharynx total length. In the pharynx glandularium subventral nuclei hardly visible. Cardia with a disk-like and a conoid part. Nerve ring encircling the slender part of pharynx at 32.8–35.5% of its length. Reproductive apparatus didelphic–amphidelphic. The reflexed ovaries are generally long, occupying 45–96 % of each genital branch, extending to trespass the junction oviduct-uterus, sometimes reaching the vagina. Oocytes in a single row except that at the ovary tip. Oviduct a simple tube, 2.7–2.8 body diameters long, ending in a short pars dilatata (25–28 µm long); a sphincter is present at the junction oviduct-uterus. Uterus simple, 5.9 body diameters long in one specimen, obscure in the other. It contains small oval spermatozoa 1–2 µm long and an egg, 45.5–48 µm long and 26.5–27.5 µm wide. Vulva longitudinal, as well as the slit between the sclerotized pieces. Vagina extending inward for about 55% of body diameter; pars proximalis vaginae cylindrical measuring 15.5–23 Μm; pars refringens vaginae, measuring 3.5–5 µm; pars distalis vaginae 3 µm deep. Pre-rectum short, 1.6–1.8 anal body diameters long; rectum as long as pre-rectum. Tail long, gradually narrowing till becoming filiform, 13.5– 17.7 anal body diameters long; the hyaline part making up 13–15 % of tail length. A dorsal and two ventral pairs of caudal pores are present.

Male. Not known.

Habitat and locality. Foest litter. Cosanga, Napo, Ecuador.

Remarks. The above described species, of which two female specimens only were found, in general morphometrics much resembles P. longicaudatus sp. n. and P. flagellicaudatus sp. n.. It differs from the former species in the relatively wider odontostyle (3.5 µm vs. 2.5 µm), shorter odontophore (31–32.5 µm vs. 39.5–42 µm) and lower and continuous lip region (3.5 µm–5 vs. 5–6 µm); from the latter it differs in the much shorter female tail (c’ 13.5– 17.7 vs. 25–26) and in the much longer odontostyle (30 µm vs. 19–24 µm).

Due to the scarce number of specimens and even more to the absence of male we refrain from naming the present species.

Figures

FIGURE 4. Paradorylaimus flagellicaudatus sp. n. A: Anterior end showing amphid; B: Female anterior end; C: Expanded pharynx; D: Female reproductive apparatus (posterior); E: Female posterior end; F: Male posterior end; G – H: entire body; G: Male, H: Female.

FIGURE 6. A – D Paradorylaimus flagellicaudatus sp. n. A: Female anterior end; B & C: Vulval regions; pre-rectum. D: Male posterior end. E – F: Paradorylaimus sp. E: Female anterior end; F: Vulval region. Scale bar 25 µm.

Tables

TABLE 3. Morphometrics of Paradorylaimus flagellicaudatus n. sp. e Paradorylaimus sp.

Species Locality Character n L (mm)	P. flagellicaudatus n. sp. Cotopaxi Female holotype Female paratypes 2 1.73 1.68±0.04	Paradorylaimus sp. Napo Male paratype Female 1 2 1.24 1.66–1.78
a	(1.65–1.66) 40 40.3±5.5	34 32–34
b	(35–46) 5.9 5.3±0.6	3.5 4.5–4.9
c	(4.8–5.2) 3.6 3.5±0.1	60.8 3.7–4.6
c’	(3.4–3.6) 26.5 25.8±0.7	0.8 13.5–17.7
V	(25–25.8) 39.9 40±0.5	42.2–44.4
G1 G2 Amphid aperture	(39.7–40.6) 11.3 11.3±0.06 (11.3–11.4) 13.6 12.7±1 (11.6–12.9) 6.5 5.8±0.9	8.5–15.7 8.9–17.7 7 7–8.5
Amphids from anterior end	(5–6) 6 6.4±0.7	5.5 6–9.5
Lip region width	(6–7) 11 10±0.7	9.5 12
Lip region height	(9.5) 5 4±0.7	3.5 3.5–5
Odontostyle length	(3.5) 19 21.6±2.4	24 30
Odontostyle width	(21.5–24) 2 2±0.3	2.5 3.5
Odontophore length	(2–2.5) 26.5 26±0.7	26.5 31–32.5
Neck length	(25–26.5) 291 318±26.5	356 363–369
Nerve ring from anterior end	(319–344) 93 97±3.5	108 121–129
Cardia length	(99) 18 20.4±3.2	17 24–30
Body diameter at neck base	(19–24) 38.5 40±6.2	36 48
Body diameter at midbody	(35–47) 43 42±5.5	36 51.5
Body diameter at anus	(36–47) 18 18.4±0.7	26.5 25–29
Anterior genital branch	(18–19) 195 190±4.6	142–279
Posterior genital branch	(186–189) 236 214±22	148–316
Anterior ovary	(192–214) 121 139.7±29.8	137–158
Posterior ovary	(124–174) 177 138.7±33.2	134–186
Anterior oviduct	(118–121) 102 93.7±19.8	139
Posterior oviduct	(71–108) 146 108.3±37.5	146
Uterus	(71–108) 186 195±27.6	304
Prerectum length	(173–226) 33.5 40.8±7.2	62.5 44.5–45.5