Oswaldocruzia lacertica, Svitin, Roman, 2017

Svitin, Roman, 2017, Two new species of Oswaldocruzia (Nematoda, Molineidae) parasitising lizards in Ukraine, Zootaxa 4263 (2), pp. 358-368 : 363-366

Oswaldocruzia lacertica sp. n.

Type material. Holotype male (collection no. NH5), allotype female (NA5); 2 male and 3 female paratypes (NP 5.1). Type specimens are stored in collection of Department of Parasitology of the Institute of Zoology, NAS of Ukraine .

Type-host. Lacerta agilis (Reptilia, Squamata : Lacertidae ).

Type-locality. Vorokhta village (Ivano-Frankivska oblast, Ukraine); [48°17'21.4"N 24°34'39.7"E].

Other localities. Lvivska oblast (4), Kyivska oblast (3), Volynska oblast (2), Cherkaska oblast (2), Ivano- Frankivska oblast (1), Rivnenska oblast (1), Poltavska oblast (1) ( Fig. 1 ).

Site of infection. Small intestine.

Etymology. The species is named after the generic name of the type-host.

Remarks. The new species is assigned to the genus Oswaldocruzia based on the presence of a well-developed cephalic vesicle, longitudinal cuticular ridges, the arrangement of caudal bursal rays and parasitism in squamate reptiles ( Durette-Desset, 1985; Anderson, 2000). This species also belongs to the Palaearctic group of Oswaldocruzia species characterised by “idiomorphic” spicules consisting of three main branches (blade, fork and shoe), with the spicular fork divided above the level of its distal third ( Ben Slimane et al., 1996).

The synlophe structure of O. lacertica is similar to that in O. lisnykiensis , though regarding the lateral alae of O. lacertica the dorsal crest is more prominent and the central crest is always conspicuous. Oswaldocruzia lacertica differs from O. lisnykiensis in males possessing a caudal bursa of type I vs. a caudal bursa of type III in O. lisnykiensis .

A caudal bursa of type I has previously been described in three species occurring in Western Palaearctic: O. ivanizkii ( Ivanitsky, 1940) Sudarikov, 1951 , O. molgeta Lewis, 1928 and O. bialata . Oswaldocruzia lacertica differs from O. ivanizkii and O.molgeta in the structure of spicules: in O. lacertica the blade is distally divided into 4 tips, the thin process of the shoe is short, and the fork is without extra branches, while in O. ivanizkii and O.

molgeta the blade is undivided, distally rounded, the thin process of the shoe is elongated, and the fork in O. ivanizkii has a small extra process. Oswaldocruzia lacertica may be easily differed from O. bialata by synlophe structure: O. bialata has a synlophe with wide semi-spherical cervical alae and without simple crests within the oesophageal region while O. lacertica has narrow triangular cervical alae and numerous crests within the oesophageal region.

Description. General. In both sexes, body thin, elongated, with maximum width near mid-length. Anterior end rounded with cuticular cephalic vesicle. Cephalic vesicle smooth, comparatively small, divided into wider anterior and thinner posterior part; division between parts often poorly visible. Apical structures: 6 externo-labial papillae, 4 cephalic papillae, 2 amphids; oral opening triangular; dorsal oesophageal tooth present ( Fig. 4 B; Fig. 5 B).

Oesophagus thin, club-shaped, cylindrical in anterior half, then widening posteriorly, posterior end rounded forming oesophageal bulb. Two excretory glands dissimilar in size, both somewhat longer than oesophagus. Position of excretory pore varying within posterior third of oesophagus. Nerve-ring encircling oesophagus near its mid-length. Small deirids situated at level of posterior quarter of oesophagus ( Fig. 4 A).

Synlophe symmetrical ( Fig. 4 C–F; Fig. 5 C–D). Narrow cervical alae present, as long as oesophagus. At level from mid-length to posterior end of oesophagus each ala consisting of three crests: increased triangular ventral crest and small but always conspicuous central and dorsal crests. On transverse sections, at level of anterior part of intestine, cervical alae small, consisting of somewhat increased dorsal and ventral crests and smaller central crest between them. Struts present, well visible at level of maximum width of cervical alae (at posterior third of oesophagus). At level of oesophageal-intestinal junction, 24–25 crests (including cervical alae) present. At body mid-length, synlophe consisting of about 40 equal crests.

Males. Measurements in text are given for holotype followed by mean values, ranges of 25 specimens and standard deviation. Body 7.5 (6.9, 4.3–9.3; 1.4) mm long, 130 (156, 100–190; 26.5) wide ( Fig. 5 A). Cervical alae (measured in 3 specimens) 555 (340–592) long, appearing at 195 (121–208) from anterior end of body. Cephalic vesicle 78 (79, 63–98; 26.5) long, 30 (37, 30–50; 5.2) wide. Oesophagus 388 (387, 288–445; 35.7) long; 4.8% (5.7%, 4.4%–8.5%; 1.2) of body length. Oesophagus width 23 (23%, 18–30; 3.0), 23 (24, 20–28; 2.3) and 53 (51, 40–73; 8.1) at level of anterior end, mid-length and posterior dilation, respectively. Nerve-ring at 185 (187, 150– 213; 17.6) from anterior end of oesophagus; 48% (48.7%, 38.7%–57.6%; 5.3) of oesophagus length. Excretory pore at 333 (294, 223–373; 49.6) from anterior end of oesophagus; 4.1% (4.3%, 2.9%–7.2%; 1.1) of body length. Deirids at 333 (319, 243–436; 53.8) from anterior end of body; 4.4% (4.6%, 3.5%–7.9%; 1.1) of body length.

Caudal bursa symmetrical, tri-lobed, arrangement of rays corresponding to type I (after Durette-Desset, 1985) ( Fig. 4 J; Fig. 5 F–G). Rays 2 and 3 parallel, slightly separated from each other at tips only, reaching edge of bursal membrane; ray 4 not reaching bursal margin, separated from rays 5 and 6; rays 5 and 6 parallel, slightly separated at tips only, almost reaching bursal margin; ray 8 separated from ray 6, almost reaching bursal margin. Dorsal ray of bursa bifurcated into two rays 10 posterior to base of rays 9. Each ray 10 with small extra branch. Genital cone (measured in 3 species) 15 (19, 15–28) long, 21 (22, 22–23) wide, with two papillae 0. Gubernaculum absent.

Spicules equal 185 long (192, 168–220; 14.0), surrounded by thin membrane, consisting of three main branches: blade, fork and shoe. Blade distally divided into 4 tips; fork bifurcated in its distal half; shoe bearing thin process, its posterior extremity slightly curved, divided into three rounded tips ( Fig. 4 I; Fig. 5 E).

Females. Measurements in text are given for allotype followed by mean values, ranges of 14 specimens and standard deviation. Body 8.4 (10.4, 7.0–14.0; 2.6) mm long, 177 (207, 150–280; 44.2) wide. Cervical alae (measured in 4 specimens) 317 (321, 317–327) long, appearing at 166 (161, 144–173) from anterior end of body. Cephalic vesicle 73 (76, 61–100; 12.3) long, 31 (39, 30–53; 6.8) wide. Oesophagus 414 (436, 370–520; 47.8) long; 4.9% (4.4%, 3.2%–5.9%; 1.0) of body length. Oesophagus width 23 (26, 19–33; 3.6), 27 (28, 25–35; 3.1) and 60 (63, 40–75) at level of anterior end, mid-length and posterior dilation, respectively. Nerve-ring at 109 (202, 109– 253; 40.6) from anterior end of oesophagus; 26.3% (46.5%, 26.3%–54.9%; 8.2) of oesophagus length. Excretory pore at 315 (316, 255–398; 43.2) from anterior end of oesophagus; 3.7% (3.2%, 2.3%–4.1%; 0.6) of body length. Deirids 431 (351, 268–455; 57.1) from anterior end of body; 5.1% (3.4%, 2.6%–5.1%; 0.8) of body length. Tail tapering, 284 (236, 207–284; 19.6) long, including thin cuticular needle on its end ( Fig. 4 H).

Vulva wide, at 5.4 (6.5, 4.2–9.0; 1.6) mm from anterior end of body, postequatorial in position (at 64% (62.6%, 58.0%–64.7%; 1.9) of body length).

Details of female genital system shape and measurements are given for allotype and 3 paratypes. Anterior uterus containing 41 (32, 36–45) eggs, posterior uterus with 43 (38, 28–47) eggs; size of eggs at late morula stage 46–58 × 70–83 (N=19). All eggs observed in morula stage, in uteri, ovejector and vulva. Vagina vera 57 (54, 51– 57) long, 15 (14, 14–15) in diameter ( Fig. 4 G). Anterior ovary beginning posterior to longer excretory gland, forming 0 (2, 0–4) bends. Posterior ovary beginning slightly anterior to vulva. Distance from anterior end of body to anterior ovary and from end of tail to posterior one 890 (820, 700–890) and 470 (577, 470–640), respectively. Length of anterior infundibulum 112 (116, 112–120), width 52 (55, 52–58). Length of posterior infundibulum 63 (85, 63–127), width 120 (75, 39–120). Anterior sphincter 36 (33, 30–36) long, 32 (38, 32–42) wide; posterior one 34 (33, 24–41) long and 29 (34, 29–41) wide. Length of anterior part of ovejector 159 (135, 94–159), maximum width 72 (65, 51–72), minimum width 66 (45, 31–56). Length of posterior part of ovejector 176 (133, 76–176), maximum width 73 (67, 50–78), minimum width 29 (36, 29–42).

Figures

FIGURE 1. Type localities and distribution of O. lisnykiensis sp. n. and O. lacertica sp. n. in Ukraine.

FIGURE 4. Oswaldocruzia lacertica. A—anterior part of body, male, ventral view, d—deirid; B— (scale bar— 50 µm) anterior end, female, apical view; C – F—transverse sections: C— (scale bar— 50 µm) female, level of anterior third of oesophagus, D— (scale bar— 50 µm) female, mid-oesophagus level, E—male, oesophageal-intestinal junction, F—female, mid-body level; Gpart of female genital system near vulva, lateral view; H—posterior part of body, female, lateral view; I—left spicule, lateral view; J—caudal bursa, ventral view.

FIGURE 5. Oswaldocruzia lacertica. A—male, general view; B— (scale bar— 50 µm) anterior end, female, optical section at oesophageal tooth level; C—male, transverse section at mid-oesophagus level; D—male, transverse section at oesophagealintestinal junction level; E—left spicule, lateral view; F—caudal bursa, lateral view, optical section at genital cone level; Gcaudal bursa, lateral view, optical section showing arrangement of rays.