Sabatieria curvispiculata, Gagarin, Vladimir G., 2013

Gagarin, Vladimir G., 2013, Four new species of free-living marine nematodes of the family Comesomatidae (Nematoda: Araeolaimida) from coast of Vietnam, Zootaxa 3608 (7), pp. 547-560 : 547-553

Genus Sabatieria Rouville, 1903

Sabatieria curvispiculata sp. n. ( Fig. 1 , Table 1 )

Type specimens. Holotype male, inventory s lide no. 102/4 and paratype males (same slide) deposited in the collection of the helminthological museum of the Institute of Ecology and Evolution, Center of Parasitology, Russian Academy of Sciences, Moscow, Russia. Paratypes, inventory slides no. TC 2.10 repl. 1 and TC 2.29 repl.1) (5 males and 3 females) deposited in the nematode collection of the Institute of Ecology and Biological Resources, Vietnamese Academy of Science and Technology, Hanoi, Vietnam.

Type habitat and locality. South China Sea, littoral zone off the coast of Vietnam, Tea Co. Latitude: 20º39.721’. Longitude: 106º41.662’–106º42.653’. Depth 1.5–5.0 m, sand, salinity 12.5–29.1 ‰. Collected in March 2010.

Description. Male. Body elongated, cylindrical, tapering towards both extremities. Cuticle marked with transverse rows of fine punctations. Lateral differentiation, consisting of larger and more widely spaced irregular punctations, commences a short distance posterior to amphidial fovea and terminates at the base of the conical portion of the tail. Somatic setae small, sparse. Mouth surrounded by six rounded lips. Inner labial sensillae not visible. Outer labial sensillae in the shape of short setae 1.5 µm long. Four cephalic setae 3.5–4.5 µm long (29–32 % of labial region width). Cervical setae about 2.5 µm long. Stoma small, glass-shaped, its walls cuticularized. Amphidial fovea in shape of spiral, with 2.5–3.0 turns and occupying 65–70% of corresponding body diameter. Pharynx slender, muscular, swollen proximally, but not forming a bulb. Cardia small, muscular, surrounded by intestinal tissue. Renette 45– 53 x 25–29 µm in size, located on ventral side of body, at level of cardia; excretory pore posterior to nerve ring, at 120–132 µm from anterior body end. Gonads diorchic; testes opposite and outstretched. Anterior testis situated to left of intestine, posterior testis to right of intestine. Two spicules equal in length, distally bent almost at a right angle. Spicule with capitulum and median cuticular projection at proximal end. Spicules 1.9–2.1 times as long as cloacal body diameter. Gubernacula paired, consisting of base and long dorso-caudal apophysis. A pair of small, elongate guiding pieces located near apical spicule ends. Fourteen to seventeen precloacal ventromedian supplements, in the form of cuticular pores. Short precloacal setae 5.0–7.0 µm long. Tail slender, with rather broad, conical anterior portion and rather narrow cylindrical posterior portion, the latter 1.0–1.1 times as long as anterior conical portion. Tail armed with numerous, short caudal setae. Tail tip enlarged, with three terminal setae 6–8 µm long. Caudal glands and spinneret well developed.

Female: Similar to male in general characteristics, but body longer and less slender. Structure of cuticle and anterior body end as in male. Cephalic setae 5.0–6.0 µm long. Amphidial fovea spiral with 2.5 turns and occupying 50–60% of corresponding body diameter, situated 0.4–0.5 labial region width from anterior body end. Pharynx muscular, widened in its base. Renette in shape of clarify baggy, situated at level of cardia. Excretory pore situated posterior to nerve ring. Reproductive system didelphic, amphidelphic; ovaries homodromous. Anterior ovary situated to right side of intestine, posterior ovary to left side of intestine. Both uteri spacious, filled with numerous spermatozoa. Eggs not observed. Vagina comparatively straight and shorter than corresponding body diameter. Vulva praequatorial, its lips not cuticularized and not protruding outside the body contour. Tail slender, comparatively long, anterior portion conical, then gradually narrowing; thin, with short terminal swelling. Caudal glands and spinneret well developed.

Differential diagnosis: Sabatieria curvispiculata sp. n. belongs to the Sabatieria praedotrix group, according to the classification of Platt (1985), and is similar in body length to S. falcifera Wieser, 1954 and S. lawsi Platt, 1983 . It differs from the former in the slenderer tail (c’ = 3.5–5.0 vs c’ = 3.0– 3.3 in S. falcifera ), shorter cephalic setae (3.5–5.0 µm long, 29–33 % of labial region width vs 7 µm long, 40 % of labial region width), vulva location (V = 44.4–46.4 % vs V = 45.7–50.9 %), differently shaped and longer spicules (76–82 µm long, 1.9–2.1 cloacal body diameter vs 66.5 µm, 1.5 cloacal body diameter) and greater number of precloacal supplements (14–17 in number vs 10 in S. falcifera ) (Wieser, 1954). From S. lawsi it differs in the longer and slenderer tail (3 c = 14.3–17.1, c’ = 3.6–4.1, Ƥ c = 12.4–15.6, c’ = 4.5–5.0 vs 3 c = 12.0–16.2, c’ = 3.1–3.7, Ƥ c = 11.7–13.3, c’ = 4.2–4.3 in S. lawsi ), shorter cephalic seta (3.5–5.0 µm long, 29–33 % of labial region width vs 5–7 µm long, 32–44 % of labial region width) and another shape and longer spicules (76–82 µm long, 1.9–2.1 cloacal body diameter vs 70–75 µm long, 1.6–1.7 cloacal body diameter in S. lawsi ) (Platt, 1983). S. curvispulata sp. n. has similarlyshaped spicules compared to S. doancanhi Nguyen Dinh Tu et al., 2008 , but differs from the latter species in the thicker body (a = 35–41 vs a = 41–54 in S. doancanhi ), shorter cephalic setae (3.5–5.0 µm long vs 5.1–5.8 µm long in S. doancanhi ), shorter spicules (76–82 µm long vs 87.2–91.8 µm long in S. doancanhi ), shorter dorsal apophysis of gubernaculum (25–30 µm long vs 38.3–52.1 long in S. doancanhi ) and smaller number of precloacal supplements (10–13 in number vs 13–18 in number in S. doancanhi ), (Nhuyen Dinh Tu et al., 2008).

Type specimens. Holotype male, inventory slide no. 102/5 deposited in the collection of the helminthological museum of the Institute of Ecology and Evolution, Center of Parasitology, Russian Academy of Sciences, Moscow, Russia. All paratype slides deposited in nematode collection of the Institute of Ecology and Biological Resources, Vietnamese Academy of Science and Technology, Hanoi, Vietnam.

The habitat and locality. South China Sea, littoral zone off the coast of Vietnam, Tea Co. Latitude: 21º25.712’–21º27.521’. Longitude: 107º50.632’–108º01.950’. Depth 1.0–3.0 m, sand, salinity 29.1–29.5 ‰. Collected in March 2010.

Description. Male. Body slender, medium-sized size, tapering towards extremities. Cuticle smooth, punctation not observed. Somatic setae short, sparse. Mouth surrounded by six rounded lips. Buccal cavity cupshaped. Inner labial sensillae not visible. Outer labial sensillae in the shape of short setae 1.5 µm long. Four cephalic setae 9.0–10.0 µm long (90–100 % of labial region width). Cervical setae 4–6 µm long, arranged in four longitudinal files of four to six setae and situated 25–30 µm from anterior body end (2.1–2.4 labial region widths). Amphidial fovea in shape of spiral with 2.5–3.0 turns and occupying 50–55 % of corresponding body diameter. Pharynx muscular, swollen proximally, but not forming a bulb. Cardia muscular, surrounded by intestinal tissue. Renette 25– 34 x 24–27 µm in size, situated at level of cardia. Excretory pore posterior to nerve ring. Gonads diorchic; testes opposite and outstretched. Anterior testis situated to left of intestine, posterior testis to right of intestine. Two spicules equal in length, curved, with capitulum and median cuticular strip at proximal end. Spicules 1.8–2.0 times as long as cloacal body diameter. Gubernacula paired, consisting of base and long dorso-caudal apophysis. A pair of small guiding pieces located near apical spicule ends. Fifteen to nineteen precloacal ventromedian supplements in the shape of cuticular pores. Tail slender, with rather broad, conical anterior portion and rather narrow cylindrical posterior portion, the latter 0.7–0.9 times as long as anterior conical portion. Tail armed with numerous short caudal setae. Tail tip enlarged, with three terminal setae 5–7 µm long. Caudal glands and spinneret well developed.

Female. Similar to male in general characteristics, but body longer. Structure of cuticle and anterior body end as in male. Cuticle smooth and not punctated. Cephalic setae 10.0–10.5 µm long. Amphidial fovea in the shape of spiral with 2.5–3.0 turns and occupying 45–55 % of corresponding body diameter. Pharynx muscular, widened in its base. Renette situated at level of cardia. Excretory pore situated posterior to nerve ring. Reproductive system didelphic, amphidelphic; ovaries homodromous. Anterior ovary situated to right side of intestine, posterior ovary to left side of intestine. Both uteri spacious, filled with numerous spermatozoa and one-two eggs, 60– 69 x 41–46 µm in size. Vagina straight and short. Vulva praequatorial, in the shape of transverse slit, its lips not cuticularized and not protruding outside the body contour. Tail slender, comparatively long, its anterior portion conical, then gradually narrowing, thin with short terminal swelling. Anterior tail portion 0.9–1.1 times as long as posterior tail portion. Caudal glands and spinneret well developed.

Differential diagnosis. Setosabatieria orientalis sp. n. is morphologically close to S. australis Riera, Nunez, Brito, 2006 , but differs from it in the comparatively shorter and less slender tail (3 c = 9.2–11.8, cʹ = 5.1–6.0, ƤƤ c = 8.2–8.5, cʹ = 5.6–6.7 vs 3 c = 7.8–8.9, cʹ = 4.8–5.2, ƤƤ c = 9.9–10.7, cʹ = 4.6–5.2 in S. australis ), smaller number of amphidial fovea turns (2.5–3.0 turns vs 3.5 turn in S. australis ), greater number of precloacal supplements (15–19 in number vs 7–9 in number in S. australis ) and shape and structure of spicules (curved spicules, with cuticular strip vs L-shaped spicules, with characteristic longitudinal median hollow in S. australis ) (Riera, Nunez, Brito, 2006).

Table 3. Morphometrics of males of valid species of the genus Setosabatieria . All measurements in µm except where indicated.

Character australis apud conicauda apud coomansi fibulata apud hilarul apud de jingjingae apud triangularis orientalis Leduc, Leduc, Probert, apud Huang, Wieser, 1954 Man, 1922 Kreis, Guo, Warwick, apud Riera et sp.n. original Gwyther, 2008 Nodder, 2012 Zhang, 2006 1929 2001 all., 2006

1231-1321 1094-1640 1601-1954 1490 1812 1856 1370-1620 1700-2371 1238-1545 33-35 25-30 31-37 34 37 38 29-34 32-44 26-39 6.5-7.1 6-8 7.5-8.5 7.4 8.6 10 7.6-9.3 8.1-15.4 6.9-9.8 8.3-8.9 15-18 9.6-11.1 13.1 8.0 9.9 10.2-11.7 9.9-14.4 9.2-11.8 4.5-5.2 1.8-2.4 4.0-4.4 3.1 – 4.8 3.6-4.1 5.2-5.3 5.1-6.0

Labial region width 10- 12 16-17 15-21 15 14 13 11 - 13 17-19 10-11

Cephalic setae length 10-11 6-8 10-16 11 14 13 8-9 20-27 9-10

Cephalic setae length as % of labial region width 90-100 38-47 63-80 73 100 100 62-83 107-159 90-100

Number of amphidial fovea turns 3.5 4.25-4.5 3.5 4.25 3.5 3.5-4.0 3.543-52 2.5 2.5-3.0

Spicules length 45-51 51-59 49-86 59 67 70 43-52 39-54 46-50

Ratio of spicule length to cloacal body diameter 1.5-1.7 1.5-1.8 1.1-1.4 1.7 – 1.8 1.0-1.6 1.2-1.7 1.8-2.0

Dorsal apophysis of gubernaculums length 19-21 11-13 17-21 20 33 29 12 -14 34-36 18-21

Number of supplements 7-9 7-9 15 17 – – 9 15 15-19 Discussion. The genus Setosabatieria was established by Platt in 1985. At present, the genus contains eight valid species. The most widespread and most morphologically variable is the type species, S. hilarula (de Man, 1922). This species is found in the North Sea, Mediterranean Sea, Atlantic Ocean off the coast of Central Africa and the USA, and in the Bay of Bengal (Gerlach & Riemann, 1973). It is probable that this name has been applied to several different nematode species in determinations. S. falcifera (Wieser, 1954) is found in the Atlantic Ocean near the coast of the USA, and S. triangularis Riera, Nunez, Brito, 2006 has been found also off the coast of the Canary Islands. The last species the largest in the genus Setosabatieria and also has the long cephalic setae (fig. 3, table 3). Two species, S. australis Leduc & Gwyther, 2008 and S. conicauda Leduc, Probert &Nodder, 2012 are found near the coast of New Zealand. These species significantly differ in morphology. S. conicauda is the smallest species in the genus and also has short cephalic setae and a short, conical tail (fig. 3, tab.3). Two species, S. coomansi Huang & Zhang, 2006 and S. jingjingae Guo & Warwick, 2001 , are found in the Yellow Sea off the coast of China. S. orientalis n. sp. is found in the South China Sea near the coast of Vietnam.

Figures

FIGURE 1. Sabatieria curvispiculata sp. n. A: Entire male; B: Entire female; C: Male head; D: Cardial region of male; E: Spicular apparatus; F: Vulva region; G: Male tail; H: Female tail. Scale bars; A, B — 250 µm; D, E, F, H— 50 µm; G – 40 µm; C— 15 µm.

Tables

TABLE 1. Morphometrics of Sabatieria curvispiculata sp. n. All measurements are in µm and the form: mean + standard deviation (range)

Character	Holotype male	Paratypes
		7 males 3 females
L	2108	2370 + 196 (2086–2633) 2647 + 135 (2510–2831)
a	38	39 + 1 (38–41) 36 + 0.9 (35–37)
b	9.4	10.6 + 0.7 (9.4–11.4) 11.4 + 0.2 (11.3–11.7)
c cʹ	15.6 3.7	15.0 + 0.9 (14.7–17.1) 13.9 + 0.1 (12.4–15.6) 3.9 + 0.3 (3.5–4.5) 4.7 + 0.2 (4.5–5.0)
V %	–	– 45.5 + 0.9 (44.4–46.6)
Labial region width	14.0	13.5 + 0.3 (13.0–14.0) 13.7 + 0.2 (13.5–14.0)
Cephalic setae length	4.0	4.0 + 0.4 (3.5–4.5) 4.5 + 0.5 (4.0–5.0)
Amphidial fovea diameter	10.0	9.5 + 0.4 (9.0–10.0) 9.2 + 0.4 (9.0–9.5)
Oesophagus length	225	224 + 5 (214–230) 231 + 15 (214–250)
Posterior end of pharynx to vulva	–	– 973 + 71 (900–1089)
Posterior end of pharynx to cloaca	1748	1996 + 187 (1726–2246) –
Vulva to anus	–	– 1251 + 58 (1193–1330)
Body width	55	60 + 6 (52–67) 82 + 3 (80–86)
Anal (cloacal) body diameter	38	37 + 2 (35–40) 43 + 2 (40–47)
Tail length	135	150 + 5 (135–160) 192 + 9 (182–203)
Spicules length (along arc)	78	79 + 2 (76–82) –
Dorsal apophysis of gubernaculum length	28	28 + 2 (25–30) –
Number of supplements	12	11 + 1 (10–13) –
Genus Setosabatieria Platt, 1985
Setosabatieria orientalis sp. n. (Fig.2, Table 2)