Pseudosteineria zhangi, Huang & Li, 2010

Huang, Y. & Li, J., 2010, Two new free-living marine nematode species of the genus Pseudosteineria (Monohysterida: Xyalidae) from the Yellow Sea, China, Journal of Natural History 44 (41 - 42), pp. 2453-2463 : 2458-2462

publication ID

https://doi.org/ 10.1080/00222933.2010.501530

persistent identifier

https://treatment.plazi.org/id/039B4C55-FFD0-FFD9-76FE-FECFFBAAF9B4

treatment provided by

Felipe

scientific name

Pseudosteineria zhangi
status

sp. nov.

Pseudosteineria zhangi sp. nov.

( Figures 3 View Figure 3 , 4 View Figure 4 )

Type material

Four males, three females collected from station 3300-4 and station 3400-0. Holotype: 31 on slide 3300406 (Station 3300-4); paratype: ♀ 1 on slide 3400001 (Station 3400-0); paratypes: three males and two females on slides 3300402, 3300403 and 3400001 respectively.

Type locality and habitat

Subtidal muddy sediment at Station 3300-4 (33° N, 123° E, water depth 30 m) and Station 3400-0 (34° N, 120° 33′ E, water depth 14.8 m) in the Yellow Sea.

Etymology

This species is named in honour of Professor Zhinan Zhang, College of Marine Life Sciences, Ocean University of China.

Measurements

Also see Table 2.

⎯348 M 1147

Holotype 31:

25 59 64 44

1360 µm; a = 21.3, b = 3.9, c = 6.3, Spic = 55

Paratype ♀ 1: ⎯320 V 1250 1460 µm; a = 20.3, b = 4.6, c = 7.0, V% = 60% 23 65 69 48

Description

Males. Body cylindrical, gradually tapering towards tail end, 1360–1745 µm long and 64–77 µm wide at maximum body diameter. Cuticle with coarse annulations, beginning at base of buccal cavity and ending at tail tip.

Buccal cavity conical, labial region set off. Six lips slightly inflated. Anterior sensilla arranged in two circles: an anterior one with six inner labial papillae and an outer one with 10 sensilla, i.e. six longer (8 µm) outer labial setae and four shorter (5 µm) cephalic setae. Prominent subcephalic setae arranged in eight short longitudinal rows just behind cephalic setae. Each group with three setae ( Figures 3C View Figure 3 , 4A, B View Figure 4 ). Length of cervical setae increasing gradually from the anterior to posterior seta in every row. Length of shortest about 15 µm, longest about 36 µm. Somatic setae short, scattered over body.

Amphidial fovea relatively small, circular, 8 µm in diameter (25% of corresponding body diameter wide), situated at level of grouped subcephalic setae, about 18 µm from anterior end ( Figure 3C View Figure 3 ).

Pharynx cylindrical, about 355 µm long (23% of total body length). Pharyngointestinal junction with cardia. Nerve ring at about 130 µm from anterior end (37% of pharyngeal length).

Ventral gland not observed.

Tail conico-cylindrical, 215–242 µm long (4.8 a.b.d.), tapering with distal third cylindrical part and three long terminal setae (22 µm). Three caudal glands obvious.

Spicules paired, equal in length, but dissimilar in shape. Right spicule slender ( Figure 4C View Figure 4 ), left one with large manubrium proximally ( Figure 4D View Figure 4 ), 56 µm (1.2 a.b.d.) long. Gubernaculum bucket-shaped, with short dorsal apophysis ( Figure 3A View Figure 3 ). Precloacal supplement absent. Anterior testis outstretched and situated to left of intestine; posterior testis reflexed and disposed to right of intestine.

Females. Similar to males in most respects. Body 1460–1655 µm long and 66–84 µm wide at maximum body diameter. Single long anterior outstretched ovary dorsal to left side of intestine, reaching into pharyngeal region. Some round adult eggs presence. ( Figure 3B View Figure 3 ). Vulva at 61% of the body length from anterior end.

Differential diagnosis

Eight groups of subcephalic setae relatively short. Amphidial fovea circular, situated at level of grouped subcephalic setae. Spicules paired, equal in length, dissimilar in form. Right spicule slender, left spicule with a large manubrium proximally. Gubernaculum bucket-shaped, with dorsal apophysis. Pseudosteineria zhangi sp. nov. is close to P. anticipans Wieser, 1956 , but different in the length of subcephalic setae, shape of spicules and structure of gubernaculum. In P. anticipans Wieser , subcephalic setae are longer (30–80 µm versus 15–36 µm); both spicules are similar; gubernaculum is complex, with distal hooks and an anteriorly directed triangular piece. This new species can be separated from other Pseudosteineria by relatively short subcephalic setae and dissimilar spicules.

Key to 13 species of Pseudosteineria (based on Tchesunov, 2000):

1. Amphidial fovea anterior to or at the level of grouped subcephalic setae........................................................ 2 Amphidial fovea posterior to subcephalic setae or not visible.......... 7

2. Males possess precloacal supplementary papillae....... P. ventropapillata No precloacal papillae in males ................................... 3

3. Two small hillocks on ventral side of the tail in males........ P. anteferens No papillae or hillocks on tail in males............................ 4

4. Gubernaculum with dorsal apophysis............................. 5 Gubernaculum without dorsal apophysis or only with weakly developed apophysis.................................................... 6

5. Spicules broad and solid, gubernaculum complex, with distal hooks......................................................... P. anticipans Spicules slender, gubernaculum simple without distal hook.............................................................. P. zhangi sp. nov.

6. Anterior sensory setae up to 12-13 µm, spicules 56 µm long........ P. pavo Anterior sensory setae up to 14-16 µm, spicules 32-39 µm long......................................................... P. sagittispiculata

7. Somatic setae very long, up to three body diameters...... P. paramirabilis Somatic setae small, usually shorter than half body diameter........... 8

8. Amphidial fovea difficult to observe............................... 9 Amphidial fovea clearly discernible, round or oval...................10

9. Spicules broad, unequal in length, the longer spicules jointed............................................................. P. sinica sp. nov. Spicules slender, equal in length.......................... P. coronata

10. Spicules solid, unequal in length.................... P. inaequispiculata Spicules slender, equal in length................................. 11

11. Gubernaculum with a prominent dorsocaudal apophysis....... P. scopae Gubernaculum apophysis relatively short..........................12

12. Males with three precloacal papilloid supplements............ P. pulchra No precloacal supplements in males........................ P. horrida

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