Two new free-living marine nematode species of the genus Pseudosteineria (Monohysterida: Xyalidae) from the Yellow Sea, China Author Huang, Y. Author Li, J. text Journal of Natural History 2010 2010-10-12 44 41 - 42 2453 2463 http://dx.doi.org/10.1080/00222933.2010.501530 journal article 10.1080/00222933.2010.501530 1464-5262 5210537 Pseudosteineria sinica sp. nov. ( Figures 1 , 2 ) Type material Four males and three females were measured and studied. Holotype : 31 on the slide R2008731-2 ; paratype : ♀ 1 on the slide R2008802-7 ; paratypes : three males and two females on the slides R2008731 - 2,3 and R2008802 - 4,6 respectively. Type locality and habitat Intertidal sandy sediment at Rizhao coast ( 119° 34′ E , 35° 26′ N ) of the Yellow Sea. Etymology This species is named for the country of the type locality, PR China . Measurements Also see Table 1 . ⎯282 M1162 Holotype 31: 1360 µm; a = 25.7, b = 4.8, c = 6.9, Spic l = 60, Spic r = 48 19 50 53 42 ⎯278 V 1176 Paratype ♀ 1: 1365 µm; a = 20.1, b = 4.9, c = 7.3, V % = 663% 20 61 68 46 Description Males. Body spindle-shaped, gradually tapering towards both extremities, more pronounced in tail region ( Figure 1B ); 1250–1360 µm long and 53–68 µm wide at maximum body diameter. Cuticle with visible annulations, beginning at base of buccal cavity and ending at tail tip. Buccal cavity with hemispherical cheilostom and conical pharyngostom ( Figures 1A , 2B ). 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 (9 µm) outer labial setae and four shorter (5 µm) cephalic setae. Prominent subcephalic setae arranged in eight short longitudinal rows (subdorsal, laterodorsal, lateroventral and subventral on both sides of body) just behind cephalic setae. Each group with 3–4 long setae. Length of subcephalic setae increasing gradually from anterior to posterior seta in every row ( Figure 2A, B ). Length of shortest about 16 µm, longest about 53 µm. Somatic setae short, scattered over body. Figure 1. Pseudosteineria sinica sp. nov. (A) Lateral view of male anterior end, showing buccal cavity, cephalic setae and subcephalic setae; (B) lateral view of female body, showing ovary, eggs and vulva; (C) lateral view of male tail end, showing spicules, gubernaculum and caudal glands. Amphidial fovea not observed. Pharynx cylindrical, about 275 µm long (21% of total body length). Pharyngo-intestinal junction with cardia. Nerve ring at about 105 µm from anterior end (at 38% of pharyngeal length). Figure 2. Pseudosteineria sinica sp. nov. (A) lateral view of female anterior end, showing cephalic setae and subcephalic setae; (B) lateral view of male anterior end, showing buccal cavity and subcephalic setae; (C) lateral view of male tail end, showing left longer spicule and caudal glands; (D) lateral view of male cloaca region, showing right shorter spicule, gubernaculum and ventral setae. Table 1. Individual measurements in µm (and averages) of Pseudosteineria sinica sp. nov.

Characters	31	32	33	34	31	♀2	♀3	Average
Total body length	1360	1305	1250	1355	1365	1185	1570	1340
Maximum body diameter	53	56	57	68	68	51	69	60
Head diameter	19	20	18	19	20	18	22	19
Length of the longest anterior sensory	9	8	9	10	10	10	11	10
seta
Length of the shortest subcephalic seta	16	15	16	18	20	18	21	18
Length of the longest subcephalic seta	55	50	54	52	60	53	55	548
Nerve ring from the anterior end	112	110	96	101	115	103	113	107
Nerve ring c.b.d.	39	42	39	42	49	38	48	42
Pharyngeal length	282	276	268	275	278	264	304	278
Pharyngeal c.b.d. at base	50	50	52	48	61	50	60	53
Rightspiculelengthasarc	48	46	42	48	—	—	—	46
Leftspiculelengthasarc	60	57	55	60	—	—	—	58
Tail length	198	180	162	192	188	167	214	186
a.b.d.	42	42	44	42	46	34	46	42
c′	4.7	4.3	3.7	4.6	4.1	4.9	4.7	4.4
Vulvafromanteriorend	—	—	—	—	856	766	994	872
Vulvac.d.	—	—	—	—	68	51	66	62
V%	—	—	—	—	63	65	63	64
a	25.7	23.3	21.9	19.9	20.1	23.2	22.8	22.4
b	4.8	4.7	4.7	4.9	4.9	4.5	5.2	4.8
c	6.9	7.3	7.7	7.1	7.3	7.1	7.3	7.2

Ventral gland not observed. Tail conico-cylindrical, 162–198 µm (about 4.2 a.b.d.) long, with distal fourth cylindrical part. On conical part of tail, long ventral setae distributed densely. Tail tip bearing three terminal setae, length to 29 µm. Three caudal glands visible. Spicules paired, unequal in length ( Figure 1C ). Left spicule longer (average 58 µm), divided into two sections jointed in middle, proximal section with large manubrium ( Figure 2C ). Right spicule shorter (46 µm), without indentation ( Figure 2D ). Both spicules curved with proximal capitulum and distal taper tip. Gubernaculum with dorsocaudal apophysis ( Figure 1C ). 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 1185–1570 µm long and 51–69 µm wide at maximum body diameter. A single anterior outstretched ovary, situated to left of intestine. Some round adult eggs presence ( Figure 1B ). Vulva at about 64% of the body length from the anterior end. Differential diagnosis Body spindle-shaped, cuticle distinctly annulated. Amphidial fovea difficult to observe. Spicules unequal in length. Left spicule longer, divided into two sections jointed in the middle. Right spicule shorter, simple, without articulation. Both spicules curved with proximal capitulum; tapered distally. Gubernaculum with dorsocaudal apophysis. Pseudosteineria sinica sp. nov. is similar to Pseudosteineria inaequispiculata (Platonova) Gerlach and Riemann, 1973 in unequal spicules, but the latter has a clearly discernible round amphidial fovea and is without apophysis of gubernaculum. This new species can be easily identified by unequal and articulated spicules from other species in Pseudosteineria .