Parodontophora huoshanensis, Li, Yongxiang & Guo, Yuqing, 2016

Li, Yongxiang & Guo, Yuqing, 2016, Free living marine nematodes of the genus Parodontophora (Axonolaimidae) from the East China Sea, with descriptions of five new species and a pictorial key, Zootaxa 4109 (4), pp. 401-427 : 411-414

Parodontophora huoshanensis sp. nov.

( Figure 6 , Figure 7 , Table 5 , Table 6 )

Type material. Two males and two females were collected from Station ZZHS in September 2012.

Holotype: ♂1 on slide number ZZHS 201209 L3113. Paratypes: ♂2 on slide number ZZHS 201209 L3112, ♀1 on slide number ZZHS 201209 L3111, ♀2 on slide number ZZHS 201209 L3102. The holotype and paratypes are deposited in the Third Institute of Oceanography, State Oceanic Administration, Xiamen.

Type locality and habitat. All specimens were collected from intertidal sandy sediment at Huoshan Island, Zhangzhou City, East China Sea. Station ZZHS: 118.025°E, 24.213°N.

Etymology. This species is named for the type locality, intertidal sediments on Huoshan Island.

Measurements. Table 5 .

Description. Body narrows gradually in the anterior region. Cuticle with faint outer striation discernible in the lateral field. Lip region more or less rounded, with six outer labial papillae. Four cephalic setae 3–4 µm, 27–33% of head diameter, 3 µm from the anterior end. Opisthocephalic setae 2–3 µm, arranged as two subdorsal groups of two longitudinally arranged setae and two single subventral setae, i.e. (2D- 1V)2. Somatic setae scattered, length 2–3 µm. Buccal cavity 26–29 µm long and 4–6 µm wide, cylindrical with conspicuous sclerotized parallel walls. Six bifurcate teeth at the tip of the buccal cavity with the anterior tip narrower than the posterior one. Armilliths absent. Amphid 3 µm from the anterior end, crook-shaped with the shorter dorsal branch and parallel much longer ventral branch. Posterior end of the amphid near the base of the buccal cavity. Length of the dorsal branch equals 0.54–0.65 of ventral branch length and the amphid length is 0.77–0.83 times the buccal cavity length. Pharynx starts at the base of buccal cavity, muscular, and gradually broadens to the base. Cardia small, rounded-conoid, surrounded with intestinal tissue. Renette cell slightly behind the base of pharynx, elongated oval, 56–91 µm, 34–60% of the pharynx length. Nerve ring at 63–65% of pharynx length. Excretory pore indistinct near cephalic setae at the anterior part of buccal cavity. Tail length 130–146 µm, conical anteriorly and cylindrical posteriorly, pointed terminal end without terminal setae. Three caudal glands open to the spinneret.

Male: Several irregular setae on the conical portion of the tail, length 3–4 µm. Reproductive system diorchic. Testes paired, opposed and outstretched. Anterior testis to the left and posterior testis to the right of the intestine. Vas deferens well developed. Spicules length 34–35 µm, paired, equal and arcuate, several slight thickened septa closes to dorsal sides, circle aperture in distal end and enlarged thickened proximal end with a front and dorsal constriction. Gubernaculum with dorsal-caudally directed apophysis 11–13 µm long, thickened edge extended into two small points. 6 fibriform precloacal supplements present, they extend 218–223 µm from cloaca to the anterior end, 16–18% of body length.

Female: Morphologically similar to the male. Unpaired setae on tail. Reproductive system ampdidelphic, ovaries outstretched. Anterior gonad to the right and posterior gonad to the left of the intestine. Vulva is at 50% of the total body length. Short vagina with thick walls is perpendicular to the longitudinal body axis. Vulval glands are present anterior and posterior to the vagina. Two spermathecae and no spermatozoa are found in uteris.

Diagnosis and relationships. Parodontophora huoshanensis sp. nov. is characterized by relatively short cephalic setae (0.27–0.33 h. d.); the positon of the posterior end of the amphid far from the base of the buccal cavity (0.77–0.83 times the length of the buccal cavity); opisthocephalic setae arranged as (2D- 1V)2; excretory pore near cephalic setae at the anterior part of buccal cavity; armilliths absent; renette cell occupying 34–60% of the pharynx length; 6 fibriform precloacal supplements present and extend 218–223 µm anteriad.

P. huoshanensis sp. nov. comes close to P. brevamphida Timm, 1952 , P. probata Smolyanko & Belogurov, 1995 , P. limnophila Wu, 2000 , P. amoyensis Zou, 2000 and P. fluviatilis Gagarin & Thanh, 2008 in the ratio of dorsal branch length of the amphid to the ventral branch length, the ratio of amphid ventral branch length to buccal cavity length, the size of renette cell and the positon of excretory pore. However, the new species can be separated from P. probata by armilliths absent, while P. probata has the large, roundedly heart-shaped in the buccal cavity. It also can differ from P. brevamphida , P. limnophila , P. amoyensis and P. fluviatilis in males have supplements and different opisthocephalic setae arrangement ( Table 6 ).

continued.

Notes: Anterior, at the anterior part of buccal cavity; Middle, at the middle of buccal cavity; 1, excretory pore about at the level of cephalic setae; 2, excretory pore almost at the anterior end of body; *, the data were calculated from original data or published pictures; -, no data; Y, present; N, absent.

Figures

FIGURE 6. Parodontophora huoshanensis sp. nov. A: lateral view of male anterior part; B: lateral view of female head; C: lateral view of copulatory apparatus; D: lateral view of male tail and spicule; E: lateral view of female tail; F: lateral view of female reproductive system. Scale bar: A, B, C, D, E = 20 Μm; F = 40 Μm.

FIGURE 7. Light micrographs of Parodontophora huoshanensis sp. nov. A: anterior body end of male, showing amphid; B: anterior body end of female, showing buccal cavity; C: lateral view of male body part, showing copulatory apparatus; D: supplements in male; E: vulva region; F: posterior body end of female; G: ovary region; H: full view of male body. Scale bars: A, B, C, D = 10 Μm; E, F = 25 Μm; G = 50 Μm; H = 200 Μm.

Tables

TABLE 5. Individual measurement of Parodontophora huoshanensis sp. nov. (in µm).

Characteristics	Holotype	Paratypes
	♂1	♂2 ♀1 ♀2
Total body length	1235	1377 1408 1325
Head diameter	12	11 12 15
Cephalic setae	4	3 4 4
Opisthocephalic setae	2	2 2 2
Buccal cavity length	26	27 27 29
Buccal cavity diameter	4	4 4 6
Amphid from anterior end	3	3 3 3
Amphid c. b. d.	17	18 17 24
Amphid dorsal branch length	13	13 13 13
Amphid ventral branch length	20	21 21 24
Nerve ring from anterior end	98	102 95 101
Nerve ring c. b. d.	30	28 34 43
Pharynx length	150	161 151 164
Pharynx c. b. d.	33	35 37 55
Renette gland length	80	75 91 56
Maximum body diameter	46	44 42 72
a. b. d.	27	30 25 34
Tail length	132	130 142 146
c'	4.9	4.3 5.7 4.3
Spicule length as chord	30	28 - -
Spicule length as arc	35	34 - -
Gubernaculum length	10	9 - -
Apophysis length	11	13 - -
Vulva c. b. d.	-	- 41 65
Vulva, %	-	- 49.5 50.1
a	26.8	31.3 33.5 18.4
b	8.2	8.6 9.3 8.1
c	9.4	10.6 9.9 9.1

TABLE 6. Comparison of Parodontophora huoshanensis sp. nov. with allied species.

Species	P. amoyensis	P. brevamphida	P. fluviatilis
Buccal cavity length (Μm)	39	18–20	19–21
Cephalic setae length/head diameter	0.51–0.54	0.7	0.41–0.48
Amphidael dorsal branch length/amphidael ventral branch(%)	66*	50*	50
Amphidael dorsal branch length/buccal cavity length	0.7*	0.8	0.7–0.8
Opisthocephalic setae arrangement	♂(2D-2V)2,♀(3D-2V)2	irregular	(3D-1V)2
Renette gland length/pharynx length (%)	48–54	40	48–59
Position of excretory pore	Anterior	Anterior2	Anterior1
Spicule length as arc (Μm)	35–36	-	19–21
Supplements	N	N	N
Armilliths	N	N	N
Reference	Zou 2000	Timm 1952	Gagarin & Thanh 2008