Abelbolla maemulensis, Hong, Ho & Lee, Wonchoel, 2014

Hong, Ho & Lee, Wonchoel, 2014, Two new species of free-living marine nematodes (Nematoda: Oncholaimida: Enchelidiidae) from Maemul Island, Korea, Zootaxa 3785 (3), pp. 419-437 : 422-424

Abelbolla maemulensis sp. nov.

Figs 2–4 , Table 1 –2

Type locality. Station SE06: sub-tidal South-east of Maemul Island (34˚ 35΄ 40˝ N, 128˚ 45΄ 13˝ E), at a depth of 77 m, in muddy sediment.

Additional locality. Station SE19: sub-tidal South-west of Maemul Island (34˚ 34΄ 46˝ N, 128˚ 25΄ 1˝ E), at a depth of 49 m, in muddy sediment.

Type material. Holotype: one male NIBRIV0000282455, collected by Hyeonggeun Kim and Kichoon Kim, at station SE 19 in December 2010, from Research Vessel Tam-Gu 7.

Paratype: two males NIBRIV0000282456 and NIBRIV0000282457, collected by Hyeonggeun Kim and Kichoon Kim, at station SE 19 in December 2010, from Research Vessel Tam-Gu 7; and two females NIBRIV0000282458 and NIBRIV0000282459, collected by Hyeonggeun Kim and Kichoon Kim, at station SE06 in December 2010, from Research Vessel Tam-Gu 7

Measurements. See Table 1 for detailed measurements and morphometric ratios.

Description. Male holotype. Habitus tubular and slender, strongly narrowed anteriorly. Cuticle smooth. Body diameter increases steadily from anterior end to base of pharynx then does not change to cloaca. Tail conicocylindrical.

Six outer labial sensilla small, with papillae form. Ten cephalic setae (4 µm) located about 0.5 hd from anterior end in one circle. Circular amphid with elongated corpus gelatum, diameter of amphid 4 µm, about 0.5 hd, located about 0.3 hd from anterior end. Anterior ten cervical setae about 9 µm long, located about 2.0 hd from anterior end in one circle. Other cervical setae (about 5 µm long) arranged irregularly.

Buccal cavity (8 µm long and 5 µm wide) in two parts with circular ring (with no denticles) separating two buccal chambers and with three unequal teeth of which one right subventral tooth (about 4 µm long) is largest. Pharynx expanding gradually and muscular along its entire length, without posterior bulbs. Nerve ring at 50% pharynx length.

Reproductive system diorchic, testes outstretched, anterior testis located 775 µm and posterior testis located 465 µm from the cloaca. Spicules paired, equal and arcuate, with a hook at the distal end, 63 µm long as arc (1.9 abd), 46 µm long as chord (1.4 abd). Gubernaculum with dorso–caudally directed apophysis, with swollen distal tip, 26 µm long (0.8 abd). Two winged precloacal supplements observed, anterior supplement (total length of anterior supplement, 0.8 abd) located 223 µm and posterior supplement (0.8 abd) located 162 µm from the cloaca. Tail 4.3 abd long with terminal setae (about 5–6 µm, more than eight).

Female paratypes. Similar to male, except body larger and longer than male (females average 1,921 µm long and 45 µm wide). Vulva at 56% of body of length. Didelphic, outstretched ovaries, anterior ovary 197 µm, posterior 231 µm long. Supplements absent.

Etymology. The species name refers to the sampling location, specifically the Maemul Island, from which the nematode was collected.

Diagnosis and remarks. Abelbolla maemulensis sp. nov. is unique within the genus, being the only species so far described which has circular amphids and a complex structure of the gubernacular apophysis. It is similar to A. huanghaiensis , described from the Yellow Sea, having similar spicule lengths and, spicule shape. Also, it is one of the shortest Abelbolla species so far described. With respect to the de Man’s ratios A. maemulensis sp. nov. differs from a (39.3 vs 47.9; 48.9; 39.5) and c (10.0 vs 11.2; 12.8; 17.2) for A. boucheri , A. huanghaiensis and A. warwicki , but b (3.4 vs 4.0; 3.6; 3.4) is quite similar to the ratios of the other species (Table 2).

TABLE 2. Comparative data table of the measurements for published and new species of Abelbolla . All measurements in µm unless otherwise stated, except ratio a, b, c, c’, d, s. Data presented are mean values, unless n = 1. Literature source: a Huang & Zhang 2004. n/a: not applicable; n/f: not in figure.

A. boucheri a A. huanghaiensis a A. warwicki a A. maemulensis Characters ♂ ♀ ♂ ♀ ♂ ♀ ♂ ♀

(n = 4) (n = 2) (n = 4) (n = 3) (n = 3) / (n = 3) (n = 2)

Figures

FIGURE 2. Abelbolla maemulensis sp. nov. A, male pharynx, holotype; B, male head, holotype; C, male habitus, holotype. Scale bars: 20 µm (A, B) and 100 µm (C).

FIGURE 3. Abelbolla maemulensis sp. nov. A, male precloacal supplements, holotype; B, male spicules and gubernaculum, holotype; C, male precloacal region and tail, holotype; D, female habitus, paratype; E, male tail end, holotype. Scale bars: 20 µm (A – C, E) and 100 µm (D).

FIGURE 4. Abelbolla maemulensis sp. nov. A, male head, showing buccal cavity, holotype; B, male head, showing amphidial fovea, holotype; C, male precloacal supplements, holotype; D, male spicules and gubernaculum, holotype; E, male tail end, showing terminal setae, holotype; F, female vulva, paratype. Scale bars: 10 µm (A – E) and 30 µm (F).

Tables

TABLE 1. Measurements of Abelbolla maemulensis sp. nov. All measurements in µm unless otherwise stated, except ratio a, b, c, c’, d, s. n / a: not applicable.

Characters	♂ Holotype ♂ 2	♂ 3	♂ Ave.	♀ 1	♀ 2	♀ Ave.
L	1535 1413	1532	1493	1710	2131	1921
mbd	39 37	38	38	42	49	45
hd	7 8	7	7	8	11	10
bcl	8 9	9	9	10	13	12
bcw	5 6	5	5	5	8	7
cep	4 6	5	5	5	6	6
AL	2 2	1	2	4	n/a	4
amp	4 5	4	4	4	n/a	4
amp cbd	8 7	8	8	8	n/a	8
cer	9 9	9	9	7	7	7
NL	201 238	239	226	247	248	247
N cbd	28 32	32	31	28	31	30
N%	50.1 52.0	50.0	50.7	50.7	37.2	43.9
PL	401 458	478	446	487	666	577
P cbd	38 37	36	37	37	46	42
abd	33 33	34	33	22	25	23
TL	142 148	158	149	146	149	148
c'	4.30 4.48	4.65	4.48	6.79	5.86	6.32
spic	46 44	50	47	n/a	n/a	n/a
spia	63 65	73	67	n/a	n/a	n/a
s	1.91 1.97	2.15	2.01	n/a	n/a	n/a
VL	n/a n/a	n/a	n/a	934	1235	1085
V cbd	n/a n/a	n/a	n/a	42	49	45
V%	n/a n/a	n/a	n/a	54.6	58.0	56.3
gub	26 28	29	28	n/a	n/a	n/a
psw	10 9	7	9	n/a	n/a	n/a
psm	5 5	5	5	n/a	n/a	n/a
ps	25 21	18	21	n/a	n/a	n/a
asw	10 9	6	8	n/a	n/a	n/a
asm	5 5	5	5	n/a	n/a	n/a
as	25 23	14	21	n/a	n/a	n/a
dps	162 132	119	138	n/a	n/a	n/a
dbs	61 95	53	70	n/a	n/a	n/a
at	775 733	686	731	n/a	n/a	n/a
pt	465 528	486	493	n/a	n/a	n/a
a	39.36 38.34	40.32	39.34	40.71	43.56	42.14
b	3.83 3.09	3.21	3.37	3.51	3.20	3.36
c	10.81 9.55	9.70	10.02	11.71	14.27	12.99
d	1.55 1.75	1.71	1.67	1.59	1.62	1.60