Ledovitia brevis, 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 : 428-435

Ledovitia brevis sp. nov.

Figs 5–7 , Table 3 –4

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.

Type material. Holotype: one male NIBRIV0000282460, collected by Hyeonggeun Kim and Kichoon Kim, at station SE06 in December 2010, from Research Vessel Tam-Gu 7.

Paratypes: one male NIBRIV0000282461 and one female NIBRIV0000282462, collected by Hyeonggeun Kim and Kichoon Kim, at station SE06 in December 2010, from Research Vessel Tam-Gu 7

Measurements. See Table 3 for detailed measurements and morphometric ratios.

Description. Male holotype. Habitus tubular and slender, strongly narrowed anteriorly. Cuticle smooth. Body diameter increasing steadily from anterior end to base of pharynx then unchanging to cloaca. Tail conicocylindrical.

Six outer labial sensilla small papillae form. Ten cephalic setae (8 µm long) in one circle located about 0.4 hd from anterior end. Amphids oval in shape, with diameter of 5 µm, about 0.4 hd, located about 0.6 hd from anterior end. Anterior ten cervical setae in one circle about 15 µm long, located about 1.5 hd from anterior end. Other cervical setae (about 18 µm long) arranged irregularly. Row of six subventral post-cloacal setae (2–5 µm long) located in conical region of tail. In cylindrical region of tail, several scattered setae (about 5 µm long) present.

Buccal cavity (15 µm long and 7 µm wide) divided in two chambers by row of denticles. Three unequal teeth in buccal cavity. Right subventral tooth (10 µm long) largest and acute; dorsal and left subventral teeth are less noticeable. Pharynx expanding gradually and muscular along its entire length, lacking posterior bulbs. Nerve ring at 39% pharynx length.

Reproductive system diorchic, testes outstretched, anterior testis located 872 µm and posterior testis 612 µm from cloaca. Spicules paired, equal and arcuate, 41 µm long as arc (1.3 abd), 34 µm long as chord (1.0 abd). Spicules curved with tapered distal tip. Gubernaculum with dorso-caudally directed apophysis, 4 µm long (0.1 abd). Two winged precloacal supplements observed; anterior supplement (0.6 abd) located 194 µm and posterior supplement (0.5 abd) located 110 µm from cloaca. Two precloacal setae (6 µm long) located immediately anterior to cloaca (0.1 abd). Tail 4.7 abd long with six terminal setae (about 7 µm long).

Female paratype. Similar to male (1,515 µm long and 47 µm wide). Vulva at 53% of body length. Didelphic, outstretched ovaries, anterior ovary 166 µm and posterior 169 µm long. Supplements absent.

Etymology. The species named after Latin “ brevis ” = short.

Diagnosis and remarks. Ledovitia brevis sp. nov. is one of the smallest Ledovitia species (1,699 µm long) described to date. It is most similar to L. pharetrata described from Chile: in having precloacal setae and caudal setae, ad in the shape of the spicule and gubernaculum. However, they differ in body length of adults (male 1,642– 1,755 µm vs 2,640 µm; female 1,515 µm vs 2,000–2,700 µm), and the spicule lengths measured as the arc (39–41 µm vs 100 µm; s: 1.3 vs 2.1).

Key to the genus Ledovitia Filipjev, 1927 (amended from Belogurov et al. 1983)

1. Submedian pairs of cephalic setae, unequal in length......................................................... 2 - Submedian pairs of cephalic setae, equal in length........................................................... 7 2. Length of shorter cephalic setae about 33% of length of longer cephalic setae............................. L. longiseta - Length of shorter cephalic setae about 50-80% of length of longer cephalic setae.................................. 4 3. Length of female tail 209 µm (c = 10.4)......................................................... L. profunda - Length of female tail less than 209 µm (c = 11–17).......................................................... 4 4. Apophysis of gubernaculum present...................................................................... 5 - Apophysis of gubernaculum absent...................................................................... 6 5. Length of spicule 48–50 µm (as chord), 58–73 µm (as arc); length of gubernaculum 10–13 µm.............. L. honorata - Length of spicule 35–38 µm (as chord); length of gubernaculum 12 µm; posterior supplement 4.2–4.5 abd distant from the

anus; anterior supplement 6.6–7.5 abd distant from the anus......................................... L. obtusidens 6. Precloacal supplements 5.8–9.6 abd distant from the anus................................................ L. fallae 7. Preanal setae and caudal setae present.................................................................... 8 - Preanal setae and caudal setae absent..................................................................... 9 8. Length of spicule 78 µm (as chord), 100 µm (as arc); body longer than 2,000 µm........................ L. pharetrata - Length of spicule 33–34 µm (as chord), 39–41 µm (as arc); body shorter than 1,800 µm...................... L. brevis 9. Length of the spicule 52–65 µm................................................................... L. hirsuta

Figures

FIGURE 5. Ledovitia brevis sp. nov. A, male pharynx, holotype; B, male head and nerve ring, holotype; C, male habitus, holotype; D, male head, holotype. Scale bars: 20 µm (B, D) and 100 µm (A, C).

FIGURE 6. Ledovitia brevis sp. nov. A, male pre – cloacal region, holotype; B, male spicules and gubernaculum, holotype; C, female habitus, paratype; D, male tail, holotype; E, male tail end, holotype. Scale bars: 20 µm (A, B, D, E) and 100 µm (C).

FIGURE 7. Ledovitia brevis sp. nov. A, male head, showing buccal cavity, holotype; B, male head, showing amphidial fovea, holotype; C, male precloacal supplements, holotype; D, male tail, showing spicules, gubernaculum, precloacal setae and terminal setae, holotype; E, female vulva, paratype. Scale bars: 10 µm (A – C) and 50 µm (D, E).

Tables

TABLE 3. Measurements of Ledovitia brevis sp. nov. All measurements in µm unless otherwise stated, except ratio a, b, c, c’, d, s. n / a: not applicable.

Characters	♂ Holotype ♂ 2	♂ Ave.	♀ 1
L	1642 1755	1699	1515
mbd	49 47	48	47
hd	12 11	12	13
bcl	15 14	15	19
bcw	7 6	7	8
cep	8 9	9	10
AL	7 5	6	10
amp	5 5	5	5
amp cbd	13 11	12	15
cer	15 14	15	14
NL	191 194	193	165
N cbd	40 38	39	35
N%	38.7 41.7	40.2	39.3
PL	493 465	479	420
P cbd	47 46	46.5	40
abd	32 32	32	27
TL	151 154	153	138
c'	4.72 4.81	4.77	5.11
spic	34 33	34	n/a
spia	41 39	40	n/a
s	1.28 1.22	1.25	n/a
VL	n/a n/a	n/a	796
V cbd	n/a n/a	n/a	47
V%	n/a n/a	n/a	0.53
gub	4 4	4	n/a
psw	6 6	6	n/a
psm	7 7	7	n/a
ps	17 17	17	n/a
asw	6 5	6	n/a
asm	7 6	7	n/a
as	20 16	18	n/a
dps	110 130	120	n/a
dbs	84 86	85	n/a
at	873 941	907	n/a
pt	612 713	663	n/a
a	33.51 37.34	35.43	32.23
b	3.33 3.77	3.55	3.61
c	10.87 11.40	11.14	10.98
d	1.65 1.54	1.60	1.58