Leptepsilonema saldanhae, Hendricks, Martin G. J. & Gibbons, Mark J., 2010

Hendricks, Martin G. J. & Gibbons, Mark J., 2010, Two new nematode species from Saldanha Bay, South Africa: Perepsilonema benguelae sp. nov. and Leptepsilonema saldanhae sp. nov. (Desmodorida, Epsilonematidae), Zootaxa 2504, pp. 20-30 : 25-27

Leptepsilonema saldanhae sp. nov.

( Figs 3 , 4 )

Measurements. Table 3 .

Material examined. Holotype male: SOUTH AFRICA, Saldanha Bay, -33.04800°; 17.98350, coarse sand in shipping channel, sublittoral (20 m), August 1999 by MGJ Hendricks (SCUBA-assisted handheld corers), NHM accession No. 2008:858. Paratypes: one female NHM accession No. 2008:859, one female Iziko South African Museum accession No. SAM A29472 .

Male. Body round in cross-section, epsilon–shaped, with swollen pharyngeal and posterior regions ( Fig. 3 A), and 114 annulations ( Table 3 ) possessing a well-developed hyaline outer layer. Annuli anteriorly directed behind cephalic capsule, changing orientation ventrally at annule 13 (anteriorly to posteriorly), annule 24 (posteriorly to anteriorly) and annule 51 (anteriorly to posteriorly); anteriorly directed annuli change orientation dorsally at annule 23. Size and distribution of vacuoles on annuli variable, indistinct in first annule, of irregular size on anterior swelling, small and distributed as longitudinal bands in narrow middle region, and as a single row on tail; absent between ambulatory setae. Somatic setae fine, mostly in pharyngeal and posterior regions of body, very long (24–34 µm). Five longitudinal rows of six to 13 ambulatory setae with hooked tips; first seta on annule 69; left external sub-ventral row with 13 collared ambulatory setae (7.4 µm long); left inner sub-ventral row with six setae (6.6 µm long); middle row with 7 setae (6.6 µm long); right inner sub-ventral row with six setae (8.8 µm long); right external sub-ventral row with 13 setae (9.6 µm long). Five thick, ventrally-directed supporting setae occur posterior to the ambulatory setae, arranged as two pairs and a singlet plus a row of three stout lateral supporting setae (3.2 µm long) on the same level as external sub-ventral setae.

mbd/(mbd) 1.5 1.2 1.2

Cephalic capsule truncated, 14.8µm long, 14.2 µm diameter ( Fig. 4 A), labial region partially extended; with four cephalic setae (7 µm); with six collared subcephalic setae (14 µm), anterior to the amphids. Amphidial fovea dorso-laterally situated, dorsally looped in an inverted open U-shape, dorsal arm stretching into the first annule, diameter about 35% of maximum corresponding body diameter. Buccal cavity lacking teeth or denticles; pharynx terminating in rounded muscular bulb with strongly cuticularized lumen walls. Tail conical, with 8 annuli; three caudal setae present; no setae on non-annulated region; caudal glands not seen.

Single, outstretched testis with large sperm cells opening into short granular vas deferens ( Fig. 4 C), ventral and partly to left of intestine in thickened posterior region of the body, behind ventral body curve. Spicules paired, arcuate, relatively slender with enlarged proximal ends forming a capitulum. Gubernaculum short, straight, 5.8 µm long. A field of four ventro-lateral copulatory thorns present on annuli surrounding the cloaca, with short supporting setae; two small subventral precloacal thorns.

Female. Similar to males in habitus ( Fig. 3 B). Cuticle with 114 annuli; vacuolar ornamentation generally as males but dorsal spiny projections more pronounced posteriorly. Amphid shape different from male, a ventrally wound spiral with 1.5 turns ( Fig. 4 B), diameter about 30 % of maximum corresponding body diameter. Reproductive system didelphic, amphidelphic; ovaries reflexed (anterior ovary bent to left side, posterior ovary to right side) ventral to intestine ( Fig. 4 D). Vagina 12.5 µm long, ending in cuticularized outer part (2 µm long) and larger, weakly cuticularized inner part. Vulva situated ventrally in posterior body half.

Diagnosis. Leptepsilonema saldanhae sp. nov. is characterised by the following combination of characters: in the male, the shape of the amphid is a dorsally looped inverted U-shape with dorsal arm overlapping the first body annule, whilst in the female it is smaller, and spiral; the anteriormost ambulatory setae of external subventral row (A sl1) are short in the male, and longer in the female; the ambulatory setae are bent; there are six prominent subcephalic setae anterior to, and two setae posterior, to the amphidial fovea, all embedded in a marked collar; the shape of the copulatory apparatus; the six ventro-lateral copulatory thorns on both sides of the cloaca; and the presence of two small postcloacal thorns and a short supporting seta/spine present at the cloacal opening. The long subdorsal somatic setae in the pharyngeal region are also diagnostic. L. saldanhae sp. nov. is similar to L. dauvini in overall body length and amphidial size, and spicule and gubernaculum lengths, but differs in sexual dimorphism of the amphid, and the number of precloacal thorns. It is similar to L. filiforme in body ratios (a, b and c) and amphidial size, but L. saldanhae sp. nov. differs from L. filiforme in size of spicules and gubernaculum, number of annulations, length of pharynx, and number and arrangement of copulatory structures.

Etymology. The species is named after the type locality, Saldanha Bay, on the west coast of South Africa.

Figures

FIGURE 3. Leptepsilonema saldanhae sp. nov. A. Male habitus. B. Female habitus. Scale represents 50 μm.

FIGURE 4. Leptepsilonema saldanhae sp. nov. A. Male anterior body region with indication of amphidial fovea and detail of body rings in surface view. B. Female anterior body region with indication of amphidial fovea and detail of body rings in surface view. C. Male posterior body region with reproductive system. D. Female posterior body region with reproductive system. Scale represents 20 μm.

Tables

TABLE 3. Morphometric measures in µm for Leptepsilonema saldanhae sp. nov. from Saldanha Bay. See Table 1 for abbreviations.

	Holotype male	Female NHM	Female SAMA
L	324.6	339	406
N	119	114	126
amph	4.5	3.2	3.9
%	35	21.7	30
cs	7	9	9
subcs	12.3	13	13
hw	14	13	13.6
hl	14.8	13	14.8
phs	32.4
ss1	31.6	21.3	23.2
ss2	33.6	13	42.7
ss3	23.9	14.7	23.9
ss4	29	22.6	28.7
A sl 1	5.8	11.6	13.6
ph	74	71	85.8
mbd ph	27	27	27
mbd	24.6	18	24.5
(mbd)	16.4	14.8	20
abd	19.4	14.2	15.5
t	29	31	34
tmr	9	12.3	14.8
spic	27
gub or v	5.9	259	265.6
a	13	16.6	18.8
b	4.4	4.7	4.8
c	11.2	11	12
c’	1.5	2.2	2.2
V		63.7	78.3