Halaphanolaimus sergeevae, Ürkmez, Derya & Brennan, Michael L., 2013

Ürkmez, Derya & Brennan, Michael L., 2013, A new species of Halaphanolaimus (Nematoda: Leptolaimidae) from the southern Black Sea (Turkey) with a modified key for species identification, Zootaxa 3691 (2), pp. 220-228 : 221-227

Description of Halaphanolaimus sergeevae n. sp.

( Figs 1–4 )

Measurements. Table 1 .

Type material. One holotype male, two paratype males and two paratype females mounted in glycerol slides. Slides number SNUFF/NEM-N12P63 (male holotype), SNUFF/NEM-N12P36 (male paratype 1), SNUFF/NEM- N12P8 (male paratype 2), SNUFF/NEM-N12P24 (female paratype 1), SNUFF/NEM-N12P40 (female paratype 2), deposited at the museum of Sinop University, Faculty of Fisheries. All samples were collected from E/V “Nautilus”, cruise NA012-003, Dive number H1152, ROV “Hercules”, using push corers, oxic zone. Collected 9th August, 2011.

Type locality. Coast of the Sinop Peninsula, located at the middle of the southern border of the Black Sea, coordinates 42º09´16´´N / 34º30´69´´E; at a depth of 90 m.

Descriptions. Male: Body slender, attenuating towards both ends. Cuticle 2 µm thick; prominently striated, striations 3µm apart. The cuticle has scattered pores with an approximate diameter of 1.5 µm. Somatic and cervical setae absent. Four cephalic setae at the base of the labial region, about 3.5 µm long (1.8 c.b.d.). A minute invagination present in the middle of the lip region. Amphidial fovea oval with a posterior break, about 4.5 µm in height with anterior border 7 µm from the highest lip margin. Ocelli absent. Cervical setae approximately 1.75 µm long and located just below the amphideal fovea. Stoma narrow, 33 µm long. Pharynx long, narrow, a pyriform posterior bulb present with length about two times its diameter. Ventral gland and nerve ring not observed. Cardia prominent, 4 µm long. Fourteen tubular supplements are located at varying distances to each other. First supplement 18 µm long situated 30 µm above the lower margin of posterior pharyngeal bulb. Second supplement 120 µm distant from the first one, 15 µm long with a 7.5 µm long visible longitudinal incision on its second half towards the distal end. The lengths of the following supplements and the distance to the previous supplement (in brackets) are 18.5 (62) µm, 16.5 (91) µm, 17 (79) µm, 19 (61) µm, 15.6 (38) µm, 18 (58) µm, 19 (63) µm, 23 (53.5) µm, 22.5 (43) µm, 21 (33) µm, 22.5 (50) µm, and 22.5 (53) µm. The distance from the last supplement to the copulatory apparatus is 88.5 µm. All tubes are distally dentated and surrounded by a cuticular sclerotization. Five of the supplements (from the seventh to eleventh) are clearly observed to have bifid proximal ends whereas those of the following three (from twelfth to fourteenth) are round and slightly swollen. Paired spicules, equal in length, bent, proximally cephalated, length 70 µm along the arc including the spicule head. Gubernaculum 33 µm, has a dorsal apophysis with its proximal end slightly bent anteriorly. Two preanal setae observed; first is 3 µm long located 4 µm from spicule, and second seta is 28 µm from the first tubular supplement. Testis paired and opposed. A few postanal setae present on the ventral side of the tail. Tail tip (17 µm) not striated, including a 1.5 µm spinneret. Tail contains well developed caudal glands.

Note: “?”measurements were not possible due to the position of the specimen on the slide.

Female: Similar to males apart from the number of supplements (five) and slight morphometrical differences ( Table 1 ). Reproductive system didelphic and amphidelphic. Each of the opposed uteri contains two large adjoining eggs. The dimensions of the anterior egg group are 54x 40– 64 x40 µm and the posterior 65x 46– 59 x46 µm with a distance of 40 µm between each group. Vagina length 16 µm (1/3 of corresponding body diameter). Vulva located at 48% of the total body length, close to the posterior end of the first group of eggs; vulval lips not protruding outside the body contour. Tail somewhat more slender than the male.

Differential diagnosis. Halaphanolaimus sergeevae n. sp. is characterized by the presence of 12–14 precloacal supplements in the male. Halaphanolaimus sergeevae n. sp. most closely resembles H. pellucidus in general body and spicule shape but differs from it by the number and location of precloacal supplements with one at the pharyngeal region (2 in H. pellucidus ), and thirteen in the precloacal region (6–7 in H. pellucidus ), smaller body size, lower De Man indices of a, b and c ’, location of amphideal fovea closer to anterior margin, and smaller labial diameter ( Table 2).

Species Characters

L a b c diam.lab. c' Spicule L male suppl.n.

cangionensis 499–571 24–37 4.7–5.5 5.7–7.6 3.5–4.5 5.0–8.1 16–18 4 harpaga 430–518 26–35 3.8–4.5 6.9–8.3 4.0–5.0 4.2–5.6 15–16 4 or 5 lorenzeni 635–735 40–45 5.3–6.1 7.4–9.1 5.0–5.5 4.5–6.5 16 4 luridus 520–760 27–37 4.7–5.8 6.8–8.7 4.0–4.5 4.0–4.5 35 4 pellucidus 1460 –1550 33–41 6.0–6.6 10.7–12.7 8.0 3.3–4.6 47–52 6 or 7 rivalis 696–754 30–37 5.3–6.1 7.8–9.9 5.5–6.0 4.0–7.8 27–28 4 sergeevae 926–1273 21–25.6 4.7–5.4 9.9–11.0 5.5–5.9 2.0–3.0 68–70 12 to 14 Halaphanolaimus sergeevae n. sp. is related to H. cangionensis , H. lorenzeni , H. rivalis and H. harpaga but it can be distinguished from these species by having longer spicules, a higher number of precloacal supplements, smaller a and c ’ values and a longer body ( Table 2).

Etymology. Named in honour of Professor Nelli G. Sergeeva from Institute of Biology of Southern Seas, Ukraine.

Figures

FIGURE 1. Halaphanolaimus sergeevae sp. nov. A. Total body of holotype male, B. Stoma of holotype male, C. Cuticular annules of holotype male, D. Tubular precloacal supplements of holotype male, E. Copulatory apparatus of holotype male, F. Tubular precloacal supplement at the level of pharyngeal bulbus of holotype male, G. Tail of holotype male, H. Pharynx of paratype female 2, I. Total body of paratype female 2. Scale bars: A & I = 100 µm; B, C, D, E, F & G = 20 µm; H = 50 µm.

FIGURE 2. Halaphanolaimus sergeevae n. sp. A. Amphid of paratype male 2, B. Stoma of paratype male 2, C. Total body of paratype male 2, D. Copulatory apparatus and tubular precloacal supplements of paratype male 2. Scale bars: A & B = 20 µm; C = 100 µm; D = 50 µm.

FIGURE 3. Halaphanolaimus sergeevae n. sp. Details of the holotype male. A. Anterior end showing the cuticularized stoma. B. Tail and cloacal region. Scale bars = 20 µm.

FIGURE 4. Halaphanolaimus sergeevae n. sp. Precloacal supplements along the mid-body of the holotype male. Scale bar = 20 µm.

Tables

TABLE 1. Measurements of Halaphanolaimus sergeevae n. sp. (All measurements in μm unless otherwise stated).

	Holotype	Paratype	Paratype	Paratype	Paratype
Characters	Male	Male2	Male3	Female1	Female2
L	1273	926	1152	1192	1313
a	21	20	25.6	23	24
b	5	4.7	4.7	5.4	5.2
c	11	10	11	12.5	12.7
V (%)	-	-	-	48	48
c.s.	2.8	3.2	2.5	3.1	3
diam.lab.	6	5.9	5.8	6.4	6.4
diam.am.	9	11	10.3	11	12
diam.ca.	49	43	41	43	44
amph.w.	?	4.3	4.2	4.5	4.3
dis.am.	6	7	6.3	6.2	7
st.l.	30	30	?	30	32
ph.v.	-	-	-	376	386
suppl.l.	25	25	23	23	21
suppl.n.	14	12	12	5	5
suppl.an.	88	84	89	10	10
sup.-sup.r.	34-116	23-202	32-158	-	-
a.d.	48	40	40	35.5	37
spic.arc.	70	68	68	-	-
gub.l.	26	25	26	-	-
c’	2.6	2.3	3	3.3	3.2
spic./T	0.6	0.7	0.7	-	-
spinn.l.	1.4	1.4	1.4	1.4	1.4