Sabatieria chukchensis, Yang & Guo & Chen & Lin, 2019

Yang, Peipei, Guo, Yuqing, Chen, Yuzhen & Lin, Rongcheng, 2019, Four new free-living marine nematode species (Sabatieria) from the Chukchi Sea, Zootaxa 4646 (1), pp. 31-54 : 35-39

Sabatieria chukchensis sp. n.

( Figures 2–4 , Tables 1–2 )

Type material. Five males and two females were collected from station CC 1.

Holotype: ♂ 1 on slide number Chukchi20100720 CC14205 . Paratypes: ♂ 2 on slide number Chukchi20100720 CC14203 , ♂ 3 on Chukchi20100720 CC14201 , ♂ 4 on Chukchi20100720 CC14206 , ♂ 5 on Chukchi20100720 CC14208 , ♀ 1 on Chukchi20100720 CC14203 , ♀ 2 on Chukchi20100720 CC14212 .

Type locality and habitat. All specimens were collected from the Chukchi Sea (52 m water depth). Station CC 1: 67.6722°N, 168.9562°W. Median grain diameter: 5.35 Md Φ, Sand: 33.34%, Silt: 58.02%, Clay: 8.63%.

Etymology. This species is named after the Chukchi Sea, the type locality.

Measurements. Table 1 .

Description. Male. Body cylindrical, tapering slightly towards both extremities. Cuticle with transverse rows of dots, lateral differentiation consisting of larger, irregularly-spaced dots. Three crowns of anterior sensilla: six inner labial papillae, six short but distinct outer labial setae and four short cephalic setae. Anterior portion of buccal cavity cup-shaped, posterior portion narrow. Amphideal fovea spiral with 2.75–3.25 turns, located immediately posterior to cephalic setae. Two pairs of ventro-sublateral cervical setae are located just posterior to amphideal fovea. Two lateroventral rows of somatic setae in precloacal region. Pharynx gradually swelling towards posterior, not forming true bulb. Nerve ring 102–136 µm from anterior end of body, at 45–59% of the pharyngeal region length. Excretory pore 123–142 µm from anterior end of body, at 54–62% of the pharyngeal region length. Tail 142–172 µm long, conico-cylindrical and with short cylindrical part. Four rows of sparse short caudal setae and three short terminal setae present. Reproductive system diorchic, with outstretched testes. Anterior testis to the left of intestine, posterior testis to the right of intestine. Spicules paired, equal, arcuate, equal to 1.2–1.6 cloacal body diameters in length, proximal part of spicule is broader and with central cuticularised projection (lamella) extending from proximal end to one third of spicule. Gubernaculum with 25–30 µm long, paired, straight apophyses. Seven papilliform pre-cloacal supplements, followed by one pre-cloacal seta. Three caudal glands situated posterior to spicule. Spinneret present.

Female. Similar to male, except for longer cephalic setae and slightly smaller amphideal fovea. Reproductive system didelphic, ovaries opposed, outstretched, with anterior branch to the left of intestine and posterior branch to the right of intestine. Mature eggs are oval-shaped. Spermatheca not observed. Vulva situated at mid-body. Granular vaginal glands present, pars proximalis vaginae surrounded by constrictor muscle. Three caudal glands situated posterior to anus. Spinneret present.

Diagnosis and relationships. Sabatieria chukchensis sp. n. is characterized by a long body (2052–2326 µm), cuticle with lateral differentiation consisting of rows of larger dots, amphideal fovea spiral with 2.75–3.25 turns, two pairs of short cervical setae present, and seven papilliform pre-cloacal supplements.

Sabatieria chukchensis sp. n. belongs to the pulchra group because of the low number of pre-cloacal supplements and two pairs of short cervical setae present. There are seven valid species in this group now. S. chukchensis sp. n. resembles S. pulchra in body length, amphideal fovea and the number of supplements, but can be distinguished from the latter in having shorter cephalic setae in males (equal to 27–34% vs 40–50% of head diameter) and length of gubernacular apophyses (25–30 vs 19–22 µm). S. chukchensis sp. n. can be differentiated from S. punctata in the number of turns of amphideal fovea (2.75–3.25 vs 3.25–3.75 turns), total body length (2052–2326 vs 1095–1160 µm) and tail length of males (c’=2.8–3.2 vs 3.2–3.9). S. chukchensis sp. n. can be differentiated from S. mortenseni , S. pisinna , S. propisinna and S. pumila in having smaller amphideal fovea in males (equal to 56–65% vs 80%; 82–87%; 77%; 69–85% corresponding body diameter, respectively). S. chukchensis sp. n. can be differentiated from S. maboyae by the length of spicules (equal to 1.2–1.6 vs 2.1 cloacal body diameters).

Figures

FIGURE 2. Sabatieria chukchensis sp. n. A: lateral view of male anterior part; B: lateral view of male tail and spicule; C: lateral view of female head; D: lateral view of female tail. Scale bar = 20 µm.

FIGURE 3. Sabatieria chukchensis sp. n. A: lateral view of male head; B: lateral view of copulatory apparatus; C: lateral view of female reproductive system. Scale bar: A, B = 20 µm; C = 100 µm.

FIGURE 4. Sabatieria chukchensis sp. n. Male: (A) lateral surface view of head region (amphideal fovea; cephalic setae); (B) lateral surface view of head region (buccal cavity); (C) two pairs of cervical setae and lateral differentiation; (E) copulatory apparatus; (F) pre-cloacal supplements; (I) spicule and tail. Female: (D) lateral surface view of head region; (G) vulva region; (H) rectal region and tail. Scale bar = 10 µm.