Sabatieria major Yang & Guo & Chen & Lin 2019, sp. n.

Sabatieria major sp. n.

(Figures 8–10, Table 4)

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

Holotype: ♂ 1 on slide number Chukchi20100720 CC14202. Paratypes: ♂ 2 on slide number Chukchi20100720 CC14202, ♂ 3 on Chukchi20100720 CC15101, ♂ 4 on Chukchi20100720 CC14208, ♂ 5 on Chukchi20100720 CC13101, ♀ 1 on Chukchi20100720 CC13102, ♀ 2 on Chukchi20100720 CC14208.

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 its body is large and thick.

Measurements. Table 4.

Description. Male. Body cylindrical, tapering slightly towards both extremities. Cuticle with transverse rows of dots, lateral differentiation consisting of larger, irregularly-spaced dots. Two dorso- and two ventro-lateral rows of short, sparse somatic setae. Three crowns of anterior sensilla: six inner labial papillae, six short but distinct outer labial setae and four short cephalic setae. Buccal cavity cup-shaped. Amphideal fovea spiral with 2.5–3.25 turns, located immediately posterior to cephalic setae. Pharynx gradually swelling towards posterior part, not forming true bulb. Nerve ring 169–186 µm from anterior end of body, at 49–56% of the pharyngeal region length. Excretory pore 188–210 µm from anterior end of body, at 57–64% of the pharyngeal region length. Tail 314–367 µm long, conico-cylindrical with four rows of sparse short caudal setae and three short terminal setae. 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 1.5–1.9 cloacal body diameters in length, and with central cuticularised projection (lamella) extending from proximal end to one third of spicule. Gubernaculum with 70–84 µm long, paired, straight apophyses. Rectal gland surrounds gubernacular apophyses and distal portion of spicules. Seventeen to thirty-two small tubular pre-cloacal supplements, followed by one pre-cloacal seta. Three caudal glands situated posterior to spicule. Spinneret present.

Female. Similar to male, but with wider body. Reproductive system didelphic, ovaries opposed, outstretched, with anterior branch to the left of intestine and posterior branch to the right of intestine. 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 major sp. n. is characterized by a long body (3879–4255 µm), short cephalic setae (4–7 µm, equal to 18–27% of head diameter), amphideal fovea spiral with 2.5–3.25 turns, and seventeen to thirty-two small tubular pre-cloacal supplements.

Sabatieria major sp. n. belongs to the praedatrix group because of the simple tubular pre-cloacal supplements and straight gubernacular apophyses. There are forty-six valid species in this group now. S. major sp. n. can be differentiated from most other species of the genus by its large and thick body. S. major sp. n. resembles S. lawsi in the structure of amphideal fovea and with central cuticularised projection (lamella) extending from proximal end to one third of spicule, but can be distinguished from it by longer total body length (3879–4255 vs 1940–2595 µm) and shorter cephalic setae (equal to 18–27% vs 32–47% of head diameter). S. major sp. n. is also close to S. vasicola in the structure of amphideal fovea and tail shape. The main differences between these two species are the total body length (3879–4255 vs 2020–2550 µm), spicules length (equal to 1.5–1.9 vs 1.3–1.4 cloacal body diameters) and cephalic setae (equal to 18–27% vs 30–40% of head diameter).