Sabatieria crassilonga, Fu & Mou & Liu & Zhang & Lin, 2025

Fu, Sujing, Mou, Jianfeng, Liu, Kun, Zhang, Shuyi & Lin, Heshan, 2025, Two new species and a new record of Comesomatidae (Nematoda, Araeolaimida) from the Southern Ocean, ZooKeys 1244, pp. 121-145 : 121-145

Sabatieria crassilonga sp. nov.

Figs 6 , 7 , 8 , 9 , Table 3

Material examined.

Holotype: • male, collected in the Amundsen Sea , 72.7167°S, 124.5031°W; depth 457 m; collected on 7 Feb. 2022; Jianfeng Mou leg.; muddy sediment; on slide no. MBSMCOIA -A 2-2-2-5 . Paratypes: • three males and three females, collected in the Cosmonauts Sea , Prydz Bay and Amundsen Sea ; 66.5038°S – 73.9433°S, 33.2992°E – 112.3525°W; depth 310-2085 m; collected on 1 Jan. 2021 – 22 Jan. 2021, Feb. 2022; Jianfeng Mou leg.; total organic carbon 0.12 % – 0.61 %; sand, 4.78 % – 55.92 %; clay, 7.62 % – 23.70 %; silt, 35.58 % – 71.51 %; mean particle diameter 4.36–6.77 mm; males on slide no. MBSMCOIA -C 2-13-2-5-3 , MBSMCOIA -A 11-00-5-10-3 , and MBSMCOIA -MF 1-2-2 ; females on slide no. MBSMCOIA -MF 1-2-2 , MBSMCOIA -C 4-11-2-4 , and MBSMCOIA -C 4-12-0-1 .

Measurements.

All measurement data are given in Table 3 .

Description.

Male. Body long (2628–3093 μm long), quite stout (maximum body width 84–136 μm), narrowing gradually towards both extremities. Cuticle with lateral differentiation of coarser, irregularly spaced punctations starting from amphid to near tail tip. Cuticle striations appearing distinct on cuticle surface under SEM (Fig. 9 ). Short somatic setae sparsely present on entire body, ~ 3 μm long. Cephalic region with distinct constriction at level of cephalic setae. Anterior sensilla in three crowns: six small inner labial papillae, six outer labial setae (3 μm long), and four cephalic setae (4–6 μm long or 0.20–0.26 corresponding body diameter long). Anterior buccal cavity cup-shaped, 4–7 μm wide, posterior portion narrow. Spiral amphidial fovea with 2.5 turns, 10–13 μm in diameter or 38–54 % of corresponding body diameter, anterior border located at the level of cephalic setae. Pharynx surrounds half of anterior buccal cavity, gradually broadening posteriorly and forming a weak posterior bulb. Nerve ring situated at 40–49 % of anterior pharynx. Secretory-excretory gland located posterior to pharynx. Secretory-excretory pore located posterior to nerve ring, 196–230 μm from the anterior end. Cardia small, partially surrounded by intestinal tissue. Reproductive system diorchic, anterior outstretched testis to the left of intestine and posterior outstretched testis to the left or right of the intestine. Spicules arcuate, equal, 1.2–1.5 cloacal body diameters long, proximal part of spicule with central cuticularized projection (lamella) extending from proximal end to ~ 1 / 3 of spicule. Gubernaculum with a long straight dorso-caudal apophysis, 42–47 μm long. One precloacal seta 3 μm long, distinct using SEM (Fig. 9 C ). Twenty or twenty-one precloacal supplements, in the form of small pores, the distance between seven posterior-most supplements more or less equal (10–12 μm), anterior nine supplements with distance between adjacent supplements (12–36 μm) increasing towards anterior (Figs 7 , 9 ). Conico-cylindrical tail 1.8–2.7 cloacal body diameters long with swollen tip bearing three terminal setae. Cylindrical part ~ 1 / 5 of total tail length. Three caudal glands present. Spinneret present.

Female. Similar to males. Reproductive system with two opposed, outstretched ovaries, with anterior ovary to the left of intestine and posterior ovary to the left or right of intestine. Spermatheca present. Vulva at 48–52 % of body length from anterior. Granular vaginal glands present. Three caudal glands present.

Diagnosis and relationships.

Sabatieria crassilonga sp. nov. is characterized by relatively stout body (a = 23–33); long body length 2628–3093 μm in males and 2910–3613 μm in females; short cephalic setae (4–6 μm long, 0.20–0.26 corresponding body diameter long); cuticle with lateral differentiation of coarser and irregularly spaced punctations extending from anterior edge of amphid to the tail region; amphidial fovea spiral with 2.5 turns; males with spicules 1.2–1.5 cloacal body diameters long. Twenty or twenty-one fine precloacal supplements. Gubernaculum with a long straight dorso-caudal apophysis, 42–47 μm long. Conico-cylindrical tail 1.8–2.7 cloacal body diameters long in male and 2.1–2.4 cloacal body diameters long in female.

Sabatieria crassilonga sp. nov. belongs to the praedatrix group based on amphids with three turns, the presence of pore-like supplements and straight apophysis. An amphid with 2 ¼, 2 ½, 2 ¾, or 3 turns are all considered as three turns ( Platt 1985). Within the praedatrix group, Sabatieria crassilonga sp. nov. most resembles S. alata Warwick, 1973 , S. coomansi Chen & Vincx, 1999 , S. major Yang, Guo, Chen & Lin, 2019 , S. triplex Wieser, 1954 , and S. palmaris Fadeeva & Belogurov, 1984 in having long body length (2600–4012 μm). The new species can be differentiated from S. alata by the ratio of a (23–31 vs 36–53 in S. alata ) and shorter tail (2.1–2.4 vs 5.5 cloacal body diameters in S. alata ), from S. coomansi by the number of precloacal supplements (20 or 21 vs 23–26 in S. coomansi ) and shorter tail (2.1–2.4 vs 3.3–3.6 cloacal body diameters in S. coomansi ), from S. major by the shorter body length (2888–3613 μm vs 3879–4255 μm in S. major ) and the lower value of c’ (1.8–2.7 vs 2.9–3.7 in S. major ), from S. triplex by the ratio of a (23–31 vs 57 in S. triplex ), length of the cephalic setae (0.20–0.26 vs 0.50 cbd in S. triplex ) and shorter tail (2.1–2.4 vs 3.7 cloacal body diameters in S. triplex ), and from S. palmaris by the ratio of a (23–31 vs 20–22 in S. palmaris ) and the ratio of c (16–18 vs 9–11 in S. palmaris ).

Sabatieria crassilonga sp. nov. is also similar to S. kelletti Platt, 1983 in the celtica group but differs from the latter by the shorter cephalic setae (0.20–0.26 vs 0.42–0.47 cbd in S. kelletti ), lower number of precloacal supplements (20 or 21 vs 21–27 in S. kelletti ) and the lower value of c’ (1.8–2.7 vs 3.6–4.3 in S. kelletti ).

Etymology.

The species is named due to its stout and long body, which derived from Latin crassa (= thick, fat, stout) and longa (= long).

Figures

Figure 6. Sabatieria crassilonga sp. nov. A. Entire male holotype; B. Entire female paratype.

Figure 7. Sabatieria crassilonga sp. nov. A. Male holotype anterior body region; B. Surface view of male holotype anterior body region showing amphidial fovea and cephalic sensilla; C. Male holotype pharyngeal body region; D. Male holotype posterior body region, showing precloacal supplements (arrow); E. Female paratype posterior body region.

Figure 8. Sabatieria crassilonga sp. nov. Light micrographs. A. Male paratype anterior part showing buccal cavity; B. Surface view of male paratype anterior body region showing amphids; C. Lateral punctations of female paratype anterior body region; D. Female paratype vulva; E. Male paratype spicule; F. Male paratype gubernaculum.

Figure 9. Sabatieria crassilonga sp. nov. Scanning electron micrographs. A. Male anterior part showing cephalic sensilla and amphids; B. Male anterior part showing amphids; C. Male posterior part showing cloaca, precloacal seta (right arrow) and precloacal supplements (left arrow); D. Male posterior body region.