Syringolaimus taniae, Coelho Lima, Lins, Da Silva & Esteves, 2009

Lima, Rita De Cássia Coelho, Lins, Lidia, Silva, Maria Cristina Da & Esteves, André Morgado, 2009, Four new species of Syringolaimus De Man, 1888 (Nematoda: Ironidae) from the Southeast Atlantic (Brazil), with redefinition of valid species and the proposal of a new key *, Zootaxa 2096, pp. 119-136 : 130-133

Syringolaimus taniae sp. n ( Fig. 7 and 8)

Type material: Two males and one female collected from stations 50, 71 and 76 (Appendix). Holotype: ♂ 1 slide number 335 MNRJ station 76; paratype ♂ 2: slide number 115 NM LMZOOUFPE station 71; allotype ♀ 1: slide number 336 MNRJ station 50.

Type locality: Campos Basin (Rio de Janeiro, Brazil). Holotype ♂ 1: found at 1350 m depth in silt-clay sediments. Layer between 2–5 centimeters. Allotype ♀ 1: found at 1050 m depth in silt-clay sediments. Layer between 0–2 centimeters.

Other localities: Campos Basin (Rio de Janeiro, Brazil). Paratype ♂ 2: D: 1350 m, SL: 2–5 centimeters.

Etymology. The specific epithet honors Tânia Nara Bezerra, who initiated studies of free-living marine nematodes at the Universidade Federal de Pernambuco, Brazil.

Description. Measurements: Holotype ♂ 1: L: 1041; hd: 10.2; amph wid: 4.8; cbd: 13.8; amph (%): 34.8; amph dist: 7.8; buc cav l: 46.8; ph: 193.5; buc cav 1/ph (%): 24.1; nr/ph (%): 62;ex pore/ph (%): not visible; bulb l: 44.4; ph/bulb l (%): 22.9; bulb d: 19.2; cbd: 24; bulb(%): 80; mbd: 21.6; abd: 21; t: 219; con/t (%): 20.5; cil/t (%): 79.5; spin: 28.2; spin/t (%): 12.9; spic: 22.8; gub: 9.6; a: 48.2; b: 5.4; c: 4.7; c’: 10.4. Paratype ♂ 1: L: 1087.5; hd: 9.6; amph wid: 5.4; cbd: 12; amph (%): 45; amph dist: 7.8; buc cav l: 45.6; ph: 207; buc cav 1/ph (%): 22; nr/ph (%): not visible; ex pore/ph: not visible; bulb l: 45; ph/bulb l (%): 21.7; bulb d: 18.6; cbd: 24; bulb (%): 77.5; mbd: 24; abd: 19.8; t: 219.6; con/t (%): 21.3; cil/t (%): 78.7; spin: 24; spin/t (%): 10.9; spic: 22.2; gub: 12; a: 45.3; b: 5.2; c: 4.9; c’: 11. Allotype ♀ 1: L: 1113; hd: 10.2; amph wid: 4.8; cbd: 12; amph (%): 40; amph dist: 7.8; buc cav l: 45; ph: 220.5; buc cav 1/ph (%): 20.4; nr/ph (%): 50.9; ex pore/ph (%): 22.3; bulb l: 47.1; ph/bulb l (%): 21.4; bulb d: 18.6; cbd: 26.4; bulb %: 70.4; mbd: 26.4; abd: 20.4; t: 208.8; con/t (%): 20.2; cil/t (%): 79.8; spin: 31.2; spin/t (%): 14.2; v: 579; v%: 52; a: 42.1; b: 5.0; c: 5.3; c’: 10.2.

Male Holotype: Slender body, with faint striations that are not easily detected. Body 1041 µm long and 21.6 µm wide. Inner labial papillae not detected; six outer labial papillae; and cephalic sensilla absent. Head diameter 10.2 µm. Amphideal fovea pocket–like, occupying 34.8 µm of corresponding body diameter. Buccal cavity cylindrical and well sclerotized, 46.8 µm deep, occupying 24% of total pharynx length. Three small, bifid and asymmetrical teeth, one dorsal and two subventral, equal in size. Pharynx muscular, with elongated terminal bulb corresponding to 22.9% of total pharynx length and occupying 80% of corresponding body diameter. Secretory–excretory pore situated just after buccal cavity. Nerve ring at 62% of total pharynx length. Rounded cardia. Ventral gland at level of cardia. Testis lying on right side of intestine, glandular part splitting testis into regions of cells of varying degrees of maturation. Short deferent duct with sperm cells in beginning of duct. Spicules with sclerotized punctuations, vellum present. Sclerotized gubernaculum. Tail with anterior portion rounded. Posterior region cylindrical–filiform, representing 79.5% of tail length. Spinneret 28.2 µm, representing 12.9% of tail length. Three caudal glands present.

Female Allotype: Female amphidelphic-didelphic; ovaries reflexed and situated ventrally in relation to the intestine. Vulva situated in middle of body, 52% from anterior end.

Diagnosis. S. taniae sp. n. is caracterized by the rounded shape of the proximal portion of the tail and the location of the secretory-excretory pore immediately after the buccal cavity.

Relationships. S. taniae sp. n. shares with S. annae sp. n. and S. filicaudatus the presence of bifid teeth and the cylindrical-filiform tail shape. In S. taniae sp. n. the proximal portion of the tail has a rounded outline before becoming cylindrical-filiform, with a spinneret; whereas the tail begins conically in S. annae sp. n. and in S. filicaudatus . The position of the secretory-excretory pore is more anterior in S. taniae sp. n. (situated immediately after the buccal cavity) than in the other two species. The spicule and gubernaculum shapes are different in S. taniae sp. n. and S. filicaudatus . The absence of cephalic papillae distinguishes S. taniae sp. n. from S. annae sp. n..

S. taniae sp. n. resembles S. renaudae in the presence of bifid asymmetrical teeth, and the cylindricalfiliform portion of the tail ending in a spinneret. However, in S. renaudae the proximal portion of the tail is conical. The two species diverge in the absence of cephalic papillae in S. renaudae ; the shape of the spermatozoids, which are flagelliform in S. renaudae and fusiform in S. taniae sp. n.; and the spicule shape.

S. taniae sp. n. also resembles S. marisalbi because of the asymmetrical chela-like bifid teeth. The body is more slender in S. taniae sp. n. (a= 48.2) than in S. marisalbi (a= 19.7). The proximal portion of the tail in S. marisalbi comprises 1/3 of the total tail length, and the spinneret is 5.8% of the total tail length; in S. taniae sp. n. these values are 1/5 and 12.9%, respectively. The presence of labial papillae and the different shapes of the spicules and gubernaculum also distinguish the two species.