Syringolaimus annae, 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 : 121-125

Syringolaimus annae sp. n. ( Figs. 1 and 2)

Type Material: Five males and five females collected from stations 61, 73, 74, 75, 76, 77 and 78 (Appendix). Holotype ♂ 1: slide number MNRJ 330 station 71 ; paratypes: ♂ 2 e ♂ 3, slide number 107–108 NM LMZOOUFPE Station 73 and 74 respectively; ♂ 4, and ♂ 5 slide number 109–110 NM LMZOOUFPE Station 75. Allotypes: ♀ 1 slide number MNRJ 331 Station 77 ; paratypes: ♀ 2, ♀ 3, ♀ 4 and ♀ 5; slide number 111–114 NM LMZOOUFPE Station 61, 74, 76 and 78 respectively.

Type locality: Campos Basin (Rio de Janeiro, Brazil). Holotype ♂ 1: found at 1350 m depth (D) in silt-clay sediments. Surface layer (SL) between 2–5 cm. Allotype ♀ 1: D: 1650 m, SL: 2–5 cm.

Other localities: Campos Basin (Rio de Janeiro, Brazil), found at 750 m, 1050 m and 1950 m depth (D) in silt-clay sediments. Surface layer (SL) between 0–2 and 2–5 cm .

Measurements: see table 1.

Etymology. The specific epithet honors Professor Ann Vanreusel from Ghent University, Belgium.

Description. Male holotype: Body 1891 µm long, maximum diameter 31.2 µm. Cuticle with delicate, almost imperceptible striations on tail region. Six small, outer labial papillae and four cephalic papillae in two different circles. Head diameter 10.8 µm. Amphideal fovea pocket-like, occupying 40% of corresponding body diameter. Buccal cavity cylindrical, sclerotized and deep, 52.2 µm long (19.6% of total pharynx length), surrounded by oblique pharynx muscles. Three asymmetrical bifid teeth of equal size, one dorsal and two subventral, arrow-shaped. Pharynx strongly muscular with an elongated basal bulb, 50.4 µm long (19% of total pharynx length), 28.2 µm in diameter (78.3% of corresponding body diameter). Secretory-excretory pore situated at 33.2% of pharynx length from anterior end in relation to total length of pharynx. Nerve ring placed slightly posterior to mid-pharynx. Cardia rounded. Ventral gland located slightly after cardia. One testis lying on right side of intestine, with a marked glandular part in its anterior region, separating cells in different stages of maturation. Vas deferens relatively short, with sperm cells forming. Spermatozoids fusiform. Spicule with lateral punctuations, strongly sclerotized. Vellum present. Gubernaculum blade-shaped. Tail conicalcylindrical, filiform in terminal region and without spinneret. Cylindrical-filiform portion comprising 74% of tail length. Three caudal glands present.

Female Allotype: Generally similar to males. Amphidelphic-didelphic, ovaries reflexed and ventral to intestine. Vulva at 52.3% of body length.

Diagnosis. This species is characterized by a conical-cylindrical tail without a spinneret, and the presence of outer and cephalic labial papillae.

Relationships. S. annae sp. n. shares with S. filicaudatus Vitiello, 1970 the presence of bifid teeth, but they are asymmetrical in the new species; and the conical-cylindrical tail shape with a filiform final portion. The new species does not have a spinneret. The spicule and the gubernaculum have different shapes, and cephalic papillae are present only in S. annae sp. n.

S. annae sp. n. is closely related to S. renaudae Gourbault & Vincx, 1985 because of the presence of outer labial papillae and cephalic papillae. The two species differ in the absence of the spinneret in S. annae sp. n., and the spicule shape. The secretory-excretory pore is situated more posteriorly in the new species, and there are no flagellate spermatozoids as observed in S. renaudae .

S. annae sp. n. resembles S. marisalbi Platonova & Mokievsky, 1994 in the teeth and tail shape. However, the new species does not have a spinneret. The conical portion of the tail occupies 1/4 and 1/5 of the total tail length, whereas in S. marisalbi this portion represents 1/3 of the total tail length. Labial and cephalic papillae are absent in S. marisalbi . The spicules of the species differ in shape, and the gubernaculum in S. marisalbi is divided at the distal end.