Spirinia lara Silva, Castro, Cavalcanti & Fonsêca-Genevois, 2009, sp. nov.

Species: Spirinia lara sp. nov.

Fig. 2–4

Holotype male: Campos Basin (Rio de Janeiro, Brazil), deep-sea, 1050 meters depth with box-corer, found in silt-clay fraction, 0–2cm profile. National Museum of Rio de Janeiro, Brazil (MNRJ 322).

Allotype female: same collection data as holotype National Museum of Rio de Janeiro, Brazil (MNRJ 323).

Paratypes 6 males: same collection data, Meiofauna Laboratory of the Zoology Department, Universidade Federal de Pernambuco, slides (102–107 NM LMZOO-UFPE).

Etymology. The species name is in honor of Lara Rodrigues Silva, daughter of the first author.

Measurements: Table 1.

Adult male. Body cylindrical, tapered towards both extremities. Cuticle with transverse striae 1.0 µm apart, less obvious in head region than in tail region. Head rounded, anterior sensilla arranged in three separated circles: six internal labial papillae (difficult to observe), six outer labial papillae and four cephalic setae. Cephalic setae at mid-level of amphidial fovea. Amphideal fovea ventrally round with external circular outline. Subcephalic setae short, level with posterior of amphidial fovea and similar length to cephalic setae. Somatic setae present in neck region. Somatic papillae associated with epidermal gland cells arranged symmetrically in pairs laterally all over body; the glands cells possess a duct through the somatic papillae, but it is difficult to see. Buccal cavity with one dorsal tooth and two minute ventrosublateral teeth. Pharynx muscular cylindrical with well developed round terminal bulb, occupying 77% of corresponding body diameter, with strongly cuticularized lumen wall and musculature with median protoplasmatic interruption. Nerve ring at 69% of the total pharynx length from anterior end. Secretory-excretory pore visible. One anterior outstretched testis lying to the left of intestine. Spicules ventrally curved, more sclerotized laterally, capitulum clearly marked and velum well developed. Gubernaculum laminar, parallel to the distal portion of the spicule. Tail conico-cylindrical. Three caudal glands.

Adult female. Quite similar to male, apart from some minor morphometrical differences in range of body length, cephalic setae, subcephalic and somatic setae (Table 1). Two opposed reflexed ovaries. Vulva at 40% from the anterior end. One egg in posterior part of the uterus.

Juvenile. Not found.

Diagnosis. Spirinia lara sp. n. is mainly characterized by the presence of somatic papillae associated with epidermal glands which are symmetrically arranged laterally along the body. The new species is further differentiated by body length (1674–1870 µm), buccal cavity armed with a dorsal and two ventrosublateral teeth, presence of subcephalic setae, somatic setae restricted to neck region, length and shape of the spicule.

Differential diagnosis. Spirinia lara sp. n. resembles Spirinia septentrionalis as described by Cobb (1914) from Antarctica, Wieser (1954) and Gerlach (1957) from Cananéia estuary in Brazil and by Pastor de Ward (1988) from Argentina, mainly in the shape of the spicules and gubernaculum. Total lengths of the specimens described by Gerlach (1957) and Wieser (1954) are similar to Spirinia lara sp. n.. Differences are in the position of the nerve ring, the total length of the spicule and the De Man ratios. The similarity of dentition is uncertain because Weiser (1954), Gerlach (1957) and Pastor de Ward (1988) did not mention the presence of teeth in the buccal cavity.

Spirinia lara is also similar to Spirinia parasitifera (Bastian, 1865) Gerlach, 1963, in the presence of the epizoic Suctoria in the tail region, concentration of somatic setae in the neck region and buccal cavity armed with three teeth. The species differ in morphometrics (Table 2), the spicules and gubernaculum are larger in S.lara, subcephalic setae are absent in S.parasitifera and present in Spirinia lara sp. n. and not differentiated from other somatic setae. The new species also possesses somatic papillae linked to epidermal glands which are absent in S. parasitifera.

The presence of the somatic papillae along the body is not found in other species of Spirinia. In S.gerlachi, S.gnaigeri, S.laevioides and S.laevis long somatic setae along the body are present, but there is no mention of association with gland cells by the authors.