Epacanthion agubernaculus, Guilherme, Betânia Cristina, Silva, Maria Cristina Da & Esteves, André Morgado, 2009

Guilherme, Betânia Cristina, Silva, Maria Cristina Da & Esteves, André Morgado, 2009, Description of a new species of Epacanthion (Thoracostomopsidae, Nematoda) from Brazil and a modified key for species identification *, Zootaxa 2096, pp. 99-108 : 101-102

Epacanthion agubernaculus sp. nov.

Material studied: One male.

Type material: Holotype MNRJ 329. Station 53 ( Figure 1 ). Type locality: Southern part of Campos Basin (Rio de Janeiro, Brazil) at 1950 m depth, in silt-clay sediments.

Etymology. The Latin " agubernaculus " refers to the absence of a gubernaculum (a = without + gubernaculus = gubernaculum).

Description (Holotype). ( Figs 2 and 3 ) Cylindrical body (L=2045.2 µm) tapering towards both extremities. Smooth cuticle. Cephalic capsule strongly sclerotized (43.2 µm). Sensilla arranged in two circles (6+10): six inner labial setae (10.8 µm), six outer labial setae (31.7 µm) and four cephalic setae (11.4 µm) in the second row. The second circle is inserted slightly above the base of the cephalic capsule (3.6 µm apart). Several setae of varying lengths present in the cervical region. Somatic setae (35.4 µm) on the body, with no distinct pattern. High lips composed of three strongly sclerotized mandibles (20.4 µm long and 4 µm wide) of two longitudinal solid bars united by a thin membrane, mandibles curved in the base of the buccal cavity where three equal teeth are found (4.8 µm long and 20.4 µm wide), one dorsal and two ventrosublateral. One gland present in the base of each tooth. Amphideal fovea indistinct. Pharynx strongly muscular (516 µm long), corresponding to 87.6% of the anterior region. Nerve ring (55.13 µm) located forward of the middle portion of the pharynx (178.5 µm) and occupying 67.3% of the corresponding body diameter. Cardia triangular. Reproductive system diorchic, testes located at the left of the intestine (in tandem), extending to the anterior region of the body, anterior testis 233.5 µm long and posterior testis 171.1 µm long. Spicules long (186 µm), transversely striated, with four points of sclerotizations concentrated in the proximal portion and in the middle of the spicules. The distance between the sclerotization points ranged from 79 µm to 121 µm. Gubernaculum absent. One tubular precloacal supplement, finely sclerotized (18 µm long and 1.8 µm wide) and placed near the proximal region of the spicules, 104.4 µm distant from the cloaca. Tail conico–cylindrical (139.2 µm long). Three pairs of setae (range 3.6–13.8 µm long) in the conical portion, no setae in the cylindrical tail region. Caudal glands not observed.

L= 2045.2; a= 25.18; b=3.9; c=14.6; c’=2.7

Figures

FIGURE 1. Study area showing sampling stations.

FIGURE 2. Male. A. Total body, B. Mandible detail, C. Head and the buccal cavity with mandibles, D. Anterior region, mandibles and Teeth, E. Anterior region with the esophageal glands, F. Setae in the tail region, G. Spicules, tail and

FIGURE 3. Male. A. Total body, B. Mandibles, C. Teeth (Mandibles), D. Buccal cavity, E. Pharynx regions, F. Somatic setae, G. Spicules, H. Tail, I. Cardia region.