Sabatieria fidelis, Botelho, Alessandra Prates, Silva, Maria Cristina Da, Sobral, Luciana Davina Tosta & Fonsêca-Genevois, Verônica Gomes, 2009

Botelho, Alessandra Prates, Silva, Maria Cristina Da, Sobral, Luciana Davina Tosta & Fonsêca-Genevois, Verônica Gomes, 2009, Two new species of Sabatieria Rouville (Nematoda: Comesomatidae) with conical-cylindrical tails, from Campos Basin, Rio de Janeiro, Brazil *, Zootaxa 2096, pp. 82-98 : 91-96

Sabatieria fidelis sp. n. ( Figures 5 , 6 , 7 , 8 ; Table 1 )

Material Studied: 2 males, 2 females.

Type material: Male holotype, slide MNRJ 320. Female paratype, slide MNRJ 321; 1 male, slide 96 NM LMZOO-UFPE, 1 female, slide 97 NM LMZOO-UFPE.

Type locality: Male holotype, station no. 54, 750 m depth, collected in May 2002. Other localities: Female paratype, station no. 41, 1222 m depth, collected in May 2002; male paratype, station no. 35, 916 m depth, collected in May 2002; female paratype, station no. 74, 750 m depth, collected in November 2002 (cf. Appendix 1).

Etymology. The species name is the Latin fidelis = faithful, because the specimens have all the characteristics that are common to Sabatieria species, and the new features are not easy to see.

Description. holotype: Cylindrical body, medium-sized, attenuated at both ends. Cuticle with transverse rows of dots, and lateral differentiation with larger and more widely spaced dots, irregularly arranged. Head slightly set off by constriction in the cephalic setae region, and with anterior sensilla arranged in three crowns: six minute internal labial papillae, six external labial papillae and four cephalic setae. Buccal cavity cupshaped. Amphidial fovea spiral, with 2 1/4 turns. Pharynx slightly clavate, gradually expanding towards the posterior end, but without distinct bulb. Cardia short and round. Nerve ring slender, located very close to middle of pharynx and anterior to secretory-excretory pore. Cellular body of ventral gland at level of posterior end of pharynx and beginning of intestine, with secretory pore in middle of pharynx. Male reproductive system diorchic, with opposed and outstretched testes. Anterior testis situated on the left and posterior testis on the right side of the intestine. Slender short paired spicules, similar in length and width and slightly curved ventrally; proximal half of septum and distal part with ventrally directed dropper-shaped tip. Several glandular cells are arranged around the spicules. Gubernaculum small, cuticularized, v-shaped in distal part, measuring 16 µm, and with narrow cuticularized apophysis of length 22 µm. Minute pore-like pre-cloacal supplements present, easily overlooked; but unfortunately the specimens are more ventrally positioned without a clear view of the number of them. Three pairs of ejaculatory glands anterior to the cloaca. Spermatozoa oval, 21 µm long. Conico-cylindrical tail with three caudal glands, ending in a spinneret. Three setae on the tail tip, measuring 3 µm.

Female Paratype: The females are similar to males except for the longer total length, shorter tail and spiral amphidial fovea with 2¼–3 turns. Reproductive system didelphic-amphidelphic; with outstretched ovaries. Anterior ovary to the left and posterior ovary to the right of the intestine, and distal part of the uterus with oocyte. Vulva at mid-body, vagina thin-walled; pars proximalis vaginae (= vagina uterina) surrounded by a well-developed constricting muscle. Granular vaginal glands present at the pars distalis vaginae. Oocytes 44–53 µm long.

Diagnosis. Sabatieria fidelis sp. n. can be differentiated by its short outstretched testes, the spicules with dropper-shaped tips and directed ventrally, the gubernaculum with a cuticularized v-shape on the distal part, and the short cephalic and somatic setae.

Discussion. In relation to Sabatieria pulchra , the similar characteristics are the number of amphidial fovea turns in females, total length, maximum diameter and spicule length. Sabatieria fidelis sp. n. differs in relation to the number of turns of the amphidial fovea in males ( Sabatieria pulchra with 2¾–3), absence of three glands in the pharyngeal region, and the proximal parts of the spicules in S. pulchra are more inflated than in Sabatieria fidelis sp. n. Another characteristic is the sexual dimorphism in Sabatieria fidelis sp. n.: females have a shorter tail and more turns in the amphidial fovea.

Sabatieria fidelis sp. n. is similar to Sabatieria falcifera with respect to the short cervical setae, number of turns of the amphidial fovea in the female (2.5 in S. fidelis sp. n. and in S. falcifera ) and spicule length (62 µm in S. fidelis sp. n. versus 66.5 µm in S. falcifera ). It can be distinguished by the cephalic setae length (3–3.7 in S. fidelis sp. n. versus 7 µm in S. falcifera ), length of the gubernaculum apophysis (22 µm in S. fidelis sp. n. versus 29 µm S. falcifera ), number of turns of amphidial fovea in the male (2.5 in S. fidelis sp. n. versus 2.7–3 in S. falcifera ).

Sabatieria fidelis sp. n. also resembles Sabatieria praedatrix in maximum diameter (64.5 in S. fidelis sp. n. versus 67 µm in S. praedatrix ) and the length of somatic setae. It can be differentiated by the de Man indexes a and c (a = 26.3–34.8; c = 13.8–20.9 in S. fidelis versus a = 50–55; c = 13.5–14 in S. praedatrix ).

In relation to Sabatieria vasicola , this new species has the same values of de Man indexes a, b and c (a = 26.3–34.8; b = 7.4–10.9; c = 13.8–20.9 in S. fidelis versus a = 26.6–32.2; b = 7.5–9.3; c = 9.1–14.7 in S. vasicola ), but can be distinguished by the length of the cephalic setae (3–3.7 µm in S. fidelis sp. n. versus 6–8 µm in S. vasicola ), spicule length (62–68 µm in S. fidelis sp. n. versus 72–82 µm in S. vasicola ), apophysis length (22 µm in S. fidelis sp. n. versus 33–34 µm in S. vasicola ) and tail length (90–150 µm in S. fidelis sp. n. versus 173–220 µm in S. vasicola ).

Figures

FIGURE 5. Sabatieria fidelis sp. n. Male. A. Total view, B. Pharyngeal region, C. Anterior end showing buccal cavity and amphid, D. Anterior end showing cuticle, E. Posterior body region showing the ejaculatory glands and tail, F. Copulatory apparatus.

FIGURE 6. Sabatieria fidelis sp. n. Male. A. Total view, B. Anterior end showing cuticle and amphid, C. Anterior end showing head and buccal cavity, D. Tail, E. Pharyngeal region, F. Copulatory apparatus.

FIGURE 7. Sabatieria fidelis sp. n. Female. A. Total view; B. Pharyngeal region; C. Head showing cuticle and amphid; D. Tail; E. Reproductive system.

FIGURE 8. Sabatieria fidelis sp. n. Female. A. Total view; B. Anterior end showing head and buccal cavity, C. Anterior end showing cuticle and amphid, D. Pharyngeal region, E. Vulva region, F. cuticle on tail region, G. tail.