Bolbonema braziliensis, Larrazábal-Filho & Neres & Esteves, 2018

Larrazábal-Filho, Alexandre L., Neres, Patrícia F. & Esteves, André M., 2018, The genus Bolbonema Cobb, 1920 (Nematoda: Desmodoridae): emended diagnosis, key to males, and description of three new species from the continental shelf off northeastern Brazil, Zootaxa 4420 (4), pp. 551-570 : 553-557

Bolbonema braziliensis sp. n.

(measurements in Table 1, Figures 2 , 3 and 4 ).

Type material: Holotype Male adult MNRJ 390 . Station CME1 (05°01'55.3''S, 36°12'20.4''W).

Paratype female: Adult, MNRJ 391. Station CME1 (05°01'21.2''S, 36°12'18.7''W).

Other paratypes: 5 females (221 and 225 LMZOO-UFPE), 6 males (226–230 LMZOO-UFPE) and 2 J1, 1 J2 and 3 J3 (231 LMZOO-UFPE), data as for holotYpe .

Etymology. The specific epithet “ braziliensis ” is given for the location where the material was found, in BraZil.

Description. HolotYpe ( Figures 2 and 3 ). BodY cYlindrical, Yellowish brown, tapering slightlY toward each end. Cuticle annulated eXcept in final portion of tail, no lateral differentiation. Eight longitudinal rows of somatic setae; two subdorsal, two subventral and four sublateral. TheY start from cervical region to level of cloaca, alternating in long setae with shorter setae. Head capsule well developed with thick cuticle without annulations. Anterior sensilla arrangement: siX outer labial papillae (difficult to see) and four cephalic setae positioned at middle level of fovea amphidialis. Fovea amphidialis crYptospiral, relativelY large, posterior border in contact with cuticle striations, occupYing 64% of diameter of head. Buccal cavitY small, with one dorsal tooth and one small ventral tooth, not alwaYs visible. PharYnX muscular with well-developed posterior bulb. Cardia and eXcretorYsecretorY sYstem not observed. Nerve ring located 54 µm from anterior region. Reproductive sYstem monorchic, with single anterior testis situated to left of intestine, outstretched. Sperm cells globular. Spicules arched, proXimal region eXpanded. Gubernaculum a bent rod dorsallY oriented. Velum absent. Two precloacal setae inserted on two small papillae ( Fig 2E ) in subventral position. Tail conical, with three small caudal glands and spinneret.

ParatYpe female ( Figures 3 and 4 ). Similar to the male in bodY siZe, with minor differences: in female, cephalic setae positioned at posterior level of fovea ( Fig 4B ). Female didelphic, ovaries antidromouslY refleXed and both genital branches to right of intestine. Vulva as simple transverse slit-like aperture. ProXimal portion of vagina slightlY cuticularised ( Fig 3C ). Globular sperm cells visible. No egg found. Vulva located at 49% of total bodY length (689 µm distant from anterior end). Tail conical.

Juveniles ( Figure 2 ). Similar to adults, eXcept not possessing some characteristics such as supplements; reproductive sYstem immature. Juveniles in stage 1, without rows of somatic setae. Five juveniles were found, two in stage 1, one in stage 2 and two in stage 3.

Diagnosis. Bolbonema braziliensis sp. n. is characteriZed bY the crYptospiral fovea amphidialis, arched spicules, gubernaculum a bent rod dorsallY oriented, and two subventral precloacal setae just above the cloaca.

Differential diagnosis. Bolbonema braziliensis sp. n. is similar to Bolbonema longisetosum ( Jensen, 1985) in the shape and siZe of the fovea amphidialis, cephalic setae at the middle level of the fovea amphidialis, spicules arched and the proXimal region eXpanded, and papilliform supplements associated with setae. It differs from B. longisetosum in the number of papillae supplements (two in B. braziliensis sp. n. and 24 in B. longisetosum ) and the absence of an apophYsis.

Bolbonema braziliensis sp. n. is comparable to Bolbonema brevicolle Cobb, 1920 in the shape of the fovea amphidialis. It differs in the absence of subcephalic setae (present in B. brevicolle ) and the shape of the spicules (eXpanded in B. brevicolle ).

Bolbonema braziliensis sp. n. can be distinguished from Bolbonema spiralis Hourston & Warwick, 2010 bY the shape of the fovea amphidialis (spiral in B. spiralis ), the presence of precloacal supplements, and the shape of the spicules and gubernaculum (arched without a rounded capitulum; and a small simple gubernaculum in B. spiralis ).

Figures

FIGURE 2. Bolbonema braziliensis sp. n. HOLOtypE MNRJ 390—A: OVERVIEW. B And C: AntERIOR REgIOn. D: cOpULAtORy AppARAtUs. E: tAIL REgIOn; And F: cEphALIc REgIOn Of jUVEnILE 3.

FIGURE 3. Bolbonema braziliensis sp. n. A–C: pARAtypE fEMALE MNRJ 391; A: tAIL REgIOn; B: cEphALIc REgIOn; C: VULVA OpEnIng. D–F: hOLOtypE MALE MNRJ 390; D: cEphALIc REgIOn; E: tAIL And spIcULEs; And F: gLObULAR spERM cELLs.

FIGURE 4. Bolbonema braziliensis sp. n. PARAtypE fEMALE MNRJ 391—A: OVERVIEW; B And C: AntERIOR REgIOn; D: tAIL REgIOn; E: OVARy And VULVA OpEnIng.