Phyllodoce ovalis sp. nov.

urn:lsid:zoobank.org:act: 098B9C86-8117-4CF7-89F8-8733722C7D66

Figure 27

Holotype. Atlantic Ocean, Margin of continental slope in Campos Basin, Brazil, Hab 9 Cang 9 R1, 21º54’43.7”S 39º50’33.0”W, 1,320 m, 11 Feb 2009 (ZUEC–POL 16530).

Paratypes A total of 15 paratypes, length 5.1± 2.3 mm for 47.3± 16.6 segments. Continental slope in Campos Basin: Hab 9 I08 R1, 21º11’4.5”S 40º8’58.4”W, 993 m, 2 Mar 2009 (1 Paratype, NHDM–865955); Hab3 A08 R2, 23º41’10.2”S 41º16’7.9”W 986 m, 3 May 2009 (1 Paratype, NHDM–865956); AMBES11 F09 R3, 20º29’3.8”S 38º23’18.5”W, 2,507 m, 13 Jun 2013 (1 paratype, ZUEC–POL 18555); AMBES11 F08 R2, 20º16’38.1”S 38º27’26.5”W, 1.904 m, 14 Jun 2013 (4 paratypes, ZUEC–POL 18587); AMBES12 E07 R2, 19º47’2.4”S 39º3’14.6”W, 16 Jun 2013 (3 paratypes, ZUEC–POL 18599); AMBES12 CANWN5 R2, 19º33’22.1”S 39º2’36.0”W, 414 m, 25 Jun 2013 (1 paratype, ZUEC–POL 18585); AMBES12 E06 R2, 19º40’1.4”S 39º7’21.9”W, 1.050 m, 26 Jun 2013 (1 paratype, ZUEC–POL 18588); AMBES12 E06 R3, 19º40’1.4”S 39º7’21.9”W, 1.050 m, 26 Jun 2013 (1 paratype, ZUEC–POL 18598); AMBES12 CNWN6 R1, 19º53’27.2”S 39º32’59.8”W, 970 m, 28 Jun 2013 (1 paratype, ZUEC–POL 18553); AMBES12 F05 R2, 19º34’20.4”S 38º41’19.8”W, 449 m, 30 Jun 2013 (1 paratype, ZUEC–POL 18586), Brazil.

Diagnosis. Oval prostomium, frontal protuberance with antennae and palps. Antennae and palps with inflated bases. Nuchal papilla club-shaped. Tentacular cirri flattened and short. Segment 1 visible dorsally. Proboscis basally with six longitudinal rows of rounded papillae and distally with six longitudinal rows of prominent and pigmented tubercles.

Description. Holotype complete, 8.0 mm long, 0.5 mm wide at median part of body, including parapodia and excluding chaetae for 59 segments. Body long, cylindrical, dorso-ventrally flattened and tapered posteriorly. Prostomium oval with anterior protuberance, where antennae and palps located. Nuchal papilla club-shaped on posterior prostomial margin (Fig. 27A). Paired frontal antennae and palps of similar lengths, dorso-ventrally flattened and cylindrical, short, robust and with inflated bases (Fig. 27A). Antennae and palps with less than 1/4 of prostomial length (Fig. 27B). Eyes absent. Proboscis basally with six longitudinal rows of rounded papillae. Distal region with six longitudinal rows of prominent and pigmented tubercles. Terminal ring not observed. Segment 1 visible dorsally. Four pairs of tentacular cirri flattened with inflated bases, biarticulated, with short cirrophores and long cirrostyles, situated of first three segments. Tentacular cirri of segment 1 reaching segment 3. Dorsal and ventral tentacular cirri of segment 2 reaching segments 3 and 2, respectively. Dorsal tentacular cirri of segment 3 reaching segment 2. Neuropodia from segment 2. Dorsal cirri symmetrical, oval to rounded, inflated from segment 4 with well-developed cirrophores and without dorsal expansions. Parapodial lobes shorter than dorsal and ventral cirri with aciculae and bundles of chaetae. Prechaetal lobes bilobate, symmetrical, and rounded (Fig. 27 C–D). Postchaetal lobes rounded. Ventral cirri horizontally oriented in relation to lobes, symmetrical and rounded (Fig. 27 C–D). Compound spinigerous chaetae from segment 2. Rostrum of chaetal shaft surrounded by several denticles, with a pair of main conical teeth; articles with serrated outer edges (Fig. 27E). Pygidium not observed.

Colour. Preserved animals show dorso-lateral black pigmentation in the prostomium and dark brown pigmentation in the anterior segments and parapodia (Fig. 27 A–C).

Habitat. Substrate composed of silt between 986 and 3.016 m.

Geographical Distribution. Atlantic Ocean, Brazil: Continental shelf and slope in Campos Basin.

Etymology. The Latin words ovalis refers to oval-shaped parapodial cirri present in this species.

Remarks. Phyllodoce ovalis sp. nov. differs from other closely related species by having antennae, palps, and tentacular cirri with inflated bases. The club-shaped nuchal papilla is a unique character of this species. The oval and inflated dorsal and ventral cirri are similar to those of the genera Mystides and Pseudomystides, and have not been reported for other species of Phyllodoce . The oval prostomium is a character shared with some species recorded for Sige and also not previously reported in Phyllodoce . The absence of eyes is a character shared with the Brazilian species P. concava sp. nov., P. lamella sp. nov., and Phyllodoce sp. B. and it seems to be common to species collected in slope depths. Phyllodoce ovalis sp. nov. presents segment 1 completely visible, character described for the genus but not observed in other species described and recorded in this study.