Phyllodoce concava, Oliveira & Magalhães & Lana, 2021

Oliveira, Verônica Maria De, Magalhães, Wagner F. & Lana, Paulo Da Cunha, 2021, Ten new species of Phyllodoce Lamarck, 1818 (Phyllodocidae, Annelida) from Brazil, Zootaxa 4924 (1), pp. 1-61: 21-24

publication ID

https://doi.org/10.11646/zootaxa.4924.1.1

publication LSID

lsid:zoobank.org:pub:8C98968D-AAF8-403C-AFCC-381B2CC76844

DOI

http://doi.org/10.5281/zenodo.4538323

persistent identifier

http://treatment.plazi.org/id/C181979A-B8EC-4E19-828B-90C3C4DC0AA4

taxon LSID

lsid:zoobank.org:act:C181979A-B8EC-4E19-828B-90C3C4DC0AA4

treatment provided by

Plazi

scientific name

Phyllodoce concava
status

sp. nov.

Phyllodoce concava   sp. nov.

urn:lsid:zoobank.org:act:C181979A-B8EC-4E19-828B-90C3C4DC0AA4

Figures 15–17 View FIGURE 15 View FIGURE 16 View FIGURE 17

Holotype. Margin of continental shelf in Campos Basin, Rio de Janeiro, Brazil, Hab6 C07 R3, 22º59’52.2”S 40º47’45.3”W, 686.1 m, 24 Jun 2008 ( ZUEC– POL 16322 View Materials ). GoogleMaps  

Paratypes. A total of 4 paratypes length 5.5 ± 3.1 mm for 41.8 ± 12.9 segments. Continental slope of Campos Basin: Hab 10 D12   R2, 23º18’34.5”S 49º35’55.6”W, 3016.4 m, 11 Jan 2009 (1 paratype, ZUEC–POL 16475) GoogleMaps   ; Hab3 C10 R1, 23º8’22.0”S 40º36’43.1”W, 1891.2 m, 9 May 2008 (1 paratype, ZUEC–POL 16584) GoogleMaps   ; AMBES11 GoogleMaps   E08 R3, 20º15’55.63”S 38º40’45.57”W, 1892 m, 15 Jun 2013 (1 paratype, ZUEC–POL 18584) GoogleMaps   ; AMBES11 GoogleMaps   C5 R3, 20º14’17.9”S 39º48’34.3”W, 395 m, 19 Jun 2013 (1 paratype, ZUEC–POL 18582) GoogleMaps   , Brazil.

Diagnosis. Conspicuous concavity in posterior margin of prostomium with one central nuchal papilla with lateral bars. U-shaped lateral bars clearly connected with a nuchal papilla and reaching half the margin in anterior prostomium. Parapodial dorsal cirri oval to rectangular in shape.

Description. Holotype incomplete, lacking pygidial cirri, 3.0 mm elongate, 0.5 mm wide median part of body including parapodia and excluding chaetae for 29 segments. Body long, dorso-ventrally flattened and tapered posteriorly. Prostomium cordiform, longer than wide, with protuberance anteriorly ( Fig. 15 View FIGURE 15 A–B). Posterior prostomial margin with constriction, one central nuchal papilla and a nuchal bar on each side. U–shaped bars, extending from base of nuchal papilla to anterior median margin of prostomium ( Fig. 15 View FIGURE 15 A–B). Paired frontal antennae and palps cylindrical, slender and of similar lengths.Antennae and palps with half the length of prostomium. Eyes absent. Proboscis dissected and divided into two parts: proximal, with oblique rows of sclerotized cusps-shape papillae ( Fig. 15 View FIGURE 15 C–D); distal with longitudinal rows of tubercles. Terminal ring not observed. Segment 1 not visible dorsally. Four pairs of cylindrical and biarticulated tentacular cirri, with short cirrophores and long cirrostyles, situated on first three segments. Tentacular cirri of segment 1, reaching segment 5. Dorsal and ventral tentacular cirri of segment 2 reaching segments 9 and 4, respectively. Dorsal tentacular cirri of segment 3, reaching segment 5. Neuropodia with chaetae from segment 2 ( Fig. 16A View FIGURE 16 ). Dorsal cirri with well-developed cirrophores without dorsal extensions and from segment 4. Dorsal cirri symmetrical, oval to quadrangular and with rounded edges anteriorly, cirri from median segments with tapered edges, and elongated posteriorly. Parapodial lobes shorter than dorsal and ventral cirri, with median light-brown aciculae and bundles of chaetae. Prechaetal lobes bilobate, symmetrical and rounded. Prostchaetal lobes rounded. Ventral cirri horizontally oriented in relation to lobes, dorso-ventrally flattened, present from segment 3. Ventral cirri asymmetrical, cordiform to conical anteriorly and on median and posterior segments slender and elongated ( Figs 16 View FIGURE 16 B–D; 17A–C). Compound spinigerous chaetae uniform from segment 2. Rostrum of chaetal shaft with three main teeth, surrounded of denticles; articles with serrated outer edges ( Fig. 17D View FIGURE 17 ) and simple capillary chaetae at median bundle of chaetae ( Fig. 16B View FIGURE 16 ). Pygidial cirri not observed.

Colour. Preserved specimens with dark brown pigmentation in the prostomium and parapodial cirri ( Fig. 15 View FIGURE 15 ). A median dorsal black stripe is present in the first five segments ( Fig. 15A, B View FIGURE 15 ).

Habitat. Collected in well-sorted fine silt sediments at 1,865 m.

Geographical Distribution. Atlantic Ocean, Brazil: Margin continental of continental slope in Campos Basin.

Etymology. The name species is derived from the Latin concavus (arched, curved), referring to the shape of the posterior part of the prostomium.

Remarks. Phyllodoce concava   sp. nov. has the U–shaped structure in the posterior part of the prostomium unique among the known species of the genus. Phyllodoce concava   sp. nov. shares the presence of capillary chaetae with P. micrognatha   sp. nov., which is a commonly observed characteristic in Protomystides   and Pseudomystides (Pleijel, 1993)   . Phyllodoce concava   sp. nov. and P. micrognatha   sp. nov. are readily distinguishable by the characteristics of the proboscis. The cuspidate chitinous proboscidial papillae in P. concava   sp. nov. are different from the chitinous hard structures observed in P. micrognatha   sp. nov. In addition, the two species differ in the shape of the prostomium because P. concava   sp. nov. has a protuberance at the anterior margin where antennae and palps are located and this is not observed in P. micrognatha   sp. nov. Another characteristic that sets it apart is the morphology of the parapodial cirri, which in P. concava   sp. nov. are oval to quadrangular, whereas in P. micrognatha   sp. nov. they are oval to sub-rectangular.

Phyllodoce concava   sp. nov. differs from P. colorata   sp. nov. and P. rosea   by the absence of eyes. Phyllodoce concava   sp. nov., P. colorata   sp. nov., P. rosea   , P. lamella   sp. nov., and Phyllodoce   sp. B differ in the morphology of the prostomium (cordiform in P. concava   sp. nov. and P. lamella   sp. nov., oval with an anterior depression in P. colorata   sp. nov., and rounded to oval in P. rosea   and Phyllodoce   sp. B.). P. ovalis   sp. nov. also lacks eyes and has long and slender tentacular cirri, unlike the other species of Phyllodoce   described here. It differs from P. concava   sp. nov. because it presents antennae and palps with inflated bases, short tentacular cirri, and rounded dorsal cirri. Phyllodoce concava   sp. nov. differs from P. medipapillata   , P. williamsi   , and P. hiatti   because these present dorsal-foliaceous cirri ( Pettibone 1963; Blake 2001). In addition, it differs from P. lamella   sp. nov. because the latter presents ventral cylindrical tentacular cirri with lateral lamella.