Phyllodoce (Ushakov, 1972)

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 : 49-50

Phyllodoce sp. A.

Figure 34

Material examined. One individual. Margin of continental shelf in Campos Basin , Rio de Janeiro, Brazil, Hab 1 Drad 37, 22º3’18.3”S 40º12’29.3”W, 63.7 m, 24 Apr 2008 ( ZUEC–POL 16430 ) .

Diagnosis. Proboscis basally with eight conical papillae irregularly distributed dorsally and six rows of conical papillae irregularly distributed on each side; proboscidial papillae absent ventrally.

Description. Specimens incomplete, ranging from 2–10 mm long, 2.0 mm wide at median part of body, including parapodia and excluding chaetae for 12–94 segments. Body long, dorso-ventrally flattened and tapered posteriorly. Prostomium cordiform, longer than wide, with deep posterior incision with a nuchal papilla. Nuchal organs well-developed. Paired frontal antennae and palps conical, long and of similar lengths. Antennae and palps 1/4 of prostomial length. One pair of brown epidermal eyes with lenses. Proboscis basally with about eight conical papillae irregularly distributed dorsally and six rows of conical papillae irregularly distributed on each side; papillae absent ventrally ( Fig. 34 A–C). Distal region with six longitudinal rows of prominent tubercles. Terminal ring with 18 oval papillae observed through dissection. Segment 1 not visible dorsally. Four pairs of cylindrical tentacular cirri, biarticulated with short cirrophores and long cirrostyles, on first three segments. Tentacular cirri of segment 1, reaching segment 4. Dorsal and ventral tentacular cirri of segment 2 reaching segments 10 and 4, respectively. Dorsal tentacular cirri of segment 3 reaching segment 7. Neuropodia and ventral cirri from segment 3. Dorsal cirri asymmetrical with well-developed cirrophores with dorsal extensions on median parapodia. Dorsal cirri of anterior segments lanceolate, on median segments lanceolate to sub-rectangular with rounded edges and tapered distal ends, and lanceolate posteriorly. Parapodial lobes shorter than dorsal and ventral cirri with light-brown aciculae and bundles of chaetae. Prechaetal lobes bilobate and symmetrical. Postchaetal lobes rounded. Ventral cirri horizontally oriented in relation to lobes, asymmetrical, dorso-ventrally flattened and beginning from segment 3; ventral cirri rounded anteriorly, rounded with tapered distal ends on medial segments, and posteriorly with distal extremities more tapered than median ones ( Fig. 34 D–F). Compound spinigerous chaetae uniform from segment 4. Rostrum of chaetal shaft surrounded of denticles; articles with serrated outer edges. Pygidial cirri not observed.

Colou r. Preserved specimens show brown pigmentation that is more intense in the anterior part of the body.

Habitat. Sandy substrates from 64 m.

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

Remarks. Only two specimens of Phyllodoce sp. A were collected and additional material is needed before it can be formally described. Phyllodoce sp. A. is very similar to P. cf. madeirensis because of the well-developed nuchal organs, cordiform prostomium, and dorsal lanceolate cirri with rounded edges. Despite these morphological similarities, the dorsal cirri are more robust in Phyllodoce sp. A. This putative species differs from both P. madeirensis and P. thalia sp. nov. in the distribution of papillae in the proximal region of the proboscis; Phyllodoce sp. A. has papillae unevenly distributed with eight conical papillae dorsally and six rows of conical papillae irregularly distributed on each side; P. madeirensis has a row of six median-dorsal papillae and six rows of papillae regularly distributed on each side; and P. thalia sp. nov. has oval papillae irregularly distributed on each side, only separated by one horizontal row of median-dorsal papillae.

Phyllodoce sp. A. differs from P. concava sp. nov., P. lamella sp. nov., P. ovalis sp. nov., and Phyllodoce sp. B. in the presence of eyes, distribution and shape of papillae in the proboscis, and parapodial cirri that are oval in P. lamella sp. nov. and Phyllodoce sp. B, and rounded in P. ovalis sp. nov. It differs from P. bipapillosa sp. nov., P. tamoya sp. nov., and P. tupana sp. nov. because these present anterior cordiform dorsal cirri. Phyllodoce colorata sp. nov., P. concava sp. nov., and Phyllodoce sp. B. are distinct from Phyllodoce sp. A on the distribution and morphology of proboscidial papillae: P. colorata sp. nov., P. concava sp. nov., and Phyllodoce sp. B. present oblique rows with cuspidate papillae ( Blake 1988; Pleijel 1993b) that are lacking in Phyllodoce sp. A.

Figures

FIGURE 34. Phyllodoce sp. A. A, dorsal view of proboscis and nuchal organ; B, irregularly distributed proboscidial papillae in lateral view; C, detail of cordiform prostomium.Abbreviations: On, nuchal organ (black arrow); Anterior view of parapodia. D, parapodium 8; E, parapodium 45; E, parapodium 89. Scale bars: A–C, 0.5 mm; D, 0.1 mm; E, 0.15 mm; F, 0.8 mm.