Diplocirrus acafi, Teixeira, Juliana Henrique, Rizzo, Alexandra Elaine & Santos, Cinthya Simone Gomes, 2015

Teixeira, Juliana Henrique, Rizzo, Alexandra Elaine & Santos, Cinthya Simone Gomes, 2015, Three new species of Diplocirrus Haase, 1915 (Polychaeta: Flabelligeridae) from Campos Basin in SE Brazil, Zootaxa 4027 (2), pp. 287-295 : 292-293

Diplocirrus acafi sp. nov.

( Figure 3 A–D)

Type material. Brasil. Atlantic Ocean. Southeastern coast, Campos Basin. Holotype: ( UERJ 5573-HAB16 C3 R3), 77 m, 0 3 July 2009 (22º 46' 50,350" S 41º 3' 39,080" W). Paratypes: 1 paratype ( UERJ 5574-HAB8 A6 R2), 400.8 m, 0 1 February 2009 (23º 37' 53,970" S 41º 19' 47,574" W), 1 paratype ( UERJ 5577-HAB13 FOZ 43 R2), 68 m, 15 March 2009 (22º 11' 55,016" S, 40º 32' 14,086" W) 1 paratype ( UERJ 5576-HAB16 B4 R2), 107 m, 0 2 July. 2009 (23º 10' 0,820" S 41º 3' 12,720" W), 1 paratype ( UERJ 5575-HAB17 FOZ 43 R2), 97 m, 24 July 2009 (22º 12' 26,776" S 40º 14' 14,985" W).

Diagnosis. Sediment particles of about the same size and homogeneously distributed throughout body, all papillae of the same length along body, 7 noto- and 5 neurochaetae per bundle throughout body.

Description. Holotype complete; body cylindrical, anteriorly tapered, light brown; 5 mm long, 0.4 mm wide, cephalic cage 0.7 long, for 29 chaetigers. Paratypes with 24–32 chaetigers, 3.2–5 mm long, 0.3–0.5 mm wide, cephalic cage 0.5–0.7 mm long. Tunic with thin layer of fine sediment grains, papillate. Papillae ½ as long as neurochaetae, papillae capitate (longer than wide). Fine sediment particles on papillae basis only, papillae are not distributed homogeneously, more numerous on the anterior and posterior region and chaetal lobes, the same-sized throughout. Four rows of papillae per chaetiger. Cephalic hood not exposed. Anterior region not dissected to avoid damage. Cephalic cage chaetae as long as body width. Only notochaetae of chaetiger 1 form cephalic cage, chaetae directed dorsally. Seven notochaetae per bundle throughout, anterior dorsal margin of first chaetiger papillate, papillae similar to those along body. Some notochaetae twice as long as the others in the same bundle, 5 neurochaetae per bundle along body. Chaetigers all of same size. Ventrolateral gonopores absent. Chaetae emerge from body wall. Median notochaetae about ½ of body width. Notochaetae 1/6 longer than neurochaetae. All notochaetae multiarticulated capillaries. Neurochaetae multiarticulated capillaries only in first chaetiger; from chaetiger 2 to end of body, chaetae thicker and falcate. All articles of noto- and neurochaetae of about same length. Neurochaetae thicker than notochaetae and of same thickness along capillary length. Posterior region tapered; terminal anus.

Remarks. Diplocirrus acafi sp. nov. and D. octobranchus (Hartman, 1965) have fine sediment particles only on the base of the papillae, absence of ventrolateral gonopores, and only notochaetae of chaetiger 1 make up the cephalic cage. However, Diplocirrus acafi sp. nov. has sediment of the same size homogeneously distributed, papillae in greater number in the anterior and posterior regions and in chaetal lobes, all papillae of about the same size along the body, 4 rows per chaetiger, 7 noto- and 5 neurochaetae per bundle throughout the body. Diplocirrus octobranchus presents sediment particles composed of a few larger sand grains, especially on the dorsum, papillae of varying lengths, longer dorsally and on chaetal lobes, may be as long as chaetae, shorter in the rest of the body, 4–5 rows per chaetiger, 4–5 notochaetae and 2–8 neurochaetae in the first chaetiger, 7 noto- and 2–5 neurochaetae in the median region.

Etymology. The species epithet, acafi , is a composition from Dr. A ntonio Ca rlos de F re i tas, whose species is named, for his friendship and contribution to the world of nature photography, including the new species described herein.

Distribution. Southeastern Atlantic coast, Campos Basin, Brazil, in soft bottom from 5 to 174 m depth.

Figures

FIGURE 3. Diplocirrus acafi sp. nov. (A) Holotype (UERJ 5573), oblique lateral view. (B) Same, chaetiger 10, notochaetae. (C) Same, neurochaetae. (D) Papillae capitate. Scale bars: A: 0.6 mm, B: 27 µm, C: 20 µm, D: 25 µm.