Diplocirrus rugosus, 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 : 289-291

Diplocirrus rugosus sp. nov.

( Figure 1 A–E)

Type material. Brazil. Atlantic Ocean. Southeastern coast, Campos Basin. Holotype: ( UERJ 5570-HAB 17 I5 R3), 140 m, 21 Jul. 2009, (21º 22' 58.560" S, 40º 15' 15.721" W). Paratype: ( UERJ 5571-HAB 13 I5 R2; 43 inds), 147 m, 0 6 Jul. 2009 (21º 22' 57.858" S 40º 15' 15.648" W).

Diagnosis. Sediment particles dispersed, body papillae abundant, twice as long in chaetal lobes, 4–5 notochaetae per ramus, 3–4 neurochaetae throughout the body.

Description. Holotype complete (HAB 17 I5 R3; Fig. 1 A), 7.3 mm long, 1 mm wide, cephalic cage 2.5 mm long, for 32 chaetigers. Body cylindrical, swollen anteriorly, yellowish brown in color. Paratypes complete, 1.4–7.3 mm long, 0.4– 0.7 mm wide, cephalic cage 0.3–2.5 mm long, for 20–35 chaetigers. Tunic with a thin layer of fine sediment grains, papillated. Papillae short relative to size of chaetae, papillae capitate. Fine sediment particles on papillae basis only, papillae ¼ as long as notochaetae, about eight transverse rows in chaetiger 10, papillae twice as long as chaetal lobes, with same size throughout body. Cephalic hood exposed in one specimen; palps and branchiae lost; prostomium low cone; eyes not observed. Caruncle poorly developed, not reaching posterior margin of branchial plate, lateral ridges low, median keel not projected. Palps long, thick; palp keels rounded, reduced. Lateral lips larger, thick, dorsal lip smaller, rhomboid, ventral lip reduced, rounded. Cephalic cage chaetae as long as body width. Only notochaetae of chaetiger 1 present in cephalic cage, chaetae directed dorsally. 4–5 notochaetae per ramus throughout body, anterior dorsal margin of first chaetiger papillated, papillae similar to those along body. Chaetigers all of the same length. 3–4 neurochaetae per bundle throughout body. Ventrolateral gonopores absent. Chaetae emerge from body wall. Noto- and neurochaetae of same size from chaetiger 2, notochaetae as long as ½ body width and neurochaetae ¼ as long as notochaetae. All noto- and neurochaetae multiarticulated. Notochaetae with articles longer basally, medium-sized medially and short distally; neurochaetae with all articles of same-size, tips falcate, smooth. Both chaetae tapering distally. Posterior region tapers into a rounded lobe, terminal anus.

Remarks. Diplocirrus rugosus sp. nov. is similar to Diplocirrus sp. from Morocco because both species have anterior chaetigers of similar size to those present in the posterior ones, body coated with sediment and many short papillae, giving a velvety appearance. However, Diplocirrus rugosus sp. nov. differs from Diplocirrus sp. from Morocco because the first has dispersed sediment particles and papillae twice as long as chaetal lobes, while the second has abundant sediment particles forming a thin layer and short papillae laterally. Diplocirrus rugosus sp. nov. differs from Diplocirrus salazarvallejoi sp. nov. and Diplocirrus acafi sp. nov. because the first has body wall with sand particles and the others not. Furthermore, Diplocirrus rugosus sp. nov. has papillae twice as long as chaetal lobes while Diplocirrus salazarvallejoi sp. nov. described below has all papillae of same size on ventral and dorsal regions and Diplocirrus acafi sp. nov. described below has all papillae of the same length along body.

Etymology. The epithet of this new species refers to the presence of short papillae, which, when viewed under a light microscope, give a rugose or rough appearance to the body.

Distribution. Southeastern Atlantic coast, Campos Basin, Brazil, in soft bottom from 52 m to 147 m.

Figures

FIGURE 1. Diplocirrus rugosus sp. nov. (A) Holotype (UERJ 5570), ventral view. (B) Same, oblique lateral view. (C) Same, chaetiger 10, notochaetae (inset: basal and medial chaetal regions). (D) Same, one neurochaeta. (E) Capitate papillae. Scale bars: A – B: 0.5 mm, C: 45 µm, D-E: 30 µm.