Fauveliopsis magalhaesi, Salazar-Vallejo & Zhadan & Rizzo, 2019

Salazar-Vallejo, Sergio I., Zhadan, Anna E. & Rizzo, Alexandra E., 2019, Revision of Fauveliopsidae Hartman, 1971 (Annelida, Sedentaria), Zootaxa 4637 (1), pp. 1-67 : 27-29

Fauveliopsis magalhaesi new species

Figures 13 , 14

urn:lsid:zoobank.org:act:0B7FB8D2-BAD8-47D9-9A28-E8CF1191E676

TL: South Atlantic Ocean, Campos Basin, off Rio de Janeiro, 2445 m depth.

D: South Atlantic Ocean, in sediments at 2445 m water depth.

Type material. South Atlantic Ocean, Campos Basin, off Rio de Janeiro. Holotype ( UERJ 1336 ): HAB4 #D11 (22°52’10.284” S, 40°05’14.448” W), R3, 0–2 cm, 2455 m depth, box corer, 22 May 2008 (8.4 mm long, 0.5 mm wide, 26 chaetigers, complete; GP not seen) . Paratypes ( ECOSUR 208 , 1 SEM):AMB124, #E9F5 (20°34’50.48” S, 38°27’07.640” W), R1+R3, 0–10 cm, 2494 m, 22 Dec. 2011. One paratype ( ECOSUR 209 , 1 SEM): AMB11 #C7 (20°17’37.38” S, 39°42’36.72” W), R3 0–10 cm, 1355 m, 19 Jun. 2013 .

Etymology. The species name is made after Dr. Wagner Magalhães in recognition of his careful study of polychaetes species, and for his friendship especially with one of the authors (AER). The epithet is a noun in the genitive case.

Diagnosis. Fauveliopsis with long body, posteriorly swollen, divided into three different regions by integument and chaetation. Integument rugose, papillated anteriorly (ca. 10 first chaetigers), followed by a transitional less rugose papillated region, and a third region (posterior chaetigers) weakly papillated, almost smooth. First 3 chaetigers: aA/Aa, with safety-pin falcate (SPF) neurochaetae; chaetigers 4 to 16–25 (depending on body size): cA/Ac (except for replacement chaetae); ca. 10 last chaetigers with multiple neurochaetae: cA/1–3A1–3c. Ventral shield usually present, elongate.

Description. Holotype (UERJ 1336) with long body, posteriorly swollen, divided into three different regions by integument and chaetal features ( Figs 13A , 14A ). Anterior and median segments distinct, posterior ones indistinct. Whitish, without pigmentation ( Fig. 13A ).

Prostomium invaginated, fused to peristomium ( Fig. 13B ). Peristomium marginating mouth. Mouth as a vertical incision, distal, with inverted T-shaped opening.

Integument opaque, very rugose, papillated along anterior region (first 10–12 chaetigers; Fig. 14B, C ), with about 15 rows of triangular papillae, followed by a less rugose, papillated transitional region, papillae slightly small- er than those present along anterior region ( Fig. 14C ). Posterior region (last 10 chaetigers) rugose, almost smooth, except for a few minute papillae, transparent ( Fig. 14D ). Triangular papillae with a dorsal pore, arranged on rugose ridge ( Fig. 14E ).

First 10–12 segments sharply demarcated by tranverse sulci. Segments of median and posterior regions indistinct ( Fig. 14F ).

Parapodia lateral, flat and little developed in anterior and posterior regions, even inconspicuous in median region. Interramal papilla pedunculate, tip granulated, located between notopodia and neuropodia along anterior region; smaller and closer to notopodia in median and posterior regions.

In first segments chaetae directed anteriorly, following ones directed laterally or posteriorly. First 4 segments with aA/Aa, i.e. one capillary and one stouter and curved acicular; neurochaetae safety-pin falcate (SPF). From chaetiger 4 to 16–25 (depending of body size) noto- and neuropodia with one capillary and one acicular each on median chaetigers (cA/Ac). Last 10 chaetigers with multiple neurochaetae: usually cA/1–3A1–3c ( Fig. 13C ). Replacement chaetae can be present in noto- and neuropodia along body.

Genital papilla not seen. Pygidium inconspicuous, with minute papillae close to anal opening. Probably living in scaphopod shells.

Remarks. Fauveliopsis magalhaesi n. sp. resembles F. adriatica and F. magna , as indicated above. They differ, as indicated in the key above, because F. magalhaesi n. sp. does not have genital papillae (GP), and its integument is both rugose and papillate, whereas the two other species have GP and their integument is papillate, not rugose.

F. magalhaesi n. sp. has safety-pin falcate neurochaetae on the first three chaetigers; one capillary and one acicular chaeta per ramus on the median region, and posterior chaetigers with 1–3 capillaries and 1–3 acicular neurochaetae (more chaetae can also be present in notochaetae of the posterior chaetigers). Two species, F. adriatica from the Mediterranean and F. glabra from the Northeastern Pacific have the same chaetal pattern. However, these last two species have body papillated, while in F. magalhaesi n. sp. the body is rugose and papillated anteriorly, and only the posterior region is papillated, with a transitional region between them.

One of the characteristics of the species of Fauveliopsis is the variable number of segments. The number of chaetigers varies from 14 to 29, as well as its body length and width (0.9–6.5 mm long, 0.15–0.6 mm wide). Thus, there was no pattern regarding the number of segments and body length and width. The shape and the size of the body are directly related to the mode of life of those organisms, which inhabit gastropod or scaphopod shells.

Figures

FIGURE 13. Fauveliopsis magalhaesi n. sp., paratype (ECOSUR 208). A. Complete specimen, dorsal view. B. Same, anterior end, dorsal view. C. Same, posterior region, dorsal view. Scale bars: A: 0.2 mm; B–C: 0.7 mm.

FIGURE 14. Fauveliopsis magalhaesi n. sp., paratype.A (ECOSUR 208). A. Complete specimen, dorsal view. B. Same, anterior end, dorsal view. C. Same, median region, dorsal view. D. Same, posterior region, dorsal view. E. Epithelial papillae. F. Last chaetigers and pygidium, dorsal view. Scale bars: A: 330 µm, B, 140 μm, C: 150 μm, D: 200 μm, E: 20 μm, F: 110 μm.