Kirkegaardia zafirae, Freitas & Ribeiro & Ruta, 2022

Freitas, Roberta, Ribeiro, Rannyele Passos & Ruta, Christine, 2022, Kirkegaardia Blake, 2016 (Annelida: Cirratulidae) from Southeastern Brazil with description of nine new species, PLoS ONE (e 0265336) 2016 (5), pp. 1-27 : 20-21

Kirkegaardia zafirae sp. nov.

urn:lsid:zoobank.org:act:1D92DB03-61C4-4E0B-BA5A-8245AA04BD87 .

Fig 12

Material examined. BRAZIL: Campos Basin – Holotype – -19.87264444˚S -39.99265000˚W, 26 m, 17/12/2010, one ind., ( MNRJP-003017 );– Paratypes – -19.79245278˚S -39.72085556˚W, 34 m, 14/12/2010, one ind., ( MNRJP-003018 ); -19.95913611˚S -39.89185833˚W, 43 m, 16/12/ 2010 one ind., ( MNRJP-003019 ) .

Diagnosis. Dorsal tentacles on posterior margin of peristomium. First pair of branchiae on the posterior margin of peristomium, posterior-lateral to tentacles, second pair located in first setiger. Thoracic region slightly expanded with 10–13 setigers and dorsal groove. Abdominal parapodia modified with 6–8 serrated notopodial setae and 8–10 serrated neurosetae capillary setae per segment. Pre-pygidial segments expanded with ventral groove.

Description. Holotype with 120 setigers; 3.3 mm long, thoracic region 0.11 mm wide and 0.26 mm high, and abdominal region 0.13 mm wide. Prostomium conical and broad ( Fig 12A ). Eyes absent. Peristomium elongated, with lateral 2–3 annular grooves, not crossing dorsal surface ( Fig 12A ). Dorsal tentacles on posterior region of the peristomium. First pair of branchiae in final portion of peristomium, posterior-lateral to tentacles, second pair located in first setiger; branchiae visible up to posterior abdominal region ( Fig 12A ). Thoracic region slightly expanded with 10–13 setigers and dorsal groove ( Fig 12A ). Abdominal region with narrow segments, wider than long ( Fig 12B ). Parapodia reduced, barely visible in optical microscopy. Thoracic parapodia with 3–5 smooth capillaries per fascicle. Abdominal parapodia modified with 6–8 serrated notopodial setae and 8–10 serrated neurosetae capillary setae per segment. Abdominal notosetae slightly longer than abdominal neurosetae. Denticulated neurosetae from setigers 20–35 ( Fig 12C ). Notosetae and neurosetae modified with well-developed denticles along edge ( Fig 12C and 12D ). Pre-pygidial segments expanded with ventral groove ( Fig 12E ). Pygidium with a conical ventral lobe ( Fig 12E ).

Remarks. Kirkegaardia zafirae sp. nov. is similar to K. siblina (Blake, 1996) [ 2], in that they both have an expanded pre-pygidial region, but K. siblina has only neurosetae denticulated while K. zafirae sp. nov. has noto- and neurosetae denticulated. In addition, K. siblina has a prominent achaetous segment between the peristomium and the setiger 1, and K. zafirae sp. nov. has no achaetous segment. Kirkegaardia zafirae sp. nov. belongs to the Kirkegaardia baptisteae -tesselata group due to their similar morphology, species in this group have elevated thoracic parapodia, and a mid-dorsal channel is not produced, although a dorsal crest sometimes develops. In the pre-setigerous area, dorsal ridges and rings are present or absent. From the group K. baptisteae was the only species that has denticulated notosetae, K. zafirae sp. nov. differs from K. baptisteae in that its pre-pygidial region is not flattened ventrally. For all these differences, K. zafirae sp. nov. was considered as new to science.

Etymology. This species is named in honor of Dr. Zafira da Silva de Almeida for her valuable contribution to marine biodiversity research and the conservation of aquatic resources in Brazil.

Figures

Fig 12. Kirkegaardia zafirae sp. nov. (A) anterior end, lateral view; (B) abdominal segments, lateral view; (C) neuropodial setae in posterior region; (D) notopodial setae in posterior region; (E) posterior parapodia, pre-pygidial region. A–E (MNRJP-003017). Scale bars: 100 μm (A-E). Type locality.Atlantic Ocean: Campos Basin (Brazil). Habitat. Fine sediments, sand with biodebris, 26 to 43 m depth. Distribution. Presently known only from Atlantic Ocean: Campos Basin (Brazil). Methyl Green. No pattern, stain not retained. https://doi.org/10.1371/journal.pone.0265336.g012