Kirkegaardia goytaca, 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 : 9-11

Kirkegaardia goytaca sp. nov.

urn:lsid:zoobank.org:act:0C21AF49-C7AD-4686-8AD6-CE74CEB54ABA

Fig 5

Material examined. BRAZIL: Campos Basin – Holotype – -19.95913611˚S -39.89185833˚W, 43 m, 16/12/10, ( MNRJP-002990 ); Paratypes – -19.59332222˚S -39.68905833˚W, 21 m, one ind. , 16/07/13, ( MNRJP-002991 ) .

Diagnosis. Peristomium and thoracic region with dorsal crest joining with and continuing with the peristomial crest. Noto- and neurosetae denticulated.

Description. Holotype with 76 setigers, body 4.6 mm long, 0.12 mm wide in thoracic region, and 0.13 mm wide in abdominal region. All specimens incomplete. Prostomium short conical ( Fig 5A ); Eyes absent. Peristomium elongate, with a single short posterior ring; with a prominent dorsal crest along most of length, merging with thoracic crest ( Fig 5A ). Dorsal tentacles on short peristomial ring ( Fig 5A ). First pair of postero-lateral branchiae to the tentacles; second pair of branchiae in setiger 1 dorsal to notosetae ( Fig 5A ), continuing segmentally to middle of abdominal region. Thoracic region narrowing after about 14–16 setigers, with a thoracic crest ending. After end of thoracic crest, thoracic region with a narrow groove, visible in light microscope ( Fig 5A ). Abdominal segments wider than long. Parapodia with poorly developed lobes. Thoracic parapodia with 5–6 capillary noto- and neurosetae per segment. Posterior abdominal parapodia with 4–5 denticulated notosetae ( Fig 5B ) and six or seven denticulated neurosetae per segment ( Fig 5C ). Denticulated neurosetae appear from abdominal setigers 30 to 38. Abdominal neurosetae smaller than notosetae in first abdominal segments, noto- and neurosetae of same size in middle segments of abdominal region. Pre-pygidial segments and pygidium absent.

Remarks. Kirkegaardia goytaca sp. nov. is similar to K. carinata Blake, 2016 [ 22] in that both have a narrow body, abdominal segments wider than long, thoracic crest, tentacles in the posterior portion of the peristomium, and first pair of postero-lateral branchiae to the tentacles between the peristomium and the first setiger. However, K. carinata presents the first pair of branchiae inserted in the groove that separates the peristomium from the first setiger, while K. goytaca sp. nov. has the first pair of branchiae inserted in the peristomial ring. In addition, K. goytaca sp. nov. has a peristomial crest, while K. carinata only thoracic crest. The presence of a peristomial crest throughout the peristomium brings K. goytaca sp. nov., K. jongo sp. nov. and K. papaveroi sp. nov. to a group of four species, Kirkegaardia dorsobranchialis-heterochaeta . Kirkegaardia goytaca sp. nov. differs from K. cristata in having only a single ring at the end of the peristomium, while K. cristata has three well-marked peristomial rings. Kirkegaardia goytaca sp. nov. differs from K. annulosa in having the thoracic region very narrow, while K. annulosa has a thoracic region expanded. Kirkegaardia goytaca sp. nov. also differs from K. kladara in having the first pair of branchiae inserted in the final portion of the peristomium, while in K. kladara the first pair of branchiae occurs from the first thoracic setiger. For all these characteristics, the species was considered as new to science.

Etymology. This name is in honor of the extinct local ethnic group uetaká, also known as Goytacá. These native people lived along lowlands from the northern Macaé River to Espírito Santo State, a coastal region that comprises a large part of the sampling sites where this and the other Kirkegaardia species of the present study were collected.

Figures

Fig 5. Kirkegaardia goytaca sp. nov. (A) anterior end, dorsal view; (B) notopodial capillary denticulated; (C) neuropodial capillary denticulated. A–C (MNRJP-002990). Scale bars; 200 μm (A-C). Type locality.Atlantic Ocean: Campos Basin (Brazil). Habitat. Fine sediments (clay) and sandy sediments organically enriched, 21 and 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.g005