Glyphohesione campensis, Ribeiro & Barbosa & Freitas & Zanol & Glasby & Ruta, 2020

Ribeiro, Rannyele Passos, Barbosa, Aline Da Cruz, Freitas, Roberta, Zanol, Joana, Glasby, Christopher J. & Ruta, Christine, 2020, Pilargidae (Annelida: Phyllodocida) from coastal and deep waters of the Southwestern Atlantic, with descriptions of two new species, Zootaxa 4878 (1), pp. 56-76 : 64-66

Glyphohesione campensis sp. nov.

Figure 6 A–G

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Material examined. BRAZIL: Campos Basin : Holotype: 21º13’38.308”S, 40º14’57.803”W, 417 m, one specimen, 5.ii.2009 (MNRJP-002724). Paratypes: 21º40’23.730”S, 40º58’23.765”W, 18 m, one specimen, 19.vii.2009 (MNRJP-002725); 22º56’2.563”S, 41º53’51.338”W, 48 m, one specimen, 28.ii.2009 (MNRJP-002726); 22º59’1.044”S, 40º48’27.955”W, 380.6 m, one specimen, 1.ii.2009 (MNRJP-002727); 22º19’2.381”S, 40º5’27.062”W, 383.8 m, one specimen, 31.i.2009 (MNRJP-002728); 21º56’11.947”S, 39º57’45.285”W, 720 m, one specimen, 4.ii.2009 (MNRJP-002729); 21º40’16.833”S, 39º58’6.138”W, 1,005.8 m, three specimens, 08.ii.2009 (MNRJP-002730).

Diagnosis. Notopodial spine from fifth chaetiger. Dorsal cirri of anterior chaetigers about half the length of body width. Neurochaetae finely serrated with entire and straight tips, up to eight per parapodium.

Description. Fixed specimens whitish over most of body, orange-coloured on anterior region. The following description is based on the holotype: 3 mm long, 0.30 mm width (at widest point, including parapodia) and 24 chaetigers. Body dorsoventrally flattened; first five or six anterior segments distinctly wider and inflated than more posterior ( Fig. 6A ). Body surface smooth, no papillae. Prostomium bilobed, slightly wider than long; three long and slender antennae, median antenna posterior to lateral antennae; eyes absent ( Fig. 6B ). Two biarticulated palps, palpophore large, and palpostyle about one-third shorter than lateral antennae. Proboscis cylindrical, without papillae. Peristomium indistinct from prostomium, two pairs of tentacular cirri twice longer than lateral antennae; dorsal tentacular cirri 1.2x longer than ventral ones ( Fig. 6D, E ). Parapodia sub-biramous.

Dorsal and ventral parapodial cirri elongated and slender. Dorsal cirri about half the length of anterior body width. Dorsal cirri on first chaetiger 2.5x longer than following and 1.3x longer than dorsal tentacular cirri ( Fig. 6D ). Ventral cirri shorter than dorsal cirri. Notopodial lobe reduced. Notopodial spines ventral to dorsal cirri, one per notopodium, present from fifth to last chaetiger ( Fig. 6C, F ). Neuropodial lobes well developed and conical, with eight finely serrated neurochaetae with entire and straight tips ( Fig. 6G ). Pygidium slender, without papillae and with two elongated cirri ( Fig. 6A ).

Distribution. Atlantic Ocean—Brazil, Campos Basin, specimens examined in this study.

Remarks. This species is assigned to the genus Glyphohesione due to the presence of simple chaetae, a straight notopodial spine located ventral to the dorsal cirri, elongated palpostyles, and the position of lateral and median antennae. There are currently three described species in the genus: G. klatti ( Friedrich 1950) , type species of the genus described from the North Sea, Germany; G. longicirrata Licher, 1994 , from Gulf of Mexico, USA and G. nicoyensis Dean, 1998 , from Gulf of Nicoya, Costa Rica. However, the new species described here differs in the first appearance of notopodial spines, relative length of dorsal cirri in relation to body width and the number of neurochaetae. The notopodial spines of Glyphohesione campensis sp. nov. begin on the fifth chaetiger, while in G. klatti they emerge from chaetigers 5–8, in G. nicoyensis they emerge from chaetigers 7–10, and in G. longicirrata between chaetigers 10–15. Also, the new species differs in the relative length of dorsal cirri in relation to the anterior body width: in G. klatti and G. nicoyensis cirri length is one-quarter of the body width, in G. longicirrata dorsal cirri are as long as the body width; and in Glyphohesione campensis sp. nov. they are half of the body width. Regarding the variation in structure and number of neurochaetae, G. klatti has up to 25 finely serrated chaetae with entire and curved tips; G. longicirrata , up to 14 finely serrated chaetae with minutely bifid tips; G. nicoyensis , up to 18 finely serrated chaetae with entire and curved tips; and Glyphohesione campensis sp. nov., up to 8 finely serrated chaetae with entire and straight tips ( Table 1 ). Additionally, Glyphohesione campensis sp. nov. differs from G. nicoyensis in lacking eyespots ( Table 1 ).

Etymology. Named after the type locality because the species presents a wide distribution along the Campos Basin.

Figures

FIGURE 6. Glyphohesione campensis sp. nov. A. Whole body. B. Anterior body showing prostomium, peristomium and first chaetigers. C. Parapodium from midbody. D–G. SEM images. D. Anterior body showing peristomium and first chaetigers, specimen was damaged during fixation procedures. E. Detail of tentacular cirri, left side. F. Parapodial detail showing notopodial spine, left parapodium of chaetiger 10. G. Serrated neurochaetae from midbody parapodia, chaetiger 10. All pictures in dorsal view.Abbreviations. Dc: dorsal cirrus, La: lateral antenna, Ma: median antenna, Ns: notopodial spines, Pb: proboscis, Pt: prostomium, Py: pygidium, Tdc: tentacular dorsal cirrus. Scale bars: 200 µm (A), 100 µm (B–D), 50 µm (E, F), 10 µm (G).