Hermundura tricuspis Müller, 1858

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 : 68-71

Hermundura tricuspis Müller, 1858

Figure 9 A–D

Hermundura tricuspis Müller, 1858: 216 , pl. 7, figs 19–20.

Parandalia tricuspis Salazar-Vallejo 1990: 512–515 , figs 3a–e.

Material examined. BRAZIL: Campos Basin: 21º55’18.918”S, 40º55’0.625”W, 16 m, two specimens, 11.iii.2009 (MNRJP-002741); 78 m, three specimens, 21.ii.2009 (MNRJP-002742); 23º1’47.127”S, 41º58’29.231”W, 80 m, two specimens, 28.ii.2009 (MNRJP-002743); State of Espírito Santo: Peroá Cangoá : 19º32’00”S, 39º35’00”W, one specimen ( IBUFRJ0388 ) . State of Santa Catarina: Itajaí : 26°54′30″S, 48°39′45″W, one specimen ( IBUFRJ1143 ) .

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Description. Fixed specimens whitish. Largest individual measuring 30 mm long, 0.45 mm wide and 65 chaetigers (MNRJP-002741). Body sub-cylindrical, surface smooth. Prostomium trapezoidal, antennae and eyes absent ( Fig. 9A ). Two palps fused and biarticulated, palpophores large and palpostyles reduced to small papillae. Proboscis not observed. Peristomium set off from prostomium; tentacular cirri absent. Parapodia uniramous in first chaetiger, following parapodia biramous ( Fig. 9A ). Second chaetiger with a pair of subepidermal ocelli. Notopodium reduced to small lobes from chaetiger two ( Fig. 9B ). Notopodial spines present from seventh chaetiger to the end of the body. Neuropodium well developed, ventral cirri present from fourth chaetiger to last. Neurochaetae comprising six capillaries finely hirsute spirally ( Fig. 9B, D ). Segmentation of the posterior region weakly marked; chaetigers gradually longer from chaetiger 15. Pygidium rounded and concave, with three cirri ( Fig. 9C ).

Distribution. Atlantic Ocean—Brazil ( Amaral et al. 2003; Attolini & Tararan 2001; Paiva 1993); Uruguay and Argentina ( Salazar-Vallejo & Orensanz 1991); Argentina, Mar del Plata ( Palacios et al. 2005). Pacific Ocean—Gulf of Nicoya, Costa Rica ( Dean 1998).

Remarks. Hermundura tricuspis resembles H. fauveli but differs in having eyespots and notopodial spines from seventh chaetiger, while H. fauveli has notopodial spines from the ninth chaetiger. Furthermore, H. fauveli has the first five chaetigers with segmentation very marked ( Pettibone 1966); this is absent in specimens examined from this study. All diagnostic characters observed in the specimens of this study confer to the description of the neotypes by Salazar-Vallejo (1990). Additionally, no morphological variation was observed in the material examined.

Figures

FIGURE 9. Hermundura tricuspis. A. SEM, anterior end, dorsal view. B. SEM, parapodium, dorsolateral view. C. SEM, posterior end, dorsolateral view. D. SEM, neuropodium, ventrolateral view.Abbreviations. Chaet 1: first chaetiger, Nec: neurochaeta, Noc: notochaetae, Pp: palp, Pt: prostomium, Py: pygidium, Pyc: pygidial cirrus. Scale bars: 100 µm (A, C), 200 µm (B, D).