Nereis anoculepitoka, Bergamo, Carrerette, Shimabukuro, Santos & Sumida, 2023
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publication ID |
https://doi.org/ 10.1093/zoolinnean/zlad122 |
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DOI |
https://doi.org/10.5281/zenodo.11355970 |
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persistent identifier |
https://treatment.plazi.org/id/642787B7-FF97-FF89-48A9-6055FE971860 |
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treatment provided by |
Plazi |
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scientific name |
Nereis anoculepitoka |
| status |
sp. nov. |
Nereis anoculepitoka View in CoL sp.nov.
( Figs 3–8 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 View Figure 8 )
urn:lsid:zoobank.org:act:1DFCB3FC-DDAC-4FC0-9D8E-4A0E81F58B85
Type series: Holotype and paratypes 1–20 coll. 21 May 2015, continental margin off Espirito Santo state, Espírito Santo basin, Brazil, 21°27ʹ0.5″S, 39°53ʹ47.4″W, 1491 m depth; holotype ( MZUSP5344 View Materials ), incomplete, 29 chaetigers (cht), 32.54 mm long, 3.6 mm wide; paratype 1 (ColBIO-DS 00179), incomplete, 23 cht, 18.5 mm long, 2.7 mm wide; paratype 2 (MZUSP5345), incomplete, 33 cht, 20 mm long, 2.6 mm wide; paratype 3 (MZUSP5346) female epitoke, incomplete, anterior end damaged, 20 cht, 11.2 mm long, 1.7 mm wide; paratype 4 (ColBIO-DS 00180), incomplete, 19 cht, 8.5 mm long, 1.5 mm wide; paratype 5 (ColBIO-DS 00181), incomplete, 23 cht, 6.2 mm long, 0.9 mm wide; paratype 6 (ColBIO-DS 00182), female epitoke, complete, 74 cht, 54.82 mm long, 3.3 mm wide; paratype 7 (MZUSP5347), incomplete, 17 cht, 21.8 mm long, 3.5 mm wide; paratype 8 (MZUSP5348), incomplete, 50 cht, 35.1 mm long, 4.8 mm wide; paratype 9 (ColBIO-DS 00183), incomplete, 30 cht, 28 mm long, 3.6 mm wide; paratype 10 (MZUSP5349), incomplete, 13 cht, 5.8 mm long, 1.7 mm wide; paratype 11 (MZUSP5350), female epitoke, incomplete, 40 cht, 32 mm long, 3.5 mm wide; paratype 12 (ColBIO-DS 00184) male epitoke, complete, 59 cht, 20.9 mm long, 1.5 mm wide ; paratype 13 (ColBIO-DS 00185), incomplete, 21 cht, 16.25 mm long, 2 mm wide ; paratype 14 (MZUSP5351), incomplete and damaged, 42 cht, 33.09 mm long, 3 mm wide ; paratype 15 (MZUSP5352), male epitoke, complete, 63 cht, 40.13 mm long, 2.7 mm wide ; paratype 16 (ColBIO-DS 00186), incomplete, 38 cht, 23.9 mm long, 2 mm wide ; paratype 17 (ColBIO-DS 00187), incomplete, 22 cht, 11.1 mm long, 1.4 mm wide ; paratype 18 (ColBIO-DS 00188), incomplete, 60 cht, 54.34 mm long, 3.5 mm wide ; paratype 19 (MZUSP5353), incomplete, 15 cht, 13.69 mm long, 2.5 mm wide ; paratype 20 (MZUSP5354), mounted in SEM stub, incomplete, 24 cht, 7.23 mm long, 1 mm wide .
Description: Holotype atokous, with cylindrical body, slightly flattened dorsoventrally from mid-body.
Prostomium slightly wider than long, with one pair of frontal antennae and one pair of biarticulated palps ( Figs 3A, B View Figure 3 , 5A View Figure 5 ). Antennae conical to subulate, slightly shorter or with the same length as palps, pointed laterally ( Figs 3A, B View Figure 3 , 5A View Figure 5 ). Palpostyles cylindrical to rounded and palpophores cylindrical, slightly flattened dorsoventrally ( Figs 3B, C View Figure 3 , 5A View Figure 5 ). Eyes absent ( Figs 3A, C, E View Figure 3 , 5A View Figure 5 ). Peristomium slightly shorter than prostomium and twice the length of chaetiger 1 ( Fig. 3A, C, E View Figure 3 ), with four pairs of tentacular cirri; posterodorsal cirri reaching posterior part of chaetiger 5 ( Fig. 3C, E View Figure 3 ).
Pharynx with numerous black, small and easily detachable paragnaths on both rings, with the following arrangement: area I = 2–4 in a vertical row; area II = 10–20 on each side, mainly in two or three rows; area III = 11–34, in three or four rows in ellipse; area IV = 18–35 on each side, in four or five rows in triangle; area V = 0; area VI = 2–7 on each side, mostly in two transverse rows; areas VII–VIII = ~130, mainly concentrated in the grooves.
First two parapodia uniramous ( Fig. 4A View Figure 4 ), all subsequent parapodia biramous ( Figs 4B, C View Figure 4 , 5D View Figure 5 ).Uniramous parapodia with dorsal cirri two-fifths longer than dorsal ligule. Ventral ligule slightly longer than dorsal ligule. Both ligules rounded to digitiform, with same width; ventral ligule half longer than acicular lobe. Ventral cirri slightly longer than ventral ligule ( Fig. 4A View Figure 4 ).
Biramous parapodia with dorsal cirri one-fifth longer than notopodial ligule on anterior parapodia ( Fig. 4B View Figure 4 ) and two-fifths longer on posterior parapodia ( Figs 4C View Figure 4 , 5D View Figure 5 ). Notopodial ligule slightly longer than notopodial lobe. Both notopodial ligule and lobe tapering. Notopodial lobe three times the length of neuropodial lobe on anterior parapodia ( Fig. 4B View Figure 4 ) and four-fifths longer on posterior parapodia ( Figs 4C View Figure 4 , 5D View Figure 5 ), with same width; neuropodial lobe sub-conical. Neuropodial ligule almost twice the length of neuropodial lobe on anterior parapodia ( Fig. 4B View Figure 4 ) and one-fifth longer on posterior parapodia ( Figs 4C View Figure 4 , 5D View Figure 5 ). Ventral cirri one-fifth shorter than neuropodial ligule.
Uniramous parapodia with supra-acicular chaetae ( Fig. 4D View Figure 4 ) homogomph spinigers ( Figs 4G View Figure 4 , 5C View Figure 5 ) and heterogomph falcigers ( Figs 4I View Figure 4 , 5B View Figure 5 ); sub-acicular chaetae ( Fig. 4D View Figure 4 ) homogomph spinigers and both heterogomph spinigers ( Figs 4H View Figure 4 , 5F View Figure 5 ) and falcigers. Biramous parapodia with notochaetae ( Fig. 4E View Figure 4 ) homogomph spinigers in all chaetigers (more numerous at anterior ones) and homogomph falcigers ( Figs 4J View Figure 4 , 5E View Figure 5 ) in posterior chaetigers, maximum of three per parapodia. Blades of homogomph falcigers with round tips totally serrated and easily detached.
Supra-acicular neurochaetae ( Fig. 4F View Figure 4 ) homogomph spinigers and heterogomph falcigers. Sub-acicular neurochaetae ( Fig. 4F View Figure 4 ) as homogomph and heterogomph spinigers, and heterogomph falcigers. Blades of homogomph spinigers twice the length of heterogomph ones. Heterogomph falcigers serrated with ≥ 20 teeth and slightly curved tips.
Pygidium with one pair of pygidial cirri, as long as the last eight chaetigers ( Fig. 3D View Figure 3 ).
Variation: Nereis anoculepitoka male and female epitokes are described in the following Epitoky section. Of 21 specimens found in this study, epitokes encompass 24%, of which 60% are females and 40% males. Live atokous specimens were white to yellowish pale in colour, with a dorsal blood vessel and other smaller reddish vessels visible dorsally by transparency ( Fig. 6A View Figure 6 ). Intraspecific variations include uniramous parapodia with ligules digitiform or more rounded, biramous parapodia with dorsal cirri with the same length as the notopodial ligule, notopodial ligule six-fifths the length of notopodial lobe on anterior parapodia, and specimens with randomly distributed pigment spots slightly more restricted to parapodia.
Epitoky: Live male epitokes with anterior body portion similar in colour to atoke and medial to posterior body portion red ( Fig. 6B, C View Figure 6 ). Epitokes also lack eyes, but with parapodial modification, differing in atokes ( Fig. 7A View Figure 7 ), male epitokes ( Fig. 7B View Figure 7 ) and female epitokes ( Fig. 7C View Figure 7 ).
Male epitokes with uniramous parapodia similar to atoke ones ( Fig. 8A View Figure 8 ). Biramous anterior parapodia with elongated noto- and neuropodium ( Fig. 8B View Figure 8 ). Notopodial lobe with an extended dorsal contact and nearly rectangular ( Fig. 8B View Figure 8 , arrow). Neuropodial lobe with an extended lower neuropodial crescent ( Fig. 8G View Figure 8 ). Dorsal cirri slender, almost twice the length of notopodial ligule. Notopodial ligule tapering, with the same size as the notopodial lobe and one-fifth shorter considering the dorsal contact.Notopodial lobe triangular,two-fifths shorter than neuropodial lobe and half the length of the lower neuropodial crescent. Considering the dorsal contact length, notopodial lobe one-fifth shorter than neuropodial lobe and one-third shorter than lower neuropodial crescent. Lower neuropodial crescent tapering. Neuropodial lobe triangular and the same length as the neuropodial ligule. Neuropodial ligule tapering, with rounded tips. Ventral cirri slender, twice the length of neuropodial ligule.
Biramous modified parapodia with notopodia still elongated and neuropodia less elongated than in anterior parapodia ( Fig. 8C View Figure 8 ). Notopodia with elongated, fan-like area before the dorsal cirri and without extended dorsal contact. Neuropodia without lower neuropodial crescent, but with a large subpodial ligule and fan-like postchaetal lobes. Dorsal cirri slender, with crenulations (Fig. 7B), 1.4× longer than notopodial ligule. Notopodial ligule tapered to subconical, slightly shorter than notopodial lobe. Notopodial lobe of the same shape as notopodial ligule, slightly wider. Notopodial lobe 1.3× longer than neuropodial lobe and slightly longer than postchaetal lobe. Neuropodial lobe subconical, 1.3× longer than subpodial ligule, and postchaetal lobe almost twice the length of subpodial lobe. Subpodial lobe twice the length of neuropodial ligule, both digitiform. Ventral cirri slender, three times the length of neuropodial ligule.
Biramous parapodia of anterior chaetigers of male epitokes with notochaetae heterogomph falcigers, homogomph spinigers and modified homogomph spiniger with wider paddle-like blades ( Fig. 8L View Figure 8 ). Supracicular neurochaetae absent ( Fig. 8G View Figure 8 ); subacicular neurochaetae only epitokous homogomph spiniger. Biramous parapodia of posterior chaetigers with only epitokous homogomph spinigers in both noto- and neuropodium.
Female epitokes with uniramous parapodia similar to atoke ones ( Fig. 8D View Figure 8 ). Biramous anterior parapodia not modified ( Fig. 8E View Figure 8 ), but with different chaetae conformation.Biramous posterior modified parapodia of female epitokes with slightly prolonged neuropodia, with a subpodial ligule and a fan-like postchaetal lobe, wider than in male ( Fig. 8F View Figure 8 ). Dorsal cirri slender, 1.4× longer than notopodial ligule. Notopodial ligule digitiform to tapered, one-fifth shorter than notopodial lobe. Notopodial lobe subconicaltotriangular, withthesamelengthasneuropodiallobe and one-fifth shorter than fan-like postchaetal lobe. Neuropodial lobe subconical, with same length as subpodial ligule and 1.4× longer than postchaetal lobe. Subpodial lobe digitiform, almost three times the length of neuropodial ligule. Neuropodial ligule digitiform. Ventral cirri slender, almost three times the length of neuropodial ligule.
Biramous parapodia of anterior non-modified chaetigers of female epitokes with similar chaetae to atokes, with the addition of supracicular neurochaetae heterogomph falcigers with short yellow hoods at blade tips ( Fig. 8J View Figure 8 ). Biramous modified parapodia with supracicular notochaetae homogomph spinigers ( Fig. 8L View Figure 8 ), post notopodial lobe, with only tips visible ( Fig. 8F View Figure 8 , arrow). Supracicular neurochaetae ( Fig. 8H View Figure 8 ) heterogomph spinigers, modified homogomph spinigers, with blades covered by orange hoods ( Fig. 8K View Figure 8 ), modified heterogomph falcigers, with blades covered by thick orange hoods ( Fig. 8I View Figure 8 ) and modified heterogomph falcigers with yellow hoods, same as present in anterior chaetigers. Subacicular neurochaetae ( Fig. 8H View Figure 8 ) only modified homogomph spinigers and modified heterogomph falcigers, with thicker and yellowish to orange blades. Both yellow and orange colours of the hoods are probably related to different stages of sclerotization, and the colour may vary.
Remarks: Nereis anoculepitoka is an eyeless species represented by large specimens, inhabitants of organic falls, such as whale bones and wood blocks. Although the absence of a character is usually weak evidence for taxonomic accounts, the lack of an important sensory structure, such as the eyes, which is present in almost all Errantia polychaetes, is commonly used as a diagnostic character. Therefore, Nereis anoculepitoka differs from the majority of Nereis species by the absence of eyes, especially from species inhabiting shallow waters that present welldeveloped eyes. Another character to support the differentiation of Nereis anoculepitoka from shallow-water Nereis species is the morphology of the paragnaths, which are all small and fragile, easily detachable from the pharynx.
The absence of eyes is a character more common in Nereis species from deep waters, which Nereis anoculepitoka resembles. According to Blake (1985) and Blake and Hilbig (1990), the deep-sea Nereis group also can be characterized by some degree of elongation in the posterior parapodia (usually in one of the lobes). This group is composed by the following species: Nereis abyssa Imajima, 2009 , Nereis angelensis Fauchald, 1972 , Nereis anoculis Hartman, 1960 , Nereis anoculopsis Fauchald, 1972 , Nereis fossae Fauchald, 1972 , Nereis ligulata Hilbig, 1992 , Nereis pisciesae Blake % Hilbig, 1990, Nereis profundi Kirkegaard, 1956 and Nereis sandersi Blake, 1985 . The majority of representatives from the deep-sea group share the absence of eyes with Nereis anoculepitoka , with the exception of Nereis angelensis and Nereis fossae . Still, Nereis anoculepitoka lacks elongation of posterior parapodia, therefore differing from all other species of this deep-sea group. Beside elongation of the parapodia, Nereis anoculepitoka differs from other deep-sea Nereis species by other characters, such as posterodorsal tentacular cirri length, morphology of the blade of homogomph falcigers and paragnath formula ( Tables 3 View Table 3 and 4 View Table 4 ).
There are other species of Nereis inhabiting the deep sea that were not included in the group, cited by Blake (1985) and Blake and Hilbig (1990), although most of them also present some degree of parapodia elongation. These species are as follows: Nereis caymanensis Fauchald, 1977b , Nereis eugeniae ( Kinberg, 1865) , Nereis longisetis McIntosh, 1885 , Nereis rava Ehlers, 1868 , Nereis surugaense Imajima, 1972 , Nereis tricirrata Lin et al., 2022 and Nereis zonata Malmgren, 1867 . Apart from Nereis eugeniae and Nereis tricirrata , all other species present eyes and therefore differ from Nereis anoculepitoka . Other important taxonomic features that characterize the species and distinguish them from Nereis anoculepitoka are reported in Tables 3 View Table 3 and 4 View Table 4 .
Nereis eugeniae was described by Kinberg (1865) from the Strait of Magellan, Chile, originally in the genus Nicon , then was transferred to Nereis by Ehlers (1897) and revised by Monro (1930), but the descriptions vary considerably among these studies. Originally, the species was described as presenting eyes, but covered by a cuticle in atokous specimens, yet some specimens are described as eyeless, with variation probably related to fixation and transparency of the covering cuticle. Additionally, the species lacks elongation of the parapodia, and in the combination of these characters it resembles Nereis anoculepitoka . However, Nereis anoculepitoka also differs from Nereis eugeniae in depth and habitat of occurrence ( Table 3 View Table 3 ). The specimens of Nereis eugeniae are much longer, with the holotype measuring 74 mm and specimens measuring ≤ 170 mm, whereas specimens of Nereis anoculepitoka present from 20 to 54 mm. The paragnath formula is also different between these two species, as can be seen in Table 4 View Table 4 .
Nereis anoculepitoka resembles Nereis tricirrata , an eyeless species from the deep waters of the South China Sea, inhabiting soft sediments, but in an area presenting cold seeps. As seen in Table 3 View Table 3 , both species present similar sizes and slightly different length of the posterodorsal tentacular cirri, but the homogomph falcigers differ in relationship to the number and size of the teeth (Table 3). The number of jaw teeth and the number and distribution of the paragnaths is also different between both species ( Table 4 View Table 4 ), with the pharynx of Nereis tricirrata lacking paragnaths in areas I, III and V and presenting fewer paragnaths in the remaining areas.
Etymology: The epithet ‘anoculepitoka’ is formed by union of the words anoculum, a Latin word for the absence of eyes, and the noun epitoka, referring to the reproductive strategy of epitoky, because this is the first reported species of Nereis presenting epitokes without eyes.
Occurrence: Reported in whale bones and wood blocks in the continental slope at 1491 m depth, in the Espirito Santo Basin, Southwest Atlantic.
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