Diagnosis.

Mid- to small-sized exogonines, body wall smooth, without papillae. Palps fused along most of their length by dorsal membrane, usually leaving short distal notch. Prostomium with three antennae, four eyes and sometimes two anterior eyespots. Two pairs of peristomial cirri. Dorsal cirri on chaetiger 2 present or absent. Antennae, peristomial and dorsal cirri throughout spindle-shaped to elongate, tapered. Ventral cirri digitiform, usually shorter than parapodial lobes. Parapodial glands absent. Compound chaetae as heterogomph falcigers, blades sub-bidentate to bidentate. Dorsal and ventral simple chaetae present. Aciculae usually subdistally sinuous and inflated, with long, filiform tip. Pharynx wide, with opening smooth or with marginal papillae in a few species; tooth rhomboidal to ovate, usually slightly away from anterior margin of pharynx. Proventricle relatively large, usually about as long as pharynx, with numerous slender muscle cell rows. Reproduction by epigamy, with dorsal brooding of eggs attached by capillary chaetae [17].

Remarks.

Some species in the key were not examined for the present article, characters based on the literature: S. breviarticulata, S. heterocirra and S. longiarticulata from [20]; S. limbata, S. clavata and S. euritmica from [7] and [20].

Salvatoria longiarticulata (Nogueira, San Martín & Amaral, 2001) [21] comb. nov.

Table 1

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Table 1. Taxonomic and biogeographic data on the species of Salvatoria recorded for Brazilian waters, with reference to voucher material.

https://doi.org/10.1371/journal.pone.0250472.t001

Grubeosyllis longiarticulata Nogueira, San Martín & Amaral, 2001: 1788–1791, Fig 5 [21].

Material examined.

Project BioPol-NE—State of Paraíba, João Pessoa, Praia do Cabo Branco (7°08’S 34°47’W), intertidal: 20 specimens, coll. 02 February 2010.

Remarks.

The material analysed herein matches the original description provided by [21] from São Paulo, except for details on the teeth of falciger blades and a slight variation on the number of muscle cells rows in the proventricle. Specimens from Paraíba have both teeth shorter and directed forwards, and proventricle with ca. 17 rows of muscle cells, while material from São Paulo has falciger blades with longer teeth directed slightly upwards, and 24 rows of proventricular muscle cells.

Type locality.

Ilha dos Alcatrazes, Santos, São Paulo, Brazil (SW Atlantic).

Distribution.

Southwestern Atlantic, Brazil (states of Paraíba and São Paulo). First record for this species in Northeastern Brazil and also after original description (Fig 1A–1C).

Salvatoria cf. nitidula (Verrill, 1900) [18] comb. nov.

Fig 2, Table 1.

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Fig 2. Salvatoria cf. nitidula.

A, anterior body, dorsal view; B, falcigers, anterior and midbody parapodia; C, falcigers, posterior parapodium; D, dorsal simple chaeta; E, ventral simple chaeta; F, G, aciculae, anterior and posterior body, respectively. Scale bars: A, 0.11 mm; B–G, 10 μm.

https://doi.org/10.1371/journal.pone.0250472.g002

Salvatoria nitidula. Fukuda, 2010 [30]: 183–187, Fig 54.

Material examined.

Project ‘BIOTA’—State of São Paulo, Ubatuba, Praia de Picinguaba (23°22’31’’S 44°50’21’’W), on rocky shore: 2 specimens (MZUSP 4266), coll. 9 May 2001; 8 specimens (MZUSP 4267), coll. 10 May 2001; 1 specimen, coll. 11 October 2001; 11 specimens (MZUSP 4268), coll. 17 October 2001; on Sargassum sp.: 124 specimens (MZUSP 4269), coll. 18 October 2001; 2 specimens (date unknow); on phytal: 1 specimen (MZUSP 4270), coll. 8 October 2001. Caraguatatuba–Praia Martim de Sá (23°37’34’’S 45°22’31’’W), on rocky shore: 9 specimens (MZUSP 4264), coll. 19 September 2001; 3 specimens (MZUSP 4265), coll.21 September 2001; 2 specimens (date unknow); on Sargassum sp.: 1 specimen, coll. 27 September 2001; 2 specimens, coll. 16 March 2001. São Sebastião–Praia da Baleia (23°46’48’’S 45°39’51’’W), on rocky shore: 2 specimens (MZUSP 4263), coll. 13 December 2001; Praia de Toque-Toque Grande (23°50’12’’S 45°30’40’’W), on rocky shore: 1 specimen, coll. 10 April 2001. Project ‘BioPol-SP’—Ubatuba–Praia do Perequê-Mirim (23°29’20’’S 45°06’25’’W): 2 specimens, coll. 5 January 2003. São Sebastião–Praia do Araçá (23°48’54’’S 45°24’24’’W): 1 specimen, coll. 17 April 2003; 3 specimens, coll. 15 July 2003; 6 specimens, coll. 25 September 2003; 4 specimens (MZUSP 4262), coll. 20 July 2005. Santos–Ilha das Palmas (24°00’34’’S 46°19’25’’W): 2 specimens, coll. 5 October 2005.

Description.

Small-sized body; longest specimen examined 2.37 mm long and 0.18 mm wide, with 31 chaetigers (Table 1). Palps subtriangular, almost totally fused, leaving a distal notch (Fig 2A). Prostomium subrectangular, as long as palps (Fig 2A), with two pairs of eyes in open trapezoidal arrangement (Fig 2A), anterior eyespots usually present; antennae spindle-shaped to slightly subulated, median antenna inserted between eyes, slightly longer than prostomium and palps together, lateral antennae slightly shorter than median antenna, inserted anteriorly on prostomium, slightly away from margin, reaching beyond tips of palps (Fig 2A). Peristomium as long as anterior body chaetigers; peristomial cirri with same shape as antennae; dorsal peristomial cirri slightly shorter than median antenna; ventral peristomial cirri about half length of dorsal ones (Fig 2A). Dorsal cirri with same shape as antennae; dorsal cirri of chaetiger 1 slightly longer than median antenna, subsequent dorsal cirri short, similar in length to lateral antennae (Fig 2A). Ventral cirri digitiform, inserted at bases of parapodial lobes. Parapodial lobes smooth, distally bilobate. Anterior and midbody parapodia with 6 falcigers each throughout. Shafts of falcigers slightly spinulated, subdistally inflated and distally tapered (Fig 2B and 2C). Blades of falcigers spinulated, bidentate, distal tooth slightly larger than subdistal one on anterior and midbody parapodia (Fig 2B), teeth about same size on posterior parapodia (Fig 2C); blades of falcigers with dorso-ventral gradation in length (Fig 2B and 2C), 30–10 μm long on anterior and midbody parapodia, 25–10 μm long on posterior parapodia (Table 1). Dorsal simple chaetae present from chaetiger 1, slightly thinner than shafts of falcigers of same fascicle, with short subdistal spines, distally bidentate, distal tooth slightly longer (Fig 2D); ventral simple chaetae only present on posteriormost parapodia, sigmoid, smooth, bidentate, teeth similar in size (Fig 2E). Anterior parapodia with two aciculae each, one of which thin, straight, distally tapered, with acute tip sometimes protruding from parapodial lobe, other acicula subdistally inflated and slightly twisted, with acute tip (Fig 2F); single acicula per parapodium from midbody, subdistally inflated and slightly twisted, with long and thin, needle-like tip (Fig 2G). Semicircular pygidium with paired anal cirri, similar in shape to dorsal cirri. Pharynx through 3.5–4 segments (Fig 2A); tooth relatively long, rhomboidal to ovate, slightly away from anterior margin of pharynx; proventricle extending for 3–4.5 chaetigers, with 16–20 rows of muscle cells (Table 1).

Remarks.

The species Salvatoria nitidula was described from Bermuda, in the North Atlantic American coast, so the presence of animals belonging to this species along the Brazilian coast would not be totally surprising. However, the original description of the species is very brief and does not mention important characters, such as details of pharyngeal structures and compound chaetae. San Martín [19] reported S. nitidula (as Grubeosyllis nitidula), describing animals similar to those herein analysed, from Cuba, Bermuda, and the Gulf of Mexico, however, with considerable doubts due to the lack of information in the original description. One noticeable difference is related to the length of dorsal and ventral peristomial cirri: about this character, in the original description Verrill [18] describes “Tentacular cirri two on each side, of about the same length”, while both our specimens and those analysed by [19] show ventral peristomial cirri with about half length of dorsal ones. Nonetheless, herein we follow [19] in also assigning this species with caveats, until we can examine the syntypes or a redescription based on Bermudan specimens is provided.

The Mediterranean Salvatoria vieitezi (San Martín, 1984) [16] shares with S. cf. nitidula the size of the proventricle, the spinulation pattern of falciger blades and the morphology of aciculae, dorsal and ventral simple chaetae. However, S. vieitezi differs from S. cf. nitidula by having only one acicula per parapodium throughout, subdistally curved, with acute tip; blades of dorsalmost falcigers up to 20 μm long, with long spines directed upwards, more conspicuous at mid-length of blades; intermediate and ventralmost falcigers with blades with straight spines slightly shorter than in S. cf. nitidula, 13 μm and 10 μm long, respectively. S. vieitezi can be also differentiated by its pigmentation pattern, with dark-red transverse stripes on the dorsum of each segment, more evident in live animals, but often preserved in fixed material.

Another species similar to Salvatoria cf. nitidula by sharing the overall morphology of antennae and peristomial and dorsal cirri throughout is Salvatoria heterocirra (Rioja, 1941) [28], described from the Pacific coast of Mexico. However, S. heterocirra differs from S. cf. nitidula by having only one acicula per parapodium throughout, distally rounded, hollow; falciger blades with short spinulation, distally bidentate, with subdistal tooth of even sizes throughout, without variation; and proventricle slightly smaller, through 2–2.5 segments [28]. On the other hand, S. cf. nitidula has two aciculae per parapodium on anterior body, falciger blades with subdistal tooth varying in size along the body and proventricle extending through ~3–4.5 segments.

Salvatoria heterocirra was identified among Brazilian material by [24], based on body size, number of segments and of eyes, shape of palps, antennae and peristomial cirri, length of dorsal cirri of the chaetiger 1 and length and number of muscle cell rows of the proventricle; on the occasion, the author considered the pharyngeal size as the only difference between his specimens and the original description of S. heterocirra. Nonetheless, the set of characters used by [24] to justify this identification is shared by several species within the genus. Moreover, comparing the description presented by [24] with the original description of the species [28], a discrepancy in the shape of falciger blades was noticed. Although this character was not described in detail, the drawings by [28] illustrate the falciger blades of S. heterocirra as having small size variation, short spinulation and approximately equal sized teeth. In addition, [28] described the species as having only 1 acicula per parapodium, differing from [24], which follows the pattern described herein for S. cf. nitidula. [24] informs that type material of S. heterocirra was not analysed for that study, but also makes no reference to these differences in his discussion. S. heterocirra sensu [24] was also later identified in the Brazilian coast, with restrictions, by [20] (as Grubeosyllis cf. heterocirra), perhaps in both cases being the species identified herein as S. cf. nitidula. To proper address this question and solve this issue it is necessary to reanalyses the material studied by [20, 24], but this has not been done for the present paper.

Distribution.

South Atlantic, Brazil (State of São Paulo) (Fig 1A and 1C). Current distribution of S. nitidula—Atlantic Ocean: Bermuda (type locality), Caribbean Sea, Gulf of Mexico, Cuba [19].

Salvatoria nitiduloides n. sp.

urn:lsid:zoobank.org:act:781214DA-DD13-42BE-9FE2-09113289A79F

Figs 3–5, Table 1.

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Fig 3. Salvatoria nitiduloides n. sp., SEM.

(A, B). Anterior body, dorsal and ventral views, respectively; (C). Close up view of the anterior end, dorsal view; (D). Detail of ciliated nuchal organ; (E). Parapodia 2–4, ventral view; (F). Posterior parapodia, ventro-lateral view. Arrows pointing to ciliated nuchal organs; dc–dorsal cirrus; pd–parapodial lobe; pd2, pd3, pd4 –parapodial lobes of chaetigers 2, 3 and 4 respectively; pe–peristomium; pr–prostomium; vc–ventral cirrus. Scale bars: A–B, 50 μm; C, E–F, 20 μm; D, 5 μm.

https://doi.org/10.1371/journal.pone.0250472.g003

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Fig 4. Salvatoria nitiduloides n. sp., SEM.

(A, B). Dorsalmost falcigers, anterior parapodium; (C). Ventralmost falcigers, parapodium 2; (D). Ventralmost falciger, midbody parapodium; (E). Ventralmost falcigers, posterior parapodium; (F–G). Dorsal simple chaetae, posterior parapodium; (H). Ventral simple chaeta, posterior parapodium; (I). Posterior parapodia, frontal view. pd–parapodial lobe; vc–ventral cirrus; dc–scar of dorsal cirrus insertion (cirrus absent). Scale bars: A–B, D–F, 5 μm; C, G–I, 2 μm.

https://doi.org/10.1371/journal.pone.0250472.g004

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Fig 5. Salvatoria nitiduloides n. sp.

(A, B). Falcigers, anterior and posterior parapodia, respectively; (C). Dorsal simple chaeta, posterior parapodium; (D). Ventral simple chaeta posterior parapodium; E, F, aciculae, anterior and posterior parapodia, respectively. Scale bar: 10 μm.

https://doi.org/10.1371/journal.pone.0250472.g005

Salvatoria cf. nitidula. Paresque, 2014 [31]: 310–313, Figs 3–6.

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Fig 6. Photographs of the holotypes.

(A). Salvatoria marielleae n. sp., entire body, dorsal view; (B). Salvatoria ypsiloides n. sp. brooding eggs dorsally, entire body, dorsal view. Scale bars: A, 0.5 mm; B, 0.3 mm.

https://doi.org/10.1371/journal.pone.0250472.g006

Type series.

Holotype: Project ‘BioPol-NE’—State of Pernambuco, Ilha de Itamaracá, recifes de Itamaracá (07°43.9’S 34°49.2’W), 1 m deep: (MZUSP 4824), coll. 15 December 2012. Paratypes:—State of Paraíba, Praia do Coqueirinho (07°18’S 34°47’W), Paratype 1 (MZUSP 4825), coll. 28 August 2011; Paratype 2 (MZUSP 4826), Paratype 3 (MZUSP 4827), coll. 01 September 2011.—State of Pernambuco, Tamandaré, Praia dos Carneiros (08°42.8’S 35°4.9’W), intertidal: Paratype 4 (MZUSP 4828), coll. 22 June 2013.

Material examined.

Project ‘BioPol-NE’—State of Paraíba, Mataraca, Barra de Camaratuba (06°36’S 34°57’W), intertidal: 15 specimens, coll. 12 August 2010; Baía da Traição, Praia do Farol (06°41’S 34°55’W), intertidal: 6 specimens, coll. 09 August 2010; Rio Tinto, Barra de Mamanguape (06°45’S 34°55’W), intertidal: 24 specimens, coll. 11 August 2010; Cabedelo, Píer de Cabedelo (06°58’S 34°50’W), intertidal: 2 specimens, coll. 12 February 2009; João Pessoa, Praia do Cabo Branco (07°08’S 34°47’W), intertidal: 1 specimen, coll. 09 February 2009; 23 specimens, coll. 02 February 2010; Recife do Picãozinho (07°4.2’S 34°49.3’W), 1 m deep: 2 specimens, coll. 15 September 2012; Conde, Praia de Jacumã (07°14’S 34°47’W), intertidal: 3 specimens, coll. 29 January 2010; Praia de Tabatinga (07°19’S 34°47’W), intertidal: 15 specimens; coll. 17 September 2012; Praia do Coqueirinho (07°18’S 34°47’W), 12 specimens, coll. 28 August 2011; Praia de Tambaba (07°21’S 34°47’W), 1 specimen, coll. 30 August 2011. State of Pernambuco, Goiana, Pontas de Pedra (07°37’S 34°48’W), 4 specimens, coll. 13 December 2012; Ilha de Itamaracá, recifes de Itamaracá (07°43.9’S 34°49.2’W), 1 m deep: 13 specimens, coll. 15 December 2012; Ponta do Jaguaribe (07°44’S 34°49’W), intertidal: 5 specimens, coll. 11 December 2012; Tamandaré, Praia dos Carneiros (08°42.8’S 35°4.9’W), intertidal: 1 specimen, coll. 22 July 2013; Sirinhaém, Barra do Sirinhaém (08°36.7’S 35°2.4’W): 8 specimens, coll. 23 July 2013.

Description.

Small-sized body; longest specimen examined 2.2 mm long, 0.20 mm wide, with 29 chaetigers. Palps triangular, distally rounded, almost totally fused, leaving a distal notch (Fig 3A and 3C). Prostomium rectangular, shorter than palps (Fig 3A and 3C), with two pairs of eyes in open trapezoidal arrangement, anterior eyespots usually present; antennae spindle-shaped to slightly subulated, median antenna inserted between eyes, longer than prostomium and palps together, lateral antennae inserted on anterior margin of prostomium, reaching beyond tips of palps (Fig 3A). Ciliated nuchal organs between prostomium and peristomium (Fig 3A, 3C and 3D). Peristomium as long as anterior body chaetigers; peristomial cirri with same shape as antennae; dorsal peristomial cirri as long as median antenna; ventral peristomial cirri about half length of dorsal ones (Fig 3A and 3B). Dorsal cirri of chaetiger 1 slightly longer than median antenna, dorsal cirri of chaetigers 2 and 3 shorter (Fig 3A), dorsal cirri of chaetigers 4 and 5 as long as dorsal cirri of chaetiger 1 or slightly shorter (Fig 3A); following dorsal cirri irregularly alternating long, as long as body width at corresponding chaetiger or slightly shorter, and short, shorter than body width at corresponding chaetiger. Ventral cirri digitiform, inserted at bases of parapodial lobes, not reaching their tips (Figs 3B, 3E, 3F and 4I). Parapodial lobes, smooth, distally bilobate (Fig 3A and 3E). Anterior and midbody parapodia with 7–10 falcigers each; posterior parapodia with 3–4 each. Shafts of falcigers slightly spinulated and inflated subdistally, tapering distally (Figs 4A–4E, 5A and 5B). Blades of falcigers spinulated, bidentate, distal tooth larger than subdistal one throughout (Figs 4A–4E, 5A and 5B); within each fascicle, blades of dorsalmost falcigers with longer spines than remaining falcigers (Figs 4A–4E, 5A and 5B); blades of falcigers with dorso-ventral gradation in length, 22–8 μm, 25–12 μm and 24–11 μm long on anterior, mid- and posterior body parapodia, respectively. Dorsal simple chaetae present from anterior parapodia, slightly thinner than shafts of falcigers of same fascicle, with short subdistal spines, distally bidentate, teeth of similar size, progressively more triangular posteriorwards (Figs 4F, 4G and 5C); ventral simple chaetae only present in posteriormost parapodia, sigmoid, as thick as shafts of falcigers of same fascicle, with short subdistal spines, distally bidentate, distal tooth larger (Figs 4H and 5D). Anterior parapodia with two aciculae each, one of which straight, with acute tip, another subdistally inflated and twisted, with long, thin, needle-like tip (Fig 5E); from midbody onwards, single acicula per parapodium, of latter type, stouter posteriorly (Fig 5F). Semicircular pygidium with paired anal cirri, similar in shape to posterior body dorsal cirri, but longer. Pharynx through 3–4 segments; tooth relatively long, rhomboidal to ovate, slightly away from anterior margin of pharynx; proventricle extending for 2–3 chaetigers, with 19–22 rows of muscle cells.

Reproduction.

Some specimens were found brooding eggs dorsally, from around chaetigers 8–20, with 1 or 2 eggs per chaetiger.

Remarks.

Members of Salvatoria nitiduloides n. sp. are characterized by the length pattern of anterior body dorsal cirri. These animals are similar to S. clavata from the Iberian Peninsula, according to the redescription provided by [7], in overall body shape and by the falciger blades having distal tooth larger than the subdistal one throughout. San Martín [7] noticed different morphotypes of S. clavata in his material and considered those more than just intraspecific variation, suggesting the occurrence of a species complex. Salvatoria clavata is characterized by having parapodial lobes papillated, with at least three small papillae; blades of falcigers on anterior body with dorso-ventral gradation in length, 19–12 μm long, dorso-ventral gradation in length absent on posterior body, with blades 11–12 μm long; blades of falcigers with short, straight spines on anterior body and with stouter, short, straight spines on posterior body; dorsal simple chaetae bidentate, with short subdistal tooth; and single acicula per parapodium, acuminate [7]. Specimens of S. nitiduloides n. sp. described herein differ from the description of S. clavata from the Iberian Peninsula by having smooth parapodial lobes, without papillae; longer blades of falcigers, with dorso-ventral gradation in length throughout, 22–8 μm, 25–12 μm and 24–11 μm long on anterior, mid- and posterior body parapodia, respectively; longer spinulation on the cutting edges of the blades of dorsalmost falcigers throughout; dorsal simple chaetae with both teeth triangular, similar in length; and anterior parapodia with two aciculae with acute tip each, one of which straight, another subdistally inflated and twisted.

Salvatoria nitiduloides n. sp. is similar to S. nitidula [18, 19] and S. cf. nitidula characterized above, in overall shape of body, antennae and cirri throughout. However, members of S. nitiduloides n. sp. have the median antenna inserted slightly posteriorly, between posterior pair of eyes; dorsal peristomial cirri similar in size to median antenna; dorsal cirri from chaetigers 4 and 5 as long as those of the chaetiger 1, and subsequent dorsal cirri shorter; falciger blades with distal tooth larger than the subdistal one throughout; falciger blades shorter, 22–8 μm, 25–12 μm and 24–11 μm long on anterior, mid- and posterior body parapodia, respectively. In contraposition, both S. nitidula and S. cf. nitidula have median antenna inserted between the anterior pair of eyes; dorsal peristomial cirri shorter median antenna; dorsal cirri from chaetiger 1 longer than remaining; falciger blades with distal tooth larger than subdistal one on anterior and midbody parapodia, teeth about same size on posterior body; and falciger blades longer, 30–10 μm on anterior and midbody parapodia, respectively. Also, S. nitiduloides n. sp. also differs from S. cf. nitidula by having ventral simple chaetae subdistally spinulated under SEM and proventricle shorter, extending for up to 3 segments.

Type locality.

Ilha de Itamaracá, Pernambuco, Brazil (SW Atlantic).

Distribution.

South Atlantic, Brazil: states of Paraíba and Pernambuco (Fig 1A and 1B).

Salvatoria marielleae Nascimento, Fukuda & Paiva n. sp.

urn:lsid:zoobank.org:act:4A89DBDD-4BD0-4743-B965-6EB45A017BCB

Figs 6A, 7–9, Tables 1 and 2.

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Fig 7. Salvatoria marielleae n. sp.

(A). Entire body, dorsal view; (B), (D), (F). Falcigers, anterior, mid- and posterior body, respectively; (C), (E), (G). Aciculae, anterior, mid- and posterior body, respectively; (H). Dorsal simple chaeta; (I). ventral simple chaeta. Scale bar: A, 0.18 mm; B–I, 6 μm.

https://doi.org/10.1371/journal.pone.0250472.g007

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Fig 8. Salvatoria marielleae n. sp., paratype 3 (MZUSP 3593), SEM.

(A). Incomplete specimen, dorsal view; (B). Anterior body, dorsal view. Arrows pointing to ciliated nuchal organs. Scale bars: A–B, 100 μm.

https://doi.org/10.1371/journal.pone.0250472.g008

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Fig 9. Salvatoria marielleae n. sp., paratype 3 (MZUSP 3593), SEM.

(A–C). Falcigers, anterior body; (D–E). Falcigers, midbody; (F–G). Falcigers and dorsal simple chaetae, posterior body. Scale bars: A–B, 4 μm; C, 10 μm; D–G, 6 μm.

https://doi.org/10.1371/journal.pone.0250472.g009

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Table 2. Morphological variations of selected characters among specimens in the type series of Salvatoria marielleae n. sp.

https://doi.org/10.1371/journal.pone.0250472.t002

Type series.

Holotype: Project ‘Island Syllids’—Fernando de Noronha Island, Praia do Atalaia (03°50’55”S 32°24’45”W), 0.5 m deep, on red algae: (MNRJP 1918), coll. 23 April 2016. Paratypes: Fernando de Noronha Island, Praia do Atalaia (03°50’55”S 32°24’45”W), 0.5 m deep, on red algae–Paratype 1 (MZUSP 3592), Paratype 2 (MNRJP 1919), Paratype 3 (MZUSP 3593, mounted for SEM), coll. 23 April 2016. Morphometric data of specimens from the type series are given in Table 2.

Other material examined.

Project ‘ProTrindade’—Trindade and Martin Vaz Archipelago, Ilha de Martin Vaz (20°30’45”S 29°18’21”W), 12m depth: 1 specimen (MZUSP 2325), coll. 24. Jul 2013.

Comparative material examined.

Brania brevypharyngea Banse, 1972 [33]. North Pacific Ocean—USA, Washington, San Juan Island, False Bay (48°28’56”N 123°03’52”W), ~1.5 m deep, among aggregate of Bansella oregonica (Banse, 1956) [34] tubes: Holotype (USNM 40711), leg. & det. K. Banse, 29 June 1969.

Description.

Small-sized species, longest specimen examined Paratype 1 (MZUSP 3592), 2.3 mm long, 0.18 mm wide, with 22 chaetigers; holotype complete (MNRJP 1918) (Figs 6A and 7A), 1.9 mm long, 0.18 wide, with 21 chaetigers (Table 2). Palps with approximately same length as prostomium, reniform to triangular, dorsally united by membrane for ¾ of their length (Figs 7A, 8A and 8B). Prostomium subpentagonal (Figs 7A, 8A and 8B), with two pairs of eyes in open trapezoidal arrangement, anterior pair slightly larger than posterior one, and pair of anterior eyespots (Fig 7A). Antennae spindle-shaped, all of same length; median antenna inserted slightly anterior to posterior pair of eyes, sometimes exceeding length of palps and prostomium, lateral antennae inserted in front of anterior pair of eyes, away from anterior margin of prostomium (Figs 7A and 8B). Two ciliated nuchal organs dorsolaterally between prostomium and peristomium (Fig 8A and 8B). Peristomium with two pairs of peristomial cirri; dorsal peristomial cirri with approximately same length as antennae, ventral peristomial cirri ⅓ shorter than dorsal cirri (Figs 7A and 8B). Peristomial and dorsal cirri throughout digitiform, distally tapered, with bases slightly thickened; dorsal cirri of chaetiger 1 longer than those of chaetigers 2‒8; midbody dorsal cirri all similar in length or slightly shorter than those of chaetiger 1 (Figs 7A and 8A). Ventral cirri digitiform, shorter than parapodial lobes. Parapodia with 7‒5 falcigers each throughout; falciger blades spinulated, with relatively short, coarse spines, and strongly bidentate, with teeth similar in size and rounded space inbetween (Figs 7B, 7D, 7F, 9A–9E and 9G); blades on mid- and posterior body chaetigers with proximal part slightly broader, tapering distally (Figs 7F, 9D, 9E and 9G); blades of falcigers with dorsoventral gradation in length (Table 2), 21‒9 μm long on anterior body (Figs 7B and 9A‒9C), 21‒10 μm long on midbody (Figs 7D, 9D and 9E), and 20‒10 μm long on posterior body chaetigers (Figs 7F and 9G). Dorsal simple chaetae present from proventricle level (Table 2), thinner than falciger shafts, slightly sigmoid, bidentate (Fig 7H), with subdistal tooth about same size or slightly larger than distal one, and spinulated, serrate in appearance (Fig 9F and 9G). Ventral simple chaetae present only on posterior body parapodia (Table 2), about as thick as falcigers shafts, strongly sigmoid and bidentate, with teeth about same size, apparently smooth (Fig 7I). Single acicula per parapodium throughout, subdistally inflated and curved, with acute tip pointing upwards (Figs 7C, 7E and 7G). Pygidium with pair of anal cirri, about same length or longer than dorsal cirri of posterior chaetigers (Figs 6A and 7A). Pharynx through 3 segments, anterior margin smooth; pharyngeal tooth ovate, located near anterior margin of pharynx; proventricle through ~2.5 segments, with 18‒19 muscle cell rows (Figs 6A and 7A and Table 2).

Remarks.

Salvatoria marielleae n. sp. has the prostomium slightly broader than palps; antennae spindle-shaped and peristomial and dorsal cirri tapered with slightly stouter bases; dorsal peristomial cirri longer than ventral ones; dorsal cirri of chaetiger 1 longer than those of chaetigers 2‒8; midbody dorsal cirri about same length or slightly shorter than those of chaetiger 1.

Salvatoria nitidula [18] is the species most similar to S. marielleae n. sp. by the overall body shape and morphology of antennae and chaetae. However, S. nitidula has palps slightly broader than prostomium; antennae and peristomial cirri about same shape; both dorsal and ventral peristomial cirri similar in length; dorsal cirri about same length as peristomial cirri or the width of corresponding segment [18]. Specimens of S. nitidula from Cuba, Bermuda, and Gulf of Mexico [19], have falciger blades bidentate with distal tooth slightly larger than subdistal one in anterior and midbody parapodia, whereas S. marielleae n. sp. has teeth of similar sizes throughout. The specimens described by [19] have stronger dorsoventral gradation in the length of the blades, 30‒14 μm on anterior body and 25‒15 μm on posterior body, whereas S. marielleae n. sp. presents falciger blades with 21‒9 μm on anterior body, 21‒10 μm on midbody, and 20‒10 μm on posterior body. In addition, specimens of S. marielleae n. sp. have dorsal simple chaetae from the proventricle level and ventral simple chaetae smooth under optical microscope, whereas the specimens of S. nitidula analysed by [19] have dorsal simple chaetae from the first chaetigers onwards, and ventral simple chaetae slightly spinulated. Finally, S. nitidula presents two aciculae per parapodium on anterior body chaetigers, one of which straight, distally pointed, slightly protruding from parapodial lobes, the other subdistally inflated, twisted, with acute tip, while S. marielleae n. sp. presents only one acicula per parapodium throughout, of the latter type.

The specimens of S. cf. nitidula characterized herein differ from S. marielleae n. sp. in having median antenna longer than lateral ones; lateral antennae inserted closer to anterior margin of the prostomium; antennae, peristomial and dorsal cirri spindle-shaped to subulated; dorsal cirri of chaetiger 1 longer the remaining; and blades of falcigers longer, with up to 30 μm and 25 μm on anterior and posterior body, respectively. In contraposition, S. marielleae n. sp. has all antennae of similar size; lateral antennae inserted away from the anterior margin of prostomium; peristomial and dorsal cirri slightly different from the antennae, digitiform, distally tapered, with bases slightly stouter; falciger blades shorter, with up to 21 μm and 20 μm long on anterior and posterior parapodia, respectively, with teeth of similar size throughout and rounded space inbetween; ventral simple chaetae smooth; single acicula per parapodium throughout, subdistally inflated, with acute tip.

Salvatoria nitiduloides n. sp. is also similar to S. marielleae n. sp., by the overall body shape and by having falciger blades and dorsal and ventral simple chaetae bidentate and spinulated, and aciculae with similar morphology. However, S. nitiduloides n. sp. differs from S. marielleae n. sp. by having antennae and dorsal cirri throughout spindle-shaped to subulated; falciger blades with distal tooth larger than subdistal one and oblique space inbetween; ventral simple chaetae subdistally spinulated; and two aciculae per parapodium on anterior body chaetigers, one thin, straight, the other subdistally inflated, with acute tip. Differently, S. marielleae n. sp. has antennae typically spindle-shaped; dorsal cirri morphologically different from antennae, digitiform, distally tapered, with bases only slightly stouter; falciger blades with teeth of similar size and rounded space inbetween; ventral simple chaetae smooth; and single acicula per parapodium throughout, subdistally inflated and twisted, with acute tip.

Salvatoria brevipharyngea (Banse, 1972) [33] and S. euritmica (Sardá, 1984) [27] are also similar to S. marielleae n. sp. in the overall body shape and morphology of antennae, cirri and chaetae, especially regarding the bidentate falciger blades, with teeth of similar sizes and rounded space between teeth. However, S. brevipharyngea, described from the North Pacific coast of the United States, and so far only known from that area [33, 35], is a larger species, up to 3 mm in length and with 31 chaetigers (against up to 2.3 mm long, with 22 chaetigers, as in members of S. marielleae n. sp.); it also has a slightly shorter pharynx (~2.5 segments) and slightly larger proventricle (~3.5–4.5 segments, with 20–25 muscle cell rows) than S. marielleae n. sp., which shows the pharynx extending for three segments and the proventricle, for 2–2.5, with 18–19 muscle cell rows. Finally, the aciculae in S. brevipharyngea are subdistally inflated and slightly oblique, with rounded tip, different from the aciculae with filiform, needle-like tips, as common in the genus and present in S. marielleae n. sp.

Salvatoria euritmica, described and with occurrences throughout the Mediterranean and also occurring in the North Atlantic European coast, Cuba, Brazil and Australia [7, 17], is also a larger species than S. marielleae n. sp., up to 4 mm in length and with 29 chaetigers. It also differs from S. marielleae n. sp. in having all dorsal cirri of similar length throughout, except for those from chaetiger 1, which are longer; falcigers with longer blades (31–9 μm long, against 21–9 μm long in S. marielleae n. sp.); and in presenting up to two aciculae per anterior body parapodium, one of which subdistally inflated and twisted, similar to the single acicula present in each parapodium of S. marielleae n. sp., but without the acute, needle-like tip, the other acicula being nearly straight, subdistally inflated, with tapering tip. It is worth mentioning that, as specimens of S. euritmica from different localities show slight differences among them [7, 17], the comparison above was made based on European specimens. Thus, this would be another good target for focused taxonomic investigations, to check whether it is a case of species complex.

Etymology.

This species is named after Marielle Franco da Silva, known as Marielle Franco (27.Jun.1979–14.Mar.2018) a Brazilian black woman, sociologist, politician, feminist and human rights advocate, murdered after dedicating her life to assist the minorities in Brazil. Marielle, Presente!

Type locality.

Fernando de Noronha island, Pernambuco, Brazil (SW Atlantic).

Distribution.

South Atlantic, Brazil: Fernando de Noronha and Trindade islands (Figs 1A, 1D and 1E).

Salvatoria neapolitana (Goodrich, 1930) [23]

Fig 10 and Table 1.

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Fig 10. Salvatoria neapolitana.

(A). Falcigers, anterior body and midbody; (B). Falcigers, posterior body; (C). Dorsal simple chaeta; (D). Acicula. Scale bar: 10 μm.

https://doi.org/10.1371/journal.pone.0250472.g010

Pionosyllis neapolitana Goodrich, 1930 [23]: 651–666, Figs 1–12.

Pionosyllis subterranea Hartmann-Schröder, 1956 [25]: 89–91, Figs 6–9.

rania subterranea. Westheide, 1974a [24]: 10–14, Abb. 6; 1974b [36]: 279–281, Abb. 40.

Grubeosyllis neapolitana. Jiménez et al., 1994 [37]: 52–53, Figs 1–2.

Salvatoria neapolitana. San Martín, 2003 [7]: 182–184, Fig 94.

Examined material.

Project ‘BIOTA’—State of São Paulo, Ubatuba, Praia de Picinguaba, (23°23’49’’S 45°58’00”W), 12.1 m deep: 1 specimen, coll. 21 August 2001; (23°24’154’’S 44°59’540’’W), 7.9 m deep: 2 specimens (MZUSP 4276), coll. 21 August 2001; (23°27’033’’S 45°03’013’’W), 5 m deep: 3 specimens, coll. 21 August 2001; (unknow date): 1 specimen, coll. 12 November 2001; (unknow date): 4 specimens, coll. 12 Nov. 2001; on Sargassum sp. (unknow date): 4 specimens; interstitial in sand: 20 specimens (MZUSP 4275), coll. 22 August 2001. State of São Paulo, São Sebastião, Praia de São Francisco (23°44’54’’S 45°24’33’’W), interstitial in sand: 36 specimens (MZUSP 4271–4273), coll. 27 May 2001; 59 specimens (MZUSP 4277–4280), coll. 15 October 2001; 1 specimen (MZUSP 4274), coll. 14 January 2002.

Description.

Small-sized body, longest specimen analysed with 23 chaetigers, 1.8 mm long, 0.15 mm wide (Table 1). Short palps, reniform to triangular. Prostomium subpentagonal, with 2 pairs of eyes in trapezoidal arrangement; median antenna inserted between posterior pair of eyes, much longer than palps and prostomium together, lateral antennae inserted in front of anterior pair of eyes, 2/3 length of median antenna. Peristomium as long as or slightly shorter than subsequent chaetigers; dorsal peristomial cirri of about same length as median antenna, ventral peristomial cirri almost same length as lateral antennae. Antennae, peristomial and dorsal cirri throughout with similar morphology, with bases slightly inflated, tapering distally, smooth to strongly wrinkled; dorsal cirri present on all chaetigers, those of chaetiger 1 longer than remaining, progressively shorter towards posterior body; ventral cirri digitiform, about same length as parapodial lobes. Anterior and midbody parapodia with ca. 10 falcigers each, posterior body parapodia with 2–5 falcigers each; falciger shafts subdistally spinulated, spines more conspicuous on dorsalmost chaetae of anterior body and midbody chaetigers (Fig 10A and 10B); blades sub-bidentate, with thin, spine-like subdistal tooth, and strongly spinulated, with oblique spines on dorsalmost blades of anterior parapodia, progressively smaller and straighter ventralwards (Fig 10A and 10B); blades with conspicuous dorsoventral gradation in length, 19–9 μm long throughout. Dorsal simple chaetae present on all chaetigers, sigmoid, unidentate, subdistally spinulated (Fig 10C); ventral simple chaetae present on posteriormost chaetigers, same morphology as dorsal simple chaetae, about half thickness of falcigers shafts. Single acicula per parapodium throughout, distally hollow, with tip slightly inflated and oblique (Fig 10D). Anal cirri longer than posterior body dorsal cirri. Pharynx extending through 3 chaetigers, anterior margin surrounded by soft papillae and conical tooth at ¹/₃ of its length; proventricle through ~ 3.5 segments, with ~ 20 muscle cell rows.

Remarks.

Salvatoria neapolitana has rounded, distally hollow aciculae, unusual for Salvatoria but characteristic of the genus Brania Quatrefages, 1866 [15]. Nevertheless, this species is undoubtfully placed in Salvatoria for a characteristic set of characters, such as the morphology of the dorsal simple chaetae, position of pharyngeal tooth and length of pharynx and proventricle, the latter without a conspicuous midline formed by the arrangement of the muscle cell rows, typical of Brania.

Salvatoria neapolitana resembles S. vieitezi in the morphology of falciger blades–bidentate, with subdistal tooth clearly smaller than distal one, conspicuously spinulated, with some spines directed upwards, and with dorsoventral gradation in length. Conversely, S. vieitezi differs from S. neapolitana by having clearly bidentate blades, although with subdistal tooth slightly smaller than distal one, and marked differences between blades of dorsalmost and ventralmost falcigers within same fascicle, the former with long spines directed upwards, the latter with short, straight spines; additionally, S. vieitezi presents dorsal, transverse dark-red stripes on each segment and has acuminated aciculae, with acute and filiform tips, as typical of the genus [7].

Another species with falciger blades with small, spine-like subdistal tooth is S. kerguelensis McIntosh, 1885 [14], which also shares with S. neapolitana the size of the antennae, peristomial and dorsal cirri throughout, and proventricle proportions. However, S. kerguelenesis differs from S. neapolitana in having dorsal simple chaetae slightly less sigmoid than in animals belonging to the latter species, and aciculae subdistally inflated and slightly twisted, with acute tip, as typical of Salvatoria [17] and different from the distally hollow aciculae of S. neapolitana.

Salvatoria heterocirra also has falcigers with bidentate and spinulated blades and aciculae with distally inflated, hollow tip. Conversely, S. heterocirra differs from S. neapolitana in having dorsal simple chaetae conspicuously more sigmoid than in S. neapolitana and falciger blades with teeth of similar size, with characteristic rounded space inbetween [28].

The specimens examined herein differ from the Mediterranean ones (lectotype and paralectotype assigned by [37]) by having shorter falciger blades, 32–12 μm and 26–12 μm long on anterior and posterior parapodia, respectively, for Mediterranean specimens [7, 37], and blades 19–9 μm long throughout in the specimens herein examined.

Type locality.

Naples Bay, Italy, Mediterranean Sea, Atlantic Ocean.

Distribution.

Pacific Ocean: Galapagos islands; Atlantic Ocean: Mediterranean Sea, France, Spain, Italy, Canary Islands, Brazil (State of São Paulo) (Fig 1A–1C).

Salvatoria ypsiloides Nascimento, Fukuda & Paiva n. sp.

urn:lsid:zoobank.org:act:BD9C46A5-4384-45B6-9413-C4FED88513B8

Figs 11–13, Tables 1 and 3.

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Fig 11. Salvatoria ypsiloides n. sp.

(A). Anterior body, dorsal view; (B), (D), (I). Falcigers, anterior, mid- and posterior body, respectively; (C), (E), (J). Aciculae, anterior, mid- and posterior body, respectively; (F–G). Dorsal simple chaetae, mid- and posterior body, respectively; (H). Ventral simple chaeta. Scale bars: A, 0.14 mm; B–J, 10 μm.

https://doi.org/10.1371/journal.pone.0250472.g011

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Fig 12. Salvatoria ypsiloides n. sp., SEM.

(A). Anterior body, dorso-lateral view; (B). Anterior body, ventral view; (C). Anterior parapodia, ventral view; (D). Prostomium and peristomium (pharynx everted), ventral view. ch1 –chaetiger 1; dc–dorsal cirrus; dpc–dorsal peristomial cirrus; la–lateral antenna; ma–median antenna; pd–parapodium; pe–peristomium; ph–pharynx (everted); pp–palps; pr–prostomium; vc–ventral cirrus; vpc–ventral peristomial cirrus. Scale bars: A, D, 10 μm; B, 50 μm; C, 20 μm.

https://doi.org/10.1371/journal.pone.0250472.g012

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Fig 13. Salvatoria ypsiloides n. sp., SEM.

(A–B). Falcigers, anterior and midbody, respectively; (C). Falcigers, dorsal and ventral simple chaetae, midbody; (D). Falcigers, posterior body; (E–F). Dorsal simple chaetae; (G). Ventral simple chaeta, posterior body. Scale bars: A–E, G, 10 μm; F, 2 μm. dsc–dorsal simple chaeta; vsc–ventral simple chaeta.

https://doi.org/10.1371/journal.pone.0250472.g013

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Table 3. Morphological variation of selected characters among specimens in the type series of Salvatoria ypsiloides n. sp.

https://doi.org/10.1371/journal.pone.0250472.t003

Type series.

Holotype: Project ‘Island Syllids’—Fernando de Noronha Island, Praia do Atalaia (03°50’55’’S 32°24’45’’W), 0.5 m deep, on algae: (MNRJP 1915), coll. 23 April 2016. Paratypes: Fernando de Noronha Island, Praia do Atalaia (03°50’55’’S 32°24’ 45’’W), 0.5 m deep, on algae: Paratype 1 (MZUSP 3590), Paratype 2 (MNRJP 1916), Paratype 3 (MZUSP 3591), Paratype 4 (MNRJP 1917) and Paratype 5, mounted for SEM (MNRJP 1984), all coll. 23 April 2016. Project ‘Habitats’—State of Rio de Janeiro, Campos Basin, soft bottom: 21°44’19”S 40°17’15”W, 50 m deep: 5 paratypes (MZUSP 3779), coll. 08 July 2009. Morphometric data of selected specimens from the type series are given in Table 2.

Additional material examined.

Project ‘Island Syllids’—Fernando de Noronha Island, Praia do Atalaia (03°50’55”S 32°24’45”W), 0.5 m deep, on algae: 6 specimens (MNRJP 1917), coll. 23 April 2016. Project ‘AMBES’—State of Espírito Santo, Espírito Santo Basin, soft bottom: 18°36’31”S 39°9’33”W, 39 m deep: 1 specimen (MZUSP 3731), coll. 17 January 2012; 19°18’6”S 39°23’23”W, 38 m deep: 2 specimens (MZUSP 3741), coll. 15 July 2013; 19°47’32”S 39°43’15”W, 41 m deep: 4 specimens (MZUSP 3746), coll. 15 December 2010; 19°53’27”S 39°32’59”W, 970 m deep: 1 specimen (MZUSP 3733), coll. 28 June 2013; 20°10’2”S 40°8’31”W, 25 m deep: 2 specimens (MZUSP 3729), coll. 20 January 2012; 20°12’20”S 39°57’59”W, 50 m deep: 14 specimens (MZUSP 3730), coll. 20 January 2012; 20°34’47”S 40°11’31”W, 41 m deep: 1 specimen (MZUSP 3725), coll. 12 July 2013; 20°34’53”S 40°6’27”W, 50 m deep: 1 specimen (MZUSP 3728), coll. 21 January 2012; 21°2’45”S 40°32’29”W, 25 m deep: 1 specimen (MZUSP 3723), coll. 22 January 2012; 21°4’1”S 40°18’50”W, 49 m deep: 3 specimens (MZUSP 3724), coll. 22 January 2012. Project ‘Habitats’—State of Rio de Janeiro, Campos Basin, soft bottom: 21°11’0”S 40°28’27”W, 26 m deep: 15 specimens (MZUSP 3771), coll. 05 March 2009; 21°44’18”S 40°17’14”W, 49 m deep: 35 specimens (MZUSP 3769), coll. 09 March 2009; 21°59’4”S 40°25’12”W, 53 m deep: 1 specimen (MZUSP 3777), coll. 06 July 2009; 22°6’56”S 40°38’58”W, 53 m deep: 5 specimens (MZUSP 3758), coll. 26 February 2009; 22°7’43”S 40°18’46”W, 73 m deep: 1 specimen (MZUSP 3763), coll. 24 February 2009; 22°12’53”S 40°51’12”W, 52 m deep: 2 specimens (MZUSP 3756), coll. 26 February 2009; 22°46’54”S 41°3’33”W, 78 m deep: 1 specimen (MZUSP 3772), coll. 02 July 2009; 22°55’7”S 42°0’49”W, 29 m deep: 1 specimen (MZUSP 3753), coll. 28 February 2009.

Description.

Small-sized species, longest specimen examined Paratype 1 (MZUSP 3590), ca. 2.2 mm long, 0.12 mm wide, with up to 32 chaetigers; holotype complete (MNRJP 1915), 1.65 mm long, 0.14 mm wide, with 30 chaetigers (Figs 6B, 11A and Table 3). Palps shorter than prostomium (Fig 11A), united by dorsal membrane, with small distal notch (Figs 6B and 11A). Prostomium subpentagonal, with two pairs of eyes in wide open trapezoidal arrangement, nearly aligned, anterior pair larger than posterior one; eyespots small, frequently inconspicuous, close to anterior margin of prostomium (Fig 11A); antennae spindle shaped to digitiform, slightly enlarged at mid-length; median antenna inserted between posterior pair of eyes, sometimes slightly exceeding length of palps; lateral antennae shorter, inserted in front of anterior pair of eyes, at anterior margin of prostomium (Figs 11A and 12A). Peristomium slightly shorter than anterior chaetigers; dorsal peristomial cirri about as long as lateral antennae (Figs 11A and 12A); ventral peristomial cirri with ¾ length of dorsal peristomial cirri. Dorsal cirri all about same length throughout, elongate, digitiform, almost of uniform width along their length (Figs 11A and 12B), frequently with hollow appearance more pronounced close to tip, sometimes distally slightly swollen. Ventral cirri digitiform inserted on basal ⅓ of parapodial lobes, not reaching their tips (Fig 12C); some ventral cirri distally hollow, similar to dorsal cirri. Parapodia with 5–7 compound falcigers each throughout; blades strongly bidentate, on anterior body distal tooth slightly shorter than subdistal one (Figs 11B and 13A), teeth about same size on mid- and posterior body chaetigers (Figs 11D, 11I and 13D); angle between teeth wider and subdistal tooth progressively slightly larger than distal one ventralwards within each fascicle (Fig 11B, 11D and 11I); blades spinulated, dorsalmost falcigers with larger and thickened spines, usually directed upwards, reaching base of subdistal tooth in a few dorsalmost falcigers, spines short, straight, in remaining falcigers (Figs 11B, 11D, 11I, 13A and 13C and 13D); blades with marked dorsoventral but inconspicuous antero-posterior gradation in length (Table 3), measuring 18‒7.4 μm long on anterior body (Figs 11B and 13A), 18‒8 μm long on midbody (Figs 11D and 13B and 13C), and 19‒8 μm long on posterior body (Figs 11I and 13D). Dorsal simple chaetae present on all chaetigers (Table 3), slightly sigmoid, distally bifid with unequal sizes, “ypsiloid”, spinulated, with short spines reaching between tips (Figs 11F–13G, 13C, 13E and 13F). Ventral simple chaetae present from midbody onwards (Table 3), about as thick as falciger shafts, strongly sigmoid, smooth and bidentate, subdistal tooth slightly larger than distal one, with wide angle inbetween (Figs 11H and 13G). Parapodia from first few chaetigers with up to three aciculae each, progressively diminishing to single acicula per parapodium from midbody onwards; on anterior body, each parapodium with one acicula straight, with rounded tip, usually protruding from parapodial lobe, another subdistally bent and, occasionally, a third acicula, much thinner, straight (Fig 11C); on mid- and posterior body, aciculae subdistally inflated and curved, twisted, with tapered tip pointing upwards (Fig 11E and 11J). Pygidium with pair of thin anal cirri about twice as long as posterior body dorsal cirri. Pharynx through 4‒5 segments (Figs 6B, 11A and Table 3), anterior margin smooth (Fig 12B and 12D); pharyngeal tooth ovate, at about ⅔ of pharynx; proventricle through 4.5‒5.5 segments, with 26‒29 muscle cell rows (Figs 6B and 11A and Table 3).

Remarks.

Salvatoria ypsiloides n. sp. is characterized by having palps shorter than prostomium; median antenna inserted between posterior pair of eyes; dorsal cirri elongate, digitiform, almost of uniform width along their length and distally hollow in appearance, present on all chaetigers; tooth at about ⅔ of the pharynx; falcigers with strongly bidentate blades, with wide angle between teeth, except for dorsalmost chaetae in each fascicle, which teeth are closer to each other; dorsal simple chaetae present from anterior body, distally bifid, with “ypsiloid” shape; and ventral simple chaetae sigmoid and bidentate, with subdistal tooth slightly larger than distal one. Salvatoria euritmica, S. nitidula and S. rugulosa (Verrill, 1900) [18] are the most similar species to S. ypsiloides n. sp., in overall body shape or by sharing some of the above features. However, S. ypsiloides n. sp. differs from all congeners by the apparently distally hollow dorsal cirri and by the unique shape of the dorsal simple chaetae, looking ‘ypsiloid’.

Salvatoria euritmica and S. nitidula resemble S. ypsiloides n. sp. by possessing falcigers with strongly bidentate, spinulated blades, but both differ from S. ypsiloides n. sp. in having palps slightly longer than the prostomium; antennae and dorsal cirri throughout larger and rather spindle-shaped (although only slightly tapered distally in S. nitidula); pharyngeal tooth inserted near anterior margin of pharynx; blades of falcigers with narrower angle between teeth than in S. ypsiloides n. sp., and with shorter spinulation in the dorsalmost blades; dorsal simple chaetae present from midbody (from anterior body in S. nitidula), bidentate, with short teeth and short spines; and ventral simple chaetae bidentate, with teeth similar to those of the falcigers [7, 17, 19].

Salvatoria rugulosa was described from Bermuda [18] and has been recorded from Florida, Gulf of Mexico and Cuba [19]; it resembles S. ypsiloides n. sp. in having the pharyngeal tooth located away from the anterior margin of pharynx and by having falcigers with bidentate, spinulated blades. In contraposition, S. rugulosa differs from S. ypsiloides n. sp. in having conical to triangular palps; short, spindle-shaped antennae and dorsal cirri throughout; all blades of falcigers with teeth closer to each other than in S. ypsiloides n. sp.; dorsal simple chaetae thin, bidentate, with teeth similar in size; and ventral simple chaetae less sigmoid, with teeth similar in size [18, 16].

Type locality.

Fernando de Noronha Island, Pernambuco, Brazil (SW Atlantic).

Distribution.

South Atlantic: NE Brazil (state of Pernambuco: Fernando de Noronha Archipelago), SE Brazil (states of Rio de Janeiro–Campos Basin–and Espírito Santo–Espírito Santo basin) (Fig 1A, 1C and 1D).

Etymology.

The specific name refers to the characteristic “ypsiloid” appearance of the dorsal simple chaetae.

Salvatoria sp.

Figs 14 and 15 and Table 1.

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Fig 14. Salvatoria sp.

(A). Anterior body, dorsal view; (B). Parapodial lobe from chaetiger 1; (C). Posterior end, dorsal view; (D). Parapodial lobe from chaetiger 8. Scale bars: A, C, 0.14 mm; B, D, 27 μm.

https://doi.org/10.1371/journal.pone.0250472.g014

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Fig 15. Salvatoria sp.

(A–C). Falcigers, anterior, mid- and posterior body, respectively; (D). Acicula, posterior body; (E). Dorsal simple chaeta, midbody; (F). Ventral simple chaeta, posterior body. Scale bar: A–F, 7 μm.

https://doi.org/10.1371/journal.pone.0250472.g015

Material examined.

Project ‘Island Syllids’—Fernando de Noronha Island, Buraco da Raquel (03°50’11”S 32°24’34”W), 1 m deep, in association with the sponge Plakortis insularis: 1 specimen (MZUSP 4115), coll. 23 April 2016. Description. Small-sized body, complete, 1.3 mm long, 0.14 wide, with 20 chaetigers. Palps slightly shorter than prostomium, reniform to triangular, dorsally completely united by membrane (Fig 14A). Prostomium subpentagonal (Fig 14A), with two pairs of eyes in open trapezoidal arrangement (Fig 14A). Antennae spindle-shaped; median antenna lost, scar indicating insertion between anterior pair of eyes; lateral antennae almost as long as palps and prostomium together, inserted in front of anterior pair of eyes, slightly away from anterior margin of prostomium (Fig 14A). Peristomium with two pairs of peristomial cirri, dorsal peristomial cirri about same length as lateral antennae, ventral peristomial cirri about half length of dorsal ones (Fig 14A). Dorsal cirri distally tapered, with bases slightly thickened, present on all chaetigers; dorsal cirri of chaetiger 1 longer than remaining, slightly exceeding width of segment; remaining dorsal cirri shorter than segment width; from chaetiger 2 onwards, cirri alternating in length, without defined pattern (Fig 14A). Ventral cirri digitiform, shorter than parapodial lobes. Parapodial lobes conical, about ¼ of corresponding segment width, distally with 2–3 papillae (Fig 14B and 14D). Parapodia with 6‒7 falcigers each, on anterior body and midbody chaetigers, 3 falcigers on each posterior body parapodium; falcigers with shafts slightly spinulated subdistally; falciger blades spinulated, with coarse spines directed slightly upwards, and strongly bidentate, distal tooth slightly larger than subdistal one (Fig 15A–15C); blades with dorsoventral gradation in length, measuring 22‒7 μm long on anterior body (Fig 15A), 23‒7 μm long on midbody (Fig 15B), and 20‒6 μm long on posterior body (Fig 15C). Dorsal simple chaetae present from second chaetiger onwards, thinner than falciger shafts, slightly sigmoid, unidentate, spinulated, serrate in appearance (Fig 15E). Ventral simple chaetae present only on two posteriormost chaetigers, thicker than dorsal simple chaetae, although not as thick as falciger shafts, sigmoid, unidentate, apparently smooth (Fig 15F). Single acicula per parapodium throughout, subdistally inflated and curved, with acute tip pointing upwards (Fig 15D). Pygidium with pair of anal cirri slightly longer than dorsal cirri of chaetiger 1 (Fig 14C). Pharynx through 3.5 segments, anterior margin apparently smooth; pharyngeal tooth rhomboidal, located slightly away from anterior margin of pharynx; proventricle through ~3 segments, with ~15 muscle cell rows (Fig 14A).

Remarks.

As we found a single specimen of Salvatoria sp., we preferred not to investigate the specimen under SEM, what made it difficult to discern more detailed characters. Furthermore, the median antenna, which is an important taxonomic character, is missing in this specimen, precluding more specific identifications. The specimen was found with the sponge Plakortis insularis Moraes & Muricy, 2003 [38], without information whether the specimen was over or within the sponge.

The specimen presents some similarities with S. clavata from the Iberian peninsula, described by [7], in the overall morphology of the antennae and dorsal cirri, in the presence of characteristic distal papillae on parapodial lobes and, to some extent, in the morphology of the falciger blades. However, S. clavata differs from Salvatoria sp. for being larger and wider, 3.5 mm long, 0.35 mm wide, with 35 chaetigers; by having shorter parapodial lobes; more falcigers per parapodium, 10 chaetae on anterior body, 7–4 on posterior body; blades of falcigers with marked dorso-ventral gradation in length only in anterior parapodia, and with slightly shorter spines; both dorsal and ventral simple chaetae bidentate and spinulated; and proventricle with more muscle cell rows, 20–23.

San Martín [7] pointed out that there are at least three different forms registered as S. clavata in the Iberian peninsula, two by [39] and one by [40], each one deviating somewhat from the description presented by [7], who, nonetheless, considered them as intraspecific variations.

As mentioned above, S. cf. nitidula characterized herein is similar to S. clavata from the Iberian Peninsula reported by [7]. In comparison to Salvatoria sp., S. cf. nitidula differs by having longer and wider body, 2.37 mm long, 0.18 mm wide, with 31 chaetigers; palps as long as prostomium, with a distal notch; both dorsal and ventral simple chaetae bidentate and spinulated; and proventricle with more muscle cell rows, 16–20.

Other congeneric species similar to Salvatoria sp. is S. marielleae n. sp., by the overall morphology of antennae, dorsal cirri throughout and falciger blades. Nevertheless, Salvatoria sp. has dorsal cirri larger and slightly thicker; parapodial lobes distally papillated; falciger blades with distal tooth slightly larger than the subdistal one throughout and with thicker spines; and both dorsal and ventral simple chaetae unidentate and less sigmoid.

Distribution.

South Atlantic: NE Brazil (state of Pernambuco: Fernando de Noronha Island) (Fig 1A and 1D).