Odontosyllis guarauensis , Fukuda, Marcelo Veronesi, Nogueira, João Miguel De Matos, Paresque, Karla & Martín, Guillermo San, 2013

Fukuda, Marcelo Veronesi, Nogueira, João Miguel De Matos, Paresque, Karla & Martín, Guillermo San, 2013, Species of Odontosyllis Claparède, 1863 (Annelida: Polychaeta: Syllidae) occurring along the Brazilian coast, Zootaxa 3609 (2), pp. 142-162: 154-160

publication ID

http://dx.doi.org/10.11646/zootaxa.3609.2.2

publication LSID

lsid:zoobank.org:pub:3A3D9A7D-6207-457B-B1FC-744A9202EB6B

persistent identifier

http://treatment.plazi.org/id/03AC87D7-1209-FFE0-36BE-C188CD43FA3A

treatment provided by

Plazi

scientific name

Odontosyllis guarauensis
status

sp. nov.

Odontosyllis guarauensis  sp. nov.

Figures 1View FIGURE 1 C; 4–7; Table 3

Material examined. Project ‘BIOTA’. Ubatuba—Praia de Picinguaba (23 ° 22 ’ 31 ”S 44 ° 50 ’ 21 ”W), on rocky shore: 1 spec. (MZUSP 1239), 10 May 2001; 4 specs (MZUSP 1025), 17 Oct 2001; 1 spec. (MZUSP 1240), 18 Oct 2001. São Sebastião—Praia da Baleia (23 ° 48 ’ 54 ”S 45 ° 39 ’ 51 ”W), on Sargassum  : 4 specs (MZUSP 1222), 14 Nov 2001. Project ‘BioPol-SP’. Ubatuba—Praia de Domingas Dias (23 ° 30 ’00”S 45 °08’ 38 ”W): 1 spec. (MZUSP 1023), 2 Nov 2002. São Sebastião—Praia da Baleia (23 ° 48 ’ 54 ”S 45 ° 39 ’ 51 ”W): 1 spec. (MZUSP 1241), 23 Jul 2005; Praia de Toque-Toque Grande (23 ° 50 ’ 12 ”S 45 ° 30 ’ 40 ”W): 1 spec., 21 Jul 2005. Guarujá—Praia de Pernambuco (23 ° 58 ’ 20 ”S 46 ° 11 ’02”W): 2 specs (MZUSP 1024), 22 Jun 2006. Itanhaém—Praia do Sonho (24 ° 11 ’ 44 ”S 46 ° 48 ’05”W): 3 specs, 26 Aug 2003. Peruíbe—Praia do Guaraú (24 ° 22 '02"S 47 °00' 35 "W), intertidal, in Bostrychia  sp.: 97 specs (MZUSP 1020, holotype; MZUSP 1021, paratype 1; ZUEC-POL 11893, paratype 2; MNCN 16.01 / 14459, paratype 3; ZUEC-POL 11894, paratype 4; MNCN 16.01 / 14460, paratype 5; MZUSP 1022, thirty paratypes; ZUEC-POL 11895–11897, thirty paratypes; MNCN 16.01 / 14461, twenty paratypes), 19 May 2008.

Type series. Data of selected specimens of the type series are provided in Table 3.

Additional material examined. Odontosyllis polycera (Schmarda, 1861)  . Indian Ocean, Australia: Western Australia, Albany, Frenchman Bay, Goode Beach: 1 spec. (ZMH P- 18131), coll. & det. G. Hartmann-Schröder, 21 Nov 1975; South Australia, Port Lincoln: 2 specs (ZMH P- 18550), coll. & det. G. Hartmann-Schröder, 3 Dec 1975; South Australia, Port MacDonnel, Cape Northumberland: 1 spec. (ZMH P- 18772), coll. & det. G. Hartmann- Schröder, 18 Dec 1975.

Description. Medium-sized body, holotype largest specimen collected, 9 mm long, 0.70 mm wide, with 81 segments (Table 3). Conspicuous pigmentation on living animals, as nearly triangular patch on prostomium, below occipital flap, and large dark spots scattered across dorsum, roughly arranged in one broad transverse stripe mostly on anterior half of each chaetiger ( Fig. 5View FIGURE 5 A); pigmentation slightly fading after preservation ( Fig. 4View FIGURE 4 A). Palps rounded to kidney-shaped, basally fused, each with two rows of cilia, one close to posterior border, another at midlength, present dorsally and ventrally, additional tufts of cilia on internal side of each palp dorsally, from midlength to tip ( Figs 5View FIGURE 5 C –F; 6 A –C). Prostomium ovate with two pairs of eyes in rectangular to trapezoidal arrangement and one pair of small anterior eyespots; lateral antennae inserted on anterior margin of prostomium, as long as palps or slightly longer; median antenna inserted slightly anteriorly to middle of prostomium, ~ 1.5 times as long as lateral antennae ( Figs 4View FIGURE 4 A; 5 A –F; 6 A –C); nuchal organs as one pair of broad semi-circular rows of cilia posterior to eyes of posterior pair, extending dorsally below occipital flap and laterally around prostomium, until close to base of palps ( Figs 5View FIGURE 5 D –F; 6 B); prostomium with additional pair of rows of cilia between anterior and posterior pairs of eyes ( Figs 5View FIGURE 5 D; 6 B –C). Peristomium dorsally short, with large, roughly rectangular occipital flap almost as wide as prostomium, covering posterior and, sometimes, anterior pairs of eyes ( Figs 4View FIGURE 4 A; 5 A –B, D –F; 6 B –C); dorsal peristomial cirri slightly longer than median antenna, ventral peristomial cirri about as long as median antenna, in ventro-lateral position, laterally to mouth ( Figs 4View FIGURE 4 A; 5 C –F; 6 A –C). Dorsal cirri of chaetiger 1 inserted dorsally to following cirri, 1.5–2 times as long as median antenna, dorsal cirri throughout about as long as median antenna, alternating longer and shorter cirri, longer cirri directed upwards and inserted dorsally to shorter cirri ( Fig. 5View FIGURE 5 F). Antennae, peristomial and anterior dorsal cirri with minute tufts of cilia ( Figs 5View FIGURE 5 D –F; 6 A –E); peristomial and dorsal cirri with short cirrophores ( Figs 5View FIGURE 5 D –F; 6 A –E). Ventral cirri short, ovate, not extending beyond parapodial lobes ( Figs 5View FIGURE 5 C; 6 A –B, D). Parapodia distally bilobed ( Figs 5View FIGURE 5 C, F; 6 A –B, D), lobes about same size or posterior lobe slightly larger. Anterior parapodia with 12–18 falcigers each, midbody with 9–15, posterior parapodia with 4–9 falcigers each (Table 3); falcigers with subdistally spinulated shafts; from midbody, shafts of dorsalmost falcigers with subdistal, nearly triangular enlargement and thin, straight tip ( Figs 1View FIGURE 1 C; 4 C –D; 7 E, G); connective between shafts and blades wrinkled to slightly spinulated; falcigers with blades slightly spinulated and bidentate, distal tooth larger than subdistal one ( Figs 4View FIGURE 4 B –D; 7 A –H); blades with inverted dorso-ventral gradation in length, 12–22 μm long on anterior chaetigers, 12–21 μm long on midbody, 10–17 μm long on posterior chaetigers (Table 3). Dorsal simple chaetae only present on posterior chaetigers (Table 3), thin, ~ 1 / 5 as thick as shafts of falcigers, poorly spinulated subdistally, distally rounded ( Fig. 7View FIGURE 7 G); ventral simple chaetae, if present, only on last chaetigers (Table 3), sigmoid, bidentate, tips resembling those of blades of falcigers, about half as thick as shafts of falcigers ( Fig. 7View FIGURE 7 H). Anterior parapodia with up to three aciculae each, midbody with two, posterior parapodia with one acicula each; aciculae irregularly enlarged distally, with slight progressively increasing thickness towards posterior parapodia ( Fig. 4View FIGURE 4 E –G). Pharynx through ~ 4–4.5 segments (Table 3), trepan with 9 teeth and two lateral plates ( Fig. 4View FIGURE 4 H); proventricle through 5–7.5 segments (Table 3), with numerous packed transverse and oblique muscle cell rows ( Fig. 4View FIGURE 4 A).

Remarks. Odontosyllis guarauensis  sp. nov., belongs to the same group of species as O. aracaensis  sp. nov., with short, bidentate falciger blades. However, Odontosyllis guarauensis  sp. nov., can be distinguished from most of those species by the morphology of chaetae and trepan, besides the pigmentation pattern (Table 2).

The nearly triangular subdistal enlargement of the shafts of posterior body dorsalmost falcigers of O. guarauensis  sp. nov., has never been referred to in other descriptions of species of Odontosyllis  , but a similar configuration is present in O. polycera  (MVF, pers. obs.). In addition, O. polycera  resembles O. guarauensis  sp. nov., in the overall body shape, size of the occipital flap, and in the occurrence of falcigers with inverted dorsoventral gradation in lengths of the blades. However, O. polycera  differs from O. guarauensis  sp. nov., in having falciger blades with a much smaller subdistal tooth, sometimes reduced to an enlarged spine or even absent, while in O. guarauensis  sp. nov., the subdistal tooth is always conspicuous, though smaller than the distal one. These differences also apply to the ventral simple chaetae, which have tips similar to those of falcigers. Furthermore, O. polycera  has two types of aciculae, one subdistally enlarged, with crown of subdistal spines and short acuminate tip, and another thicker, subdistally oblique and distally rounded, slightly protrudring from parapodial lobes sometimes, while the aciculae of O. guarauensis  sp. nov., are all irregularly enlarged distally ( Fig. 4View FIGURE 4 E –G). Finally, the trepan of O. polycera  has 5–8 teeth and 2 lateral plates, while in O. guarauensis  sp. nov., it has 9 teeth and 2 lateral plates ( Fig. 4View FIGURE 4 H).

Etymology. The species is named after the Praia do Guaraú (Guaraú beach, in Peruíbe, State of São Paulo) where it was found in the greatest abundance, frequently crawling over the algae Bostrychia  sp.

Conclusions

We herein describe two new species of Odontosyllis  , a widespread genus of Syllidae  , which is recognized by the usual presence of a peristomial occipital flap covering the posterior part of the prostomium, and by the characteristic trepan with teeth pointing backwards. Identification to species level, however, is considerably more difficult, since many species are defined by different combination of characters, some of them with tenuous morphological variations. Many of the ~ 49 described species (Verdes et al. 2011) correspond to single reports and some lack informative taxonomic characters (especially the older descriptions). We provide here a list of characters (Table 2) as a first step to encourage a much needed revision of this group.

In our paper we also pay special attention to the morphology of the falciger shafts, which is usually disregarded. In the species of Odontosyllis  so far investigated, we noticed three different morphologies for the shafts of posterior body dorsalmost falcigers, which are more evident when comparing the dorsalmost and ventralmost chaetae ( Fig. 1View FIGURE 1 A –D):

1) subdistally inflated shafts with thin, straight tip ('regular' syllid type) ( Fig. 1View FIGURE 1 A –B);

2) shafts of dorsalmost chaetae with nearly triangular subdistal enlargement, with thin, straight tip ( Fig. 1View FIGURE 1 C); 3) shafts of dorsalmost chaetae subdistally inflated with thin, sigmoid tip ( Fig. 1View FIGURE 1 D).

We suggest that this character should be investigated in other species of Odontosyllis  , to check if it could provide useful information to resolve relationships within the genus.