Sphaerosyllis pontica, Martín, 2017

Martín, Guillermo San, 2017, Taxonomic contribution to the genus Sphaerosyllis (Annelida: Syllidae: Exogoninae) in the Black Sea, Zootaxa 4329 (3), pp. 281-291 : 284-288

publication ID

https://doi.org/ 10.11646/zootaxa.4329.3.6

publication LSID

lsid:zoobank.org:pub:A6346Fde-974C-4B40-8C81-116E3B39B1C7

DOI

https://doi.org/10.5281/zenodo.6039440

persistent identifier

https://treatment.plazi.org/id/2C11783F-FFE9-0B39-FF77-7BA53273F971

treatment provided by

Plazi

scientific name

Sphaerosyllis pontica
status

sp. nov.

Sphaerosyllis pontica View in CoL sp. nov.

( Figs 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Material examined. Black Sea, Bulgarian coast, off Varna, Sta. 191-4 (VA2), 43.1382°N, 28.2447°E, 33.7 m depth, muddy sand, POS 363 cruise of R/V “Poseidon”, 23 March 2008, holotype ( MNINGA PLY084 About PLY ) GoogleMaps ; same data for 10 paratypes ( MNINGA PLY085 About PLY ) GoogleMaps ; same data for 2 paratypes mounted on SEM stub ( MNINGA PLY 086 About PLY ) GoogleMaps ; Romanian coast, off Constanța, Sta. BS 07/CT04, 44.0835°N, 29.0336°E, 44.5 m depth, grey mud, April 2007, 6 paratypes ( MNINGA PLY090 About PLY ) GoogleMaps ; Romanian coast, off Eforie Nord, Sta. S-RO1-003, 43.8306°N, 30.1347°E, 100.5 m depth, well compressed, whitish mud with Modiolula phaseolina (Philippi, 1844) , SESAME 1 cruise of R/V “Mare Nigrum”, 8 April 2008, 4 paratypes (MNINGA PLY087); same data for 2 paratypes mounted on permanent slides ( MNINGA PLY089 About PLY ) GoogleMaps .

Additional material: Black Sea, without collection data, 8+ specimens ( MNINGA 30.268).

Description. Body small, slender, with well-marked segments, pale yellowish, without colour markings, 1.5– 3.1 mm long, 0.16–0.32 mm wide, for 23–33 chaetigers ( Fig. 3A View FIGURE 3 ). Holotype 2.7 mm long, 0.21 mm wide for 31 chaetigers. Small glandular papillae scattered over dorsum ( Figs 2A View FIGURE 2 , 3D View FIGURE 3 ). Prostomium rectangular, wider than long ( Fig. 2A View FIGURE 2 ). Two pairs of red-brownish, coalescent (touching each other on lateral sides) lensed eyes in trapezoidal arrangement on posterior half of prostomium; anterior pair (16.3–22.4 µm in diameter) slightly larger than posterior ones (12.2–19.3 µm in diameter). Antennae short, similar in length, pyriform with bulbous bases and short narrow distal tips, of similar length to or slightly shorter than prostomium ( Figs 2A View FIGURE 2 , 3B View FIGURE 3 ). Median antenna (31.6–41.8 µm) inserted more posteriorly than lateral antennae (30.6–45.9 µm), approximately on middle of prostomium; lateral antennae inserted on anterior margin of prostomium. Palps broad, fused along their entire length, similar in length to prostomium, with a dorsal notch, sometimes directed downwards. Peristomium well developed, of similar length to subsequent segments, with a dorsal fold dorsally covering posterior part of prostomium. One pair of pyriform peristomial cirri (16.3–27.5 µm), much shorter than antennae, situated slightly anteriorly to anterior eyes, antero-laterally directed ( Fig. 2A View FIGURE 2 ). Dorsal cirri small (30.6–47.9 µm), shorter than parapodial lobes, with bulbous bases and short tips. Dorsal cirri absent on chaetiger 2. Parapodial lobes conical, short, with few subterminal, digitiform papillae ( Fig. 3E View FIGURE 3 ). Parapodial glands present from chaetiger 4 to last chaetiger, spherical, with fibrillar material ( Fig. 2A–C View FIGURE 2 ), a rounded papilla on dorsal part of each gland ( Fig. 3C–E View FIGURE 3 ); parapodial glands apparently absent in some segments of some specimens. Ventral cirri digitiform, shorter than parapodial lobes ( Figs 2B View FIGURE 2 , 3E View FIGURE 3 ). Anterior parapodia with 5–6 compound heterogomph chaetae with short unidentate blades of similar size, about 10.7–15.3 µm in length ( Figs 2E View FIGURE 2 , 4A View FIGURE 4 ). Blades of one or two dorsalmost compound chaetae with up to 7 moderately long spines along cutting edges; blades of ventral compound chaetae smooth. Tips of shafts always smooth. Towards posterior of body, number of chaetae per parapodium and length of blades slightly decrease; only 3–4 compound chaeta in last parapodia, all with smooth blades, about 10.2–14.3 µm in length ( Figs 2H, K View FIGURE 2 , 4B, C View FIGURE 4 ). Dorsal simple chaetae unidentate, straight, smooth, pointed, present from chaetiger 1, stouter in posterior chaetigers ( Figs 2D, G, J View FIGURE 2 , 4D View FIGURE 4 ). Ventral simple chaetae more slender than dorsal ones, unidentate, slightly curved, pointed, present on posterior chaetigers (in last 7–11 chaetigers) ( Fig. 2L View FIGURE 2 ). Anterior parapodia (approx. first 5–7 chaetigers) with two aciculae each, one straight and thin and other stouter, with tip bent forward at about right angle ( Fig. 2F View FIGURE 2 ); single acicula in each remaining parapodia, of latter type, most posterior ones thicker ( Fig. 2I, M View FIGURE 2 ). Pygidium short, rounded lobe, with a pair of anal cirri (45.9–71.4 µm), similar in shape to dorsal cirri but stouter and 2–2.5 times longer than posterior dorsal cirri ( Figs 2C View FIGURE 2 , 3C View FIGURE 3 ). Pharynx slender, extending over 2–3 chaetigers, opening with a crown of around 10 small, soft papillae; pharyngeal tooth conical, bluntly rounded anteriorly, located terminally. Proventricle short, barrel-shaped, 138–204 µm long, 110–154 µm wide, extending through 1.5–2.5 chaetigers, with about 12–15 indistinct muscle cell rows ( Fig. 2A View FIGURE 2 ).

Biology. Two epigamic males (2.4 and 3.1 mm long, both with 33 chaetigers) with natatory chaetae were present in sample MNINGA PLY090. They had masses of spermatozoa, two per chaetiger, from chaetiger 9 to chaetigers 22–27. Natatory chaetae slender, up to 721 µm long, decreasing gradually in length towards posterior end, first present from chaetiger 10. Last 2–3 chaetigers without natatory chaetae. No other epitokal modifications were observed in those two specimens.

Remarks. The new species most closely resembles Sphaerosyllis climenti del Pilar Ruso & San Martín, 2012, described from off Alicante, Spain, Western Mediterranean Sea, Sphaerosyllis parabulbosa San Martín & López, 2002 , described from off Sisargas Islands, A Coruña, NW Spain, and Sphaerosyllis thomasi San Martín, 1984 , described from the Balearic Islands but also reported in other parts of the Mediterranean. All these species have in common the median antenna inserted more posteriorly than the lateral antennae, pyriform dorsal cirri, with bulbous bases and narrow, short tips, shorter than the parapodial lobes, lacking on chaetiger 2, and the anterior parapodia with two aciculae each, one straight and one with bent tip.

Sphaerosyllis pontica sp. nov. differs from Sphaerosyllis parabulbosa in having conical parapodial lobes rather than rounded, dorsal simple chaetae beginning from the anterior parapodia rather than from the midbody parapodia, dorsal simple chaeta without spines on margin, shaft heads without spines, and blades without subdistal spine on posterior dorsalmost chaetae. Also, the blades of compound chaetae (10–15 µm long) are slightly shorter than in Sphaerosyllis parabulbosa (13–17 µm).

Sphaerosyllis pontica sp. nov. differs from Sphaerosyllis thomasi in having the blades of compound chaetae longer than in Sphaerosyllis thomasi (7–8 µm), with smoother serrations, and the shaft with smooth tips. In addition, in Sphaerosyllis pontica sp. nov. the eyes are arranged in a wide trapezium rather in a rectangle.

Finally, Sphaerosyllis pontica sp. nov. differs from Sphaerosyllis climenti in having the blades of compound chaetae slightly longer than in the latter (7–10 µm) and having the parapodial glands with fibrillar material instead of granular. In spite of the filling of some parapodial glands in Sphaerosyllis pontica sp. nov. sometimes appears as granular (depending on the angle of view), they are in fact fibrillar (better seen with phase contrast).

Sphaerosyllis levantina Faulwetter, Chatzigeorgiou, Galil, Nicolaidou & Arvanitidis (2011) View in CoL , from Israel, and S. boeroi Musco, Çinar & Giangrande (2005) View in CoL , from Italy and Cyprus, are also species with fibrillar glands, described from relatively near areas. However, these species have longer blades on compound chaetae, especially the latter, with more spines on margin, very different from those of Sphaerosyllis pontica View in CoL sp. nov., which are short and smooth or provided with short spines on margin of blades.

Type locality. Black Sea (Bulgarian and Romanian coasts).

Habitat. Mud and muddy sand at 33.7–100.5 m depth.

Geographical distribution. So far known only from the Black Sea.

Etymology. The species epithet pontica (Latin, adjective, feminine) is derived from the ancient name of the Black Sea ( Pontus Euxinus ), the type locality of the species.

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Phyllodocida

Family

Syllidae

Genus

Sphaerosyllis

Loc

Sphaerosyllis pontica

Martín, Guillermo San 2017
2017
Loc

Sphaerosyllis pontica

Martín 2017
2017
Loc

Sphaerosyllis levantina

Faulwetter, Chatzigeorgiou, Galil, Nicolaidou & Arvanitidis 2011
2011
Loc

S. boeroi Musco, Çinar & Giangrande (2005)

Musco, Cinar & Giangrande 2005
2005
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