Sphaerosyllis taylori Perkins, 1981

Martín, Guillermo San, 2017, Taxonomic contribution to the genus Sphaerosyllis (Annelida: Syllidae: Exogoninae) in the Black Sea, Zootaxa 4329 (3), pp. 281-291 : 282-284

Sphaerosyllis taylori Perkins, 1981

( Fig. 1 )

Material examined. Black Sea, Romanian coast, Mangalia, 43.8042°N, 28.5917°E, 1.2 m depth, in muddy fine sand with Zostera (Zosterella) noltei , 6 August 2015, 3 specimens (MNINGA PLY083).

Description. Body relatively short and broad, pale yellowish, 1.0– 2.3 mm long, 0.21–0.27 mm wide, for 15– 29 chaetigers. Both largest and smallest specimens complete. Small glandular papillae scattered over dorsum and parapodia. Prostomium more or less rectangular, wider than long ( Fig. 1A ). Two pairs of lensed, orange eyes in a nearly rectangular arrangement, very close to each other on lateral sides, but not coalescent; anterior eyes ovoid (11.2–22.4×6.1–12.2 µm), slightly larger than posterior more or less rounded eyes (6.1–16.3 µm). Antennae pyriform, with bulbous bases and cylindrical extended tips, longer than prostomium. Median antenna (~102 µm) slightly longer than lateral ones (65.3–96.9 µm), inserted more posteriorly than lateral antennae, between anterior pair of eyes; lateral antennae inserted on anterior margin of prostomium ( Fig. 1A ). Palps broad, fused dorsally along their entire length, with a dorsal medial furrow, about 1.5–2 times longer than prostomium. Peristomium well developed, with a dorsal fold that dorsally covers posterior part of prostomium. Peristomial cirri (42.8–66.3 µm) bulbous, similar to dorsal cirri and antennae, but slightly smaller than antennae ( Fig. 1A ). Dorsal cirri (62.2–77.5 µm) slightly smaller than antennae, longer than parapodial lobes, with bulbous bases and cylindrical tips, similar in size throughout body. Dorsal cirri absent on chaetiger 2. Parapodial lobes conical, with some very small papillae. Parapodial glands distinct, spherical, with fibrillar material, present from chaetiger 4 to last chaetiger, with a thick mamilliform papilla on its dorsal side. Ventral cirri digitiform, slightly shorter than parapodial lobes. Compound chaetae heterogomph, short-bladed falcigers, numbering about 5–6 in anterior parapodia ( Fig. 1B ), 4–5 in midbody parapodia ( Fig. 1D ) and 3–4 in posterior parapodia ( Fig. 1F ). Shaft tips of compound chaetae smooth. Blades of falcigers unidentate, about 9.2–12.2 µm in length, without marked dorso-ventral gradation in length; anterior dorsalmost blades with about 9 moderately long spines ( Fig. 1B ), remaining blades with smooth cutting edges ( Fig. 1B, D, F ). One dorsal simple, smooth, slightly curved, pointed chaetae present from chaetiger 1, slender anteriorly, stouter in posterior chaetigers. Ventral simple chaetae more slender than dorsal ones, pointed, smooth, slightly curved, present on posterior chaetigers ( Fig. 1F ). Acicula solitary, stout, with tips bent forward at about right angle ( Fig. 1B, D, F ). Pygidium short, rounded lobe, with a pair of anal cirri (51.0–91.8 µm), similar in shape to dorsal cirri but 1.5–2 times larger than posterior dorsal cirri ( Fig. 1E ). Pharynx rusty-reddish in colour, extending over 2– 2.5 chaetigers; pharyngeal tooth apparently diamond-shaped, located terminally. Proventricle barrel-shaped, small, longer than wide, 115–171 µm long, 97–125 µm wide, extending through 1.5–3.0 chaetigers, with about 12–14 indistinct muscle cell rows ( Fig. 1C ).

Remarks. The Black Sea specimens agree with the original description of Sphaerosyllis taylori from Hutchinson Island, Florida, Atlantic coast of the USA, by Perkins (1981). However, in the Black Sea material the palps are somewhat shorter than the lateral antennae and there are no spines in the distal part of the shaft of dorsalmost compound chaetae.

Sphaerosyllis taylori is very similar to S. hystrix , but differs in having the pharynx and the proventricle of nearly equal length, compound chaetae with shorter blades with fewer serrations and of similar length in each parapodium (no dorso-ventral gradation of the falciger blade length) and throughout the body, smooth, dorsal simple chaetae in all parapodia, and in general smaller body size.

Habitat. The specimens found inhabited shallow sandy sediments with dwarf eelgrass Zostera (Zosterella) noltei .

Geographical distribution. Gulf of México: Florida, Connecticut, Maryland ( Perkins 1981; Uebelacker 1984); Grand Caribbean Sea (Russell 1991; Salazar-Vallejo 1996; Ruíz-Ramírez & Salazar-Vallejo 2001); Norwegian Sea ( Ramos et al. 2010); English Channel ( Olivier et al. 2012); Atlantic coast of Spain ( San Martín 2003); Mediterranean Sea: Tyrrhenian Sea ( Gambi et al. 1998), Aegean Sea ( Çinar & Ergen 2002), Levantine Sea ( Çinar et al. 2003; Mutlu et al. 2010; Abd-Elnaby & San Martín 2010), Sea of Marmara ( Çinar et al. 2011), and the Black Sea (new record).

Figures

FIGURE 1. Light microscopy (LM) photographs of Sphaerosyllis taylori Perkins, 1981: (A) Anterior end, dorsal view; (B) Anterior parapodium (chaetiger 14), antero-dorsal view, showing dorsal simple chaeta, compound chaetae with serrated and smooth blades, and solitary acicula with bent tip; (C) Proventricular region, dorsal view, showing parapodial glands with fibrillar content; (D) Mid-body parapodium (chaetiger 23), antero-dorsal view, showing dorsal simple chaeta, compound chaetae with smooth blades and solitary acicula with bent tip; (E) Posterior end, dorsal view; (F) Posterior parapodium (chaetiger 26), antero-dorsal view, showing dorsal simple chaeta, compound chaetae with smooth blades, ventral simple chaeta and acicula with bent tip. a — acicula; cc — compound chaetae; ds — dorsal simple chaeta; la — lateral antenna; ma — median antenna; pc — peristomial cirrus; vs — ventral simple chaeta. Scale bars: A, C, E = 0.1 mm; B, D, F = 50 µm.