Autolytus tyrrhenicus Cognetti, 1953

Çinar, Melih Ertan & Gambi, Maria Cristina, 2005, Cognetti’s syllid collection (Polychaeta: Syllidae) deposited at the Museum of the Stazione Zoologica ‘‘ Anton Dohrn’ ’ (Naples, Italy), with descriptions of two new species of Autolytus, Journal of Natural History 39 (10), pp. 725-762 : 740-742

Autolytus tyrrhenicus Cognetti, 1953

( Figure 8 )

Autolytus tyrrhenicus Cognetti 1953b, p 125 –127, Figure 2 ; Cognetti 1957, p 72 –73, Figure 16.

? Autolytus prolifer: Dales 1951, p 119 –127, Figure 1 (non O. F. Müller 1788).

Material examined

SZN-POL8, Station 7, Santa Lucia, 17 March 1954, on algae, 0–1 m, coll. Cognetti.

Description

Specimen complete, with stolon, female.

Stock. Stock 2.63 mm long, 0.12 mm wide, H+ 1050.82 mm, for 26 chaetigers, pale yellowish. Prostomium almost rounded, with two pairs of reddish eyes in open trapezoidal arrangement; anterior pairs larger, with lenses; one pair of ocular specks ( Figure 8A ). Median antenna originating between anterior eyes, thick, extending back to chaetiger 10; lateral ones in front of ocular specks, half length of median one. Palps hardly visible dorsally. Nuchal epaulettes reaching anterior margin of chaetiger 2. Peristomium distinct dorsally, with two pairs of tentacular cirri; dorsal ones reaching chaetiger 6; ventral ones half as long as dorsal. Dorsal cirri on chaetiger 1 thicker and longer than subsequent ones; extending back to chaetiger 10. Except for dorsal cirri on chaetigers 1–3, others shorter than body width; cirrophores less developed. Antennae and cirri without discernible inclusions. Parapodia somewhat conical in anterior region, rounded after proventricular region, with dense spherical inclusions; especially numerous within distal parts of parapodia, giving them a pouch-like appearance ( Figure 8C ). Falcigers numbering six to eight on anterior parapodia, strongly bidentate, proximal tooth larger than distal one ( Figure 8E ); blades finely serrated, 7.5 Mm (superior falcigers) to 10 Mm (inferior falcigers) long; shafts of falcigers with coarse spines distally. Falcigers on posterior parapodia morphologically similar to those on anterior parapodia, but with shorter blades (5–7.5 Mm long). Simple dorsal chaeta bayonet-shaped, slightly curved, finely serrated distally, from chaetiger 3 ( Figure 8F ). Proventricle 0.19 mm long, 0.10 mm wide, through two chaetigers, with 20 muscle cell rows. Pharynx between chaetigers 1 and 7, with one sinuation; trepan with two, large, sharp, triangular lateral teeth and eight small, sharp, equal teeth in between.

Stolon. Complete, 0.98 mm long, 0.12 mm wide, for 15 chaetigers. Prostomium ovalshaped, with two pairs of reddish eyes; anterior eyes larger ( Figure 8B ). Median and lateral antennae club-shaped, as long as prostomium. Peristomium reduced dorsally, with two pairs of small tentacular cirri. Except for dorsal cirri on chaetigers 1 and 2, remaining cirri shorter than body width. Parapodia rounded with spherical inclusions. Falcigers numbering four to five on parapodia; blades ca 7.5 Mm long throughout. Bayonet-shaped dorsal simple chaeta from chaetiger 2. Pygidium with long anal cirri.

Remarks

Autolytus tyrrhenicus displays close morphological affinity with A. antondohrni sp. nov., but differs from it by a number of characters discussed under ‘‘Remarks’’ section for A. antondohrni . The figure ( Figure 1 ) drawn by Dales (1951) seems to be identical to A. tyrrhenicus in having a similar trepan and dorsal cirri. However, if it exists, the material collected and identified by Dales should be examined in order to reach a reliable conclusion.

Distribution

Known only from the type locality; Santa Lucia, Gulf of Naples, Western Mediterranean ( Cognetti 1953b, 1957). Probably on the coast of England; Thames estuary ( Dales 1951).

Figures

Figure 1. Map of the investigated area with location of sampling sites.

Figure 2. (A) Anterior and posterior parts of Autolytus antondohrni with a stolon; (B) trepan; (C) inferior falciger on anterior parapodium; (D) dorsal simple chaeta. Scale bar: 100 Mm (A); 11 Mm (B); 5 Mm (C, D).

Figure 8. (A) Anterior part of Autolytus tyrrhenicus; (B) stolon; (C) middle parapodium; (D) trepan; (E) inferior falciger on anterior parapodium; (F) dorsal simple chaeta. Scale bar: 100 Mm (A, B); 22 Mm (C); 26 Mm (D); 4.3 Mm (E, F).