Autolytus antondohrni, Çinar & Gambi, 2005

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 : 727-730

Autolytus antondohrni sp. nov.

( Figure 2 )

Autolytus prolifer: Cognetti 1957 (in part), p 63 (non O. F. Müller 1788).

Material examined

SZN-POL6, Holotype, Station 5, Mergellina, September 1953, on algae, 0–2 m, coll. Cognetti.

Description

Specimen complete, with stolon, female.

Stock. Stock 2 mm long, 0.12 mm wide, H+ 1050.65 mm, with 26 chaetigers; stolon 1.32 mm long, 0.17 mm wide for 20 chaetigers. Prostomium oval, with two pairs of reddish eyes in a close trapezoidal arrangement; anterior pair larger (20 Mm in diameter); one pair of reddish ocular specks (7.5 Mm in diameter) on anterior margin of prostomium ( Figure 2A ). Median antenna originating between anterior eyes, thick, extending to chaetiger 11; lateral antennae next to ocular specks, reaching chaetiger 5. Palps fused, hardly visible dorsally. Nuchal epaulettes reaching posterior margin of chaetiger 1. Peristomium reduced dorsally, with two pairs of tentacular cirri; dorsal ones extending to chaetiger 6; ventral ones to chaetiger 4. Dorsal cirri on chaetiger 1 reaching chaetiger 10; those on chaetiger 2 longer than subsequent ones. Dorsal cirri between chaetiger 3 and 7 slightly shorter than body width; remaining dorsal cirri obviously shorter than body width. Cirrophores less developed; shorter than parapodial lobes. Antennae and cirri with small spherical inclusions. Dorsum of body after proventricular region with dense, relatively large inclusions. Large, conspicuous, yellowish, globular oily inclusions within parapodia and randomly on bases of dorsal cirri. Parapodia conical. Falcigers on anterior parapodia numbering seven, bidentate; distal tooth smaller than proximal one ( Figure 2C ); blades of superior falcigers 7.5 Mm long, those of inferior ones 10 Mm long. Falcigers on posterior parapodia morphologically similar to those on anterior ones, but with shorter blades (5– 7.5 Mm long). Dorsal simple chaeta bayonet-shaped ( Figure 2D ), slightly curved, serrated distally and subdistally, from chaetiger 4. Acicula numbering one per parapodium, thin, tapering. Proventricle 0.18 mm long, 0.10 mm wide, through 2.5 segments, with 26 muscle cell rows. Pharynx with one large sinuation, between chaetigers 1 and 8; trepan with two large, sharp lateral teeth accompanied by eight small, blunt, equal teeth ( Figure 2B ).

Stolon. Prostomium subrectangular, with two pairs of eyes ( Figure 2A ). Median antenna missing, lateral antennae thin, long. Dorsal cirri on chaetiger 1 long, others short; half length of body width; all containing small inclusions. Parapodia rounded, with conspicuous, yellowish oily inclusions. Falcigers numbering five on parapodia, bidentate; blades 5 Mm (superior ones) to 7.5 Mm (inferior ones) long throughout. Pygidium with two long anal cirri.

Remarks

Autolytus antondohrni sp. nov. can be easily distinguished from other Autolytus species by having a trepan with two, long, sharp lateral teeth, accompanied by eight small, blunt, equal teeth; a pair of nuchal epaulettes extending to posterior margin of chaetiger 1; short dorsal cirri, with small, spherical inclusions; two or three very large oily granules within parapodia and bases of dorsal cirri; and large spherical inclusions on dorsum of body after chaetiger 9. The most morphologically similar species to A. antondohrni is A. tyrrhenicus which has a trepan with two long lateral teeth accompanied with eight small ones. However, the nature of the small teeth is different: sharp and triangular in A. tyrrhenicus ; blunt and almost rectangular in A. antondohrni . The other difference between the two species is the distribution and types of granules within parapodia, cirri and dorsum of the body; dorsal cirri of A. tyrrhenicus include sparse needle-shaped granules ( Figure 8C ), whereas A. antondohrni contains dense, spherical, amber-coloured inclusions. Parapodia of A. antondohrni contain two or three very large oily inclusions, whereas those of A. tyrrhenicus are pouch-like, expanded distally, containing dense, small spherical inclusions. Unlike A. tyrrhenicus , the dorsum of the body of A. antondohrni bears dense and spherical inclusions. The length and number of muscle cell rows of the proventiculus is another important difference; occupying 2.5 segments and having 26 muscle cell rows in A. antondohrni versus occupying two segments and having 20 muscle cell rows in A. tyrrhenicus . The median antenna of A. tyrrhenicus is longer than that of A. antondohrni . Finally, the prostomium of Sacconereis of A. tyrrhenicus is longer than that of A. antondohrni and bears relatively shorter antennae.

Etymology

The species is named after Anton Dohrn, founder of the Stazione Zoologica of Naples.

Distribution

Known only from the type locality ( Mergellina , Gulf of Naples, western Mediterranean) .

? Proceraea brachycephala :

Marenzeller 1874).

Figures

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).