Proceraea scapularis ( Claparède, 1864 )

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 : 742-745

Proceraea scapularis ( Claparède, 1864)

( Figure 9 )

Autolytus (Stephanosyllis) scapularis Claparède 1864, p 567 –569, Plate 7, Figure 5 .

? Proceraea scapularis: Okada 1933, p 647 –653, Figure 6b .

Autolytus pictus: Cognetti 1957 (in part), p 67 (non Ehlers 1864).

Material examined

SZN-POL5, one specimen, Station 2, Banco d’Ischia, 7 October 1954, on coralligenous substrata and Posidonia oceanica , 30 m, coll. Cognetti.

Description

Specimen complete, 12.5 mm long, 0.55 mm wide, H+ 1052.50 mm, for 76 chaetigers, yellowish, two black dorsolateral lines along body, from the conjunction of nuchal organs to chaetiger 13; lines becoming thicker towards posterior end; blackish pigmentation present along side of nuchal organs ( Figure 9A ). Prostomium somewhat trapezoidal, with two pairs of large reddish eyes, overlapping; anterior eyes larger, accompanied by small spherical reddish bodies. Median antenna missing; its scar between eye pairs; lateral ones emerging from anterior margin of prostomium, tapering, ending with a blackish knob, extending to chaetiger 8. Palps small, visible dorsally. Nuchal epaulettes conspicuous, reaching middle region of chaetiger 2, with dense cilia only along outer margin; cilia on anterior-lateral margin of nuchal organs relatively longer, reaching level of anterior eyes ( Figure 9A ). Peristomium narrow, with two pairs of tentacular cirri; dorsal ones long, reaching chaetiger 6; ventral ones extending to chaetiger 2. Dorsal cirri on chaetiger 1 long, reaching chaetiger 13, tip missing. Dorsal cirri on chaetiger 2 extending to chaetiger 5, with a blackish knobbed tip. Remaining dorsal cirri on anterior parapodia shorter than body width, relatively thin and without knobbed tip; dorsal cirri on middle and posterior parapodia shorter than those on anterior ones. Cirrophores of tentacular cirri and dorsal cirri on chaetigers 1 and 2 relatively well-developed; those of other dorsal cirri indistinct. Cirri and antennae with sparse spherical inclusions. Anterior parapodia large, somewhat rectangular in shape; posterior ones relatively short. Falcigers on anterior parapodia numbering six, with shafts coarsely serrated distally; blades bidentate, distal tooth shorter and thinner than proximal ( Figure 9C ); spines on cutting edge indistinct; blades of superior falcigers 7.5 Mm long, those of inferior ones 10 Mm long. Falcigers on posterior parapodia numbering six, with relatively short blades, 5 Mm (superior ones) to 7.5 Mm (inferior ones) long; bidentate, distal and proximal teeth somewhat similar in size and thickness; blades of superior falcigers with concave cutting edge ( Figure 9D ). Dorsal bayonet chaeta thick, with an arista 10 Mm long, distally serrated, from chaetiger 14. Each parapodium with two distally rounded aciculae. Proventricle massive, 0.90 mm long, 0.47 mm wide, through 2.5 segments, with about 42 muscle cell rows. Pharynx with one sinuation, between chaetigers 3 and 7; trepan with nine larger, sharp teeth alternating with nine smaller, triangular teeth in two circlets; bases of lateral teeth with a prominent, triangular ridge ( Figure 9B ). Pygidium conical, with two thick, short anal cirri.

Remarks

The morphological features of Cognetti’s specimen nearly coincide with the original description and figures given by Claparède (1864). However, the Neapolitan specimen shows some discrepancies; eyes are relatively large and overlapping each other, whereas the figures drawn by Claparède show that eyes are small and in close trapezoidal arrangement; Cognetti’s specimen has relatively longer lateral antennae and dorsal cirri on chaetiger 1 than Claparède’s specimen; the tips of lateral antennae, tentacular cirri and dorsal cirri on chaetiger 1 and 2 of Cognetti’s specimen are bulbous and black-coloured; this feature had not been noted in the original description of P. scapularis . Proceraea scapularis resembles P. picta Ehlers, 1864 , which was originally described from the Adriatic Sea ( Ehlers 1864), in having the same number of teeth in the trepan. However, P. scapularis differs from P. picta in a number of characters; the former has two black lateral lines on the dorsum of the body, whereas the latter has brown squares along lateral sides of the body; the nuchal epaulettes of P. scapularis have dense black pigmentation, whereas such pigmentation has not been reported on P. picta ; in contrast to P. picta , palps of P. scapularis are visible dorsally. Proceraea okadai ( Imajima 1966) from Japan has a close morphological similarity with P. scapularis in having two longitudinal black bands on dorso-lateral sides of the body, but P. okodai has shorter nuchal epaulettes (extending to anterior margin of chaetiger 1 in P. okadai versus to anterior margin of chaetiger 3 in P. scapularis ).

Distribution

Proceraea scapularis was previously reported from the western Mediterranean; type locality (Port-Vendres, Gulf of Lion) ( Claparède 1864). Okada (1933) also reported this species around Plymouth, England. However, the previous records of Proceraea picta especially from the western Mediterranean should be re-examined to find out the ‘‘true’’ distributional pattern of P. scapularis .

Figures

Figure 5. (A) Anterior and posterior parts of Autolytus mediterraneus; (B) trepan; (C) inferior falciger on anterior parapodium; (D) dorsal simple chaeta. Scale bar: 100 Mm (A); 14.5 Mm (B); 6.4 Mm (C, D).

Figure 6. (A) Anterior part of Autolytus neapolitanus; (B) trepan; (C) inferior falciger on anterior parapodium; (D) dorsal simple chaeta. Scale bar: 100 Mm (A); 28 Mm (B), 6 Mm (C, D).

Figure 9. (A) Anterior and posterior parts of Proceraea scapularis; (B) trepan; (C) falcigers on anterior parapodium; (D) falcigers on posterior parapodium; (E) dorsal simple chaeta. Scale bar: 100 Mm (A); 29 Mm (B); 4.2 Mm (C–E).