Proceraea picta Ehlers 1864

Proceraea picta Ehlers, 1864 (Fig. 24A–F)

Proceraea picta Ehlers, 1864: 256 –263, pl. 11, fig. 8–17, pl. 12, fig. 1–2; Langerhans 1879: 577 – 578, fig. 28A–B; Okada 1933a: 647 –653, figs 2,5–6; 1934; 1937: 441–490, figs 19A–B, 29– 30; Hamond 1967: 1 –4, fig. 1; Hartmann­Schröder 1971: 183 –184; Cantone 1971: 924 –926, figs 2–3; Hartmann­Schröder 1996: 189 –190; Parapar et al. 1996: 144 –146, fig. 1 g –h; San Martín 2003: 469 –473, figs 256A–F, 257A–H, 258A–C; Nygren & Sundberg 2003: GenBank sequences, 16S rDNA partial sequence AF474271, and 18S rDNA partial sequence AF474317.

Myrianida picta Quatrefages 1866: 63.

Autolytus (Proceraea) pictus Saint­Joseph 1887: 222 –226, pl. 11, fig. 100–105.

Autolytus pictus McIntosh 1908: 211 –214, pl. 47, fig. 1, pl. 49, fig. 8, pl. 71, fig. 2, pl. 79, fig. 21; Elwes 1908: 201; Southern 1914: 41; Allen 1915: 604; 1927: 871–874, fig. 1; Fauvel 1923: 315 –316, fig. 121A–F; Okada 1929a; Segrove 1938: 93; Fauvel 1936a: 32 –33; Cognetti 1957: 67; 1961: 303; Durchon & Wissocq 1964; Wissocq 1964; Verger­Bocquet 1979; 1983.

? Autolytus (Proceraea) picta Augener 1913: 265 –267.

Material examined. Spain: 4 spms (rear ends in author's collection for DNA analyses), El Caboda, Trafalgar, 36°11'N 6°01'W, dive, 5 m, Corallina sp., Codium sp., sponges, hydroids, Nov 1999. France: 1 spm, Banyuls­sur­Mer, 42°28.9'N 03° 08.2E, sponges, hydroids, dive, 10 m, May 1997; 1 spm, Banyuls­sur­Mer, 42°28.9'N 03° 08.2E, dive, 1–3 m, algae, hydroids, 23 Apr 2001; 1 spm, Banyuls­sur­Mer, 42°28.6'N 03°09.7'E, dive, 30 m, "coralligene", 26 Apr 2001. Wales: 13 spms (5 spms in formalin, 3 spms on slides (rear ends in author's collection for DNA analyses), and 5 spms in author's collection for DNA analyses), Black Point, 53° 18.75N 4° 2.43E, algae, bryozoans, hydroids, intertidal, May 2000.

Diagnosis. Proceraea with nuchal epaulettes reaching end of chaetiger 1; characteristic colour markings with 2 black longitudinal lines, and brown squares.

Description. Length 8–18.2 mm for 56–80 chaetigers; width 0.3–0.55 mm. Live specimens with 2 longitudinal dark brown­black lines at each side of dorsum; dorsum brown except for a middorsal band, and transverse segmental bands at every second, third or forth segment that appear to be white; nuchal organs dark brown to black; antennae and first dorsal cirri brown; eyes red (Fig. 24A, B). Ciliation present on prostomium, nuchal epaulettes, and a few segments ventrally.

Eyes confluent or almost confluent (Fig. 24B); eye spots absent. Palps in dorsal view projecting 1/4 of prostomial length (Fig. 24B), fused. Extension of nuchal epaulettes to end of chaetiger 1 (Fig. 24B).

Median antenna reaching chaetiger 11–14 (n=7). Lateral antennae and dorsal tentacular cirri, length 2/3 of median antenna. Ventral tentacular cirri 1/3–1/2 as long as dorsal pair. First dorsal cirri as long as median antenna, second dorsal cirri as long as ventral tentacular cirri. Alternation in direction of cirri not assessed. Dorsal cirri from chaetiger 3, of equal length, 1/3 of body width. Cirrophores on tentacular segment and first dorsal cirri present; cirrophores otherwise absent. All appendages cylindrical.

Parapodial lobes rounded conical, small. Anterior chaetigers with 2–3 aciculae, 1–2 in median and posterior. Chaetal fascicle with 10–18 compounds in anterior chaetigers, 4–8 in median and posterior. Compound chaetae in anterior 20–30 chaetigers with small distal tooth (Fig. 24D), more posterior with large distal tooth, still smaller than subdistal tooth (Fig. 24E); serration present. Single thick bayonet chaetae (Fig. 24F), beginning between chaetiger 15–45.

Pharynx with short sinuation anterior to proventricle. Trepan in tentacular segment or chaetiger 1–3, with 18 unequal teeth, 9 large and 9 smaller (Fig. 24C); 1 large alternating with 1 small, arranged in 2 rings. Basal ring present; infradental spines absent (Fig. 24C). Proventricle equal in length to 2.5–4 segments in chaetiger 6–10 with 45–48 rows of muscle cells (n=11). Anal cirri length equal to half of body.

Reproduction and morphology of reproductive stages. Schizogamy by anterior scissiparity behind chaetiger 13. Following descriptions extracted from literature (Saint­ Joseph 1887; McIntosh 1908; Fauvel 1923; Okada 1933a; Okada 1937; Durchon & Wissocq 1964; Hamond 1967). Male with 6+29.2(+/­2.2)+21.9(+/­4.7) chaetigers (n=146) (Durchon & Wissocq 1964), length 7.4 mm (Saint­Joseph 1887). Colour as in stock in region a and c, region b with a median dark brown streak, interrupted by pale bands at the usual intervals, lateral on parapodia granular brown. Tentacular cirri 2 pairs. Achaetous knobs not mentioned. As judged from illustrations, all appendages cylindrical; cirri in region a, slightly longer than cirri in region b. Female with 6+16.2(+/­1.4)+36.1(+/­4.7) chaetigers (n=114) (Durchon & Wissocq 1964). Colour as in stock; appendages brown with colourless tips, except for antennae, tentacular cirri, and first dorsal cirri. Tentacular cirri 2 pairs. Achaetous knobs not mentioned. Appendages cylindrical, longest in region b. Cirrophores present in region b (Hamond 1967: fig. 1). Stolonization period from end of February to end of September (Durchon & Wissocq 1964).

Habitat. Amongst hydroids, algae.

Distribution. North East Atlantic as far north as the British Islands, Mediterranean.

Remarks. Proceraea picta is easily identified on its colour pattern. Preserved specimens may not be possible to separate from P. scapularis, P. pseudopicta, P. fasciata, and P. madeirensis. In 16SrDNA and 18S rDNA P. p i c t a and P. scapularis are almost identical, but a larger sample of individuals of both types from different areas are needed to draw any conclusions. In this study, the two taxa are treated as separate species.