Proceraea pleijeli Nygren, 2004, sp. n.

Proceraea pleijeli sp. n. (Fig. 25A–E)

Proceraea sp3 Nygren & Sundberg 2003: GenBank sequences, 16S rDNA partial sequence AF474272, and 18S rDNA partial sequence AF474318.

Material examined. Spain: holotype SMNH 5947 (rear end in author's collection for DNA analyses) and 1 spm on slide (rear end in author's collection for DNA analyses), Sancti Petri, Chiclana, 36°23'N 6°13'W, floating docks, 1 m, sponges, hydroids, Nov 1999.

Diagnosis. Proceraea with characteristic colour markings as brown, orange, and white transverse bands.

Description. Length 8.1–9.6 mm for 60–70 chaetigers, width 0.5 mm. Live specimens with 2 longitudinal black lines at each side of dorsum, between each segment a dark brown transverse band interrupted by 2 thinner orange bands, in between these a thin white band (Fig. 25B); every third or forth segment the white band is wider and the orange bands indistinct; nuchal epualettes brown; antennae, dorsal tentacular cirri, and first dorsal cirri brown; eyes dark red. Preserved material without colour markings. Ciliation present on prostomium, nuchal epaulettes, and a few segments ventrally.

Eyes large, confluent (Fig. 25A); eye spots absent. Palps in dorsal view projecting 1/ 5–1/4 of prostomial length (Fig. 25A), fused. Extension of nuchal epaulettes from half to end of chaetiger 1 (Fig. 25A).

Median antenna reaching chaetiger 10–14 (n=2). Lateral antennae and dorsal tentacular cirri, length 1/2 of median antenna. Ventral tentacular cirri 1/3 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. Cirrophores on tentacular segment and first dorsal cirri present; cirrophores otherwise absent. Dorsal cirri from chaetiger 3, of equal length, 1/3 of body width (Fig. 25A). All appendages cylindrical.

Parapodial lobes rounded conical, small. Anterior chaetigers with 2–3 aciculae, 1–2 in median and posterior. Chaetal fascicle with 10–12 compounds in anterior chaetigers, 3–8 in median and posterior. Compound chaetae with small distal tooth in anterior 20 chaetigers (Fig. 25D), more posterior with larger distal tooth, still somewhat smaller than subdistal tooth (Fig. 25E); serration present. Single thick bayonet chaetae beginning at chaetiger 13.

Pharynx with 1 sinuation anterior to proventricle. Trepan in tentacular segment or chaetiger 1, with 18 unequal teeth, 9 large and 9 smaller (Fig. 25C); 1 large alternating with 1 small, arranged in 2 rings. Basal ring present; infradental spines absent. Proventricle equal in length to 3 segments in chaetiger 5–7 with 44–46 rows of muscle cells (n=2). Anal cirri equal in length to 1/2 of body width.

Reproduction. Unknown.

Habitat. Amongst hydroids and tunicates.

Distribution. North East Atlantic. Spain. Only known from type locality.

Etymology. Named in honour of Fredrik Pleijel.

Remarks. Easily identified alive, but apart from colour pattern identical in morphology to P. p i c t a and P. scapularis. In the examined gene sequences it is similar but clearly distinct from these two taxa.