Proceraea anopla ( Monro, 1933 ) Monro, 1933

Nygren, Arne, 2004, Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680, pp. 1-314 : 43-44

Proceraea anopla ( Monro, 1933) comb. n. (Fig. 5A–E)

Autolytus (Autolytides) anoplos Monro, 1933: 38 –39, fig. 16A–F; Fauchald 1977b: 18 –19, fig. 3F–K.

Material examined. Panamá: 6 syntypes BMNH 1932.12.24.185–190, Límon Bay, Colón, from wreck covered with sponges and Balanus, St. George Pacific expedition 1923–24. USA: 2 spms (1 rear end in author's collection for DNA analyses) LACM VC­ 1367, 1368, British Virgin Islands, Guana Island, Long Point, 1–2 m, barnacles off vertical boulders, 19 Jul 2000.

Diagnosis. Proceraea with characteristic colour markings in red and black; nuchal epaulettes reaching end of chaetiger 2; dorsal cirri from chaetiger 3 ovoid to egg shaped; thin bayonet chaeta subdistally denticulated.

Description. Length 27–60 mm for 120–245 chaetigers, width 0.2 mm. Live specimens with conspicuous colour markings (Fig. 5A, B); posterior part of prostomium and nuchal epaulettes red, thick black longitudinal line in between nuchal epaulettes, each following segment with more or less rectangular black bar, followed immediately by red rectangular bar; anterior appendages brilliant white due to presence of glands, dorsal cirri from chaetiger 3 reddish­black; eyes red. Preserved material with black markings preserved as brown, dorsal cirri from chaetiger 3 brown. Ciliation present on prostomium, nuchal epaulettes, and ventrally on few segments.

Eyes confluent or almost confluent; eye spots absent. Palps in dorsal view projecting c. 1/3 of prostomial length (Fig. 5B), fused. Extension of nuchal epaulettes from end of chaetiger 1 to end of chaetiger 2 (Fig. 5B).

Median antenna reaching c. chaetiger 12 in preserved specimens. Lateral antennae and dorsal tentacular cirri, length 1/2–4/5 of median antenna. Ventral tentacular cirri 1/2 as long as dorsal pair. First dorsal cirri equal in length to median antenna. Second dorsal cirri 1.5 times longer than following cirri. Alternation in direction of cirri not assessed. Dorsal cirri from chaetiger 3, of equal length, 1/5–1/3 of body width, proportionally longer in more posterior chaetigers. Cirrophores of tentacular cirri and first dorsal cirri present; cirrophores otherwise absent. Antennae, tentacular cirri, and first and second dorsal cirri cylindrical, all other dorsal cirri ovoid to egg shaped (Fig. 5A, B).

Parapodial lobes rounded conical, small. Anterior chaetigers with 2 aciculae, 1–2 in median and posterior. Chaetal fascicle with 10–15 compounds in anterior chaetigers, 4–5 in median and posterior. Distal tooth equal in size to subdistal tooth (Fig. 5D); serration present. Single thin bayonet chaetae, subdistally denticulated (Fig. 5E), beginning between chaetiger 7–150.

Pharynx with 1 to several sinuations anterior and lateral to proventricle. Trepan in chaetiger 4–5 (n=5), with 18 unequal teeth; 9 large and 9 smaller; 1 large alternating with 1 small, arranged in 2 rings (Fig. 5C). Basal ring present; infradental spines absent (Fig. 5C). Proventricle equal in length to 2–3 segments in chaetiger 8–12 with 45–62 rows of muscle cells (n=2). Anal cirri lost.

Reproduction and morphology of epitokous stages. Schizogamous reproduction by anterior scissiparity. One type specimen has a head developed behind chaetiger 13. Types also include one immature female stolon (20mm). Three antennae present, 2 pairs of tentacular cirri and achaetous knobs present, poorly developed nuchal epaulettes, no swimming chaetae. Prostomium with concave anterior margin. Antennae and dorsal tentacular cirri fusiform, ventral tentacular cirri cylindrical, dorsal cirri as in stock.

Habitat. With Balanus and sponges.

Distribution. Central West Atlantic, Caribbean Sea. British Virgin Islands, and Panamá.

Remarks. Proceraea anopla is easily identified both alive and preserved as its characteristic colour pattern preserves well as brown colour markings. Apart from the distinctive coloration, P. anopla appears most similar to Imajimaea zonata with which it shares the thin bayonet chaetae and ovoid dorsal cirri. However, the trepan differ between the two, P. anopla has a trepan of 9 large and 9 smaller teeth, arranged in 2 separate rings, while I. zonata has over 80 spine shaped and equal teeth in a single ring. Proceraea anopla was originally interpreted as having no teeth, thus referred to Autolytus (Autolytides) ; Fauchald (1977b) described the trepan as having 25 unequal teeth. A typical " Proceraea "­trepan as described above was observed on the specimens from British Virgin Islands.