Procerastea halleziana Malaquin, 1893

Nygren, Arne, 2004, Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680, pp. 1-314 : 94-95

Procerastea halleziana Malaquin, 1893

Procerastea halleziana Malaquin, 1893: 81 , pl. 8, fig. 26A–C, pl. 11, fig. 1–14; Potts 1911: 30 –31, fig 10A–B; Allen 1921: 131 –176, pl. 11–16; Fauvel 1923: 325 –326, fig. 126D–H; Caullery 1925; Langhammer 1928: 1 –44, pl. 1–3; Okada 1929a; 1929b: 325 –328, fig. 1; 1934; 1937: 470–471, fig. 21A– B. Gidholm 1967: 208 –209, fig. 29A–F; Hamond 1969c; Hartmann­ Schröder 1971: 187 –189, fig. 60A–B; Hamond 1974; Alós 1989: 330–333, figs 1–3; Kirkegaard 1992: 260 –262, fig. 128A–D; Hartmann­Schröder 1996: 191 –193, fig. 83A–B; Genzano & San Martín 2002: 165 –170, figs 1A–I, 2A–G, 3A–C; San Martín 2003: 453 –456, figs 248A– I, 249A–F.

Procerastea perrieri Fauvel 1916: 439 –440.

Diagnosis. Procerastea with both uni­ and bidentate simple chaetae together with compounds in anterior 4 chaetigers; trepan with 16–28 small equal teeth.

Description. Type material lost. Description based on Gidholm (1967), if not otherwise stated. Length up to 25 mm ( Allen 1921). Live specimens yellowish. Ciliation reduced.

Eyes confluent or separated; eye spots absent. Palps small, in dorsal view not projecting in front of prostomium. Nuchal epaulettes reaching end of tentacular segment. Dorsal cirri from chaetiger 2 absent. Appendages clavate.

Parapodial lobes small. Unknown number of aciculae. Chaetal fascicle with 4–7 chaetae, in anterior 4 chaetigers with uni­ or bidentate simple chaetae, together with bidentate compounds; following chaetigers with bidentate compounds. Both simple and compounds with small distal tooth; serration absent. Single thick bayonet chaetae, distally dilated, present.

Pharynx with distinct sinuation anterior to proventricle. Trepan in chaetiger 1 with c. 16–28 equal small teeth. Basal ring absent; infradental spines absent. Proventricle equal in length to 1–2 segments in chaetiger 5–6 with c. 24–32 rows of muscle cells.

Reproduction. Schizogamy by anterior scissiparity. Female stolons taken in October ( Okada 1929b). Asexual reproduction by fragmentation described by Allen (1921) and Langhammer (1928).

Morphology of epitokous stages.

Male. Description extracted from Allen (1921) and Okada (1937). Length c. 5.5 mm for 6+(20–26)+(10–20) chaetigers, width 0.5 mm in region a excluding parapodial lobes, 1.0 mm in region b including parapodial lobes. Ciliation not mentioned.

Eyes large, 2 pairs, with lenses; eyes situated on ventral and dorsal side of prostomium, ventral pair larger. Palps absent. Nuchal epaulettes not described. Median antenna, inserted on posterior part of prostomium, behind dorsal pair of eyes, reaching middle of region b. Pair of lateral bifid antennae inserted on anterior margin of prostomium. Outer ventral rami shorter than inner dorsal rami. Pair of small frontal processes inserted anterolaterally to dorsal pair of eyes. Tentacular cirri 2 pairs. First dorsal cirri, equal in length to median antenna; achaetous knobs not mentioned, possibly absent. Dorsal cirri in region a as short leaf­like processes; dorsal cirri in region b even shorter; dorsal cirri in region c tapering towards the end. Cirrophores not described.

Parapodia in region a and c as in stock; in region b large flattened and equipped with well­developed notopodia. Aciculae not described. Pygidium with two short cirri, equal in length to cirri in region c.

Female. Description extracted from Allen (1921) and Okada (1929b; 1937). Length c. 6 mm for 6+14+(28–32) chaetigers, width in region a 0.3 mm excluding parapodial lobes, in region b 0.5 mm including parapodial lobes. Live specimens orange with chocolate brown flecks on parapodia and lateral walls of body; greenish eggs, when maturing more yellow. Ciliation not described.

Eyes large, 2 pairs, with lenses; eyes situated on dorsal and ventral side of prostomium, ventral pair larger. Palps absent. Nuchal epaulettes reaching beginning of chaetiger 1. Median antenna inserted medially on prostomium, reaching chaetiger 3. Pair of lateral antennae inserted on anterior margin, slightly shorter than median antenna. Tentacular cirri 2 pairs. First pair of dorsal cirri, equal in length to median antenna; achaetous knobs not described, possibly absent. Cirri on chaetiger 1–5 minute, knob­like; cirri on chaetiger 6 distinctly longer, equal in length to 1/3 of body width; cirri in region b much longer than in region a, equal in length to body width; cirri in region c about equal in length to short cirri in region a, tapering towards the posterior. Cirrophores distinct in region b, other cirrophores not illustrated.

Parapodia in region a and c small, in region b with notopodial lobes and bundles of swimming chaetae. Aciculae not detailed. Pygidium with 2 cirri, equal in length to cirri in region c. Eight pear shaped egg sacs, 4 alternating on each side, present.

Habitat. Algae, hydroids, bryozoans, stones, shells and gravel 1– 150 m. Feeds on Tubularia larynx , T. indivisa , T. crocea and Syncoryne eximia ( Allen 1921; Caullery 1925; Hamond 1969c; Genzano & San Martín 2002).

Distribution. Atlantic coast of Europe from Biscay to Skagerrak. Atlantic coast of Argentina.

Remarks. Procerastea halleziana is most similar to P. nematodes , and P. australiensis . All have the simple chaetae restricted to chaetiger 1–4. Procerastea halleziana is the only one of these taxa with a unidentate simple chaetae, and also has more teeth in its trepan, between 15–30 compared to 6–10 in P. nematodes and P. australiensis .